ALBERT

Description:    We studied the intra-annual wood formation in a Norway spruce provenance experiment in southern Finland from 2004–2008. Two Finnish provenances, northern and southern, as well as German and Hungarian provenances were included. Timing of tracheid formation and differentiation, and tracheid dimensions were determined from periodically extracted microcores. The aim was to determine the differences between the years and provenances in the timing of the xylogenesis and in the xylem characteristics. Year-to-year variation was high both in timing of tracheid formation and xylem characteristics, while between-provenance differences were small. The onset of tracheid formation varied from early May to late June in different trees in different years. The onset of tracheid formation was not closely related to the annual variations of temperature sum. In all the years, daily temperatures exceeded the threshold +5°C for several weeks before the onset of tracheid formation. The highest tracheid formation rate occurred after the summer solstice in all years and generally coincided with the highest daily temperatures during the growing season. Tracheid production ceased early in 2006 due to a mid-summer drought. Cell differentiation continued late in autumn as non-mature tracheids were still observed around mid-September. No clear differences between the provenances in the timing of tracheid formation were observed, although the Finnish provenances tended to initiate tracheid formation slightly earlier than the other provenances. The tree-ring widths of the Finnish provenances were also wider, while tracheid diameter of the German provenance was slightly smaller. Our results indicate that between-tree variation in the timing of wood formation is high compared with the latitude effect of seed source. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s00468-011-0616-0 Authors Tuomo Kalliokoski, Southern Finland Regional Unit, Finnish Forest Research Institute, P.O. BOX 18, 01301 Vantaa, Finland Mehedi Reza, Southern Finland Regional Unit, Finnish Forest Research Institute, P.O. BOX 18, 01301 Vantaa, Finland Tuula Jyske, Southern Finland Regional Unit, Finnish Forest Research Institute, P.O. BOX 18, 01301 Vantaa, Finland Harri Mäkinen, Southern Finland Regional Unit, Finnish Forest Research Institute, P.O. BOX 18, 01301 Vantaa, Finland Pekka Nöjd, Southern Finland Regional Unit, Finnish Forest Research Institute, P.O. BOX 18, 01301 Vantaa, Finland Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    We derive and analyze a model that relates the growth rate of cross-sectional area (‘csa’) at any height on the central stem of a tree to crown-length dynamics. The derivation is based, in part, on assumptions that (a) active csa on the central stem relates allometrically to the length of crown above the cross section, and (b) inactive csa is proportional to active csa within the crown. We also assume that the deactivation rate of csa beneath the crown is determined, in part, by the rate of crown rise. Integration of the growth-rate model under an additional assumption—that total crown length is constant after stand closure—provides a simple model of annual or periodic growth of total csa that can be fit to standard growth data. Three implications of the assumptions and integration are notable: (1) total csa within the crown scales allometrically with stem length above the cross section; (2) for a special case, total csa beneath the crown scales with stem length above the cross section; more generally, csa scales with a linear combination of the stem and crown lengths; and (3) the stem beneath the crown forms to approximate a frustum of a quadratic paraboloid. Basal area data from a loblolly pine ( Pinus taeda L.) spacing trial show good agreement with (1) and (2), and with an empirical model developed from the special case of (2). Data from the plots of a Norway spruce ( Picea abies (L.) Karst.) thinning trial, where crown length remained approximately constant, show good agreement with (2) and the empirical model. Prediction (3) is demonstrated by simulation. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-011-0608-0 Authors Harry T. Valentine, US Forest Service, 271 Mast Road, Durham, NH 03824-4600, USA Annikki Mäkelä, Department of Forest Ecology, University of Helsinki, Helsinki, 00014 Finland Edwin J. Green, Department of Ecology, Evolution and Natural Resources, Cook College, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901-8551, USA Ralph L. Amateis, Department of Forest Resources and Environmental Conservation, College of Natural Resources and Environment, VPI&SU 304-A Cheatham Hall (mail code: 0324), Blacksburg, VA 24061, USA Harri Mäkinen, Vantaa Research Unit PL 18, The Finnish Forest Research Institute, 01301 Vantaa, Finland Mark J. Ducey, Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, USA Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Morphological and histocytological characteristics of Acacia mangium shoot apical meristems (SAMs) were assessed in natural and in vitro conditions in relation to heteroblasty. In the natural environment, SAMs with a mature-phyllode morphology were much bigger, contained more cells with larger vacuolated area, or vacuome, and lower nucleoplasmic ratios than those from the juvenile type (Juv). In these latter, nuclei appeared more voluminous, evenly and lightly stained, with clearly distinguishable nucleolei and less abundant chromocenters. In vitro, where reversions from mature to juvenile morphological traits do occur unpredictably, heteroblasty was less obvious in the SAM characteristics examined. In vitro SAMs corresponding to the juvenile and mature types showed similarities with outdoor Juv SAMs, but could be distinguished from these latter by a much larger vacuome that might be induced by the culture conditions. These findings encourage pursuing the investigations at the chromatin and nucleolus level in SAM zones where heteroblasty-related differences have been detected. Content Type Journal Article Category Original Paper Pages 1-14 DOI 10.1007/s00468-012-0680-0 Authors Clemence Hatt, CIRAD-BIOS, UMR AGAP PHIV-MRI, TA 40/02 Avenue Agropolis, 34398 Montpellier Cedex 5, France François Mankessi, CRDPI, B.P 1291, Pointe-Noire, Congo Jean-Baptiste Durand, CIRAD-BIOS, UMR AGAP and INRIA, Virtual Plants, TA A-108/02, Avenue Agropolis, 34398 Montpellier Cedex 5, France Frédéric Boudon, CIRAD-BIOS, UMR AGAP and INRIA, Virtual Plants, TA A-108/02, Avenue Agropolis, 34398 Montpellier Cedex 5, France Fabienne Montes, CIRAD-BIOS, UMR AGAP PHIV-MRI, TA 40/02 Avenue Agropolis, 34398 Montpellier Cedex 5, France Marc Lartaud, CIRAD-BIOS, UMR AGAP PHIV-MRI, TA 40/02 Avenue Agropolis, 34398 Montpellier Cedex 5, France Jean-Luc Verdeil, CIRAD-BIOS, UMR AGAP PHIV-MRI, TA 40/02 Avenue Agropolis, 34398 Montpellier Cedex 5, France Olivier Monteuuis, CIRAD-BIOS, UMR AGAP, TA A-108/03-Avenue Agropolis, 34398 Montpellier Cedex 5, France Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    In earlier-maturing coffee clones, owing to the shorter time required for fruit filling and ripening, photo-assimilates should be transported to fruits in a period shorter than that found in intermediate- or late-maturing clones. We hypothesised that at a given source-to-sink ratio, a presumably greater sink strength in early-maturing clones relative to intermediate- and late-maturing individuals should be correlated to increased rate of net carbon assimilation ( A ) and greater photo-assimilate transport to the fruits. Overall, earlier-maturing clones displayed greater A rates than the intermediate-maturing clones, which, in turn, had higher A than their late counterparts. Changes in A were largely associated with changes in stomatal conductance. Only marginal alterations occurred in the internal-to-ambient CO 2 concentration ratio, the carbon isotope composition ratio, soluble sugars and chlorophyll a fluorescence parameters. Some changes in starch pools were detected among treatments. To the best of our knowledge, this is the first report showing evidence that increased precociousness of fruit growth and maturation results in higher A and thus increased source strength, a fact associated to a large degree with higher stomatal aperture. Content Type Journal Article Category Short Communication Pages 1-6 DOI 10.1007/s00468-012-0685-8 Authors Leandro E. Morais, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil Paulo C. Cavatte, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil Kelly C. Detmann, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil Lilian M. V. P. Sanglard, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil Cláudio P. Ronchi, Campus Rio Paranaíba, Universidade Federal de Viçosa, Rio Paranaíba, MG 38810-000, Brazil Fábio M. DaMatta, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    We investigate the characteristics of individual tree response to competition on source–sink balance through the functional–structural plant model GreenLab. Four Chinese pine ( Pinus tabulaeformis Carr.) trees were destructively sampled and were divided into two groups: high-density group and low-density group. First, the effects of density on organ dimensions and on organ relative mass were analysed based on experimental measurements. These were primary indicators of the plant response to competition. Second, the hidden parameters of the GreenLab model, as well as a tree-specific characteristic surface, were estimated using the data of total tree biomass for needle and wood compartments, for each of the four trees in parallel. The quality of the fitting is finally validated using data of individual organ mass at shoot level for the sampled branches. The Mann–Whitney Student’s t test showed that there were significant differences between the shoot attributes of the two groups for shoot diameter, shoot biomass and needle biomass. No significant difference was found for current year shoot lengths of the two groups. The parametric identification of the model allowed estimating and comparing the amount of biomass that was allocated to primary growth and to secondary growth in the two density conditions. It showed that biomass allocated to secondary growth (ring compartment) was the most strongly affected by density, and that the organ demand satisfaction ratio profiles of each of these trees were a relevant, integrated indicator of the tree state. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-012-0683-x Authors Hong Guo, Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing, 100091 China Xiangdong Lei, Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing, 100091 China Paul-Henry Cournede, Applied Mathematics and Systems Laboratory, Ecole Centrale Paris, 92290 Chatenay-Malabry, France Veronique Letort, Applied Mathematics and Systems Laboratory, Ecole Centrale Paris, 92290 Chatenay-Malabry, France Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Bioactive gibberellins (GAs) affect nearly every process during plant growth and development. In the present study, endogenous GA 3 and GA 4 levels in young leaves of 2- to 4-year-old birch ( Betula platyphylla ) trees were analyzed using liquid chromatography–tandem mass spectrometry (LC–MS/MS) during the phase from May to August. Concurrently, changes in the levels of GAs during each day were also determined in 4-year-old trees. Furthermore, the levels of GAs were analyzed in 15 four-year-old juvenile birch trees (yet to bolt/flower) and in 15 adult trees (just starting to bolt/flower) during different stages of growth. Our results displayed the basic various patterns of GA 3 and GA 4 levels of the transient variation over a single day and the periodic variation in the growth period from May to August in different ages of birch trees. The results suggested that GA 3 and GA 4 had a significant effect on promoting birch growth and flowering. This study also defined the optimal time period for the determination of a foliar spray of GA 3 and GA 4 to promote birch growth. Our study provides a theoretical foundation for the further investigation of the effects of GA 3 and GA 4 on the growth and development of birch trees. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0688-5 Authors Rongshu Zhang, State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin, 150040 People’s Republic of China Yucheng Wang, State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin, 150040 People’s Republic of China Guifeng Liu, State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin, 150040 People’s Republic of China Yuefeng Wang, State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin, 150040 People’s Republic of China Jun Li, State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin, 150040 People’s Republic of China Xuewei Wang, State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin, 150040 People’s Republic of China Chuanping Yang, State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin, 150040 People’s Republic of China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The aim of the present study was to investigate differences in stem radial increment between the savanna and forest ecotypes of Plathymenia reticulata at an ecotonal site. It was hypothesised that even under similar climate conditions, the savanna and forest ecotypes exhibit differences in radial growth, phenology, and water status because of differences in wood density. Stem radial increment, phenology, and water potential were evaluated monthly. The radial increment was positively related to precipitation and displayed no increment (or decrement) in months with low rainfall. A negative relationship was observed between radial growth and wood density, with the forest ecotype exhibiting a higher radial increment than the savanna ecotype. Midday water potential (Ψ MD ) was also negatively related to wood density. Compared to the forest ecotype, the savanna ecotype displayed lower values of Ψ MD during the dry season and started leaf senescence earlier at the beginning of the dry season. Leaf fall improved water status, resulting in leaf flushing even without a significant increase in rainfall. Radial growth significantly increased only after the crown leaf cover was completed. The results confirmed the importance of wood density in the differential responses of ecotypes in relation to growth, water status, and phenology. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s00468-012-0690-y Authors Marcos Miranda Toledo, Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, CEP 31270-901 Brazil Elder Antônio Sousa Paiva, Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, CEP 31270-901 Brazil Maria Bernadete Lovato, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, CEP 31270-901 Brazil José Pires de Lemos Filho, Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, CEP 31270-901 Brazil Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Mixed species plantations of Eucalyptus and N 2 -fixing species can be significantly more productive than monocultures. The aim of this study was to determine whether the improved growth resulted from increases in photosynthesis, light absorption and light-use efficiency, in addition to previously measured increases in leaf area, water-use efficiency and higher ratios of annual above-ground net primary production per unit of total annual below-ground carbon allocation in 1:1 mixtures near Cann River, Victoria, Australia. Light-saturated photosynthetic rate ( A max ), electron transport ( J ), stomatal conductance ( g s ) and foliar nitrogen concentrations were higher for Eucalyptus globulus trees growing in mixtures than those in monocultures. Similar increases in maximum rates of carboxylation ( V cmax ), Rubisco, chlorophyll, and phosphorus concentrations were not significant. In contrast, A max , V cmax and J did not vary between mixtures and monocultures for A. mearnsii , whose growth was negligible by age 15 years. Mixtures also absorbed 24 and 41% more light than E. globulus and A. mearnsii. , respectively, and were 38 and 154% more light-use efficient in the mixtures compared to monocultures. The increased nutrient availability in mixtures appeared to increase productivity of E. globulus by increasing the photosynthetic capacity of the foliage, as well as the leaf area, light absorption and light-use efficiency of the canopy. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-012-0696-5 Authors David I. Forrester, Department of Forest and Ecosystem Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, VIC 3121, Australia Kate Lancaster, Department of Forest and Ecosystem Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, VIC 3121, Australia John J. Collopy, Department of Forest and Ecosystem Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, VIC 3121, Australia Charles R. Warren, School of Biological Sciences, The University of Sydney, Sydney, NSW 2006, Australia Michael Tausz, Department of Forest and Ecosystem Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, VIC 3121, Australia Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    This comparative study examines the ecophysiology of four endemic plant species abundant in the coastal temperate rainforests of Prince William Sound, Alaska. Photosynthesis in Alnus crispa ssp . sinuate (Betulaceae), Rubus spectabilis (Rosaceae), Vaccinium alaskaense and V. ovalifolium (Ericaceae) was measured with a MINI-Pulse Amplitude Modulated (PAM) fluorometer. A. sinuate (sun) and R. spectabilis (partial shade) had higher photosynthetic capacities (maximum apparent photosynthetic electron transport rates, ETR max ) and higher light saturation intensities ( I k ) than V. alaskaense (partial shade) and V. ovalifolium (shade). A. sinuate was less sensitive to photoprotective down regulation through the xanthophyll cycle (qE) than R. spectabilis . Vaccinium species showed similar photosynthetic characteristics except V. ovalifolium was sensitive qE while V. alaskaense was not. A comparison of A. sinuate trees growing in the ‘sun’ versus ‘shade’ revealed sun trees had higher ETR max and I k than shade trees. High photochemical quenching (qP; 0.893–0.978), associated with photochemical productivity, measured along with low non-photochemical quenching (qN; 0.252–0.678) at I k revealed shade plants are acclimated to low ambient light, and have limited use for qN. Nonetheless, at higher light intensities, all species are ready to safely dissipate excess light in non-photochemical quenching to heat based on qN (~0.6–0.8) and NPQ (~0.7–2.6). These findings illustrate the adaptive responses of plants growing at high latitudes with respect to photoacclimation. Differences between plants were correlated to their position along the natural light gradient created by the forest canopy. Content Type Journal Article Category Original Paper Pages 1-14 DOI 10.1007/s00468-012-0689-4 Authors Antonietta Quigg, Department of Marine Biology, Texas A&M University at Galveston, 200 Seawolf Parkway, Galveston, TX 77553, USA Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The development of dormancy, frost resistance and cryotolerance of in vitro apple plants ( Malus domestica Borkh.), cv. Greensleeves during their exposure to cold hardening was studied. In vitro cultures were cold hardened at 4°C under a short photoperiod up to 25 weeks. The dormancy status, non-structural saccharides, proline, water content and frost resistance were evaluated for optimization of cryopreservation. According to regrowth tests, in vitro cultures exhibited endogenous dormancy after the maximal frost resistance was reached. The highest regeneration ability of shoot tips after cryopreservation by encapsulation–dehydration method coincided with the period of the plant’s dormant state and maximum of frost resistance. All studied saccharides and proline exhibited the maximal values at the beginning of cold hardening and/or the dormancy phase. Contrary to the accumulation of saccharides and proline, water content showed the inverse time behaviour. According to these results, the cold hardening-induced endodormancy, high frost resistance and accumulation of saccharides and proline are the important prerequisites for the successful cryopreservation of shoot tips of in vitro grown apple plants. Content Type Journal Article Category Original Paper Pages 1-12 DOI 10.1007/s00468-012-0694-7 Authors Alois Bilavčík, Crop Research Institute, Drnovská 507, 16106 Prague 6-Ruzyně, The Czech Republic Jiří Zámečník, Crop Research Institute, Drnovská 507, 16106 Prague 6-Ruzyně, The Czech Republic Martin Grospietsch, Crop Research Institute, Drnovská 507, 16106 Prague 6-Ruzyně, The Czech Republic Miloš Faltus, Crop Research Institute, Drnovská 507, 16106 Prague 6-Ruzyně, The Czech Republic Petra Jadrná, Crop Research Institute, Drnovská 507, 16106 Prague 6-Ruzyně, The Czech Republic Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The photosynthetic responses to a flowering-inductive water-stress period and recovery were studied and compared in two Citrus species. Under greenhouse conditions, Fino lemon and Owari satsuma trees were subjected to moderate (−2 MPa at predawn) and severe (−3 MPa) water stress levels and were re-watered after 60 days. Vegetative growth was inhibited during the stress assays, and strong defoliation levels were reported, especially in Fino lemon. In both species, bud sprouting was induced after re-watering. Flowers and vegetative shoots developed in Owari satsuma after a drought period, and the development was independent of the stress level. In Fino lemon, vegetative shoots and flowers were primarily formed after moderate and severe stress, respectively. The photosynthetic rate and stomatal conductance were reduced by water stress, and a marked increase in water-use efficiency at the moderate water deficit level was observed. Nevertheless, the photosynthetic apparatus was not damaged, since the maximum quantum yield, photosynthetic pigment concentrations and Rubisco level and activity did not change. Furthermore, the measured malonyldialdehyde (MDA) and peroxidase activity indicated that oxidative stress was not specifically triggered by water stress in our study. Therefore, the gas exchange, fluorescence and biochemical parameters suggested that diffusional limitations to photosynthesis predominated in both of the studied Citrus species, and explained the rapid recovery of the photosynthetic parameters after rehydration. The net CO 2 fixation rate and stomatal conductance were recovered within 24 h in Fino lemon, whereas 3 days were required in Owari satsuma. This suggests the presence of some metabolic limitations in the latter species. Furthermore, the sensibility of the defoliation rates, the accumulation of proline and the stomatal behaviour in response to water stress indicated a higher drought tolerance of Fino lemon, according to its better acclimation to hot climates. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s00468-011-0657-4 Authors Catarino Ávila, Colegio de Postgraduados, Campus Veracruz, Veracruz, México José Luis Guardiola, Departamento de Producción vegetal, Área de Fisiología vegetal, Universitat Politècnica de València, Edificio 3 K. Camino de Vera sn, 46022 Valencia, Spain Sergio G. Nebauer, Departamento de Producción vegetal, Área de Fisiología vegetal, Universitat Politècnica de València, Edificio 3 K. Camino de Vera sn, 46022 Valencia, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The number of described pathogenic and non-pathogenic Erwinia species associated with pome fruit trees, especially pear trees, has increased in recent years, but updated comparative information about their similarities and differences is scarce. The causal agent of the fire blight disease of rosaceous plants, Erwinia amylovora , is the most studied species of this genus. Recently described species that are pathogenic to pear trees include Erwinia pyrifoliae in Korea and Japan, Erwinia spp. in Japan, and Erwinia piriflorinigrans in Spain. E. pyrifoliae causes symptoms that are indistinguishable from those of fire blight in Asian pear trees, Erwinia spp. from Japan cause black lesions on several cultivars of pear trees, and E. piriflorinigrans causes necrosis of only pear blossoms. All these novel species share some phenotypic and genetic characteristics with E. amylovora . Non-pathogenic Erwinia species are Erwinia billingiae and Erwinia tasmaniensis that have also been described on pome fruits; however, less information is available on these species. We present an updated review on the phenotypic and molecular characteristics, habitat, pathogenicity, and epidemiology of E. amylovora , E. pyrifoliae , Erwinia spp. from Japan, E. piriflorinigrans , E. billingiae, and E. tasmaniensis. In addition, the interaction of these species with pome fruit trees is discussed. Content Type Journal Article Category Review Pages 1-17 DOI 10.1007/s00468-011-0644-9 Authors Ana Palacio-Bielsa, Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Avda. Montañana 930, 50059 Zaragoza, Spain Montserrat Roselló, Laboratorio del Servicio de Sanidad Vegetal y Protección Fitosanitaria, Generalitat Valenciana, Ctra. de Alicante a Valencia Km. 276.5, 46460 Silla, Valencia, Spain Pablo Llop, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. de Moncada a Náquera Km 4.5, 46113 Moncada, Valencia, Spain María M. López, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. de Moncada a Náquera Km 4.5, 46113 Moncada, Valencia, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The uncommon ability of monoembryonic seeds of Eugenia to develop seedlings after cutting or even after the removal of more than half of their storage tissue has recently been reported. Some Eugenia species are included among those at risk of disappearing, so the regeneration of plantlets from fragments of seeds could be an important mechanism both for the production of more than one normal seedling per seed and to understand the survival strategies of these species. Because the period in which this ability is present has not been studied, we analyzed the regenerative capacity of seeds of five Brazilian native species of Eugenia , considering two levels of maturity and three germination phases. Mature seeds have a greater potential to regenerate than immature ones; germinating seeds showed that the longer the root protrusion, the smaller the potential to regenerate new seedlings. However, our results clearly demonstrate that the ability to regenerate new roots or complete seedlings is present during a long period from the beginning of development until the late phases of germination. Cutting is potentially important to obtain plants on a larger scale. Because of intense predation of these seeds, this ability could be linked to an essential strategy for survival even after the removal of more than half of the storage tissues. As an alternative strategy to orthodox seeds, whose preservation is based on tolerance to desiccation, the recalcitrant seeds of Eugenia probably adopted the great reserve quantity and the regenerative capacity, allowing them to undergo successive germinations. Content Type Journal Article Category Short Communication Pages 1-9 DOI 10.1007/s00468-011-0648-5 Authors Carmen C. Teixeira, Departamento de Botânica, Instituto de Biociências, Universidade Estadual Paulista “Julio de Mesquita Filho”, CP 510, Botucatu, SP CEP 18618-000, Brazil Claudio J. Barbedo, Núcleo de Pesquisa em Sementes, Instituto de Botânica, CP 3005, Sao Paulo, SP CEP 01061-970, Brazil Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Several old cultivars, and breeding clones of European pear Pyrus communis L. originating from Belgium, England, Sweden, and Switzerland were evaluated for their resistance/susceptibility to fire blight. Studies were carried out during three consecutive years 2007–2009 in the greenhouse of Warsaw University of Life Sciences, Poland. Strain 691 of Erwinia amylovora was used for artificial infection of plants. Genotypes included in this study considerably varied in their resistance to fire blight. The most resistant was the old English cultivar ‘Hessle’. The other two genotypes, i.e., ‘Gränna Rödpäron’ originating from Sweden, and Pyrus communis FG 1606 from Switzerland were included in a group of low susceptible ones. The most susceptible were Cra Py H 18, Cra Py V 22 and Cra Py W 14 from Belgium. Content Type Journal Article Category Original Paper Pages 1-7 DOI 10.1007/s00468-011-0646-7 Authors Andrzej A. Przybyla, Department of Pomology, Faculty of Horticulture and Landscape Architecture, Warsaw University of Life Sciences, Warsaw, Poland Kamila L. Bokszczanin, Department of Plant Genetics, Breeding, and Biotechnology, Faculty of Horticulture and Landscape Architecture, Warsaw University of Life Sciences, Warsaw, Poland Malgorzata Schollenberger, Department of Plant Pathology, Faculty of Horticulture and Landscape Architecture, Warsaw University of Life Sciences, Warsaw, Poland Dariusz Gozdowski, Department of Experimental Design and Bioinformatics, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, 159 Nowoursynowska Str, 02-776 Warsaw, Poland Wieslaw Madry, Department of Experimental Design and Bioinformatics, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, 159 Nowoursynowska Str, 02-776 Warsaw, Poland Slawomir Odziemkowski, Department of Pomology, Faculty of Horticulture and Landscape Architecture, Warsaw University of Life Sciences, Warsaw, Poland Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The effects of the culture system used for embryo proliferation were investigated with the aim of improving multiplication rates and somatic embryo quality in two embryogenic lines of Quercus robur derived from mature trees (B-17 and Sainza). Embryo proliferation medium was defined following comparison of five different semi-solid media, and the highest multiplication rates (based on the total number of embryos and number of cotyledonary-shaped embryos) were achieved with medium supplemented with 0.44 μM benzyladenine for both lines. Embryo proliferation on semi-solid medium was compared with that obtained by a temporary immersion system (TIS), in which four cycles with immersion frequencies of 1 min every 6, 8, 12 or 24 h were tested. TIS promoted a significant increase in proliferated embryo biomass, with the growth index (GI) two and four times higher than in semi-solid medium in B-17 and Sainza genotypes, respectively. An immersion cycle of 1 min every 8 or 12 h produced approximately 700 somatic embryos (B-17) and 1,500 somatic embryos (Sainza) per RITA ® bioreactor, with significant differences in the latter genotype with respect to gelled medium. TIS had also a significant effect on somatic embryo synchronization as it enabled a higher production of cotyledonary embryos (90%), which represents increases of 14% (B-17) and 20% (Sainza) with respect to gelled medium. For germination of embryos proliferated in TIS two maturation systems were applied: (1) culture in semi-solid medium containing 6% sorbitol or (2) culture by TIS (without sorbitol) at a frequency of 1 min immersion every 48 h. Germination ability was higher after maturation on sorbitol medium and plantlet conversion occurred in 48% (B-17) and 13% (Sainza) embryos. TIS produced large numbers of well-developed cotyledonary embryos, hence reduced the cost and labor. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-011-0639-6 Authors Rubén Mallón, Instituto de Investigaciones Agrobiológicas de Galicia, CSIC, Avda. de Vigo s/n, Apartado 122, 15780 Santiago de Compostela, Spain Purificación Covelo, Instituto de Investigaciones Agrobiológicas de Galicia, CSIC, Avda. de Vigo s/n, Apartado 122, 15780 Santiago de Compostela, Spain Ana María Vieitez, Instituto de Investigaciones Agrobiológicas de Galicia, CSIC, Avda. de Vigo s/n, Apartado 122, 15780 Santiago de Compostela, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Obtaining representative values of green wood properties is essential for studies investigating the biomechanical aspects of tree development and ecology. Here, we compare the biomechanical properties of wood stored in various conditions between their collection in the field and their measurement. The study was performed on a large sample of wood specimens from different tropical species and different location in the trees, representing a wide diversity in wood structures. Elastic and viscoelastic properties are measured on green wood, and measured again after storage in different conditions: immersion in cold water during various durations, storage in an ethanol solution with or without washing in water, and air drying with or without rehydration. The systematic and random errors induced by these storage methods are quantified. Storage in cold water is the best way to preserve wood native properties. Soaking in ethanol is a fair alternative regarding elastic properties, but induces a significant change in viscoelastic properties. Air drying causes important, and partly irreversible, changes in mechanical properties. However, regarding elastic properties, this change is a systematic bias so that the air-dried elastic modulus provides a good basis for comparative studies of green wood stiffness. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-011-0636-9 Authors Jana Dlouhá, Laboratoire de Mécanique et Génie Civil (LMGC), Université Montpellier 2, CNRS, Place E. Bataillon, cc 048, 34095 Montpellier, France Tancrède Alméras, Laboratoire de Mécanique et Génie Civil (LMGC), Université Montpellier 2, CNRS, Place E. Bataillon, cc 048, 34095 Montpellier, France Bruno Clair, Laboratoire de Mécanique et Génie Civil (LMGC), Université Montpellier 2, CNRS, Place E. Bataillon, cc 048, 34095 Montpellier, France Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Cell wall-degrading enzymes of Venturia inaequalis are supposed to be fungal virulence factors whereas phenolic compounds of the host plant may be involved in defence. Since phenolic structures are predestined for an interaction with proteins we studied the effects on enzymes and proteins in course of in vitro culture and with preparations from culture filtrates and mycelia, respectively. The native compounds epicatechin, catechin, phloridzin, chlorogenic acid, caffeic acid, p -coumaric acid and phloridzin tested under non-oxidizing conditions had no or weak effects on enzyme activities . A significant inhibition of pectinase was only detected with the highest concentrations of procyanidins and phloretin. Aerobe conditions resulted in a fast oxidation of most phenolics which was enhanced by fungal phenoloxidases. Generally, no inhibition of fungal growth occurred in vitro but distinct irreversible effects on proteins and enzymes were detected with oxidized phenolics in course of in vitro-cultures as well as with the corresponding preparations. Efficacy of inhibitory activity in in vitro-cultures depended on media, culture technique and time course. Direct treatment of enzyme preparations with the oxidized phenolics resulted in a distinct inhibition of cellulolytic and especially pectinolytic activity. Apart from cellulase pattern altered by phenolics, in vitro-culture zymograms revealed a non specific reduction of enzymatic activities, whereas action on total culture filtrate proteins resulted in specific effects due to phenolic compounds and incubation time. An attempt was made to characterize the oxidation products of epicatechin. Chromatographic fractionation revealed a non-resolvable complex of inhibitory compounds which were not consistent with the typical yellow oxidation products. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-011-0647-6 Authors Beate Golba, Julius Kuehn-Institute, Federal Research Centre for Cultivated Plants, Institute for Plant Protection in Fruit Crops and Viticulture, Schwabenheimer Straße 101, 69221 Dossenheim, Germany Dieter Treutter, Institute of Fruit Sciences, Technische Universität München, Dürnast 2, 85354 Freising-Weihenstephan, Germany Andreas Kollar, Julius Kuehn-Institute, Federal Research Centre for Cultivated Plants, Institute for Plant Protection in Fruit Crops and Viticulture, Schwabenheimer Straße 101, 69221 Dossenheim, Germany Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Plant architecture highly constrains pest infestation but is rarely considered in studies on plant–insect interactions. We analysed the relationships between apple tree architectural traits manipulated by tree training and within-branch development of Dysaphis plantaginea (rosy apple aphid, RAA), a major apple pest, during its multiplication wingless phase in spring. We hypothesised that the degree of branching had an effect on RAA within-branch infestation. In an experimental apple orchard, the infestation by aphid wingless forms was surveyed in two consecutive spring seasons within branches manipulated to design contrasted architectures differing in shoot numbers, shoot density and branching orders. Whatever the branch management system, aphid infestation was higher on long versus short, fruiting versus vegetative, and growing versus non-growing shoots. Either less infested shoots or less severe infestation were observed in the most branched system. A pattern of within-branch short-distance infestation was confirmed. Moreover, the number of branching points between two shoots exerted a high constraint on this infestation pattern. Beside possible trophic effects due to plant growth patterns already documented in the literature, a high degree of branching is likely to be a key-architectural trait to constrain within-branch aphid infestation. This opens new perspectives on the manipulation of branch architecture as a mean giving partial control of pests towards sustainable fruit production. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-011-0629-8 Authors Sylvaine Simon, INRA, Unité Expérimentale Recherche Intégrée UE695 Gotheron, 26320 Saint-Marcel-lès-Valence, France Karine Morel, INRA, Unité Expérimentale Recherche Intégrée UE695 Gotheron, 26320 Saint-Marcel-lès-Valence, France Emilie Durand, INRA, Unité Expérimentale Recherche Intégrée UE695 Gotheron, 26320 Saint-Marcel-lès-Valence, France Géraldine Brevalle, INRA, Unité Expérimentale Recherche Intégrée UE695 Gotheron, 26320 Saint-Marcel-lès-Valence, France Thierry Girard, INRA, Unité Expérimentale Recherche Intégrée UE695 Gotheron, 26320 Saint-Marcel-lès-Valence, France Pierre-Éric Lauri, INRA, UMR AGAP, #1334, Equipe ‘Architecture et Fonctionnement des Espèces Fruitières’, CIRAD Lavalette, Avenue Agropolis, TA A-108/03, 34398 Montpellier Cedex 5, France Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Differences in the timing of cell death, differentiation and function among three different types of ray parenchyma cells in the hardwood Populus sieboldii  ×  P . grandidentata which form uniseriate and homocellular rays were examined and clarified. Ray parenchyma cells died within 5 years, and the disappearance of nuclei from ray parenchyma cells did not occur successively from the pith side, even within individual radial cell lines of a given ray. Cell death occurred earliest in contact cells, which were connected to adjacent vessel elements through pits, in the fourth annual ring from the cambium. Cell death occurred next in intermediate cells, which were located within the same cell lines as contact cells but were not adjacent to vessel elements, in the fourth annual ring from the cambium. Finally, isolation cells, which were located within the other cell lines of a given ray, died in the fifth annual ring from the cambium. Secondary wall thickenings in contact cells and intermediate cells were initiated before those in isolation cells in the current year’s xylem. Most starch grains were localized in intermediate cells, and there were more lipid droplets in contact cells and intermediate cells than in isolation cells. In addition, the largest quantities of protein were found in contact cells. Our results indicate that the position within a ray and neighboring short-lived vessel elements might affect the timing of cell death and differentiation and, thus, the function of long-lived ray parenchyma cells in Populus sieboldii  ×  P . grandidentata . Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s00468-011-0640-0 Authors Satoshi Nakaba, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan Shahanara Begum, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan Yusuke Yamagishi, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan Hyun-O Jin, College of Life Sciences, Kyung Hee University, Yongin, 446-701 Korea Takafumi Kubo, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan Ryo Funada, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The climate sensitivity of radial growth in European beech ( Fagus sylvatica L.) was analyzed within a narrow valley in the Swabian Alb (southwestern Germany). We collected stem disks from three aspects (NE, NW and SW) of trees belonging to different social classes. Common climatic factors limiting growth across the valley were identified using a principal component analysis (PCA). Further, we performed hierarchical cluster analysis (HCA), redundancy analysis (RDA) and bootstrapped correlation analysis to reveal differences in chronologies and climate-growth relationships between aspect and social class. Climatic variables considered in our analyses were monthly and seasonal data on temperature and precipitation, as well as a self-calibrating Palmer drought severity index (sc-PDSI). We identified drought in the period June–August as the most prominent factor limiting growth across the valley. Dominant and co-dominant trees at the NW and SW aspects were found to be particularly drought sensitive, whereas intermediate trees were less susceptible to drought. Underlying causes of established climate–growth relationships are discussed in the context of drought susceptibility, tree-size modulation and tree physiological processes. Content Type Journal Article Category Original Paper Pages 1-12 DOI 10.1007/s00468-011-0645-8 Authors Ernst van der Maaten, Institute for Forest Growth, University of Freiburg, Tennenbacherstrasse 4, 79106 Freiburg, Germany Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Although studies have addressed the chemical analysis and the biological activity of oleoresin in species of Copaifera , the cellular mechanisms of oleoresin production, storage, and release have rarely been investigated. This study detailed the distribution, ontogeny, and ultrastructure of secretory cavities and canals distributed in leaf and stem, respectively, of Copaifera trapezifolia , a Brazilian species included in a plant group of great economic interest. Axillary vegetative buds, leaflets, and portions of stem in primary and secondary growth were collected and processed in order to study the anatomy, histolocalization of substances, and ultrastructure. Secretory cavities are observed in the foliar blade and secretory canals in the petiolule and stem. They are made up of a uniseriate epithelium delimiting an isodiametric or elongated lumen. Biseriate epithelium is rarely observed and is a novelty for Leguminosae. Cavities and canals originate from ground meristem cells and the lumen is formed by schizogenesis. The content of the cavities and canals of both stem and leaf is oily and resinous, which suggests that the oleoresin could be extracted from the leaf instead of the stem. Phenolic compounds are also detected in the epithelial cell cytoplasm. Cavities and canals in the beginning of developmental stages have polarized epithelial cells. The cytoplasm is rich in smooth and rough endoplasmic reticula connected to vesicles or plastids. Smooth and rough endoplasmic reticulum and plastids were found to be predominant in the epithelial cells of the secretory cavities and canals of C. trapezifolia . Such features testify the quantities of oleoresin found in the lumen and phenolic compounds in the epithelial cell cytoplasm of these glands. Other studies employing techniques such as correlative light electron microscopy could show the vesicle traffic and the compartmentalization of the produced substances in such glands. Content Type Journal Article Category Original Paper Pages 1-7 DOI 10.1007/s00468-011-0642-y Authors Juliana Foresti Milani, Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café s/no, Ribeirão Preto, SP 14040-903, Brazil Joecildo Francisco Rocha, Departamento de Botânica, Instituto de Biologia, Universidade Federal Rural do Rio de Janeiro, C.P. 74582, Seropédica, RJ 23890-000, Brazil Simone de Pádua Teixeira, Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café s/no, Ribeirão Preto, SP 14040-903, Brazil Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Erwinia amylovora is a polyphagous bacterium causing fire blight on apple, pear and over 130 other plant species belonging mainly to the Rosaceae family. Although E. amylovora is regarded as a very homogenous species, the particular strains can differ in pathogenic ability as far as their host range is concerned (e.g. those originating from Rubus or Maloidae plants) as well as by the extent of the disease they cause. It was found that strains originating from North America are generally more genetically heterogeneous than those from Europe. Diversity of E. amylovora is also related to streptomycin resistance as a result of its application to control of fire blight. The level of genetic heterogeneity of E. amylovora is so low (comparative genome analysis revealed a similarity of over 99% for the two genomes tested) that standard DNA-based techniques fail in detection of intra-species variability. Amplified fragment length polymorphism was found to be most useful for differentiation of strains of fire blight causal agent as well as techniques ensuing release of pan-genome sequences of two E. amylovora strains: multi-locus variable number of tandem repeats analysis and clustered regularly interspaced short palindrome repeats. Content Type Journal Article Category Review Pages 1-10 DOI 10.1007/s00468-011-0643-x Authors Joanna Puławska, Pomology Division, Research Institute of Horticulture, ul. Pomologiczna 18, 96-100 Skierniewice, Poland Piotr Sobiczewski, Pomology Division, Research Institute of Horticulture, ul. Pomologiczna 18, 96-100 Skierniewice, Poland Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Concerning forest communities, not much is known about the relationship between wood traits and environmental conditions. Using a succession series, we analyzed which wood anatomical traits were correlated with successional stage and asked which traits and which environmental factors were particularly important for the trait–environment relationship. An extensive dataset of 11 groups of wood traits was generated for 93 woody species that occurred in 27 permanent plots in a secondary subtropical secondary broadleaved forest in Zhejiang Province (SE-China) and subjected to Fourth Corner Analyses, using different permutation models. We encountered a strong relationship of wood porosity, visibility of growth rings and vessel arrangement to the successional gradient. Compared to biotic community characteristics such as density of plants, abiotic environmental variables such as soil characteristics, aspect and inclination of the plots showed only marginal correlations to wood anatomical traits. Furthermore, the link between environment and species composition of the forest communities was found to be more important in explaining the trait–environment relationship than between the communities and species wood traits. In addition, our results support the idea that most of the species in the subtropical forest might be functionally equivalent. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-011-0632-0 Authors Martin Böhnke, Institute of Biology/Geobotany and Botanical Garden, Martin-Luther University Halle-Wittenberg, Am Kirchtor 1, 06108 Halle (Saale), Germany Nadine Kreißig, Institute of Biology/Geobotany and Botanical Garden, Martin-Luther University Halle-Wittenberg, Am Kirchtor 1, 06108 Halle (Saale), Germany Wenzel Kröber, Institute of Biology/Geobotany and Botanical Garden, Martin-Luther University Halle-Wittenberg, Am Kirchtor 1, 06108 Halle (Saale), Germany Teng Fang, Gutianshan National Nature Reserve, Zhejiang, 324306 China Helge Bruelheide, Institute of Biology/Geobotany and Botanical Garden, Martin-Luther University Halle-Wittenberg, Am Kirchtor 1, 06108 Halle (Saale), Germany Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Temporal instability of climate signal in tree-ring width of the five dominant species ( Pinus nigra , P. sylvestris , P. uncinata , Abies alba , Fagus sylvatica ) growing under Mediterranean mountainous climate was studied over the last century (1910–2004). To disentangle the tree–climate–site complex, the effects of both soil water availability (SWA) (dry, mesic and humid sites) and altitude (from 430 to 1,690 m) were investigated on the response patterns. Responses to climate were analysed using bootstrapped correlation coefficients from 17 ring-width chronologies built from 293 trees sampled in 64 stands in South-Eastern France. Temporal analyses were performed considering forty-six 50-years intervals (from 1910–1959 to 1955–2004). May–June drought was the primary limiting factor. For P. sylvestris , summer precipitation also played a key role. F. sylvatica was the less responding species with no clear common pattern. Low SWA led to an increasing correlation with precipitation in May for P. nigra and A. alba . Precipitation from May to August prevailed on the driest conditions for P. sylvestris . Correlation analyses suggested that warm autumn or winter enhanced growth, except for F. sylvatica . For P. nigra , the importance of April temperature increased with increasing altitude. Temporal analyses revealed a stability of sensitivity for the highest contexts ( P. uncinata and F. sylvatica ). At lower altitudes, the correlation with minimum temperature in April increased while temperature more often exceeded the threshold of 0°C over the last decades. For precipitation, a decrease in the strength of correlation was observed without close relationships with local xericity. Content Type Journal Article Category Original Paper Pages 1-15 DOI 10.1007/s00468-011-0638-7 Authors F. Lebourgeois, AgroParisTech, UMR1092, Laboratoire d’Étude des Ressources Forêt Bois (LERFoB), ENGREF, 14 rue Girardet, 54042 Nancy, France P. Mérian, AgroParisTech, UMR1092, Laboratoire d’Étude des Ressources Forêt Bois (LERFoB), ENGREF, 14 rue Girardet, 54042 Nancy, France F. Courdier, INRA, UR629 URFM, Écologie des Forêts Méditerranéennes, Site Agroparc, Domaine Saint-Paul, 84914 Avignon Cedex 9, France J. Ladier, Office National des Forêts, Département Recherche et Développement, Actiplus, ZI St Joseph, 04100 Manosque, France P. Dreyfus, INRA, UR629 URFM, Écologie des Forêts Méditerranéennes, Site Agroparc, Domaine Saint-Paul, 84914 Avignon Cedex 9, France Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    We analysed proline, abscisic acid, (ABA), jasmonic acid (JA), indole acetic acid (IAA) and salicylic acid (SA) accumulation after summer drought at two Pinus pinaster provenance-progeny trial sites. The aim of the study was to evaluate P. pinaster phenotypic plasticity and intraspecific variation in the endogenous concentrations of these metabolites and to determine the best stress indicators for family and population discrimination. The environmental effect was remarkable, as striking differences between the sites were obtained for all indicators except for SA, which was unaffected by the environmental conditions. The levels of proline, ABA and IAA were higher in the xeric than in the mesic site. In contrast, JA was higher in the mesic site. The higher variation displayed at the family level led to family differences for all parameters and sites. Differences in proline and ABA between populations were exclusively found in the xeric site, where the population from the wet climate showed higher accumulation. This study provides evidence for differentiation among P. pinaster populations and families in their plastic responses to drought and highlights the importance of considering intraspecific variability when evaluating biochemical stress indicators in environmental studies. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-011-0651-x Authors L. Corcuera, Unidad de Recursos Forestales, C.I.T.A., Avda de Montañana 930, 50059 Zaragoza, Spain E. Gil-Pelegrin, Unidad de Recursos Forestales, C.I.T.A., Avda de Montañana 930, 50059 Zaragoza, Spain E. Notivol, Unidad de Recursos Forestales, C.I.T.A., Avda de Montañana 930, 50059 Zaragoza, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Acrocomia aculeata is an oil producing tropical palm tree with exceptional potential for producing biofuel. As the propagation of this species is often difficult because of its pronounced seed dormancy, the present work examined the morphology and the anatomy of zygotic embryos and seedlings during in vitro germination. Embryos were put in MS media supplemented with organic compounds and cultivated in the dark at 30°C for 20 days. The dry weights, lengths, and diameters of the cotyledonary petioles, haustoria, roots, ligules, and leaf sheaths of embryos obtained from mature seeds and seedlings removed from culture were measured every 2 days; anatomical and histochemical evaluations were performed on embryos and seedlings removed from culture after 2, 5, 8, 10, 12, and 15 days. Elongation of the embryo axis was observed to initiate after 2 days. Elongation of the cotyledonary petiole was observed starting on the fifth day; this is a morphological indication of germination that is associated with the formation of starch and raphides as well as the differentiation of tracheary elements. The growth of the cotyledon is due to increases in cell volumes as well as the development of a meristematic band peripheral to the haustorium. In spite of the fact that the radicle is less differentiated than the plumule, radicular development is precocious and the root emerges first, indicating the absence of morphological dormancy. Atrophy of the haustorium and the accumulation of phenolic compounds in subepidermal cell layers occur due to culturing conditions. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s00468-011-0659-2 Authors Leonardo Monteiro Ribeiro, Programa de Pós-Graduação em Biologia Vegetal, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais 31270-901, Brazil Denise Maria Trombert Oliveira, Departamento de Botânica, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais 31270-901, Brazil Queila de Souza Garcia, Departamento de Botânica, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais 31270-901, Brazil Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The present study investigated drought-induced responses of non-enzymatic antioxidants in four diverse mulberry genotypes ( Morus indica L. S-36, M-5, MR-2 and V-1). Inside the glasshouse, potted plants were subjected to four water regimes for 75 days: (a) control: pots maintained at 100% pot water holding capacity (PC) (b) low water stress: 75% PC (c) medium water stress: 50% PC and (d) high water stress: 25% PC. Photosynthetic leaf gas exchange and non-enzymatic antioxidants including α-tocopherol, ascorbic acid (AA), glutathione, proline and total carotenoids were measured in leaves at regular intervals. Amongst all, V-1 was relatively drought tolerant and showed exceeded accumulation of α-tocopherol and AA-glutathione pool in association with higher carotenoids and proline contents. Susceptible S-36, M-5 and MR-2 could not induce any significant up-regulation in AA-glutathione pool leading to endogenous loss of α-tocopherol and more lipid peroxidation. Reactive oxygen species (ROS) like hydrogen peroxide (H 2 O 2 ) and superoxide (O 2 · − ) showed apparent accumulation in water-stressed leaves and significantly contributed to lipid peroxidation in susceptible genotypes when compared to V-1. Our study demonstrated that proline, AA and glutathione were the major non-enzymatic antioxidants in mulberry with α-tocopherol and carotenoids as good additional indicators for drought stress tolerance. These non-enzymatic antioxidants can cumulatively render effective protection against oxidative damage and can be considered as reliable markers for screening drought-tolerant mulberry genotypes. Content Type Journal Article Category Original Paper Pages 1-16 DOI 10.1007/s00468-011-0665-4 Authors Anirban Guha, Photosynthesis and Plant Stress Biology Laboratory, Department of Plant Sciences, University of Hyderabad, Hyderabad, 500046 India Debashree Sengupta, Photosynthesis and Plant Stress Biology Laboratory, Department of Plant Sciences, University of Hyderabad, Hyderabad, 500046 India Girish Kumar Rasineni, Photosynthesis and Plant Stress Biology Laboratory, Department of Plant Sciences, University of Hyderabad, Hyderabad, 500046 India Attipalli Ramachandra Reddy, Photosynthesis and Plant Stress Biology Laboratory, Department of Plant Sciences, University of Hyderabad, Hyderabad, 500046 India Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The temperature dependences of net photosynthetic rate ( P N ), stomatal conductance ( g s ), transpiration rate ( E ) and dark respiration ( R D ) of four neem ( Azadirachta indica A. Juss) provenances of 11 years old were measured in three seasons of 2006 in the dry-hot valley area of southwest China under field conditions. The results indicated that P N of four neem provenances showed clear parabolic responses with the increase of temperature. The optimum temperature of P N was around 25°C in initiation stage and 30°C in prosperous stage except for neem originating from Jodhpur (MA) provenance which was very close to the mean daily temperature of the preceding week while it was around 27°C (MA provenance excepted) in last stage which was rather close to the mean daily maximum temperature of the preceding week. The optimum temperature for P N of MA provenance was about 2–4°C higher than that of the other three neem provenances in prosperous stage and last stage. According to the fitted parameters of photosynthetic temperature response curves, the photosynthetic performance in prosperous stage was more sensitive to temperature changes than that in initiation stage and last stage while the photosynthetic performance of neem originating from MA provenance was less sensitive to temperatures than that of neem originating from Kalyani, New Delhi and Kulapachta provenances in each growing stage. Furthermore, the temperature ranges for P N of MA provenance were much wider than those of the remaining provenances in each growing stage. These differences in photosynthetic temperature acclimation between neem provenances not only reflected temperature regime of native habitats of these provenances but suggested that MA provenance could be more tolerant to extreme temperatures compared with the remaining provenances. The temperature response curves of g s and E were generally similar in form in the same growing stage for all neem provenances; however, shape of the response curves in initiation stage and last stage was similar to parabolic curve while that in prosperous stage was similar to linear relation. The temperature for maximum g s and E in initiation stage was close to the optimum temperature of P N , but the maximum g s reached at much lower temperature than P N and E in last stage. The response of R D to temperature increased exponentially with temperature; however, there were obvious differences in different growing stages. R D in initiation stage was markedly higher than that in prosperous stage and last stage at a given temperature for four neem provenances. These results suggested that four neem provenances can acclimate to their growing environment through changed photosynthetic ecophysiological responses in course of subjecting to seasonal variation of temperature. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-011-0670-7 Authors Y. X. Zheng, Research Institute of Resource Insects, Chinese Academy of Forestry, Kunming, 650224 China J. C. Wu, Research Institute of Resource Insects, Chinese Academy of Forestry, Kunming, 650224 China Y. P. Zhang, Research Institute of Resource Insects, Chinese Academy of Forestry, Kunming, 650224 China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Apple scab, one of the most damaging diseases in apple worldwide is caused by the fungal pathogen Venturia inaequalis . Pathogen-induced gene expression was analyzed in leaves of greenhouse- and field-grown trees of the scab susceptible cultivar Golden Delicious and the resistant cultivar Rewena using the macroarray technique. The results show that the defence of the Vf -resistant cultivar Rewena is based on different mechanisms than the basal defence response of the susceptible Golden Delicious: whereas lignification seems to play an essential role in scab defence of Rewena, a thaumatin-like as well as a flavonoid gene are assumed to be involved in the mostly insufficient defensive response of Golden Delicious. Furthermore, a method was developed for quantification of the V. inaequalis in infected leaves using real-time quantitative reverse transcription-PCR. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-011-0663-6 Authors Christine Holzapfel, Unit of Fruit Science, Centre of Life and Food Sciences Weihenstephan, Technische Universität München, Dürnast 2, 85354 Freising, Germany Barbara Meisel, Monsanto South Africa (Pty) Ltd, 2 Vermeulen St, Petit, 1512 South Africa Fritz Thümmler, vertis Biotechnologie AG, Lise-Meitner-Str. 30, 85354 Freising, Germany Christoph Leser, Unit of Fruit Science, Centre of Life and Food Sciences Weihenstephan, Technische Universität München, Dürnast 2, 85354 Freising, Germany Dieter Treutter, Unit of Fruit Science, Centre of Life and Food Sciences Weihenstephan, Technische Universität München, Dürnast 2, 85354 Freising, Germany Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    This paper addresses the identification and characterization of developmental patterns in the whole structure of a sympodial species, the apple tree. Dedicated stochastic models (hidden variable-order Markov chains) were used to (i) categorise growth units (GUs) on the basis of their morphological characteristics (number of nodes and presence/absence of flowering) and position along axes, (ii) analyse dependencies between successive GUs and (iii) identify repeated patterns in GU sequences. Two successive phases, referred to as “adolescent” and “adult”, were identified in two apple tree cultivars. In the adolescent phase, “very” long monocyclic GUs were followed by long polycyclic GUs, whereas in the adult phase medium GUs were preferentially followed by short GUs. Flowering GUs constituted a preferential pathway between vegetative GUs of decreasing vigour (long, medium and short) and generated patterns that were interpreted with respect to fruiting regularity. The proposed modelling gave a global and quantitative picture of the two-scale structuring of apple tree ontogeny: a coarse scale corresponding to the succession of the previously mentioned phases and a fine scale corresponding to the alternation between flowering and vegetative GUs. This led us to propose a synthetic scheme of apple tree ontogeny that combines growth phases, polycyclism and flowering, and which could be transposed to other sympodial trees. Content Type Journal Article Category Original Paper Pages 1-15 DOI 10.1007/s00468-011-0661-8 Authors Evelyne Costes, INRA, UMR AGAP, Architecture and Functioning of Fruit Species Team, 34398 Montpellier, France Yann Guédon, CIRAD, UMR AGAP and INRIA, Virtual Plants, 34398 Montpellier, France Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Pome fruit genetic resources collections constitute a highly valuable resource not only for fruit breeding but also for direct use by nurseries, growers, and home gardeners. In order to use these resources efficiently and sustainably, reliable evaluation data on fruit and tree characteristics must be generated. Here we focus on pome fruit genetic resources evaluated phenotypically and genotypically for susceptibility to apple scab ( Venturia inaequalis ), powdery mildew ( Podosphaera leucotricha ), fire blight ( Erwinia amylovora ), pear rust ( Gymnosporangium sabinae ) and storage diseases (e.g., Penicillium expansum ). Examples are presented of several ongoing projects throughout Europe, with the aim to evaluate fruit genetic resources for disease susceptibility and potential use in breeding and for commercial use. The COST action 864 has fostered international cooperation in the evaluation of pome fruit genetic resources, and some of these evaluations therefore involve research groups from several of the participating countries. Content Type Journal Article Category Review Pages 1-11 DOI 10.1007/s00468-011-0660-9 Authors Markus Kellerhals, Research Station Agroscope Changins-Wädenswil, ACW, Wädenswil, Switzerland David Szalatnay, Research Station Agroscope Changins-Wädenswil, ACW, Wädenswil, Switzerland Kaspar Hunziker, Research Station Agroscope Changins-Wädenswil, ACW, Wädenswil, Switzerland Brion Duffy, Research Station Agroscope Changins-Wädenswil, ACW, Wädenswil, Switzerland Hilde Nybom, Department of Plant Breeding and Biotechnology, SLU Balsgård, Kristianstad, Sweden Masoud Ahmadi-Afzadi, Department of Plant Breeding and Biotechnology, SLU Balsgård, Kristianstad, Sweden Monika Höfer, Institute for Breeding Research on Horticultural and Fruit Crops, Julius Kühn-Institut (JKI), Dresden-Pillnitz, Germany Klaus Richter, Institute for Epidemiology and Resistance Resources, Julius Kühn Institute, Quedlinburg, Germany Marc Lateur, Department of Life Science, Unit of Breeding and Biodiversity, Centre Wallon de Recherches Agronomiques (CRA-W), Gembloux, Belgium Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Subarctic mountain birch ( Betula pubescens ssp. czerepanovii ) forests in northern Fennoscandia have shown a slight recovery from recent severe defoliation by the winter moth ( Operophtera brumata ). This development in trees is hypothesized to be a result of ameliorated growing conditions through increased summer temperatures. We examined if accumulated thermal sum affects the ability of mountain birches to tolerate foliage losses. We quantified the number of leaf-bearing short shoots, the emergence of inflorescences and the seasonal height growth of long shoots in both intact and defoliated trees. We also determined the concentrations of carbon and nitrogen in leaves and carbohydrates in roots. Our results show that defoliation constrained the growth of long shoots, as well as the emergence of inflorescences regardless of thermal sum accumulation. However, the number of leaf-bearing short shoots did not differ between intact and defoliated trees. In the both tree groups, the amounts of emerging leaves increased as a response to thermal sum accumulation. Also the leaf carbon concentration increased in defoliated trees at higher thermal sums, whereas it decreased in intact controls. Generally, the mean carbohydrate concentrations were greater in roots of defoliated than intact trees. However, with increased thermal sums, root carbohydrates increased in intact trees but remained the same in defoliated trees. We conclude that thermal sum accumulation does not greatly promote the recovery of mountain birches. Although the damaged trees produced more leaves at warmer growing sites, this did not increase their height growth or carbohydrate gain in roots. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-011-0652-9 Authors Liisa Huttunen, Section of Ecology, Department of Biology, University of Turku, 20014 Turku, Finland Pekka Niemelä, Section of Biodiversity and Environmental Science, Department of Biology, University of Turku, 20014 Turku, Finland Vladimir Ossipov, Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, 20014 Turku, Finland Matti Rousi, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, 01301 Vantaa, Finland Tero Klemola, Section of Ecology, Department of Biology, University of Turku, 20014 Turku, Finland Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    A study was conducted to determine which bud (terminal or lateral) breaks first, and thereby exerts primigenic dominance, on ‘Granny Smith’ and ‘Golden Delicious’, 1-year-old apple ( Malus  ×  domestica Borkh.) shoots grown in two locations in the Western Cape, South Africa, with differing degrees of chilling. Primigenic dominance of laterals was more common in a warm area than a cool area, and more common in ‘Granny Smith’ than ‘Golden Delicious’. Laterals rarely broke before the terminal in ‘Golden Delicious’, and so differences in lateral development due to position of first bud to break were only analyzed in ‘Granny Smith’ shoots from this point on in the study. In ‘Granny Smith’, lateral budbreak and growth was influenced by the position of the first bud to break on the shoot, but did not differ between locations. On ‘Granny Smith’ shoots with primigenic dominance of the terminal, lateral budbreak and growth was suppressed, in accordance with the typical ‘delayed foliation’ commonly observed in warm winter climates. However, when at least one lateral broke before the terminal, lateral budbreak and growth were similar to previous observations in cold winter areas. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s00468-011-0634-y Authors Karen Maguylo, Department of Horticultural Science, University of Stellenbosch, Matieland, 7602 South Africa Nigel C. Cook, Department of Horticultural Science, University of Stellenbosch, Matieland, 7602 South Africa Karen I. Theron, Department of Horticultural Science, University of Stellenbosch, Matieland, 7602 South Africa Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Stomata are leaf structures that are essential for regulating gas exchange and water balance in terrestrial plants. Accurately quantifying stomatal characteristics is consequently of great importance for understanding the physiological processes of plants under different environmental conditions. The objective of this study was to investigate the spatial distribution pattern of stomata on leaflet surfaces, and the possible mechanisms that influence this pattern, particularly leaf expansion. To achieve this, we used geostatistical tools combined with an analysis of biometric relationships of leaves from Hymenaea courbaril L. Our analysis indicates that stomata show a clear spatial structure in this species: average values of foliar expansion rates (ERs) were different on right and left-hand sides of the primary venation of each leaflet and there was a close relationship between the spatial pattern of stomatal density and leaf expansion rate. Such differences in lateral expansion may therefore be partially responsible for the heterogeneous distribution of stomata documented here and in other studies. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-011-0620-4 Authors Giordane Augusto Martins, Departamento de Biologia, Universidade Federal de Lavras, Caixa Postal 3037, Lavras-MG, 37200-000 Brazil Angela Maria Soares, Departamento de Biologia, Universidade Federal de Lavras, Caixa Postal 3037, Lavras-MG, 37200-000 Brazil João Paulo Rodrigues Alves Delfino Barbosa, Departamento de Biologia, Universidade Federal de Lavras, Caixa Postal 3037, Lavras-MG, 37200-000 Brazil José Marcio de Mello, Departamento de Ciências Florestais, Universidade Federal de Lavras, Caixa Postal 3037, Lavras-MG, 37200-000 Brazil Evaristo Mauro de Castro, Departamento de Biologia, Universidade Federal de Lavras, Caixa Postal 3037, Lavras-MG, 37200-000 Brazil Antonio Carlos Ferraz, Departamento de Ciências Florestais, Universidade Federal de Lavras, Caixa Postal 3037, Lavras-MG, 37200-000 Brazil Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The genus Erwinia includes plant-associated pathogenic and non-pathogenic species. Among them, all species pathogenic to pome fruit trees ( E. amylovora, E. pyrifoliae, E. piriflorinigrans, Erwinia sp. from Japan) cause similar symptoms, but differ in their degrees of aggressiveness, i.e. in symptoms, host range or both. The presence of plasmids of similar size, in the range of 30 kb, is a common characteristic that they possess. Besides, they share some genetic content with high homology in several genes associated with exopolysaccharide production and hence, with virulence, as well as in some other genes. Knowledge of the content of these plasmids and comparative genetic analyses may provide interesting new clues to understanding the origin and evolution of these pathogens and the level of symptoms they produce. Furthermore, genetic similarities observed among some of the plasmids (and genomes) from the above indicated pathogenic species and E. tasmaniensis or E. billingiae , which are epiphytic on the same hosts, may reveal associations that could expose the mechanisms of origin of pathogens. A summary of the current information on their plasmids and the relationships among them is presented here. Content Type Journal Article Category Review Pages 1-16 DOI 10.1007/s00468-011-0630-2 Authors Pablo Llop, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera Km 4.5, 46113 Moncada, Valencia, Spain Silvia Barbé, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera Km 4.5, 46113 Moncada, Valencia, Spain María M. López, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera Km 4.5, 46113 Moncada, Valencia, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Seed dispersal is an important factor influencing the genetic structure of forest tree populations. Knowledge about the seed shadow is important to assess the ability of tree species to colonize new and disturbed habitats or to respond to environmental change by migrating to more suitable habitats. In a seed trap experiment, we investigated local seed dispersal distances of silver fir seeds ( Abies alba Mill.) by explicitly identifying mother trees. For this purpose, we matched microsatellite genotypes of maternal tissues of seeds with the genotypes of adult trees in the studied stand. Furthermore, we analysed the effect of morphological traits on dispersal distance, and we assessed the number of contributing mother trees and compared the seed density of the closed forest-stand with the adjacent blowdown. Based on 674 seeds collected in a grid of 37 seed traps, a significant decline in seed density was observed from within the forest to the forest blowdown area 〉40 m from the forest edge. A median dispersal distance of 31 m was determined for filled seeds based on direct assignment of seeds to their mother trees. This was higher than that determined in the previous studies using different methods. Dispersal distance was negatively correlated to seed-weight, but this was partially compensated for by the length of seed wings. A very large number of unassigned maternal genotypes (435) suggested that dispersal distance might have been underestimated. Lessons for future studies were: to perform a full genotypic inventory of adult trees in a defined perimeter, to increase the number of microsatellite markers and to study several sites over a period of several years. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-012-0676-9 Authors Eva Cremer, Department of Conservation Biology, Faculty of Biology, Philipps-University of Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany Birgit Ziegenhagen, Department of Conservation Biology, Faculty of Biology, Philipps-University of Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany Katrin Schulerowitz, Department of Conservation Biology, Faculty of Biology, Philipps-University of Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany Christina Mengel, Department of Conservation Biology, Faculty of Biology, Philipps-University of Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany Kathrin Donges, Department of Mycology, Faculty of Biology, Philipps-University of Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany Ronald Bialozyt, Department of Conservation Biology, Faculty of Biology, Philipps-University of Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany Erwin Hussendörfer, FB Wald und Forstwirtschaft, FH Weihenstephan, Am Hochanger 5, 85354 Freising, Germany Sascha Liepelt, Department of Conservation Biology, Faculty of Biology, Philipps-University of Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Conifer needles are extraordinarily variable and much of this diversity is linked to the water transport capacity of the xylem and to xylem conduit properties. However, we still know little about how anatomical characteristics influence the hydraulic efficiency of needle xylem in different parts of the crown. In this study we evaluated needle function and anatomy in Norway spruce families exposed to different light conditions. We measured tracheid and needle characteristics of sun-exposed and shaded current-year needles in two experimental plots: a control plot and a thinned plot with 50% reduction in stand density. Sun-exposed needles had a larger tracheid lumen area than shaded needles, and this was caused by a larger maximum tracheid lumen diameter, while the minimum lumen diameter was less plastic. Sun-exposed needles had also higher theoretical hydraulic conductivity than shaded needles. Thinning leads to increased radiation to the lower branches, and presumably exposes the upper branches to stronger water stress than before thinning. Thinning affected several needle parameters both in sun-exposed and shaded needles; tracheid lumens were more circular and minimum tracheid lumen diameter was larger in the thinned plot, whereas maximum tracheid lumen diameter was less plastic on both plots. This study demonstrates that needle xylem structure in Norway spruce is clearly influenced by the light gradient within the tree crown. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-012-0684-9 Authors Roman Gebauer, Institute of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic Daniel Volařík, Institute of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic Josef Urban, Institute of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic Isabella Børja, Norwegian Forest and Landscape Inst., PO Box 115, 1431 Ås, Norway Nina Elisabeth Nagy, Norwegian Forest and Landscape Inst., PO Box 115, 1431 Ås, Norway Toril Drabløs Eldhuset, Norwegian Forest and Landscape Inst., PO Box 115, 1431 Ås, Norway Paal Krokene, Norwegian Forest and Landscape Inst., PO Box 115, 1431 Ås, Norway Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    A tree’s crown interacts with atmospheric variables such as CO 2 , temperature, and humidity. Physioecology of leaves/needles (e.g. δ 13 C, mobile carbohydrates, and nitrogen) is, therefore, strongly affected by microclimate in and surrounding a tree crown. To understand the physiological responses of leaves to changes in air temperature and moisture, we measured δ 13 C, soluble sugars, starch, and total nitrogen (N) concentrations in current year and 1-yr-old needles of Pinus koraiensis trees, and compared the growing season air temperature and relative humidity within and outside P. koraiensis crowns along an elevational gradient from 760 to 1,420 m a.s.l. on Changbai Mountain, NE China. Our results indicated that needle N and mobile carbohydrates concentrations, as well as needle δ 13 C values changed continuously with increasing elevation, corresponding to a continuous decrease in air temperature and an increase in relative humidity. Needle carbon and nitrogen status is highly significantly negatively correlated with temperature, but positively correlated with relative humidity. These results indicate that increases in air temperature in combination with decreases in relative humidity may result in lower levels of N and mobile carbohydrates in P. koraiensis trees, suggesting that future climate changes such as global warming and changes in precipitation patterns will directly influence the N and carbon physiology at P. koraiensis individual level, and indirectly affect the competitive ability, species composition, productivity and functioning at the stand and ecosystem level in NE China. Due to the relatively limited range of the transect (760–1,420 m) studied, further research is needed to explain whether the present results are applicable to scales across large elevational gradients. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-012-0784-6 Authors Caifeng Yan, State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164 China Shijie Han, State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164 China Yumei Zhou, State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164 China Xingbo Zheng, Research Station of Changbai Moutain Forest Ecosystems, Chinese Academy of Sciences, Erdaobaihe, 133613 China Dandan Yu, State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164 China Junqiang Zheng, State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164 China Guanhuan Dai, Research Station of Changbai Moutain Forest Ecosystems, Chinese Academy of Sciences, Erdaobaihe, 133613 China Mai-He Li, State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164 China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Small conifer seedlings (mini-seedlings) are less damaged by the large pine weevil Hylobius abietis (L.) (Coleoptera: Curculionidae) compared to conventional seedlings. Chemical difference between the seedling types is one possible explanation for this phenomenon. In the present paper, the emissions of volatile organic compounds (VOC) of 7- to 43-week-old Norway spruce [ Picea abies (L.) Karst.] seedlings were analyzed. Collection and identification of the volatiles was made by solid phase micro-extraction and gas chromatography mass spectrometry (SPME–GC–MS). The enantiomers of α-pinene and limonene were separated in a two-dimensional GC (2D-GC). Most of the seedlings represented either a limonene- or a bornyl acetate-chemotype. Only minor changes in the volatile composition of the two types of seedlings were found during the first year. Age-related changes, however, were found in the volatiles released by wounded phloem where green leaf volatiles (GLVs) and borneol were the dominated VOC for young seedling. The attractive compound for the pine weevil, α-pinene, was first detected in the phloem emissions of 18- to 22-week-old seedlings. Different storage conditions of the seedlings during the winter/early spring-phase influenced the volatile composition in the phloem. High amount of GLVs was characteristic for the 43-week-old seedlings stored in naturally changing outdoor temperature, but not present in the seedlings winter-stored at a constant temperature of −4 °C. The possible role of these observed differences in odor emissions between seedlings of different age and physiological status for the feeding preferences of the large pine weevil is discussed. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-012-0783-7 Authors Astrid Kännaste, Ecological Chemistry Group, Department of Chemistry, Royal Institute of Technology, 100 44, Stockholm, Sweden Tao Zhao, Ecological Chemistry Group, Department of Chemistry, Royal Institute of Technology, 100 44, Stockholm, Sweden Anders Lindström, School of Industrial Technology and Management, Dalarna University, 781 88, Borlänge, Sweden Eva Stattin, School of Industrial Technology and Management, Dalarna University, 781 88, Borlänge, Sweden Bo Långström, Department of Ecology, Swedish University of Agricultural Sciences, 750 07, Uppsala, Sweden Anna-Karin Borg-Karlson, Ecological Chemistry Group, Department of Chemistry, Royal Institute of Technology, 100 44, Stockholm, Sweden Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The seasonal cambial activity of five tropical tree species was investigated at Khao Yai National Park. The species studied were Tetrameles nudiflora , Magnolia baillonii, Canarium euphyllum Kur , Toona ciliata , and Spondias axillaris . Cambial activity was quantified by counting layers of undifferentiated cells in the cambium zone from wood anatomical micro sections prepared from wood samples collected in monthly intervals from July 2010 to June 2011. The relationship between cambial activity and climatic factors was investigated by using Pearson’s correlation. The growth dynamics of five studied species differed considerably. The cambium of Tetrameles nudiflora and Magnolia baillonii was most active when rainfall reached its maximum amount in June (mid rainy season), whereas the cambium of Canarium euphyllum , Toona ciliata , and Spondias axillaris was most active in March during the transition from the dry to the wet season. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0794-4 Authors Nathsuda Pumijumnong, Faculty of Environment and Resource Studies, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom 73170, Thailand Supaporn Buajan, Faculty of Environment and Resource Studies, Mahidol University, Salaya, Phutthamonthon, Nakhon Pathom 73170, Thailand Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Genes of cellulose and lignin synthesis are important for tree breeding because their activity greatly affects wood properties as well as general growth. The expression (transcript abundance) of genes of cellulose and lignin synthesis in tangential xylem scrapes at breast height sampled at the end of June (middle of active growing season) was related to wood properties in five fast-growing and six slow-growing families of Eucalyptus urophylla from a combined progeny test and seedling seed orchard grown for 10 years in northern Vietnam. Cellulose synthase A ( CesA) genes encoding proteins active in the primary cell wall, EuCesA4 and EuCesA5 , were more highly expressed than EuCesA1 , EuCesA2 and EuCesA3 , encoding genes active in the secondary cell wall. EuCesA4 expression was correlated with that of EuCesA5 ( r  = 0.49, P  = 0.040) and EuCesA5 with EuCesA6 ( r  = 0.46, P  = 0.040). EuCesA4 expression was significantly higher in the fast-growing group and was correlated with cellulose content ( r  = 0.51, P  = 0.011). Over 2 kb of the EuCesA gene was sequenced in 24 trees extending from the 5′ untranslated region through six exons and six introns and revealed 83 polymorphisms and rapid decay of linkage disequilibrium over 500 bp. EuCesA4 activity in xylem is involved in the genetic control of cellulose content, and the gene may have potential for marker-aided selection. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-011-0664-5 Authors Tran Ho Quang, Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Box 7080, 750 07 Uppsala, Sweden Henrik Hallingbäck, Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Box 7080, 750 07 Uppsala, Sweden Niclas Gyllenstrand, Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Box 7080, 750 07 Uppsala, Sweden Sara von Arnold, Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Box 7080, 750 07 Uppsala, Sweden David Clapham, Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Box 7080, 750 07 Uppsala, Sweden Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Hydrogen peroxide plays a critical role in the expression of disease resistance in several plant/pathogen interactions. It serves as a substrate for oxidative cross-linking of various plant cell wall components leading to the reinforcement of the cell structure, as a direct toxin against the pathogen and as a signal molecule for the induction of defence-related genes in the adjacent, still healthy tissues. In plant cells, enzymes and redox metabolites act in synergy to carry out the detoxification of hydrogen peroxide and other reactive oxygen species (ROS). Superoxide dismutase (SOD) catalyses the dismutation of superoxide to hydrogen peroxide, catalase (CAT) dismutates hydrogen peroxide to oxygen and water, and ascorbate peroxidase (APX) reduces hydrogen peroxide to water by utilising ascorbate as specific electron donor. These are considered some of the main enzymatic systems for protecting cells against oxidative damage. These enzymes are present in various isozyme forms in several cell compartments and their expression is genetically controlled and regulated both by developmental and environmental stimuli, according to the necessity to remove ROS produced in cells. The aim of this study was to determine the possible role of these antioxidants in the defence mechanism of Pyrus communis cv. Conférence leaf tissue after an infection with Erwinia amylovora . Shoots of 2-year-old pear trees cv. Conférence were infected with E. amylovora strain SGB 225/12, were mock infected or left untreated. To account for structural changes, not only a difference was made between control, infected and mock-infected leaves, but we also included a distinction between young and old leaves, because it is known that older leaves are less susceptible for fire blight infections. Leaf samples were taken at specific time points after infection and the expression pattern of not necrotic tissue close to the infection site was analysed for their diverse isoforms of SOD, APX and CAT by using real time qPCR. In this study, no striking differences in transcription patterns of these enzymes between control, mock infected and E. amylovora infected leaves were observed. However, a significant difference between the expression levels of some genes in young and old leaves was noticed. These differences could partially explain the different progression rate by which E. amylovora infects, invades and causes necrosis in young and old leaves. Content Type Journal Article Category Original Paper Pages 1-7 DOI 10.1007/s00468-011-0666-3 Authors K. Vrancken, Molecular and Physical Plant Physiology, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium H. Schoofs, Pomology Department, PC Fruit Research Station, Fruittuinweg 1, 3800 Sint-Truiden, Belgium T. Deckers, Pomology Department, PC Fruit Research Station, Fruittuinweg 1, 3800 Sint-Truiden, Belgium R. Valcke, Molecular and Physical Plant Physiology, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Acylcyclohexanediones and antagonistic bacteria sprayed alone or in combination have been shown to suppress fire blight of apple and pear. Acylcyclohexanediones, such as prohexadione-calcium and trinexapac-ethyl, increase plant resistance and are effective against the shoot blight phase of the disease. Antagonistic bacteria, such as Pantoea agglomerans , compete with the pathogen ( Erwinia amylovora ) for space and nutrients on stigmas, which prevents blossom blight. Potential synergistic effects of acylcyclohexanediones with P. agglomerans for fire blight suppression were investigated on leaves and flowers of apple and pear. Acylcyclohexanediones modified the composition of apple nectar and stigmatic secretions, which resulted in moderately higher epiphytic populations of P. agglomerans strain P10c. In experiments in apple orchards, the combination of acylcyclohexanediones and P. agglomerans gave the greatest protection against blossom blight and shoot blight. In pear orchards, under natural infection conditions, a similar result was obtained for the 3 of the 4 years of the experiment. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-011-0672-5 Authors Francesco Spinelli, Dipartimento di Colture Arboree, Alma Mater Studiorum-Università di Bologna, viale Fanin 46, 40127 Bologna, Italy Joel L. Vanneste, The New Zealand Institute for Plant and Food Research Ltd. Ruakura Research Centre, Private Bag 3123, Hamilton, 3240 New Zealand Guglielmo Costa, Dipartimento di Colture Arboree, Alma Mater Studiorum-Università di Bologna, viale Fanin 46, 40127 Bologna, Italy Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Several analytical techniques such as gas chromatography–mass spectrometry, proton transfer reaction–mass spectrometry and laser photoacoustic detection, were used to characterize the volatiles emitted by Erwinia amylovora and other plant-pathogenic bacteria. Diverse volatiles were found to be emitted by the different bacterial species examined. The distinct blend of volatiles produced by bacteria allowed their identification using an electronic nose (e-nose). The present study reports the discrimination of E. amylovora , the fire blight pathogen, from other plant-associated bacteria using an e-nose based on metal oxide semiconductor sensors. Two different approaches were used for bacterial identification. The first one was the direct comparison of the odorous profiles of unknown bacterial isolates with four selected reference species. The second approach was the use of previously developed databases representing the odorous variability among several bacterial species. Using these two strategies, the e-nose successfully identified the isolates in 87.5 and 62.5% of the cases, respectively. Finally, the profiling of the volatiles emitted by E. amylovora lead to identify some metabolic markers with a potential biological activity in vitro . Content Type Journal Article Category Original Paper Pages 1-12 DOI 10.1007/s00468-011-0667-2 Authors Francesco Spinelli, Dipartimento di Colture Arboree, University of Bologna, Viale Fanin 46, 40127 Bologna, Italy Antonio Cellini, Dipartimento di Colture Arboree, University of Bologna, Viale Fanin 46, 40127 Bologna, Italy Joel L. Vanneste, The New Zealand Institute for Plant and Food Research Ltd., Ruakura Research Centre, Private Bag 3123, Hamilton, 3240 New Zealand Maria T. Rodriguez-Estrada, Dipartimento di Scienze degli Alimenti, University of Bologna, Viale Fanin 40, 40127 Bologna, Italy Guglielmo Costa, Dipartimento di Colture Arboree, University of Bologna, Viale Fanin 46, 40127 Bologna, Italy Stefano Savioli, Dipartimento di Scienze degli Alimenti, University of Bologna, Viale Fanin 40, 40127 Bologna, Italy Frans J. M. Harren, Radboud University, Life Science Trace Gas Facility, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands Simona M. Cristescu, Radboud University, Life Science Trace Gas Facility, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The induction of somatic embryogenesis from shoot apices and leaf explants of shoot cultures derived from 6- to 7-year-old white oak ( Quercus alba L.) trees is reported in this study. Embryogenic response was obtained in two out of the three genotypes evaluated with embryo induction frequencies up to 50.7% for WOQ-1 and 3.4% for WOQ-5 genotypes. The embryogenic explants formed translucent nodular structures and cotyledonary-stage somatic embryos, which developed from callus tissue, indicating an indirect embryogenesis process. An efficient procedure was developed for WOQ-1 material on the basis of the most appropriate leaf developmental stage. Growing leaves excised from two nodes below the shoot apex showed the highest embryogenic induction index. These leaves contain cells in an undifferentiated state, as shown by the presence of precursor cells of stomata, absence of intercellular spaces and low starch content in the mesophyll cells. Nodular structures and/or somatic embryos began to arise 7–8 weeks after culture initiation, although most emerged after 9–12 weeks in culture. The sequence of application of media for somatic embryo induction was optimized with a two-step procedure consisting of culturing the explants in medium supplemented with 21.48 μM NAA and 2.22 μM BA for 8 weeks and transfer of explants into plant growth regulator-free medium for another 12 weeks. Clonal embryogenic lines were established and maintained by secondary embryogenesis. Embryo germination (30%) and plantlet conversion (16.6%) were achieved after cold storage for 2 months. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-011-0662-7 Authors E. Corredoira, Instituto de Investigaciones Agrobiológicas de Galicia, CSIC, Avda. de Vigo s/n, Apartado 122, 15780 Santiago de Compostela, Spain M. C. San-José, Instituto de Investigaciones Agrobiológicas de Galicia, CSIC, Avda. de Vigo s/n, Apartado 122, 15780 Santiago de Compostela, Spain A. M. Vieitez, Instituto de Investigaciones Agrobiológicas de Galicia, CSIC, Avda. de Vigo s/n, Apartado 122, 15780 Santiago de Compostela, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Variation in leaf and shoot hydraulic conductance was examined on detached shoots of silver birch ( Betula pendula Roth), cut from the lower third (shade leaves) and upper third of the crown (sun leaves) of large trees growing in a natural temperate forest stand. Hydraulic conductances of whole shoots ( K S ), leaf blades ( K lb ), petioles ( K P ) and branches (i.e. leafless stem; K B ) were determined by water perfusion using a high-pressure flow meter in quasi-steady state mode. The shoots were exposed to irradiance of photosynthetic photon flux density of 200–250 μmol m −2  s −1 , using different light sources. K lb depended significantly ( P  〈 0.001) on light quality, canopy position and leaf blade area ( A L ). K lb increased from crown base to tree top, in parallel with vertical patterns of A L . However, the analysis of data on shade and sun leaves separately revealed an opposite trend: the bigger the A L the higher K lb . Leaf anatomical study of birch saplings revealed that this trend is attributable to enhanced vascular development with increasing leaf area. Hydraulic traits ( K S , K B , K lb ) of sun shoots were well co-ordinated and more strongly correlated with characteristics of shoot size than those of shade shoots, reflecting their greater evaporative load and need for stricter adjustment of hydraulic capacity with shoot size. K S increased with increasing xylem cross-sectional area to leaf area ratio (Huber value; P  〈 0.01), suggesting a preferential investment in water-conducting tissue (sapwood) relative to transpiring tissue (leaves), and most likely contributing to the functional stability of the hydraulic system, essential for fast-growing pioneer species. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-011-0656-5 Authors Arne Sellin, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005 Tartu, Estonia Eele Õunapuu, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005 Tartu, Estonia Eve Kaurilind, Division of Plant Biology, Department of Biosciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland Meeli Alber, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005 Tartu, Estonia Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The aim of this study was to verify if root tip vitality and ectomycorrhization in 16 mature urban linden ( Tilia vulgaris Hayne) trees, growing in roadside and park side sites, at moderately and strongly declining levels, could be associated with main soil properties. From the 738 soil and root samples collected over the four study periods, 52 ectomycorrhizae were recorded. The study demonstrated that the number of non-vital, vital non-mycorrhizal and mycorrhizal tips never differed significantly, neither among samples collected beneath the same tree nor among trees belonging to the same site and decline class, with the exception of the number of vital non-mycorrhizal tips showing significant differences among sites. Significant differences in ectomycorrhizal community composition between sites and between decline classes were found. This result may be related to the variation of the environmental variables as a whole rather than to the influence of a single or few factors, even if capability, permanent wilting point and available water are the soil parameters most significantly related to diversity in ectomycorrhizal community. Content Type Journal Article Category Original Paper Pages 1-17 DOI 10.1007/s00468-011-0641-z Authors Claudia Alzetta, Municipality of Padova, Settore Verde, Parchi, Giardini e Arredo Urbano, Via Zamboni 1, 35131 Padova, Italy Linda Scattolin, Te.S.A.F. Dept., University of Padova, V.le dell’Università 16, 35020 Legnaro, Padova, Italy Cristina Scopel, Te.S.A.F. Dept., University of Padova, V.le dell’Università 16, 35020 Legnaro, Padova, Italy Sergio Mutto Accordi, Te.S.A.F. Dept., University of Padova, V.le dell’Università 16, 35020 Legnaro, Padova, Italy Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Drought-related tree mortality has become a widespread phenomenon. Scots pine ( Pinus sylvestris L.) is a boreal species with high ecological amplitude that reaches its southwestern limit in the Iberian Peninsula. Thus, Iberian Scots pine populations are particularly good models to study the effects of the increase in aridity predicted by climate change models. A total of 78 living and 39 dead Scots pines trees were sampled at two sites located in the NE of the Iberian Peninsula, where recent mortality events have been recorded. Annual tree rings were used to (1) date dead trees; (2) investigate if there was an association between the occurrence of tree death and severe drought periods characterized by exceptionally low ratios of summer precipitation to potential evapotranspiration (P/PET); and (3) to compare the growth patterns of trees that died with those of surviving ones. Mixed models were used to describe the relationships between tree growth (in terms of basal area increment, BAI, and the percentage of latewood, LW%) and climate variables. Our results showed a direct association between Scots pine mortality and severe drought periods characterized by low summer water availability. At the two sites, the growth patterns of dead trees were clearly distinguishable from those of the trees that survived. In particular, the BAI of dead trees was more sensitive to climate dryness (low P/PET summer , high temperatures) and started to decline below the values of surviving neighbors 15–40 years before the time of death, implying a slow process of growth decline preceding mortality. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-011-0628-9 Authors Ana-Maria Hereş, CREAF/Unitat d’Ecologia, Departament de Biologia Animal, Biologia Vegetal y Ecologia, Universitat Autònoma de Barcelona, Edifici C (Facultat de Ciències), 08193 Barcelona, Spain Jordi Martínez-Vilalta, CREAF/Unitat d’Ecologia, Departament de Biologia Animal, Biologia Vegetal y Ecologia, Universitat Autònoma de Barcelona, Edifici C (Facultat de Ciències), 08193 Barcelona, Spain Bernat Claramunt López, CREAF/Unitat d’Ecologia, Departament de Biologia Animal, Biologia Vegetal y Ecologia, Universitat Autònoma de Barcelona, Edifici C (Facultat de Ciències), 08193 Barcelona, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Salinity is a major abiotic stress factor limiting plant growth and productivity. One possible method to enhance plant salt-resistance is to compartmentalize sodium ions away from the cytosol. In the present work, a vacuolar Na + /H + antiporter gene AtNHX1 from Arabidopsis thaliana , was transferred into Populus  ×  euramericana ‘Neva’ by Agrobacterium tumefaciens in order to enhance poplar salt-resistance. The results showed that the transgenic poplar were more resistant to NaCl than the wild-type (WT) in greenhouse condition. Compared with the WT, plant growth and photosynthetic capacity of the transgenic plants were enhanced, and the transgenic plants accumulated more Na + and K + in roots and leaves under the same NaCl condition, whereas malondialdehyde and relative electrical conductivity were lower. All of these properties of the transgenic poplar were likely to be a consequence of the overexpression of AtNHX1 caused Na + sequestration in the vacuoles and improved K + absorption, thus reducing their toxic effects. These results indicated overexpression of the AtNHX1 enhanced salt-resistance of poplar, and AtNHX1 played an important role in the compartmentation of Na + into the vacuoles. Therefore, this study provides an effective way for improving salt resistance in trees. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-011-0635-x Authors Chaoqiang Jiang, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095 Jiangsu, China Qingsong Zheng, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095 Jiangsu, China Zhaopu Liu, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095 Jiangsu, China Wenjun Xu, Jiangsu Quality and Technical Supervision Bureau, Nanjing, 210008 Jiangsu, China Ling Liu, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095 Jiangsu, China Gengmao Zhao, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095 Jiangsu, China Xiaohua Long, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095 Jiangsu, China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The thermal dissipation technique is widely used to estimate transpiration of individual trees and forest stands, but there are conflicting reports regarding its accuracy. We compared the rate of water uptake by stems of six tree species in potometers with sap flow ( F S ) estimates derived from thermal dissipation sensors to evaluate the accuracy of the technique. To include the full range of xylem anatomies (i.e., diffuse-porous, ring-porous, and tracheid), we used saplings of sweetgum ( Liquidambar styraciflua ), eastern cottonwood ( Populus deltoides ), white oak ( Quercus alba ), American elm ( Ulmus americana ), shortleaf pine ( Pinus echinata ), and loblolly pine ( Pinus taeda ). In almost all instances, estimated F S deviated substantially from actual F S , with the discrepancy in cumulative F S ranging from 9 to 55%. The thermal dissipation technique generally underestimated F S . There were a number of potential causes of these errors, including species characteristics and probe construction and installation. Species with the same xylem anatomy generally did not show similar relationships between estimated and actual F S , and the largest errors were in species with diffuse-porous ( Populus deltoides , 34% ) and tracheid ( Pinus taeda , 55%) xylem anatomies, rather than ring-porous species Quercus alba (9%) and Ulmus americana (15%) as we had predicted. New species-specific α and β parameter values only modestly improved the accuracy of F S estimates. However, the relationship between the estimated and actual F S was linear in all cases and a simple calibration based on the slope of this relationship reduced the error to 1–4% in five of the species, and to 8% in Liquidambar styraciflua . Our calibration approach compensated simultaneously for variation in species characteristics and sensor construction and use. We conclude that species-specific calibrations can substantially increase the accuracy of the thermal dissipation technique. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-011-0631-1 Authors Huizhen Sun, Department of Ecology, School of Forestry, Northeast Forestry University, 26 Hexing Road, Xiangfang District, Harbin, 150040 Heilongjiang Province, China Doug P. Aubrey, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA Robert O. Teskey, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Large trees are noted to decline and die over several years after defoliation or extended periods of drought. The underlying mechanisms of this decline are thought to be driven by moisture limitations to photosynthesis, but alternative considerations also suggest carbon storage limitations as a driver. This research assesses the non-structural carbohydrate reserves in crowns and roots tissues during and after defoliation by insects in trembling aspen. We monitored the non-structural carbon reserves of nine tall mature aspen forest stands over 8 years, including two defoliation events. We report on the carbohydrate dynamics in root and crown tissues during and after defoliation. Following defoliation, branch reserves recovered to levels of undefoliated control trees within the same season, while roots took up to 2 years to recover. We argue that in large trees, tissues closest to the foliage are the first sinks to access C in the phloem stream, while roots, which are more distal and separated by a long bole, will only receive adequate supplies of C when the other more proximate sinks are sated. These results support the hypothesis that in times of limited carbon assimilation, root tissues in mature trees experience the longest reduction in carbon reserves, which likely plays a critical role in tree decline and mortality. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-011-0633-z Authors Simon M. Landhäusser, Department of Renewable Resources, School of Forest Science and Management, University of Alberta, 4-42 Earth Sciences Building, Edmonton, AB T6G 2E3, Canada Victor J. Lieffers, Department of Renewable Resources, School of Forest Science and Management, University of Alberta, 4-42 Earth Sciences Building, Edmonton, AB T6G 2E3, Canada Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Erwinia amylovora , the causative agent of fire blight, colonizes primarily the flowers of the sub-family Maloideae. Commercially important fruit tree species such as apple ( Malus domestica ) and pear ( Pyrus communis ) are also affected by the disease. Epiphytic bacterial populations develop on the stigma, from where the pathogen colonizes the hypanthium, aided by moisture. Under favorable conditions, nectar provides a rich medium for growth, which allows bacterial invasion of tissues through the stomata of the nectary. The paper reviews various floral traits that may play a role in the onset and progression of the infection. Flower age, stigma morphology and longevity, the size of epiphytic bacterial population, morphology of the hypanthium, anatomy of the nectary, dynamics of nectar secretion, as well as the volume, concentration and composition of the nectar are discussed in detail, comparing traits of susceptible versus tolerant apple and pear cultivars. Management programs, aiming at the suppression of E. amylovora on floral parts by antibiotics, chemical compounds, natural substances or biological control agents, are also discussed. Content Type Journal Article Category Review Pages 1-20 DOI 10.1007/s00468-011-0627-x Authors Ágnes Farkas, Department of Pharmacognosy, Medical School, University of Pécs, Rókus u. 2., Pécs, 7624 Hungary Erzsébet Mihalik, Botanical Garden of the University of Szeged, Lövölde u., Szeged, 6726 Hungary László Dorgai, Biocenter Ltd., Temesvári krt. 62., Szeged, 6726 Hungary Tamás Bubán, Research and Extension Centre for Fruit Growing, Vadastag 2., Újfehértó, 4244 Hungary Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Cercidiphyllum japonicum is a rare endemic species of East Asia flora and a common component in riparian forests. Dendrochronological techniques were employed to trace radial growth of C. japonicum in the Shennongjia area of central China and examine its relationships with local climate. Effects of precipitation on width of C . japonicum annual rings were negligible except for some temporary negative impacts in prior winter. The variables most strongly controlling radial growth were temperatures in the previous December and during the current summer. Relationships for most pairs of ring-width and monthly/seasonal climate variables were temporally unstable but occasionally significant. Radial growth–climate relationships for C. japonicum were likely shaped by riparian site characteristics, root habits, and regional climatic regimes. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-011-0611-5 Authors Dong He, Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074 Hubei, People’s Republic of China Ming-Xi Jiang, Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074 Hubei, People’s Republic of China Xin-Zeng Wei, Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074 Hubei, People’s Republic of China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The tree constitutes an ecosystem in which microorganisms play an essential role in its functionality. Interactions that microorganisms establish with plants may be beneficial or detrimental and are of extreme importance in the exploitation of trees in agriculture as crop production systems. Fruit trees, especially pomefruit trees including apple, pear and several ornamentals are of great economic importance but its production is affected by several diseases. Fungal and bacterial fruit tree diseases are mainly controlled with chemical fungicides and bactericides, but health and environmental concerns about the use of chemical pesticides have result in strong regulatory actions and have stimulated the development of beneficial microorganisms as microbial pesticides. Up to now, several microorganisms have been registered in different countries and in the EU as biocontrol agents (BCA) covering mainly fire blight, soil-borne fungal diseases and postharvest fruit fungal rot. The key aspects in the success of this technology for disease control are related to biosafety and environmental impact of biocontrol agents, the traceability and fate in the environment and food chain, the improvement by physiological, genetic engineering or the use of mixtures or formulations as well as the industrial production and development of delivery systems for treatment application to trees. Content Type Journal Article Category Review Pages 1-12 DOI 10.1007/s00468-011-0626-y Authors A. Bonaterra, Institute of Food and Agricultural Technology-XaRTA-CIDSAV, University of Girona, Campus Montilivi s/n, 17071 Girona, Spain E. Badosa, Institute of Food and Agricultural Technology-XaRTA-CIDSAV, University of Girona, Campus Montilivi s/n, 17071 Girona, Spain J. Cabrefiga, Institute of Food and Agricultural Technology-XaRTA-CIDSAV, University of Girona, Campus Montilivi s/n, 17071 Girona, Spain J. Francés, Institute of Food and Agricultural Technology-XaRTA-CIDSAV, University of Girona, Campus Montilivi s/n, 17071 Girona, Spain E. Montesinos, Institute of Food and Agricultural Technology-XaRTA-CIDSAV, University of Girona, Campus Montilivi s/n, 17071 Girona, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The shoots of young conifer trees represent an interesting model to study the development and growth of conifers from meristematic cells in the shoot apex to differentiated tissues at the shoot base. In this work, microarray analysis was used to monitor contrasting patterns of gene expression between the apex and the base of maritime pine shoots. A group of differentially expressed genes were selected and validated by examining their relative expression levels in different sections along the stem, from the top to the bottom. After validation of the microarray data, additional gene expression analyses were also performed in the shoots of young maritime pine trees exposed to different levels of ammonium nutrition. Our results show that the apex of maritime pine trees is extremely sensitive to conditions of ammonium excess or deficiency, as revealed by the observed changes in the expression of stress-responsive genes. This new knowledge may be used to precocious detection of early symptoms of nitrogen nutritional stresses, thereby increasing survival and growth rates of young trees in managed forests. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-011-0625-z Authors Javier Canales, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Instituto Andaluz de Biotecnología, Campus Universitario de Teatinos, Universidad de Málaga, s/n, 29071 Málaga, Spain Concepción Ávila, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Instituto Andaluz de Biotecnología, Campus Universitario de Teatinos, Universidad de Málaga, s/n, 29071 Málaga, Spain Francisco R. Cantón, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Instituto Andaluz de Biotecnología, Campus Universitario de Teatinos, Universidad de Málaga, s/n, 29071 Málaga, Spain David Pacheco-Villalobos, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Instituto Andaluz de Biotecnología, Campus Universitario de Teatinos, Universidad de Málaga, s/n, 29071 Málaga, Spain Sara Díaz-Moreno, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Instituto Andaluz de Biotecnología, Campus Universitario de Teatinos, Universidad de Málaga, s/n, 29071 Málaga, Spain David Ariza, Department of Forestry Engineering, School of Forestry, Campus Universitario de Rabanales, University of Córdoba, 14071 Córdoba, Spain Juan J. Molina-Rueda, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Instituto Andaluz de Biotecnología, Campus Universitario de Teatinos, Universidad de Málaga, s/n, 29071 Málaga, Spain Rafael M. Navarro-Cerrillo, Department of Forestry Engineering, School of Forestry, Campus Universitario de Rabanales, University of Córdoba, 14071 Córdoba, Spain M. Gonzalo Claros, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Instituto Andaluz de Biotecnología, Campus Universitario de Teatinos, Universidad de Málaga, s/n, 29071 Málaga, Spain Francisco M. Cánovas, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Instituto Andaluz de Biotecnología, Campus Universitario de Teatinos, Universidad de Málaga, s/n, 29071 Málaga, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Environmental and climatic conditions affect the flower bud growth, flowering and yield performance of fruit species. Temperature and water availability appear to be important factors for temperate fruit trees in mild climates. The aim of this research was to study the involvement of temperature regime on biological processes, such as xylem differentiation and dormancy evolution, in apricot flower buds ( Prunus armeniaca L.). Over 3 consecutive years, biological and anatomical investigations were carried out in Tuscany (Italy) and Murcia (Spain) on two cultivars characterized by a different chilling requirement (CR): Currot, a traditional Spanish cultivar with a very low CR, and Stark Early Orange (SEO), a North American cultivar with a very high CR. Currot had a regular bearing, and was characterized by a synchronism between endodormancy release and xylem differentiation. On the other hand, SEO showed an irregular flower bud growth leading to flowering and fruit-set failure, even with a high level of chilling accumulation. No relationship was found in SEO between xylem development and flower bud growth reactivation. The de-synchronism between these processes could determine the poor adaptability to different environmental areas of SEO cultivar, and its very high CR is not the main hypothesised cause of the altered flower bud development. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-011-0668-1 Authors Lucia Andreini, Sant’Anna School of Advanced Studies, Piazza Martiri della Libertà 33, 56127 Pisa, Italy Raffaella Viti, Department of Trees Science, Entomology and Plant Pathology, ‘G. Scaramuzzi’, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy Susanna Bartolini, Sant’Anna School of Advanced Studies, Piazza Martiri della Libertà 33, 56127 Pisa, Italy David Ruiz, Department of Plant Breeding, CEBAS-CSIC, P.O. Box 164, Campus Universitario, 30100 Espinardo, Murcia, Spain José Egea, Department of Plant Breeding, CEBAS-CSIC, P.O. Box 164, Campus Universitario, 30100 Espinardo, Murcia, Spain Jose Antonio Campoy, Department of Plant Breeding, CEBAS-CSIC, P.O. Box 164, Campus Universitario, 30100 Espinardo, Murcia, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The dihydrochalcone phloridzin (phloretin 2′- O -glucoside) is the most abundant phenolic compound in apple trees ( Malus  ×  domestica ) and was also discussed to have an influence on the pathogen defence by shifting the dihydrochalcone profile from the glucosides to the more active aglycones. The final step in the biosynthesis of phloridzin is the glycosylation of phloretin at position 2′. Three cDNA clones from apple encoding glycosyltransferases are available which are able to catalyze the reaction in vitro. We investigated the possible role of glycosyltransferase UGT71A15 in phloridzin biosynthesis. The recombinant enzyme showed broad substrate acceptance but highest activities were observed with flavonols. Specific activities and the kinetic data indicated that phloretin is not the preferred native substrate of the UGT71A15. However, an increase of the molar ratio phloridzin:phloretin was found in transgenic lines, indicating a physiological relevance of UGT71A15 in planta, although a decrease of the total amount of dihydrochalcones in the majority of the samples was found. Unexpectedly, the increase of the phloridzin:phloretin ratio was not reflected by an increase of the total glucosyltransferase activities. In contrast, the majority of transgenic plants showed a reduced glucosylating activity with both phloretin and quercetin as a substrate, but the observed activity changes in a given sample were not similar for the two substrates. An increased susceptibility of M. robusta against the fire blight causing bacterium E. amylovora as a result of UGT71A15 overexpression could not be observed. Overexpression of UGT71A15 in transgenic apple trees also did not lead to morphological changes. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s00468-011-0669-0 Authors C. Gosch, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria H. Flachowsky, Federal Research Centre for Cultivated Plants, Institute for Fruit Breeding, Julius Kühn-Institut, Dresden, Germany H. Halbwirth, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria J. Thill, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria R. Mjka-Wittmann, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria D. Treutter, Unit Fruit Science, Technische Universität München, Freising, Germany K. Richter, Federal Research Centre for Cultivated Plants, Institute for Resistance Research and Stress Tolerance, Julius Kühn-Institut, Quedlinburg, Germany M.-V. Hanke, Federal Research Centre for Cultivated Plants, Institute for Fruit Breeding, Julius Kühn-Institut, Dresden, Germany K. Stich, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Little is known about the survival mechanisms of Erwinia amylovora outside its hosts. It has been demonstrated that it enters the viable but nonculturable state (VBNC) when exposed to different types of stress. In the VBNC state, bacterial cells remain viable but unable to grow on the solid general media where they usually do, and are thus undetectable by conventional culture-dependent methods. In this work, we have evaluated the recovery of E. amylovora VBNC cells by passage through pear plantlets, in comparison with other recovery methods commonly used for this pathogen: incubation in KB broth and inoculation of immature fruits. VBNC cells were obtained by exposure of bacterial cells to different types of stress (oligotrophy, nutrient deprivation and chlorine), and recovery assays were performed at 26°C. In all cases, the recovery of VBNC cells was more effective in plantlets than in liquid KB or immature fruits. In fact, when cells were exposed to chlorine for more than 30 min, only passage through host plant gave positive result, enabling recovery of E. amylovora cells few days after inoculation of plants. These results suggest a higher effectiveness of in planta recovery than those performed with liquid KB or detached fruits. Our results support the hypothesis of the VBNC state being part of the E. amylovora life cycle. The potential existence of this physiological state in nature should be taken in consideration in epidemiological studies of fire blight, with the aim to optimize the management and control of this disease. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s00468-011-0653-8 Authors R. D. Santander, Dpto. Microbiología y Ecología, Universidad de Valencia, Dr. Moliner 50, Burjassot, 46100 Valencia, Spain J. F. Català-Senent, Dpto. Microbiología y Ecología, Universidad de Valencia, Dr. Moliner 50, Burjassot, 46100 Valencia, Spain E. Marco-Noales, Instituto Valenciano de Investigaciones Agrarias (IVIA), Carretera Moncada-Náquera Km 4.5, Moncada, 46113 Valencia, Spain E. G. Biosca, Dpto. Microbiología y Ecología, Universidad de Valencia, Dr. Moliner 50, Burjassot, 46100 Valencia, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Fire blight ( Erwinia amylovora ) causes serious damage to pome fruit orchards, and identification of germplasm with heritable disease resistance is therefore crucial. Two dominant SCAR (sequence characterised amplified region) marker alleles (AE10-375 and GE-8019), flanking a previously identified QTL (quantitative trait locus) for resistance to fire blight on ‘Fiesta’ linkage group 7 in apple cultivars related to ‘Cox’s Orange Pippin’, were screened on 205 apple cultivars. Both marker alleles were present in 22% of the cultivars, indicating presence of the QTL allele for tolerance, and both were lacking in 25%, indicating homozygosity for absence of the QTL tolerance allele. However, 33% had only the marker allele AE10-375, while 20% had only GE-8019, suggesting that some cultivars with the dominant alleles for both of the flanking markers can carry these on separate chromosomes and may lack the QTL allele for tolerance. In 2009 and 2010, terminal shoots of greenhouse-grown grafted trees of 21 cultivars (only 20 in 2010) were inoculated with Erwinia amylovora . ‘Idared’ (susceptible) and ‘Enterprise’ (tolerant) were included as controls. Disease severity for each cultivar was expressed as percentage of necrosis in relation to entire length of shoot, and the ranking of cultivars in 2009 and 2010 was compared with a Spearman rank correlation test, P  〈 0.01. A relationship between presence of both flanking marker alleles for tolerance and level of fire blight tolerance was confirmed with a Mann–Whitney U-test, P  〈 0.01 in 2009, and P  〈 0.05 in 2010. A PCO (principal coordinate) analysis based on band profiles obtained with 12 SSR (simple sequence repeat) loci produced three loose clusters, two of which contained known offspring of ‘Cox’s Orange Pippin’, and one with cultivars that were either unrelated or had an unknown origin. Cases where DNA markers did not predict level of fire blight damage as expected, were, however, as common among descendants of ‘Cox’s Orange Pippin’ as among apparently unrelated cultivars. Obviously the ‘Fiesta’ LG 7 QTL has some predictive value, both for known ‘Cox’ relatives and others, but more efficient markers would be desirable for marker-assisted selection. Content Type Journal Article Category Original Paper Pages 1-15 DOI 10.1007/s00468-011-0649-4 Authors Hilde Nybom, Department of Plant Breeding and Biotechnology, SLU Balsgård, Fjälkestadsvägen 459, 291 94 Kristianstad, Sweden Artur Mikiciński, Pomology Division, Institute of Horticulture, Pomologiczna 18, 96-100 Skierniewice, Poland Larisa Garkava-Gustavsson, Department of Plant Breeding and Biotechnology, SLU Balsgård, Fjälkestadsvägen 459, 291 94 Kristianstad, Sweden Jasna Sehic, Department of Plant Breeding and Biotechnology, SLU Balsgård, Fjälkestadsvägen 459, 291 94 Kristianstad, Sweden Mariusz Lewandowski, Pomology Division, Institute of Horticulture, Pomologiczna 18, 96-100 Skierniewice, Poland Piotr Sobiczewski, Pomology Division, Institute of Horticulture, Pomologiczna 18, 96-100 Skierniewice, Poland Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Living tree branches are almost impossible to snap. Some show “greenstick fracture”, breaking halfway across before splitting along their length, while others simply buckle. In this study we investigated the bending failure of coppice branches of three temperate angiosperm trees: ash, Fraxinus excelsior ; hazel, Corylus avellana ; and white willow, Salix alba . We carried out bending tests, and made a series of observations on the structure, density and tensile and compressive strength of their wood to understand the pattern of failure. The three species showed contrasting behaviour; willow buckled whereas ash showed clean greenstick fracture and hazel a more diffuse greenstick fracture. These differences could be related to their wood properties. Willow buckled because its light wood had very low transverse compressive strength, particularly tangentially and was crushed by transverse stresses. Though the other species yielded in longitudinal compression on the concave side, they ultimately failed in tension on the convex side when bent because their higher density wood resisted transverse compression better. However, the crack was diverted down the midline because of the low tangential tensile strength of their wood. Differences in fracture between ash and hazel are related to fine-scale differences in their wood anatomy and mechanics. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-011-0650-y Authors A. van Casteren, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT UK W. I. Sellers, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT UK S. K. S. Thorpe, School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT UK S. Coward, School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT UK R. H. Crompton, Musculoskeletal Science Research Group, Institute of Aging and Chronic Disease, Sherrington Buildings, The University of Liverpool, Liverpool, L69 3GE UK A. R. Ennos, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT UK Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    In trees, reproduction constitutes an important resource investment which may compete with growth for resources. However, detailed analyses on how growth and fruit production interact at the shoot level are scarce. Primary canopy growth depends on the development of current-year shoots and their secondary growth might also influence the number and size of fruits supported by them. We hypothesise that an enhanced thickening of current-year shoots is linked positively to acorn production in oaks. We analysed the effect of acorn production on shoot growth of two co-occurring Mediterranean oak species with contrasting leaf habit ( Quercus ilex , Quercus faginea ). Length and cross-sectional area of current-year shoots, apical bud mass, number of leaves and acorns, xylem and conductive area, number of vessels of acorn-bearing and non-bearing shoots were measured in summer and autumn. Nitrogen and carbohydrates analyses were also performed in stems and leaves of both shoot types. Stem cross-sectional area increased in acorn-bearing shoots when compared with non-bearing shoots for both species and such surplus secondary growth was observed since summer. In bearing shoots, the total transversal area occupied by vessels decreased significantly from basal to apical positions along the stem as did the xylem area and the number of vessels. Leaves of bearing shoots showed lower nitrogen concentration than those of non-bearing shoots. Carbohydrate concentrations did not differ in stems and leaves as a function of the presence of acorns. Such results suggest that carbohydrates may preferentially be allocated towards reproductive shoots, possibly through enhanced secondary growth, satisfying all their carbon demands for growth and reproduction. Our findings indicate that acorn production in the two studied oaks depends on shoot secondary growth. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-011-0658-3 Authors Arben Q. Alla, Instituto Pirenaico de Ecología (CSIC), Avenida Montañana 1005, 50080 Zaragoza, Spain J. Julio Camarero, ARAID-Instituto Pirenaico de Ecología (CSIC), Avda. Montañana 1005, 50080 Zaragoza, Spain Melchor Maestro-Martínez, Instituto Pirenaico de Ecología (CSIC), Avenida Montañana 1005, 50080 Zaragoza, Spain Gabriel Montserrat-Martí, Instituto Pirenaico de Ecología (CSIC), Avenida Montañana 1005, 50080 Zaragoza, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The treatment of in vitro-grown shoots of the marubakaido apple rootstock with 0.5 μg stigmasterol, an end-pathway sterol of the bifurcated sterol biosynthetic pathway, in 5 μL acetone per shoot led to a significant ( p  ≤ 0.05) enhancement of the multiplication rate (MR) from 5.1 (shoots treated with 5 μL acetone only) to 10.3. This increase in the MR was due to a significant enhancement of the number of newly formed main shoots suitable for micropropagation purposes (measuring at least 15 mm in length) from 2.6 to 3.3 per explant, and of the number of newly formed primary lateral shoots from 2.2 to 5.0 per explant as well. Shoots treated with stigmasterol at 0.5 and 2.5 μg per shoot presented primary and secondary lateral shoots with significantly ( p  ≤ 0.05) longer length compared to shoots treated with acetone only. These results provide an insight into the morphological responses of the marubakaido rootstock shoots to the treatment with an end-pathway sterol. To the best of my knowledge, this is the first report on the successful use of stigmasterol for the improvement of a micropropagation system. These results also demonstrate that stigmasterol-induced shoot proliferation is a low-cost and effective way to enhance the in vitro MR for the apple rootstock. Content Type Journal Article Category Original Paper Pages 1-6 DOI 10.1007/s00468-011-0621-3 Authors A. B. Pereira-Netto, Department of Botany-SCB, Centro Politecnico, Parana Federal University, CP. 19031, Curitiba, PR 81531-970, Brazil Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    A full-length WRKY cDNA, designated as HbWRKY1 , was isolated from the latex in Hevea brasiliensis . The deduced HbWRKY1 contained 303 amino acid residues with one WRKY domain and one zinc-finger motif, and shared high identity to WRKYs from other plant species. The phylogenetic tree showed that HbWRKY1 was classified into group-II WRKYs. Many cis -acting elements related to hormone and stress responses were identified in the 1,377 bp-length 5′ regulatory sequence of HbWRKY1 , including three W-boxes, three ABREs, two MYBCOREs, one PRE, two OSE2ROOTNODULEs, one SEBFCONSSTPR10A and two HSEs. Semi-quantitative RT-PCR analysis revealed more significant accumulation of HbWRKY1 transcripts in latex and flowers than in bark, leaves and roots. The transcription of HbWRKY1 in latex was strongly induced by tapping and some wounding-signal molecules such as ethylene and jasmonic acid, and Oidium heveae attack, PEG and abscisic acid also strongly induced its expression in the leaves of H. brasiliensis . All these results suggest that HbWRKY1 mainly functions in responding to mechanical wounding, some wounding-related hormones, drought and O. heveae attack as an ethephon-induced WRKY transcriptional factor in H. brasiliensis. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-011-0623-1 Authors Quanqi Zhang, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101 China Jiahong Zhu, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101 China Yanmei Ni, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101 China Yuanbao Cai, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101 China Zhili Zhang, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101 China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    In the developing xylem bundles of young stems, the presence of immature living vessel elements can strongly restrict or even block axial hydraulic conductance, especially in newly matured vessels. Lateral connections between vessels may provide an alternative pathway for water movement to bypass these closed, living elements. Using the grapevine as a model system, the present study aimed to demonstrate the effects of living vessel elements on water movement patterns, and the importance of lateral flow for effective water conductivity in the developing bundles. Living vessel elements were detected using dye staining and the pattern of vessel development and maturation was then monitored. The importance of lateral flow was confirmed using several approaches: (1) capacity for lateral flow, (2) effect of increasing the distance of water transport, and (3) effect of ion concentrations. Living vessel elements were found along the developing bundles, they occupied a significant proportion of the distal and peripheral parts of the flow path, forming a substantial barrier to apoplastic water flow. Water in the developing xylem bundles could move easily from vessel to vessel and between secondary and primary xylem. Furthermore, data from increasing the transport length and altering the ion concentrations supported the critical contribution of the lateral flow to the total hydraulic conductance within the developing bundles. The hydraulic architecture of the developing xylem bundles is described. The results are discussed in terms of reliability and efficiency of water transport during shoot growth and development. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-011-0637-8 Authors Youcef Halis, Laboratory of Biomolecules and Plant Amelioration, Larbi Benmhidi University of Oum El Bouaghi, BP 358, Constantine Road, 04000 Oum El Bouaghi, Algeria Samah Djehichi, Laboratory of Biomolecules and Plant Amelioration, Larbi Benmhidi University of Oum El Bouaghi, BP 358, Constantine Road, 04000 Oum El Bouaghi, Algeria Mohamed Mourad Senoussi, Laboratory of Biomolecules and Plant Amelioration, Larbi Benmhidi University of Oum El Bouaghi, BP 358, Constantine Road, 04000 Oum El Bouaghi, Algeria Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The leaf vein traits of plants result partially from adaptations to environmental factors during the long-term evolution. However, no general conclusion on the variation trend of the vein density along a climate gradient or the response of such vein density–climate relationship pattern to climate changes has been made. We examined the variations in leaf vein density and other leaf traits of oriental oak ( Quercus variabilis ) in 10 in situ populations (in situ populations) across temperate-subtropical biomes and the response of the leaf vein density to environmental changes in 7 populations grown in a common garden (garden populations). The results show that the minor vein density of the in situ populations (≥3rd order) significantly decreased with increasing latitude ( r 2  = 0.44 and P  = 0.04). This pattern remained unchanged for the garden populations ( r 2  = 0.67 and P  = 0.02). The minor vein densities of both the garden and in situ populations were positively correlated to the mean annual temperature (MAT) of the origins ( r 2  = 0.66 and P  = 0.03 for the garden populations; r 2  = 0.37 and P  = 0.06 for the in situ populations), but their correlation to the mean annual precipitation (MAP) of the origins was not significant. Compared with the MAT and MAP, the vein density displayed a significantly lower correlation to climate variables in the current year or the current-year growing seasons. For the garden populations, the minor vein density significantly increased with leaf dry mass per area and decreased with petiole length and leaf length. These results imply that leaf vein density is genotypically fixed and is therefore not responsive to temporal changes in the growing conditions. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-011-0624-0 Authors Yanhua Zhu, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai, 200240 China Hongzhang Kang, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai, 200240 China Qiang Xie, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai, 200240 China Zhe Wang, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai, 200240 China Shan Yin, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai, 200240 China Chunjiang Liu, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai, 200240 China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Scots pine ( Pinus sylvestris ) grows some 400 km south of its current native limit at Wybunbury Moss, Cheshire, UK, on a peatland around a small floating bog ( Schwingmoor ). Cone and seed production of trees, which have been growing on the site for just over 100 years, were investigated over 3 years. Cones matured between September and March and seed shedding began in early April. The number of cones produced per reproductive tree ranged between 31 and 2,418, with a total average of 685 cones tree −1  y −1 . A strong relationship was found between tree diameter and seed production which allowed the prediction of annual seed production. Scots pine on this peatland produced between 766,874 and 950,000 seeds ha −1 annually with a germination percentage of 64%. The predicted number of seeds reaching the central bog (maximum of 120 m from the trees) every year was c. 16,000. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-012-0706-7 Authors Tarek A. Mukassabi, School of Life Sciences, Huxley Building, Keele University, Staffordshire, ST5 5BG UK Anthony Polwart, School of Life Sciences, Huxley Building, Keele University, Staffordshire, ST5 5BG UK Tim Coleshaw, Natural England, Attingham Park, Shrewsbury, UK Peter A. Thomas, School of Life Sciences, Huxley Building, Keele University, Staffordshire, ST5 5BG UK Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Ziziphus spina [christti] is a naturally distributed tree in subtropical, arid and semi-arid parts of Iran. It is ecologically and economically important due to its tolerance to drought and salinity. Most tree seeds are infected with parasitic and saprophytic microorganisms which decrease the seed germination and seedling establishment. The goal of this paper was to evaluate the ability of selected chemical solutions to inhibit the growth of variety of microbial contaminants in Z. spina [christti] seeds and to enhance the seed germination. Different chemical treatments were used in surface sterilization of seeds: (Treatment 1) sodium hypochlorite (NaOCl) in concentrations of 1, 2 and 4% for 20 min. (Treatment 2) hydrogen peroxide (H 2 O 2 ) in concentration of 4, 8, 12% treated for 10 min. (Treatment 3) 1% mercuric chloride (HgCl 2 ) at duration 10, 15, 20, 25 min. Seeds were scarified and aseptically, planted on agar Murashige and Skoog (MS) medium. Contaminants were identified according to their morphological and cultural characteristics. Bacterial contaminants included Xanthomonas sp. While Fungal isolates were Fusarium, Penicillium, Alternaria, Rhizopus, and Aspergillus . Our experiment reveals that 4% NaOCl followed by benomyl is the best sterilization treatment for Z. spina [christti] seeds, since the highest number of germination and highest number of sterilized seeds was observed after this treatment. Content Type Journal Article Category Original Paper Pages 1-6 DOI 10.1007/s00468-012-0705-8 Authors Elahe Ahmadi, Department of Forestry, Faculty of Natural Resources, Sari Agricultural Science and Natural Resources University, Sari, Iran Seyed Mohammad Hosseini Nasr, Department of Forestry, Faculty of Natural Resources, Sari Agricultural Science and Natural Resources University, Sari, Iran Hamid Jalilvand, Department of Forestry, Faculty of Natural Resources, Sari Agricultural Science and Natural Resources University, Sari, Iran Sekineh Kiani Savadkoohi, Faculty of Natural Resources, Mazandaran University, Sari, Iran Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    To survive new microclimatic conditions of a forest gap environment, plant species must physiologically and structurally adjust. A morpho-anatomical, ultrastructural and ecophysiological study was performed at three different times in a forest gap that was created by illegal selective logging. The study followed the early successional Actinostemon verticillatus and the late-successional Metrodorea brevifolia, to elucidate the adaptive strategies of acclimation to gaps. Additionally, Schinus terebinthifolius was included in the study in order to test the plasticity of a pioneer species that grows on forest edges, where this species had higher values of leaf thickness, leaf mass area and succulence. M. brevifolia had succulent leaves, high leaf area and a thin cuticle. A. verticillatus presented the densest leaves and was the only species to show leaf morpho-anatomical plasticity. Ultrastructural and physiological differences were observed only in A. verticillatus and M. brevifolia leaves from the gap: increase in the stroma volume, oil droplets, plastoglobuli, photochemical and non-photochemical quenching. Photosynthetic efficiency showed that the early stages of gap formation are the most critical. Acclimation strategies of A. verticillatus suggest this species invests in the efficiency of photosynthesis by increasing its leaf thickness, leaf mass area and in water content maintenance by increasing the density of its leaves, at the expense of gas exchange, was compensated by a high density of stomata. M. brevifolia compensates for the higher cost of leaves and lower leaf plasticity with ultrastructural changes that are used to adjust the photosynthetic process, which promotes a shorter leaf payback time. Content Type Journal Article Category Original Paper Pages 1-14 DOI 10.1007/s00468-012-0796-2 Authors Guilherme R. Rabelo, Setor de Biologia Vegetal, Laboratório de Biologia Celular e Tecidual/CBB/UENF, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Av. Alberto Lamego, 2000, Campos dos Goytacazes, RJ CEP: 28013-602, Brazil Ângela P. Vitória, Laboratório de Ciências Ambientais/CBB/UENF, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brazil Marcos V. A. da Silva, Setor de Biologia Vegetal, Laboratório de Biologia Celular e Tecidual/CBB/UENF, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Av. Alberto Lamego, 2000, Campos dos Goytacazes, RJ CEP: 28013-602, Brazil Ricardo A. Cruz, Setor de Biologia Vegetal, Laboratório de Biologia Celular e Tecidual/CBB/UENF, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Av. Alberto Lamego, 2000, Campos dos Goytacazes, RJ CEP: 28013-602, Brazil Elis I. B. Pinho, Laboratório de Ciências Ambientais/CBB/UENF, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brazil Douglas R. Ribeiro, Laboratório de Ciências Ambientais/CBB/UENF, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brazil Anita V. Freitas, Laboratório de Ciências Ambientais/CBB/UENF, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brazil Maura Da Cunha, Setor de Biologia Vegetal, Laboratório de Biologia Celular e Tecidual/CBB/UENF, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Av. Alberto Lamego, 2000, Campos dos Goytacazes, RJ CEP: 28013-602, Brazil Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Insect pest development is often linearly related to air temperature, without taking into account the multiple interactions between the particular host plant and pest, the microclimatic conditions actually experienced by the insect, and the non-linear response of insect development rate to temperature. In this study, using an integrative biophysical model, we have investigated effects of both climatic and tree structure changes on the development of a phytophagous leaf mining moth ( Phyllonorycter blancardella ), taking into account the heterogeneous microclimatic conditions provided by its host plant, the domestic apple ( Malus domestica ), the larval body temperature rather than the ambient air temperature, and a non-linear development rate model. Hourly body temperature dynamics of larvae homogeneously dispersed in tree canopies were simulated from hourly meteorological conditions (medium IPCC climate change scenario) within the canopy of apple trees. To analyse the effect of tree architecture on leaf miner development, both pruned and unpruned trees, and one, two and three scaffold branched trees were used. Body temperature dynamics was used to compute larval development time and mortality following the non-linear developmental model for this insect. The results showed that tree pruning influences significantly larval development time and mortality. Nevertheless, the effects of manipulating tree structure on larval development and survival were relatively weak compared with the impact of chosen climate variations. This survey also showed that the variability in insect development time within a year and insect mortality change markedly with climatic variations, and highlights the importance of using non-linear rate curves and insect body temperatures instead of air temperature in forecasting models of climate-related insect pest outbreaks. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-012-0791-7 Authors Marc Saudreau, INRA, UMR0547 PIAF, 63100 Clermont-Ferrand, France Sylvain Pincebourde, Institut de Recherche sur la Biologie de l’Insecte (IRBI, CNRS UMR 6035), Faculté des Sciences et Techniques, Université François Rabelais, 37200 Tours, France Mathieu Dassot, INRA, UMR0547 PIAF, 63100 Clermont-Ferrand, France Boris Adam, INRA, UMR0547 PIAF, 63100 Clermont-Ferrand, France Hugh D. Loxdale, Institute of Ecology, Friedrich-Schiller-University, Dornburger Strasse 159, 07743 Jena, Germany David G. Biron, INRA, UMR0547 PIAF, 63100 Clermont-Ferrand, France Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Genetic differences in individual-tree biomass partitioning, growth efficiency, and stem relative growth rate (RGR) could confer intraspecific productivity differences and might strongly influence forest ecosystem carbon storage. We examined the relationship between genotype productivity (stem volume), whole-tree biomass partitioning, growth efficiency (stem wood production per unit leaf area), and stem RGR among nine different loblolly pine ( Pinus taeda L.) genotypes from three different genetic groups of contrasting inherent genetic homogeneity: three open-pollinated (half-sib) families, three mass-control pollinated (full-sib) families, and three clonal varieties. We hypothesized that genotype productivity would be positively associated with increased partitioning to stem wood relative to other plant parts, higher stem RGR, and enhanced growth efficiency. After 3 years under plantation conditions, genotypes showed significant differences in stem volume, percent stem wood, percent branch wood, and partitioning to fine roots, yet no differences in stem RGR or growth efficiency. Furthermore, genotypic differences in stem volume were independent of genotypic differences in biomass partitioning, and overall, we found no evidence to support the hypothesized relationships. Even so, the observed variation in biomass partitioning has implications for forest C sequestration as genotypes which partition more biomass to long-lived biomass pools such as stems, may sequester more C. Moreover, the lack of a genetic relationship between stem volume and belowground partitioning suggests that highly productive genotypes may be planted without compromising belowground C storage. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s00468-012-0806-4 Authors Michael J. Aspinwall, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA John S. King, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA Steven E. McKeand, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Accurate measurements of whole tree water use are needed in many scientific disciplines such as hydrology, ecophysiology, ecology, forestry, agronomy and climatology. Several techniques based on heat dissipation have been developed for this purpose. One of the latest developed techniques is the heat field deformation (HFD) method, which relies on continuous heating and the combination of a symmetrical and an asymmetrical temperature measurement. However, thus far the development of this method has not been fully described in the scientific literature. An understanding of its underlying principles is nevertheless essential to fully exploit the potential of this method as well as to better understand the results. This paper therefore structures the existing, but dispersed, data on the HFD method and explains its evolution from an initial ratio of temperature differences proportional to vapor pressure deficit to a fully operational and practically applicable sap flux density measurement system. It stresses the importance of HFD as a method that is capable of measuring low, high and reverse flows without necessitating zero flow conditions and on several sapwood depths to establish a radial profile. The combination of these features has not been included yet in other heat-based sap flow measurement systems, making the HFD method unique of its kind. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-012-0718-3 Authors Nadezhda Nadezhdina, Institute of Forest Ecology, Mendel University of Agriculture and Forestry, Zemedelska 3, 61300 Brno, Czech Republic Maurits W. Vandegehuchte, Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium Kathy Steppe, Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Black cottonwood (BC, Populus trichocarpa ) and hybrid aspen (HA, P. tremula  ×  tremuloides ) differ in their ecology of being adapted to wet and drier conditions as riparian and early successional forest species, respectively. We tested the hypothesis that these ecological differences were reflected in higher nitrogen (N) use efficiency in HA than in BC and that HA would allocate more resources belowground than BC in the presence of high and low N availability. We expected that responses of wood properties to elevated N would be more pronounced in the species with higher wood formation in response to N supply. HA showed higher belowground biomass partitioning than BC in the presence of low (0.2 mM) and high (2 mM) N supply, but in contrast to our expectation whole-plant nitrogen use efficiency and the stem carbon-to-nitrogen balance were lower than in BC. In response to elevated N, HA exhibited stronger stimulation of biomass production than BC, especially of the stem, which showed significant increases in biomass and volume but decreases in density. Lignification, especially the production of guaiacyl (G)-compared to syringyl (S)-lignin, was delayed in HA compared with BC wood. Since G lignin leads to stronger crosslinking than S lignin, its delayed formation may have enabled stronger expansion and higher volume increment of HA than of BC stems. Our results suggest that BC, a poplar species adapted to fluctuating N supply, is less responsive to differences in N availability than aspen that occurs in low N environments. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-012-0761-0 Authors Dejuan Euring, Büsgen-Institut, Abteilung, Forstbotanik und Baumphysiologie, Georg-August Universität, Büsgenweg 2, 37077 Göttingen, Germany Christian Löfke, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Abteilung: Zellbiologie der Pflanze, Georg-August Universität, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany Thomas Teichmann, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Abteilung: Zellbiologie der Pflanze, Georg-August Universität, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany Andrea Polle, Büsgen-Institut, Abteilung, Forstbotanik und Baumphysiologie, Georg-August Universität, Büsgenweg 2, 37077 Göttingen, Germany Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Trees drought responses could be developed in the short- or in the long-term, aiming at sustaining carbon fixation and water use efficiency (WUE). The objective of this study was to examine short- and long-term adjustments occurring in different size Pinus ponderosa Dougl. ex P. & C. Laws trees in response to seasonal drought when they are growing under different competition level. The following variables were studied: branch and stem hydraulic conductivity, canopy and stomatal conductance ( gc , gs ), transpiration ( E ), photosynthesis ( A max ), wood δ 13 C (as a proxy of intrinsic WUE), leaf to sapwood area ratio ( A L : A s ) and growth in the biggest ( B ) and the smallest ( S ) trees of high ( H ) and low ( L ) density stands. A L : A s was positively correlated with tree size and negatively correlated with competition level, increasing leaf hydraulic conductance in H trees. Accordingly, higher gc and E per unit A L were found in H than in L trees when soil water availability was high, but decreased abruptly during dry periods. BL trees maintained stable gc and E values even during the summer drought. The functional adjustments observed in H trees allow them to maintain their hydraulic integrity (no apparent k s losses), but their stem and leaf growth were severely affected by drought events. i WUE was similar between all tree groups in a wet season, whereas it significantly decreased in SH trees in a dry season suggesting that when radiation and water are co-limiting gas exchange, functional adjustments not only affect absolute growth, but also WUE. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s00468-012-0759-7 Authors Javier Gyenge, Consejo Nacional de Investigaciones Científicas y Técnicas, Conicet, Buenos Aires, Argentina María Elena Fernández, Consejo Nacional de Investigaciones Científicas y Técnicas, Conicet, Buenos Aires, Argentina Santiago Varela, EEA Bariloche INTA, CC 277 (8400) San Carlos de Bariloche, Río Negro, Argentina Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    European larch trees grown outside their natural range were intensively studied in terms of their adaptability to increased late winter temperature. A total of 264 cores of larch were taken from 12 sites throughout northern Poland at sites outside of its natural range. Clustering of de-trended chronologies reveal that research sites are grouped geographically. The mean ring widths, however, are similar amongst the four regions. In total, 21 % of the single correlations for all months for tree-ring widths were significant at the 5 % error level. For earlywood and latewood, the figures are 18 and 19 %, respectively. A generally positive precipitation effect was found, however, no significant negative effect was observed. Temperature had mixed effects on ring width. Higher temperatures in late winter and early spring increased ring width in region 2. High summer temperatures in both the previous and the current year, on the other hand, generally had a negative impact on tree-ring width during the growing season. On most of the sites, the observed long-term trend for increasing temperatures in March had no significant negative influence on tree growth. The visual condition of European larch together with the lack of any negative response of tree rings to observed March temperature increase suggest that it may be beneficial to introduce this species into new areas. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0758-8 Authors Marcin Koprowski, Laboratory of Dendrochronology, Faculty of Biology and Environment Protection, Institute of Ecology and Environment Protection, Nicolaus Copernicus University, Gagarina 9, 87-100 Torun, Poland Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    In Venezuela 30,000 km 2 of land is covered by savannas, of which 410,000 ha have been planted with several species and hybrids of Eucalyptus for lumber and pulp production. Popular concern about possible diminutions in water availability of reservoirs near eucalypt plantations prompted our interest in measuring water use by these trees. Since these savannas are markedly seasonal, the response of species to seasonal drought is important. We aimed to compare the seasonal changes in single-leaf and whole-plant transpiration in a seasonally dry savanna with that of trees of E. urophylla in an experimental plantation. We also examined the seasonal changes in xylem water potential and stomatal response to air water-vapour saturation deficit ( D ) . Transpiration in eucalypts and the dominant savanna species Trachypogon vestitus and Curatella americana was evaluated using measurements of leaf gas exchange in all three species, sap flux in eucalypts , microclimatic variables and allometric and photometric determinations of green area. In E. urophylla and T. vestitus , but not in C. americana , stomatal conductance ( g s ) proved sensitive to D . Integrated values of daily courses of transpiration rate were scaled to one ha in a preliminary approach to estimating ecosystem transpiration ( E ha ). The E ha of the savanna (the sum of E ha of T. vestitus and C. americana ) was on average 2.4 times that of eucalypts during the daytime; when nocturnal eucalypt transpiration was included, the value was 1.9. The evapotranspiration calculated by the Penman–Montieth equation (ET c) of eucalypts was lower than the savanna all year round. The reference crop ET (ET o ) varied little throughout the seasons, the highest value occurring in March. The ratio E ha /ET o for the savanna was on average near one during the dry season and almost two during the rainy season; the corresponding value for E. urophylla was 0.6 for both seasons. The ratio E ha /ET c was on average 0.8 for the species and the savanna. The cumulative E ha for the days of measurements was higher in the savanna than in the eucalypts during the daytime (39.8 and 17.3 mm, respectively), as was the cumulative ET c (37.5 vs. 20.3 mm). Measured and calculated cumulative ET in eucalypts, including nocturnal values, were 22.0 and 28.4 mm, respectively. At the leaf level, both eucalypts and trees of C. americana apparently may have accessed water from deep horizons, since their values of Ψ changed less seasonally than in T. vestitus . At the ecosystem level, the species that presented the largest changes in transpiration was T. vestitus , which markedly increased savanna transpiration during the rainy season. Our results suggest that, for the days of this study, and considering the environmental conditions of the ecosystems studied, the type of measurements and the scaling procedures, stands of E. urophylla transpire less water than the savanna. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-012-0745-0 Authors Ana Herrera, Instituto de Biología Experimental, Universidad Central de Venezuela, Caracas, 1020 Venezuela Rosa Urich, Instituto de Biología Experimental, Universidad Central de Venezuela, Caracas, 1020 Venezuela Elizabeth Rengifo, Centro de Ecología, Instituto Venezolano de Investigaciones Científicas, Altos de Pipe, Caracas, Venezuela Caín Ballestrini, Instituto de Biología Experimental, Universidad Central de Venezuela, Caracas, 1020 Venezuela Armando González, Instituto de Biología Experimental, Universidad Central de Venezuela, Caracas, 1020 Venezuela Williams León, Facultad de Ciencias Forestales, Universidad de Los Andes, Mérida, Venezuela Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    In eucalypt plantations managed for solid-wood products, radial trends in wood density, microfibril angle (MFA) and stiffness (modulus of elasticity, MoE) are properties of potential commercial importance that can be affected by competition from neighbouring trees. In this study, wood properties at breast height (1.3 m) were studied on radial strips prepared from 12-mm pith-to-bark wood cores taken from 20 trees in a 22-year-old Eucalyptus nitens (Deane and Maiden) Maiden thinning trial in north-eastern Tasmania, Australia. Thinning treatments were applied at age 6 years. Trees were sampled from each of the 200, 400 stems ha −1 and unthinned control treatments. Intra-specific competition for each sampled tree was estimated using the basal area growth of surrounding trees. SilviScan™ technology was used to produce radial profiles of wood density, MFA and MoE. Results indicate a reduction in intra-specific competition through thinning of E. nitens plantations at an early age leads to a transient increase in MFA but has no significant effect on wood density or the intra-annual cycle of wood density. The correlation between the level of intra-specific competition and initial change in MFA following thinning, and a significant relationship between tree shape and mean MFA at breast height suggests the change in MFA is a post-thinning response to increased exposure and wind sway. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-012-0746-z Authors Jane Medhurst, CRC for Forestry, Private Bag 12, Hobart, TAS 7001, Australia Geoff Downes, CRC for Forestry, Private Bag 12, Hobart, TAS 7001, Australia Maria Ottenschlaeger, CRC for Forestry, Private Bag 12, Hobart, TAS 7001, Australia Chris Harwood, CRC for Forestry, Private Bag 12, Hobart, TAS 7001, Australia Rob Evans, CSIRO Materials Science and Engineering, Private Bag 33, Clayton South MDC, VIC 3169, Australia Chris Beadle, CRC for Forestry, Private Bag 12, Hobart, TAS 7001, Australia Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    A tree-ring width chronology was developed using the tree-ring cores of Huangshan pine ( Pinus taiwanensis Hayata) from the Dabie Mountains, central China. Descriptive statistics of the chronology indicated that Huangshan pine showed a common signal likely associated to climate. A correlation analysis was conducted between the chronology and climate variables, and the results demonstrated that the radial growth was positively correlated to the February–July mean temperature. The February–July mean temperature was reconstructed from AD 1869 to 2008 for the Dabie Mountains. The reconstruction can explain 49.8 % of the variance for the calibration period (1959–2008). On the decadal timescale, for the reconstructed temperature during the reliable period 1889–2008, above-mean temperature periods occurred in AD 1889–1898, 1903–1908, 1922–1933, 1945–1950, 1955–1958, and 1994–2008, whereas below-mean temperature periods occurred in AD 1899–1902, 1909–1921, 1934–1944, 1951–1954, and 1961–1993. The reconstruction indicates that the early years of the twenty-first century represent the warmest period and that the period of 1910–1919 is the coldest decade over the last 120 years. The reconstructed temperature corresponds well with the observed temperature in Wuhan, Hubei Province, suggesting that the reconstruction can represent the local climatic signals and may also reflect the regional climatic signals. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s00468-012-0757-9 Authors Yonghong Zheng, School of Resources and Environmental Science, Wuhan University, Wuhan, 430079 China Yong Zhang, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101 China Xuemei Shao, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101 China Zhi-Yong Yin, Department of Marine Science and Environmental Studies, University of San Diego, San Diego, CA 92110, USA Jin Zhang, School of Resources and Environmental Science, Wuhan University, Wuhan, 430079 China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Genetic variation within and among six populations of Juniperus excelsa M. Bieb., in a common garden in Lakes District of Turkey, was analyzed using four nuclear microsatellite primer pairs originally developed for J. communis . A total of five loci were observed as Jc037 amplified two distinct size ranges. The number of alleles observed for the species varied from 2 to 13, with an average of 4.5 alleles per locus. The mean expected heterozygosity ( H e ) of populations was 0.584, after correction for null alleles. The mean F IS value (−0.014) was close to zero showing no significant deviation from Hardy–Weinberg equilibrium. A low level of genetic differentiation was observed among populations ( F ST  = 0.028; p  〈 0.001) and Nei’s genetic distance ranged from 0.014 to 0.120 between population pairs. Furthermore, there was no significant correlation between genetic distances on the one hand and geographic distances and trait differentiation on the other hand. However, the eastern populations Beyşehir and Sorgun showed very similar genotypic structures and were differentiated from all other populations. A continuous monitoring of phenotypic traits and the association between nucleotide variation in functional genes and adaptive traits such as drought and frost tolerance of J. excelsa populations in common gardens will be useful to design effective conservation strategies in the future. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s00468-012-0807-3 Authors Cengiz Yücedağ, Department of Environmental Engineering, Faculty of Engineering, Bartın University, 74100 Bartın, Turkey Oliver Gailing, School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Microstructural properties of wood vary considerably within a tree. Knowledge of these properties and a better understanding of their relationship to the macroscopic mechanical performance of wood are crucial to optimize the yield and economic value of forest stocks. This holds particularly for the end-use requirements in engineering applications. In this study the microstructure–stiffness relationships of Scots pine are examined with a focus on the effects of the microstructural variability on the elastic properties of wood at different length scales. For this purpose, we have augmented microstructural data acquired using SilviScan-3™ (namely wood density, cell dimensions, earlywood and latewood proportion, microfibril angle) with local measurements of these quantities and of the chemical composition derived from wide-angle X-ray scattering, light microscopy, and thermogravimetric analysis, respectively. The stiffness properties were determined by means of ultrasonic tests at the clear wood scale and by means of nanoindentation at the cell wall scale. In addition, micro-mechanical modeling was applied to assess the causal relations between structural and mechanical properties and to complement the experimental investigations. Typical variability profiles of microstructural and mechanical properties are shown from pith to bark, across a single growth ring and from earlywood to latewood. The clear increase of the longitudinal stiffness as well as the rather constant transverse stiffness from pith to bark could be explained by the variation in microfibril angle and wood density over the entire radial distance. The dependence of local cell wall stiffness on the local microfibril angle was also demonstrated. However, the local properties did not necessarily follow the trends observed at the macroscopic scale and exhibited only a weak relationship with the macroscopic mechanical properties. While the relationship between silvicultural practice and wood microstructure remains to be modeled using statistical techniques, the influence of microstructural properties on the macroscopic mechanical behavior of wood can now be described by a physical model. The knowledge gained by these investigations and the availability of a new micromechanical model, which allows transferring these findings to non-tested material, will be valuable for wood quality assessment and optimization in timber engineering. Content Type Journal Article Category Original Paper Pages 1-16 DOI 10.1007/s00468-012-0801-9 Authors Leopold Wagner, Institute for Mechanics of Materials and Structures, Vienna University of Technology, Karlsplatz 13/202, 1040 Vienna, Austria Thomas K. Bader, Institute for Mechanics of Materials and Structures, Vienna University of Technology, Karlsplatz 13/202, 1040 Vienna, Austria David Auty, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU Scotland, UK Karin de Borst, School of Engineering, University of Glasgow, Rankine Building, Glasgow, G12 8LT Scotland, UK Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Thanks to acclimation, trees overcome environmental changes and endure for centuries. The anatomy of water conducting cells is an important factor determining plant success. Forming cells are coupled with the environment and their properties are naturally archived in the wood. Its variability across tree rings can thus provide a retrospective of plant’s hydraulic adjustments. In this work, we measured lumen and wall thickness of tracheids along tree-rings to explore how trees regulate their conducting system under variable plant-water conditions. Tracheids were measured along 51 dated rings of five mature Larix decidua and Picea abies trees from a low elevation site. Anatomical-based chronologies of annual growth performance, hydraulic conductance and safety, and construction costs were built. Similarities among chronologies and the relation to monthly climate data were analyzed. Most parameters displayed high annual plasticity which was partly coherent among trees and mostly associated with radial growth. In general, summer drought reduced growth and potential hydraulic conductivity of the forming ring, and increased hydraulic safety and construction costs. To evaluate the functional relevance of the annual acclimation, the conductivity of the forming ring relative to the entire sapwood needs to be assessed. Content Type Journal Article Category Original Paper Pages 1-12 DOI 10.1007/s00468-012-0802-8 Authors Marina Bryukhanova, V.N. Sukachev Institute of Forest SB RAS, Akademgorodok 50, bld. 28, Krasnoyarsk, 660036 Russia Patrick Fonti, Landscape Dynamics, WSL Swiss Federal Research Institute, Zürcherstr. 111, Birmensdorf, 8903 Zurich, Switzerland Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The process that transforms conductive sapwood to non-conductive heartwood in trees is poorly understood. Here, we use natural variation in climate to examine the environmental control of sapwood width in a widespread conifer species. We hypothesised that if sapwood width is linked to transpirational load, there would be a positive association between sapwood width, and continental gradients in mean annual rainfall, whereas age-related conversion to heartwood would be revealed from estimates of the age of the inner-most sapwood ring. Using the widespread Australian conifer Callitris columellaris we took cores from trees at 85 sites spanning a range of 168–2,117 mm in mean annual rainfall, and 14–28 °C in mean annual temperature. We found that sapwood width was remarkably similar throughout the species range, being only slightly lower in the tropics than the arid or temperate zone. There was a weak negative relationship between sapwood width and mean annual rainfall, which is in the opposite direction expected from transpirational control of sapwood width. Sapwood growth rings were wider, but there were fewer of them in the tropics than elsewhere, indicating conversion to heartwood occurred earlier here. Together with an earlier finding that tracheid diameter was largest in the tropics, our results show that differences amongst climate zones more strongly influence the hydraulic properties of sapwood than its amount. Content Type Journal Article Category Original Paper Pages 1-7 DOI 10.1007/s00468-012-0779-3 Authors Lynda D. Prior, School of Plant Science, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia Timothy J. Brodribb, School of Plant Science, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia David Y. P. Tng, School of Plant Science, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia David M. J. S. Bowman, School of Plant Science, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Mangrove forests are ecosystems made up of several woody plants living in saline coastal sedimentary habitats. In order to deal with the high salinity of the substrate, mangrove trees possess a number of different mechanisms to exclude, sequestrate or excrete the excess of salt. The black mangrove ( Avicennia germinans L.), one of the dominant species in Central America, is characterized by high levels of salt excretion through epidermal glands. In this study, our aim was to examine whether, apart from its obvious role in salt tolerance, the formation of salt crystals on the upper leaf surface of black mangrove might represent an unusual and dynamic photoprotection mechanism. For this purpose, the reflection of light and a number of physiological parameters were studied during the dry and rainy seasons in black mangroves growing in the Juan Venado Island Nature Reserve (Nicaragua). Excreted salt increased the reflectance of the leaf surface mainly in the blue and red regions of the spectrum. By removing salt crust from the leaf surface, we demonstrated that during the most stressful periods (dry season at noon), this feature allowed leaves to maintain a higher photochemical efficiency and a lower leaf temperature as compared to uncovered leaves. Furthermore, this mechanism is fully reversible when conditions become more favorable, as salt crystals dissolve, forming drops. Thus, while being a detoxification mechanism developed mainly to avoid osmotic imbalance in the tissues, the excretion of salt through the leaves in black mangroves is an example of “exaptation”, as it has positive collateral effects on the photosynthetic performance of the plant, protecting A. germinans from overheating and photodamage during the harsher periods. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0790-8 Authors R. Esteban, Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain B. Fernández-Marín, Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain A. Hernandez, Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain E. T. Jiménez, Department of Plant Biology and Ecology, Universidad de Sevilla, Sevilla, Spain A. León, Department of Plant Biology and Ecology, Universidad de Sevilla, Sevilla, Spain S. García-Mauriño, Department of Plant Biology and Ecology, Universidad de Sevilla, Sevilla, Spain C. D. Silva, Department of Plant Biology, UNAN-León, León, Nicaragua J. R. Dolmus, Department of Plant Biology, UNAN-León, León, Nicaragua C. M. Dolmus, Department of Plant Biology, UNAN-León, León, Nicaragua M. J. Molina, Department of Plant Biology, UNAN-León, León, Nicaragua N. N. Gutierrez, Department of Plant Biology, UNAN-León, León, Nicaragua M. I. Loaisiga, Department of Plant Biology, UNAN-León, León, Nicaragua P. Brito, Department Plant Biology, University of La Laguna, 38207 Tenerife, Spain J. I. García-Plazaola, Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Increasing areas of Amazonian forest are coming under flood stress due to dam construction and greater variability in river flood levels due to climate change. The physiological responses of Amazonian trees subjected to flooding are important to understand the consequences of these changes. Irradiance response curves for photosynthesis obtained from ten tropical tree species growing in flooded areas were used to fit three empirical models. The study was done in floodplains along the Uatumã River, both upstream and downstream of the Balbina Hydroelectric Dam in Brazil’s state of Amazonas (01°55′S; 59°28′W). Ten species were studied. Models compared were: non-rectangular hyperbola, rectangular hyperbola, and exponential. All models were quantitatively adequate for fitting the response of measured data on photosynthesis to irradiance for all ten species in the non-flooding and flooding periods. Considerable variation was found among the model estimates of maximum photosynthesis ( P nmax ), dark respiration ( R d ) and apparent quantum yield of photosynthesis (α). For photosynthesis, the two hyperbolas overestimated P nmax while EXP presented more realistic values. For estimating R d , RH presented the most realistic values. To avoid unrealistic value estimates of R d , we recommend adding measured R d values to the regressions. The results suggest that the EXP model presented the most realistic P nmax and α values, and, in spite of less accuracy in fitting photosynthetic irradiance curves than the RH model, it can be recommended for accessing the information used in photosynthetic irradiance curves for the leaves of tropical trees growing in Amazonian floodplains or in areas that are artificially flooded by dams. Content Type Journal Article Category Original Paper Pages 1-18 DOI 10.1007/s00468-012-0788-2 Authors U. M. dos Santos Junior, National Institute for Research in the Amazon (MCTI-INPA), Laboratory of Plant Physiology and Biochemistry, Manaus, Amazonas, Brazil J. F. de Carvalho Gonçalves, National Institute for Research in the Amazon (MCTI-INPA), Laboratory of Plant Physiology and Biochemistry, Manaus, Amazonas, Brazil Philip Martin Fearnside, National Institute for Research in the Amazon (MCTI-INPA), Department of Ecology, Manaus, Amazonas, Brazil Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    As a consequence of global change and human activities, processes of soil erosion are expected to increase in forested areas, resulting in exposed roots. Dendrogeomorphic research was conducted by analyzing exposed roots of Picea wilsonii subjected to continuous denudation along a main road in Tulugou National Forest Reserve, eastern Qilian Mountains, to reconstruct the local soil erosion dynamics. We determined the start of the exposure by examining the shifts in the ring-growth patterns from concentric to eccentric and by analyzing the detailed changes of wood anatomical features of exposed roots. We also find that the width of growth ring, the percentage of latewood and the average cell size of earlywood tracheids are all remarkable signs for soil lowering. According to the analysis of ANOVA (Fisher’s least significant difference method), the reduction of the cell size of earlywood tracheids is verified to be the key indicator for dating the first year of exposure and occurs prior to the other two indicators. Using 40 roots from 23 trees spread along the road, it has been found that erosion rates vary between 3.3 and 13.5 mm/year with an average value about 5.3 ± 2.1 mm/year. The intensity and occurrence of soil erosion may be influenced by the increase of human activities. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s00468-012-0773-9 Authors Feifei Zhou, Key Laboratory of Western China’s Environmental Systems (MOE), Lanzhou University, Lanzhou, 730000 China Xiaohua Gou, Key Laboratory of Western China’s Environmental Systems (MOE), Lanzhou University, Lanzhou, 730000 China Junzhou Zhang, Key Laboratory of Western China’s Environmental Systems (MOE), Lanzhou University, Lanzhou, 730000 China Zhiqian Zhao, Key Laboratory of Western China’s Environmental Systems (MOE), Lanzhou University, Lanzhou, 730000 China Qiuyan Chen, Key Laboratory of Western China’s Environmental Systems (MOE), Lanzhou University, Lanzhou, 730000 China Zongying Cao, Key Laboratory of Western China’s Environmental Systems (MOE), Lanzhou University, Lanzhou, 730000 China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Acetone-soluble compounds found in different root zones and stumps of Norway spruce ( Picea abies [L.] Karst), which were grown on either peatland or a mineral soil site, were studied. Samples from stumps and roots of different sizes and ages were collected a day after the trees were felled. The wood and bark of stumps and three zones of the roots were separated and extracted with acetone in an ultrasonic bath. Extracts were silylated and analysed by gas chromatography–mass spectrometry. The stilbene glucosides astringin and isorhapontin were major compounds in the spruce bark samples. The resveratrol glucoside piceid and the flavonoid catechin were also extracted from spruce bark. We also found the lignan hydroxymatairesinol in some wood extracts. Total concentrations of stilbene glucosides in bark of stumps and different root zones varied between 0.53 and 8.29 % (w/w, dry weight) with isorhapontin being the major compound. Isorhapontin concentrations were highest in the spruce samples grown on mineral soil. The bark of the roots close to the stem is a rich source of stilbenes for commercial utilisation. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0780-x Authors Harri Latva-Mäenpää, The Finnish Forest Research Institute (Metla), P.O. Box 18, 01370 Vantaa, Finland Tapio Laakso, The Finnish Forest Research Institute (Metla), P.O. Box 18, 01370 Vantaa, Finland Tytti Sarjala, The Finnish Forest Research Institute (Metla), Kaironiementie 15, 39700 Parkano, Finland Kristiina Wähälä, Laboratory of Organic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, 00014 Helsinki, Finland Pekka Saranpää, The Finnish Forest Research Institute (Metla), P.O. Box 18, 01370 Vantaa, Finland Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The role of hydrogen cyanamide (Dormex™) or thiourea in the acceleration of dormancy breaking in buds of “Ain Shemer” apple ( Malus sylvestris , Mill.) trees, and their effects on metabolic changes in the contents of proline and biogenic amines (BAs; tyramine, tryptamine, histamine, methylbutylamine and serotonin) in buds during bud break were assessed. The efficiency of bud break by these compounds was noticed to varying degrees. Breaking bud dormancy was correlated with the early date of bud break, the short duration of flowering, the high percentages of bud break and fruit set, and the high contents of proline and BAs. This finding was positively reflected in the tree’s yield. Dormex™ was found to be more effective than thiourea; therefore, we recommend using Dormex™ for early bud break, short period of flowering and high percentages of bud break and fruit set by regulating the contents of proline and BAs in buds. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0785-5 Authors Mohamed A. Seif El-Yazal, Botany Department, Faculty of Agriculture, Fayoum University, Fayoum, 63514 Egypt Mostafa M. Rady, Botany Department, Faculty of Agriculture, Fayoum University, Fayoum, 63514 Egypt Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The submerged tree volume and the projection area of mangroves play a significant role in damping tsunami inundation flow with a distinct root formation above ground. We modeled the stilt root morphology of the Rhizophora sp., especially to incorporate into a hydraulic drag of tsunami inundation simulation. The equivalent Manning’s roughness coefficient has been used as the hydraulic drag of mangroves for the computation of inundation flow [Yanagisawa et al. (Coast Shelf Sci 81: 27–37, 2009 )], but it could not elucidate the effectiveness under different tree conditions. The field data from 18 sample trees in Ranong Province, Thailand, were measured. The total number of primary roots, the root height at trunk, and the root-spread distance, the root diameter, and the vertical root angle from trunk could be estimated with the diameter of the breast height. The quadratic equation expressed the root curve of the primary stilt root, and functions to estimate root volume and projected area were derived by the integration of the equation that will be used to calculate drag force in tsunami simulation. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s00468-012-0782-8 Authors Wataru Ohira, Remote Sensing and GIS, School of Engineering and Technology, Asian Institute of Technology, Klong Luang, P.O. Box 4, Pathumthani, 12120 Thailand Kiyoshi Honda, International Digital Earth Applied Science Research Center, Chubu University, 1200, Matsumoto-cho, Aichi, Kasugai 487-8501, Japan Masahiko Nagai, Geoinformatics Center, Asian Institute of Technology, Klong Luang, P.O. Box 4, Pathumthani, 12120 Thailand Anuchit Ratanasuwan, Geo-Infomatics Division, Department of National Park, Wildlife and Plant Conservation, 61 Paholyothin Road, Ladyao, Chatuchak, Bangkok, 10900 Thailand Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    High-throughput experimental technology has provided insight into the inner functioning of plants. The current experimental technology facilitates the study of plant systems in a holistic manner, measuring observables from the genome, proteome, and metabolome up to the level of the ecosystem. The call for a systemic view in plant research is being made from multiple research fields. Although not yet fully developed for tree research, data sources are also rapidly growing in this area. Nevertheless, there are challenges and pitfalls in dealing with such increases in data. Some of these difficulties are deeply rooted in the complexity of the evolutionary systems. The lessons from complexity theory are rooted in studies performed several decades ago. Honouring principles that were formulated before bioinformatics and systems biology had been introduced facilitates the derivation of analytical methods with the potential to overcome these challenges in several ways. Content Type Journal Article Category Review Pages 1-13 DOI 10.1007/s00468-012-0777-5 Authors Wolfgang zu Castell, Scientific Computing Research Unit, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany Dieter Ernst, Institute of Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Tree-ring studies may help better understand climate variability and extreme climate event frequency and are especially useful in regions where detailed meteorological records lack. We studied the effect of droughts and unusually cold periods on Pinus sylvestris tree-ring width and wood anatomy. Study sites were selected along an altitudinal gradient on Vitosha Mountain, Bulgaria. Drought conditions caused the formation of narrow tree rings or light rings if the drought occurred in July–August at the lower altitude sites. In years with droughts in June and the first half of July, followed by precipitation in the middle of July, intra-annual density fluctuations (IADFs) were formed. Trees in the zone with optimal growth conditions produced fewer light rings and narrow rings in years with either strongest droughts or unusually cold summers. At the timberline zone, low summer temperature triggered narrow tree rings and light rings. Frost rings were formed when there was a drop in temperatures below the freezing point in the second half of May or at the beginning of June. Our findings show that studies of tree-ring anatomy may contribute to obtain further knowledge about extreme climatic events in the Balkan Peninsula and in other regions where meteorological data lack. Content Type Journal Article Category Original Paper Pages 1-17 DOI 10.1007/s00468-012-0789-1 Authors Momchil Panayotov Panayotov, Dendrology Department, University of Forestry, Kliment Ohridski 10 Blvd, 1756 Sofia, Bulgaria Nikolay Zafirov, Department of Plant Pathology and Chemistry, University of Forestry, Kliment Ohridski 10 Blvd, 1756 Sofia, Bulgaria Paolo Cherubini, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    The genus Eucalyptus includes over 700 species, some of which are the most widely planted hardwoods worldwide. Each species and subspecies of Eucalyptus present different characteristics regarding its wood quality and yield. This fact makes it very important to work with known species/subspecies so as to optimize handling and conservation of forest resources. Some of them are morphologically very similar, making it difficult to differentiate by simple observation. This is the case with Euclyptus globulus ssp globulus and E. globulus ssp maidenii , which can only be distinguished in the adult tree. These issues can be avoided using well-characterized seeds. This can be quite expensive, especially for the small growers. An alternative approach is to develop simple methods for the differentiation of the two subspecies. In this work, we develop a quick method, based on SCAR molecular markers derived from RAPD molecular markers, for the differentiation of the subspecies of E. globulus , in particular E. globulus ssp globulus and E. globulus ssp maidenii. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0792-6 Authors Mariana Richero, Microbiología, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Casilla de Correo 1157, Montevideo, Uruguay Mariana Barraco Vega, Microbiología, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Casilla de Correo 1157, Montevideo, Uruguay Maria Pía Cerdeiras, Microbiología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Casilla de Correo 1157, Montevideo, Uruguay Gianna Cecchetto, Microbiología, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Casilla de Correo 1157, Montevideo, Uruguay Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Little is known about variations in tree phenology and their driving forces on the Tibetan Plateau. Herein, we monitored shoot growth and needle unfolding of Smith fir ( Abies georgei var. smithii ) between 3,800 and 4,360 m a.s.l. in the Sygera Mountains, southeastern Tibetan Plateau. The trees were 0.45–1.48 m high and 12–39 years old. Their phenology was observed every week between May 5 and August 26, 2011. With increasing elevation, shoot growth and needle unfolding started increasingly later, thus indicating a thermal driving force. Although the weekly shoot increment was decreasing with increasing elevation, height growth at various elevations ended in the same week, implying other factors than temperature being responsible for the end of height growth. The accumulated heat sum for the onset of shoot growth appeared to be lower between 4,200 and 4,360 m than between 3,800 and 4,000 m. The anticipated spring warming will likely induce an earlier onset of shoot growth, whereas shoot growth will apparently not benefit from autumn warming. However, the lack of long-term data records precluded a robust statistical test of the underlying cause-and-effect relationships involved in the phenological variations of height growth and needle unfolding. Content Type Journal Article Category Original Paper Pages 1-7 DOI 10.1007/s00468-012-0793-5 Authors Yafeng Wang, Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese, Academy of Sciences, PO Box 2871, Beijing, 100101 China Xiaoxia Li, Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese, Academy of Sciences, PO Box 2871, Beijing, 100101 China Binod Dawadi, Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese, Academy of Sciences, PO Box 2871, Beijing, 100101 China Dieter Eckstein, Department of Wood Science, University of Hamburg, Leuschnerstrasse 91, 21031 Hamburg, Germany Eryuan Liang, Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese, Academy of Sciences, PO Box 2871, Beijing, 100101 China Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    Butia capitata , an endemic palm of the Brazilian savanna threatened by deforestation, demonstrates low germinability due to seed dormancy. The present study characterizes the structure of the zygotic embryo and describes germination and seedling development. Pyrenes were sown into sandy soil substrates to germinate, and their embryos were also cultivated in vitro in MS medium; structural evaluations were made during their development. Seedling growth through the endocarp germ pore culminates in the protrusion of the cotyledonary petiole, with the root and leaf sheaths subsequently being emitted laterally from its extremity. The embryos are composed of the cotyledon (whose proximal third has a haustorial function) and a diminutive embryo axis that is contained within the cotyledonary petiole. The protoderm, ground meristem, and procambium can be observed in their typical positions in the embryo axis and cotyledon. The development of the vegetative axis could be observed on the second day of in vitro cultivation, with elongation of the embryo axis and the beginning of the differentiation of the first eophyll. Elongation of the cotyledonary petiole and the differentiation of the parenchyma and tracheary elements were observed during the second to fifth day. Although the hypocotyl–radicle axis is less differentiated than the plumule, root protrusion occurs on the eighth day, and the leaf sheaths are only emitted between the twelfth and the sixteenth days; the haustorium atrophied during this stage. The embryonic structure of B. capitata does not impose limitations on seed germination as dormancy is of the non-profound physiological type, and the 50 % elongation of the cotyledonary petiole serves as a morphological indicator of germination. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00468-012-0797-1 Authors H. M. Magalhães, Pós-Graduação em Ciências Agrárias, Instituto de Ciências Agrárias, Universidade Federal de Minas Gerais, Avenida Universitária, 1000, Bairro Universitário, Montes Claros, MG 39404-006, Brazil P. S. N. Lopes, Pós-Graduação em Ciências Agrárias, Instituto de Ciências Agrárias, Universidade Federal de Minas Gerais, Avenida Universitária, 1000, Bairro Universitário, Montes Claros, MG 39404-006, Brazil L. M. Ribeiro, Departamento de Biologia Geral, Unimontes, Campus Prof. Darcy Ribeiro, Montes Claros, MG 39401-089, Brazil B. F. Sant’Anna-Santos, Pós-Graduação em Ciências Agrárias, Instituto de Ciências Agrárias, Universidade Federal de Minas Gerais, Avenida Universitária, 1000, Bairro Universitário, Montes Claros, MG 39404-006, Brazil D. M. T. Oliveira, Departamento de Botânica, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    A field study and an experiment under controlled conditions using pressure-flux relationships were conducted to compare the stem and whole-plant conductance in olive ( Olea europaea ) and kiwifruit ( Actinidia deliciosa ) species. Anatomical observations were also made on one-year-old stem to determine the conductive area of vessels ( A ves ) and the total xylem area ( A xyl ). Results show that A ves of kiwifruit twigs was ~2.5-fold of that in olive twigs, and the hydraulically weighted mean diameter was up to threefold that of the olive ones. One-year-old olive twigs had lower hydraulic conductivity ( k ) than the kiwifruit, while values of leaf-specific conductivity (i.e. k normalised per unit leaf area) were higher than the kiwifruit (i.e. ~49 and 29 × 10 −6  kg m −1  s −1  MPa −1 , respectively). In the field experiment, the flux of sap (heat balance method) and differences in water potential through the soil–plant system (Δ P ) were used for both species to calculate the whole-plant conductance that was normalised per unit leaf area (leaf-specific whole-plant conductance, K plant,LA ). Values of K plant,LA are attributable to the combined effect of the Δ P and anatomical features of conduits. Olive species showed a larger Δ P (2.4 MPa at midday) than the kiwifruit (0.5 MPa) which contributed to lower K plant,LA in Olea than the Actinidia plants. This information, combined with vessel density data, contributes to explain differences amidst olive and kiwifruit species, in terms of susceptibility to some drought-related hydraulic impairments induced by the Mediterranean environment. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0787-3 Authors Bartolomeo Dichio, Dipartimento delle Culture Europee e del Mediterraneo: Architettura, Ambiente, Patrimoni Culturali (DiCEM), Università degli Studi della Basilicata, Potenza, Italy Giuseppe Montanaro, Dipartimento delle Culture Europee e del Mediterraneo: Architettura, Ambiente, Patrimoni Culturali (DiCEM), Università degli Studi della Basilicata, Potenza, Italy Adriano Sofo, Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, Università degli Studi della Basilicata, Potenza, Italy Cristos Xiloyannis, Dipartimento delle Culture Europee e del Mediterraneo: Architettura, Ambiente, Patrimoni Culturali (DiCEM), Università degli Studi della Basilicata, Potenza, Italy Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    In this study the identification of epigenetic marks of closed and open chromatin states has been performed by immunofluorescence in vibratome-thick sections from poplar stems, followed by quantification of the signal in a representative population of individual nuclei on a confocal microscope. Unlike other methods often used for detection of global DNA methylation levels, the procedure hereby proposed can be applied to a wide range of specimens regardless of the purity and yield of genomic DNA extraction and in a tissue-dependent manner. Using antibodies to 5-methylcytidine and acetylated lysine 8 of histone H4, as reliable indicators of transcription incompatible and compatible chromatin states, respectively, the influence of epigenetic regulation on differential gene expression during the growth and arrest periods in xylem and phloem tissues was assessed. The fluorescence signal of 5-methylcytosine was significantly higher in winter as compared with summer. Conversely, the fluorescence signal for acetylated Lys 8 of histone H4 was significantly higher in summer than in winter in both tissues examined. Collectively, these results put forward an epigenetic control of winter dormancy in poplar stems. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00468-012-0800-x Authors Daniel Conde, Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Departamento de Biotecnología, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain Pablo González-Melendi, Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Departamento de Biotecnología, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain Isabel Allona, Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Departamento de Biotecnología, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890

Description:    There are numerous studies on water transport characteristics of trees from the base to tops, but only few deal with the variation in xylem conduit diameters from shallow to deep roots. This study compares variation in root conduit properties as a function of increasing soil depths for two oak species ( Quercus pubescens Willd and Quercus robur L.) growing on two different plots. We measured root vessel characteristics at three soil depths including 0, 50 and 100 cm, and calculated the associated root-specific hydraulic conductivities. Vessel diameter and specific hydraulic conductivity increased with increasing soil depth from 0 to 50 cm, but did not change in the deeper soil layer in both species. We conclude that freeze–thaw events in upper soil layer limit vessel diameters and thus hydraulic conductivity of roots. Content Type Journal Article Category Original Paper Pages 1-9 DOI 10.1007/s00468-012-0805-5 Authors Roman Gebauer, Institute of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic Daniel Volařík, Institute of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890