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  • Articles  (953,182)
  • Springer  (953,182)
  • Biology  (871,110)
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  • 1
    Electronic Resource
    Electronic Resource
    Mycorrhiza of forest trees — structure and function (1986)
    Springer
    Trees 1 (1986), S. 1-24 
    Details
    ISSN: 1432-2285
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197021
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  • 2
    Electronic Resource
    Electronic Resource
    Changes of adenine nucleotide and orthophosphate concentrations in buds of deciduous trees during spring reactivation (1986)
    Springer
    Trees 1 (1986), S. 42-46 
    Details
    ISSN: 1432-2285
    Keywords: Acer ; Adenine nucleotides ; Alnus ; Buds ; Deciduous trees ; Fagus ; Fraxinus ; Orthophosphate ; Quercus ; Reactivation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Concentrations of AMP, ADP, ATP, and inorganic phosphate (Pi) were determined in buds of five deciduous tree species (Acer pseudoplatanus, Alnus glutinosa, Fagus sylvatica, Fraxinus excelsior, Quercus robur) during spring reactivation from February to the middle of May. In closed buds of diffuse-porous wood trees (Acer, Alnus, Fagus), the content of adenine nucleotides (AdN) increased temporarily between the middle of February and the middle of March. The main increase of AdN concentration appeared either when buds became swollen (Fraxinus, Fagus, Quercus), or at the time of bud-break (Acer, Alnus). Pi content in general decreased during the course of reactivation. It was almost zero in buds of Quercus at bud-break and afterwards, but in Fraxinus Pi concentration rose when bud-break took place. The extremely low AdN content in Quercus buds is contrasted by a steep increase in AdN content in Fraxinus following bud-break. The decrease of AdN content in emerging leaves of Quercus and Fagus could be related to the high age of these trees.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197023
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  • 3
    Electronic Resource
    Electronic Resource
    Isolation of cuticular membranes from various conifer needles (1986)
    Springer
    Trees 1 (1986), S. 47-53 
    Details
    ISSN: 1432-2285
    Keywords: Abies ; Cuticle ; Enzymatic isolation ; Permeance ; Picea ; Pinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A method of isolating intact needle cuticles is presented. Cuticles were separated enzymatically from needles of Abies alba Mill., Picea abies (L.) Karst., Picea pungens Engelm., Pinus mugo Turra, and Taxus baccata L. Cuticle separation depended on the enzyme concentration, the developmental stage of the needles and the duration of incubation in the hydrolytic pectinase/cellulase solution. Cuticles could not be removed from needles older than 2 years. Scanning electron micrographs of enzymatically isolated cuticles are presented. The permeance coefficients for water and oxygen transport across the isolated cuticular membranes indicate their functional intactness. But permeance coefficients also show that isolation of cuticular membranes with chromic acid is an unacceptable method, since they are lo longer structurally or functionally intact following isolation by this method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197024
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  • 4
    Electronic Resource
    Electronic Resource
    Canopy structure, light microclimate and leaf gas exchange of Quercus coccifera L. in a Portuguese macchia: measurements in different canopy layers and simulations with a canopy model (1986)
    Springer
    Trees 1 (1986), S. 25-41 
    Details
    ISSN: 1432-2285
    Keywords: Canopy structure ; Quercus coccifera ; Photosynthesis ; Transpiration ; Simulation model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The structural characteristics of a diverse array of Quercus coccifera canopies were assessed and related to measured and computed light attenuation, proportion of sunlit foliage, foliage temperatures, and photosynthesis and diffusive conductance behavior in different canopy layers. A canopy model incorporating all components of shortwave and longwave radiation, and the energy balance, conductance, and CO2 and H2O exchanges of all leaf layers was developed and compared with measurements of microclimate and gas exchange in canopies in four seasons of the year. In the denser canopies with a leaf area index (LAI) greater than 5, there is little sunlit foliage and the diffuse radiation (400–700 nm) is attenuated to 5% or less of the global radiation (400–700 nm) incident on the top of the canopy. Foliage of this species is nonrandomly distributed with respect to azimuth angle, and within each canopy layer, foliage azimuth and inclination angles are correlated. A detailed version of the model which computed radiation interception and photosynthetic light harvesting according to these nonrandom distributions indicated little difference in whole-canopy gas exchange from calculations of the normal model, which assumes random azimuth orientation. The contributions of different leaf layers to canopy gas exchange are not only a function of the canopy microclimate, but also the degree to which leaves in the lower layers of the canopy exhibit more shade-leaf characteristics, such as low photosynthetic and respiratory capacity and maximal conductance. On cloudless days, the majority of the foliage in a canopy of 5.4 LAI is shaded —70%–90% depending on the time of year. Yet, the shaded foliage under these conditions is calculated to contribute only about one-third of the canopy carbon gain. This contribution is about the same as that of the upper 13% of the canopy foliage. Computed annual whole-canopy carbon gain and water use are, respectively, 60% and 100% greater for a canopy of 5 LAI than for one of 2 LAI. Canopy water-use efficiency is correspondingly less for the canopy of 5 LAI than for that of 2 LAI, but most of this difference is apparent during the cool months of the year, when moisture is more abundant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197022
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  • 5
    Electronic Resource
    Electronic Resource
    Water permeability of plant cuticles: permeance, diffusion and partition coefficients (1986)
    Springer
    Trees 1 (1986), S. 54-60 
    Details
    ISSN: 1432-2285
    Keywords: Cuticular transpiration ; Diffusion coefficients ; Plant cuticle ; Water content ; Water permeability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Using isolated cuticular membranes from ten woody and herbaceous plant species, permeance and diffusion coefficients for water were measured, and partition coefficients were calculated. The cuticular membranes of fruit had much higher permeance and diffusion coefficients than leaf cuticular membranes from either trees or herbs. Both diffusion and partition coefficients increased with increasing membrane thickness. Thin cuticles, therefore, tend to be better and more efficient water barriers than thick cuticles. We compared the diffusion coefficients and the water content of cuticles as calculated from transport measurements with those obtained from water vapor sorption. There is good to fair agreement for cuticular membranes with a low water content, but large discrepancies appear for polymer matrix membranes with high permeance. This is probably due to the fact that diffusion coefficients obtained from transport measurements on membranes with high permeance and water content are underestimated. Water permeabilities of polyethylene and polypropylene membranes are similar to those of leaf cuticular membranes. However, leaf cuticles have much lower diffusion coefficients and a much greater water content than these synthetic polymers. This suggests that cuticles are primarily mobility barriers as far as water transport is concerned.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197025
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  • 6
    Electronic Resource
    Electronic Resource
    Relationships between foliage and conducting xylem in Picea abies (L.) Karst. (1986)
    Springer
    Trees 1 (1986), S. 61-69 
    Details
    ISSN: 1432-2285
    Keywords: Branch cross-sectional area ; Leaf area ; Leaf biomass ; Picea abies ; Sapwood area
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The relationship of leaf biomass and leaf area to the conductive area of stems and branches was investigated in Picea abies. A total of 30 trees were harvested to determine if these relationships were different in different crown zones and in trees growing with and without competition for light. Two methods were compared. In the first, data were accumulated from crown zones situated at the top of trees to the bottom; in the second, data were used from individual crown zones. The results indicated that the latter method is much more sensitive in detecting differences in the relationship of leaf biomass or leaf area to conductive area. The analysis also indicated that ratios such as leaf area/sapwood area are frequently size-dependent. This size-dependency can in some cases result in the differences being abscured, but more often leads to the false impression that the relationship between the variables changes. The relationship between leaf biomass and leaf area and conductive area of stems or branches was different in different crown zones and under different growth conditions. The slopes of these regressions appear to increase with decreasing transpirational demand and decrease with increasing hydraulic conductivity. The intercepts are probably related to the amount of identified sapwood actually involved in water conductance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197026
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  • 7
    Electronic Resource
    Electronic Resource
    Rapid field determination of photosynthetic capacity of cut spruce twigs (Picea abies) at saturating ambient CO2 (1986)
    Springer
    Trees 1 (1986), S. 70-77 
    Details
    ISSN: 1432-2285
    Keywords: Forest decline ; Photosynthetic capacity ; Picea abies ; Stomatal conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Routine field determination of the parameters characterizing the activity of the photosynthetic apparatus is often difficult when attached branches of tall trees have to be used for gas exchange measurement. If severed twigs could be used, determining these parameters would be greatly facilitated. Because stomatal conductance changes when twigs or leaves are detached, CO2 assimilation is usually altered. Thus, measurements made at ambient CO2 concentration fail to accurately assess the activity of the photosynthetic apparatus because photosynthetic rates greatly depend on the supply of carbon dioxide. However, when photosynthetic carboxylation reactions are saturated by increased CO2 partial pressure in the mesophyll, CO2 assimilation rates no longer depend on instantaneous stomatal conductance, as shown by gas exchange measurements of spruce (Picea abies) twigs prior to and following detachment. Because net photosynthesis following detachment at saturating CO2 remains constant for a minimum of 15 min, photosynthetic measurements of severed twigs may be reliable. This length of time is sufficient for detaching and recutting the twig, assembling a portable minicuvette system, re-establishing steady-state conditions with the gas analyser system, and reading the data over a reasonable period of time. The method described measures the maximal photosynthetic CO2 assimilation of spruce needles of a single age-class from detached spruce twigs under the following conditions: saturating light, saturating external CO2-partial pressure, standardized temperature and air humidity in the field. The method is applicable as a routine procedure to characterize the status of the photosynthetic apparatus of spruce trees that may be damaged in the process of forest decline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197027
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  • 8
    Electronic Resource
    Electronic Resource
    Concentration gradients of free sterols, steryl esters and lipid phosphorus in the trunkwood of Scot's pine (Pinus sylvestris L.) (1987)
    Springer
    Trees 1 (1987), S. 79-81 
    Details
    ISSN: 1432-2285
    Keywords: Free sterols ; Heartwood ; Pinus sylvestris L ; Sapwood ; Steryl esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The amounts of free sterols, steryl esters and lipid phosphorus were determined in the sapwood and heartwood of mature, and in the outer and inner sapwood of young Pinus sylvestris trees. In the mature trees (up to 70 years old) the heartwood contains significantly higher amounts of free sterols than the sapwood. No radial gradient can be demonstrated in the amounts of steryl esters. Lipids extracted from the sapwood contain higher amounts of phosphorus than those from the heartwood. Stems of young Pinus sylvestris trees (up to 13 years old) show in the inner sapwood higher amounts of both free sterols and steryl esters than the peripheral younger wood zone. The inner sapwood of the young stems shows slightly higher amounts of lipid phosphorus than the outer sapwood. The results indicate that Pinus sylvestris accumulates both free sterols and steryl esters in the stems at a very early stage of the life cycle. Sterol accumulation in the innermost parts of the stems seems not to depend on heartwood formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203574
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  • 9
    Electronic Resource
    Electronic Resource
    Lipids and sterols of Pinus sylvestris L. sapwood and heartwood (1987)
    Springer
    Trees 1 (1987), S. 82-87 
    Details
    ISSN: 1432-2285
    Keywords: Pinus sylvestris ; Fatty acids ; Triacylglycerols ; Sterols ; Wood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The lipid and sterol content and composition of three lipid fractions (free fatty acids/ sterols, triacylglycerols and sterol/triterpenoid esters) extracted from three stem discs of Pinus sylvestris were assessed to investigate metabolic changes related to heartwood formation. The wood was separated into (1) cambial zone, (2) outer sapwood, (3) inner sapwood, (4) transition zone, (5) outer heartwood and 6) inner heart-wood. The fractions were separated by thin-layer chromatography (TLC) and analysed by gas-liquid chromatography (GLC). The amount of fatty acids of sapwood triacylglycerols was about 1.5% (dry wt.) but a large reduction occurred in the transition zone. In contrast, noticeable amounts of free fatty acids were present only in the heart-wood. The most important fatty acids in the sapwood fractions were 16:0, 18:0, 18:1, 18:2 (the dominant fatty acid in all fractions), 18:3 and 20:3. Together 18:1 and 18:2 formed about 70% of the total triacylglycerol fatty acids. Of the sterol/ triterpenoid esters, 18:2 and 18:3 were predominant. The fatty acid composition of all fractions changed in the transition zone. The sterols found were sitosterol, stigmastanol, campesterol and campestanol. The amount of sterol esters increased towards the heartwood, and the amount of free sterols was lowest in the inner sapwood. Sitosterol was the dominant sterol in both free sterols and sterol esters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203575
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  • 10
    Electronic Resource
    Electronic Resource
    Naturally occurring monoterpenoids in needles of Picea abies (L.) Karst (1987)
    Springer
    Trees 1 (1987), S. 88-93 
    Details
    ISSN: 1432-2285
    Keywords: 1Gas chromatography ; Picea abies ; Solvent extraction ; (Mono)terpene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary An analysis was made of the effects of different sampling and extraction techniques on the amounts and pattern of monoterpenoids isolated from needles of Norway spruce. The following isolation and analysis procedure was finally adopted: liquid nitrogen-cooled needles were pulverized by a microdismembrator, extracted with pentane overnight at 2°–3°C and concentrated to a volume not less than 3 ml/g fresh weight on a Vigreux column. The crude extract was injected splitless (with solvent split) onto a cold programmed temperature vaporized (PTV) precolumn of a gas chromatograph and the vaporizable compounds heated to a capillary column. This method was tested for production of artefacts and quantitative extraction and applied to needles of eleven 80-year-old spruce trees.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203576
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  • 11
    Electronic Resource
    Electronic Resource
    Monoterpene hydrocarbon contents of the resin from seeds of silver fir (Abies alba Mill.) (1987)
    Springer
    Trees 1 (1987), S. 94-101 
    Details
    ISSN: 1432-2285
    Keywords: Monoterpenes ; Abies alba Mill ; Resin ; Seeds ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Using gas-chromatographic methods, the variability of the contents of monoterpene hydrocarbons (α-pinene, β-pinene, Δ3carene and limonene) in the resin of silver fir seeds (Abies alba Mill.) was studied. Resin cavities were characterized according to their position on the seed surface. It was estabilished that the terpene content of the resin of cavities localized on the abaxialadaxial surfaces of the seed differs significantly, creating a gradient of resin composition around the circumference of the seed. The differences between various resin cavities of single seeds were greater than the differences between different seeds of a single cone and between seeds of various cones on a single tree. An accurate definition of the resin cavity location on the seeds appears to be a fundamental condition for the collection of a sample representing the resin composition of individual trees. Resin biosynthesis in the course of organogenesis and the control of terpene contents in the resin of various locations on the seed and the cone are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203577
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  • 12
    Electronic Resource
    Electronic Resource
    Distribution of leaf assimilates in the stem of Picea abies L. (1987)
    Springer
    Trees 1 (1987), S. 102-109 
    Details
    ISSN: 1432-2285
    Keywords: Picea abies ; Phloem transport ; Radial transport ; Stem chlorophyll
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Autoradiographic and microautoradiographic studies of 2-year-old Picea abies plants show that in summer leaf assimilates from the second-year shoot are translocated basipetally. Leaf assimilates are first transported to the stem via leaf trace phloem, then to the base of the stem in the sieve cells of the latest increment of secondary phloem. On the way down leaf assimilates move radially from sieve cells into cells of the phloem parenchyma, the vascular cambium, the rays, the inner periderm and certain cells of pith and cortex, including the epithelial cells surrounding the resin ducts. Other cells of pith and cortex remain nearly free of label, despite the long translocation time (20 h). With the exception of the vascular cambial cells, the stem cells that gain leaf assimilates by radial distribution coincide with those that contain chlorophyll and starch.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203578
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  • 13
    Electronic Resource
    Electronic Resource
    Stomatal conductance and transpiration of the two faces of Acacia phyllodes (1987)
    Springer
    Trees 1 (1987), S. 110-122 
    Details
    ISSN: 1432-2285
    Keywords: Phyllodes ; Stomatal conductance ; Transpiration ; Water potential ; Acacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The daily course of stomatal conductance and transpiration was monitored on each separate face of vertical phyllodes of various acacias. The selected phyllodes had a north-south orientation so that one side faced eastwards and the other westwards. The principal measurements were made on Acacia longifolia and A. melanoxylon in Portugal in late summer and autumn, and additional measurements were made on A. ligulata and A. melanoxylon in Australia. In Portugal, irrespective of soil moisture status, conductance showed on early morning maximum with a subsequent gradual decline and sometimes a subsidiary peak in the late afternoon. Maximum conductances appeared to be a function of soil moisture status, whereas the decline in conductance in the late morning and afternoon was correlated with changes in phyllode-to-air vapour pressure deficits rather than changes in phyllode water status. The relationship of transpiration to phyllode water potential did not appear to be influenced by soil moisture status, although transpiration was less in drier soils and in the afternoons, this latter factor contributing to a marked hysteresis in the relationship. The opposing faces of the phyllodes exhibited a high degree of synchrony, showing parallel stomatal opening and closing, despite their large differences in irradiance. Stomatal conductance tended to be higher on the eastern faces in the morning and lower in the afternoon. In A. longifolia the daily average of relative conductance was much the same for both faces, but in A. melanoxylon that of the eastern face was higher and was retained even when the normal orientation of the phyllodes was reversed by turning them through 180°. Synchrony must be achieved by the stomata of both sides responding to common environmental or endogenous signals which are perceived by both surfaces with equal sensitivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203579
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  • 14
    Electronic Resource
    Electronic Resource
    Some effects of long-term ozone fumigations on Norway spruce (1987)
    Springer
    Trees 1 (1987), S. 129-133 
    Details
    ISSN: 1432-2285
    Keywords: Ozone Photosynthesis ; Picea abies ; Stomata ; Transpiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Potted cuttings of a 12-year-old, and grafts of an 80-year-old, Norway spruce (Picea abies (L.) Karst.) were subjected to 100 or 300 μg O3·m−3 for 1215 h (45 h of daylight per week) during the growing season of 1985. At the end of the fumigation the plants did not exhibit any visible signs of injury. Whereas in the fumigation with 100μg O3·m−3 we did not detect any significant change in gas exchange, 300 μg O3·m−3 did alter the CO2 uptake after 27 weeks, and in one clone transpiration was also altered. Stomatal reaction to a change of light suggested sluggishness, but the change was not statistically significant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203581
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  • 15
    Electronic Resource
    Electronic Resource
    Respiration and photosynthesis in cones of Norway spruce (Picea abies (L.) Karst.) (1987)
    Springer
    Trees 1 (1987), S. 123-128 
    Details
    ISSN: 1432-2285
    Keywords: Carbon balance ; Cones ; Photosynthetic CO2 refixation ; Picea abies ; Respiration ; Seasonal course
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Dark respiration and photosynthetic carbon dioxide refixation in purple and green Picea abies cones were investigated from budbreak to cone maturity. The rate of dark respiration per unit dry weight and CO2 refixation capacity decreased during cone maturation. At the beginning of the growing season, photosynthetic CO2 refixation could reduce the amount of CO2 released by respiration in green and purple cones by 50% and 40%, respectively. The seasonal performance of the components of the cone carbon balance was calculated using information on the seasonal course of respiration, refixation capacity and the light response curves of cone photosynthesis, as well as the actual light and temperature regime in the field. The daily gain of CO2 refixation reached 28%–34% of respiration in green and 22%–26% in purple cones during the first month of their growth, but decreased later in the season. Over the entire growth period refixation reduced carbon costs of cone production in both cone colour polymorphs by 16%–17%.
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    URL: http://dx.doi.org/10.1007/BF00203580
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  • 16
    Electronic Resource
    Electronic Resource
    Repeat flowering in apple caused by water stress or defoliation (1987)
    Springer
    Trees 1 (1987), S. 135-138 
    Details
    ISSN: 1432-2285
    Keywords: Flowering ; Malus x domestica Borkh ; Water stress ; Defoliation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A series of experiments involving defoliation or water stress at different dates indicated that either of these treatments can make potted apple trees flower a second time in any one year, as long as the treatment is given near the end of July. The results suggest that the reflowering after a period of water stress was primarily a result of the loss of leaves that occurred when the plants were subsequently rewatered. Reflowering normally occurred only if flower primordia had already differentiated at the time of the treatment. There was an indication that in early July water stress was more effective than defoliation at stimulating reflowering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193555
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  • 17
    Electronic Resource
    Electronic Resource
    Some effects of long-term ozone fumigation on Norway spruce (1987)
    Springer
    Trees 1 (1987), S. 145-150 
    Details
    ISSN: 1432-2285
    Keywords: Ozone ; Picea abies ; Stomata ; Wax
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Potted cuttings of a 12-year-old Picea abies tree were fumigated with ozone, 100 or 300 μg O3· m−3 (50 or 150 ppb O3) being added to charcoal-filtered air during the 1985 growing season for a total of 1215 h. The wax structure of ozone-fumigated needles was no different from that of controls. Because flattened wax structures and fused wax fibrils also occurred in controls, these phenomena could not serve as bioindications for the ozone concentrations applied. A smooth layer was found beneath the soluble wax layer and covered needle surface and stomatal openings of ozone-fumigated needles to a greater extent than in controls. Wax quantity was considerably reduced by fumigation with 300 μg O3 · m−3. Leaf pigments (as extracted with the wax) were less abundant in needles treated with 300 μgO3; the smooth layer probably contributed to the impeded extraction of pigments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193557
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  • 18
    Electronic Resource
    Electronic Resource
    Seasonal variation of neutral lipids in Pinus sylvestris L. sapwood and heartwood (1987)
    Springer
    Trees 1 (1987), S. 139-144 
    Details
    ISSN: 1432-2285
    Keywords: Fatty acids ; Heartwood ; Pinus sylvestris ; Sapwood ; Seasonal variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The lipid levels and fatty acid composition of three fractions (free fatty acids, triacylglycerols and sterol/triterpenoid esters) extracted from the sapwood and heartwood of three stems of Pinus sylvestris were determined to investigate both seasonal changes in sapwood and possible metabolic changes related to heartwood formation. Seasonal changes were observed only in the amount of the free fatty acids in the sapwood: the level of free fatty acids was greatest at the beginning and end of the growing season. In the January and March samples the amount of the free fatty acid fraction in the sapwood was very small. The amount of the other fractions remained at the same level throughout the study. Marked seasonal changes in the fatty acid composition occurred only in the free fatty acid fraction of the sapwood: the saturation grade increased during the winter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193556
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  • 19
    Electronic Resource
    Electronic Resource
    Displacement of frequently occurring heacy metals in autumn leaves of beech (Fagus sylvatica) (1987)
    Springer
    Trees 1 (1987), S. 164-171 
    Details
    ISSN: 1432-2285
    Keywords: Deciduous trees ; Fagus sylvatica ; Autumn leaves ; Iron ; Lead ; Manganese ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary By utilizing energy-dispersive X-ray microanalysis the heavy metals manganese, iron, zinc and lead were determined in different tissues of beech (Fagus sylvatica L.) autumn leaves. It was observed that all four metals were accumulated in sieve element-companion cell complexes of the leaf veins in the period from the green (2 October) to the brown (23 October) leaf coloration. Concomitantly, the concentration of these metals decreased in certain tissues of the stems subtending the leaves. The major reservoirs of heavy metals in the stems were periderm, cortex, pith and xylem rays. Since sieve element-companion cell complexes of the stems showed increasing metal concentrations during the transition from the green to the brown leaf stage, and since this temporary increase also occurred in the petiole phloem, it is inferred that symplastic transport can be used in addition to apoplastic transport for the displacement of heavy metals. It is assumed that the accumulation of heavy metals in the veins of autumn leaves indicates the deposition of surplus ions which are excluded when leaves are cast off.
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    Ultrastructure of cells in the cambial region during winter hardening and spring dehardening in Salix dasyclados Wim. grown at two nutrient levels (1987)
    Springer
    Trees 1 (1987), S. 151-163 
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    ISSN: 1432-2285
    Keywords: Cambial activity ; Frost hardiness ; Phenology ; Salix ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The ultrastructure of cells in the cambial region of Salix dasyclados Wim. (clone 78056) was studied during the development of winter hardiness and the onset of cambial activity in spring. Plants were grown at relative growth rates (RG) of 8% and 12% respectively, resulting in different nitrogen content in the stems. Frost hardiness of the plants was estimated by standardized freezing tests. Plants with a higher nitrogen status ceased growth later and started re-growth earlier in spring than plants with lower nitrogen content. Differences in ability to withstand low temperatures during autumn and spring were found between plants grown in the two nutrient treatments. During the development of frost hardiness in the autumn, the number of meristematic cells in the cambial region decreased. The cessation of meristematic activity was accompanied by cell wall thickening and ultrastructural changes in the cells. Frost hardiness increased from the ability to survive -6° C in October to survival of -80° C at the beginning of December. From November to February the cambial region comprised a layer of 2–3 thick-walled cells with conspicuous ultrastructural features. Starch accumulated in plastids in September, decreased during November to March and then increased again in accordance with changes of frost hardiness. Onset of cambial activity began between the end of March and the beginning of April, as shown by increased vacuolization of meristematic cells and mitotic activity. By April, the starch content had increased and lipolysis was observed. Frost hardiness had decreased, and plants with low and high nitrogen content were able to survive -15° C and -10° C, respectively. After budburst, all axillary shoot parts were damaged at temperatures below-3° C.
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    URL: http://dx.doi.org/10.1007/BF00193558
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    Determination of choline in phloem exudates of trees (1987)
    Springer
    Trees 1 (1987), S. 189-190 
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    ISSN: 1432-2285
    Keywords: Aphids ; Choline ; Choline oxidase ; Phloem exudate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Choline, a necessary compound in an artificial diet for phloem-feeding aphids, was determined quantitatively in the phloem exudates of 16 tree species. The method used was a combination of choline oxidase action and oxygen determination with an oxygen electrode. Choline was found in all species, the concentration ranging between 36 and 5340 μM.
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    Some distinctive types of spruce mycorrhizae (1987)
    Springer
    Trees 1 (1987), S. 172-188 
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    ISSN: 1432-2285
    Keywords: Picea abies ; Mycorrhizal types ; Hyphal mantle structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary For examination and recognition of mycorrhizal types, the structure of the hyphal mantle in tangential longitudinal sections has proved to be a valuable feature for investigation. Features of hyphal mantle structure have been used for establishing an identification key. The colour of the hyphal mantle is a helpful additional characteristic, but is not useful as a diagnostic feature because of variations in advanced age and under varying environmental conditions. Rhizomorphs yield good taxonomic characteristics. The Hartig net was uniform for all types examined. When differences were observed they had to be interpreted as different stages of development. Ultrastructural examination revealed further features of mycorrhizal types: namely the shape of septal pores, presence and structure of matrix material in the region of the hyphal mantle and characteristic deposits on cell walls of the hyphae. The ten types presented can be distinguished without any ultrastructural features. As far as the fungal partners involved are concerned, basidiomycetes are clearly dominant. For the first time two basidiomycetes with continuous parenthesomes of their dolipores were found to form ectomycorrhizae. Classification of these fungi with the heterobasidiomycetes is discussed.
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    An in vitro method for establishing mycorrhizae on coniferous tree seedlings (1987)
    Springer
    Trees 1 (1987), S. 191-194 
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    ISSN: 1432-2285
    Keywords: Basidiomycetes ; Coniferous trees ; Ectomycorrhiza ; In vitro culture ; Symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A method for in vitro synthesis of mycorrhizae on coniferous tree seedlings is described. Tree seedlings (Larix decidua Mill., Picea abies (L.) Karst, and Pinus sylvestris L.) and fungi Amanita muscaria (L. ex Fr.) Hooker, Piloderma croceum Erikss. et Hjorst., Pisolithus tinctorius (Pers.) Coker et Couch, and Suillus grevillei (Klotzsch) Singer were maintained under sterile conditions in petri dishes. Typical ectomycorrhizae were established within 2–3 weeks after inoculation and within 2 months after germination of seedlings. Eventually a high percentage of mycorrhizal root tips was obtained.
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    Wind-induced tree sways (1987)
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    Trees 1 (1987), S. 195-206 
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    ISSN: 1432-2285
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Conclusions The question of how the results of investigations on wind-induced tree sways can be used in practice is often posed. First, it must be said that, according to information in the literature, no tree species can survive violent storms (with mean wind speeds over a period of 10 min higher than 30 m/s) without any damage. This threshold value for wind speed is related to the height near the top of a forest stand. Taking the results of the spectral method as a basis for the reduction of storm risk of vital conifers, necessary silvicultural action must be: (1) to influence the amount and frequency distribution of the wind force in such a way that its shere of action becomes more and more unsuitable for tree sways, and (2) to raise the characteristic frequencies of the trees' primary sways because then effective wind force takes on lower and lower values due to narrow-band energy transfer. Numerous silvicultural methods for achieving these objectives, such as cutting off the tops of crowns or chaining trees together, are described in detail by Rottman (1986).
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    Steryl glycosides and acylated steryl glycosides ofPinus sylvestris L. sapwood and heartwood (1987)
    Springer
    Trees 1 (1987), S. 215-218 
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    ISSN: 1432-2285
    Keywords: Acylated steryl glycosides ; Heartwood ; Pinus sylvestris ; Sapwood ; Sterylglycosides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The amounts of steryl glycosides (SG) and acylated steryl glycosides (ASG) were investigated in the sapwood, transition zone, inner heartwood and outer heartwood ofPinus sylvestris L. Only traces of both sterol derivates were present and their amounts decreased slightly towards the heartwood. The amount of SG decreased nearly to zero in the inner heartwood but the amount of ASG in the inner heartwood increased slightly. The suitability of enzymatic methods in SG and ASG hydrolysis, and sterol and glucose quantitative determinations, is discussed.
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    Conductance of needle and twig axis phloem of damaged and intact Norway spruce (Picea abies (L.) Karst.) as investigated by application of14C in situ (1987)
    Springer
    Trees 1 (1987), S. 207-214 
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    ISSN: 1432-2285
    Keywords: Norway spruce diseases ; Phloem conductivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Phloem conductance of14C-labelled assimilates was investigated in natural stands of Norway spruce showing substantial damage from needle yellowing and needle loss disease. Terminal current-year shoots of a branch were allowed to fix14CO2 (300–600 ppm in air) and carbon dioxide net uptake was monitored with a gas analyser. The difference between14C-uptake and the amount of radiocarbon determined in the photosynthesizing needles was interpreted to reflect assimilate export from the needles to the axis of the tree. Compared with an undamaged control tree,14C-export from the assimilating needles was not impaired in the yellowing tree and only slightly reduced in the tree showing needle loss. Incorporation of14C into starch increased significantly during autumn particularly in the tree showing needle loss. Import of radiocarbon from the14C-labelled phloem sap in twig axes and needles older than 1 year was used as a measure of phloem conductivity of older sections of a branch which showed considerable damage. Carbon uptake by these older plant parts was more pronounced than in undamaged twigs. In the case of older needles enhancement of14C-incorporation suggested an increased sink strength, while the same phenomenon in the twig axes was interpreted as a consequence of partially impaired conductivity of individual sieve elements resulting in an inhomogeneous velocity of phloem transport. The hypothesis is put forward that curtailed viability of the sieve cells is responsible for a delay of transport, which is compensated for by an augmented production of phloem elements from the cambium.
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    Heterosis in hybrid larch (Larix decidua x leptolepis) (1987)
    Springer
    Trees 1 (1987), S. 219-224 
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    ISSN: 1432-2285
    Keywords: Larix ; Heterosis ; Photosynthesis ; Stomatal conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Individual 33-year-old forest trees of the deciduous conifer speciesLarix decidua, Larix leptolepis andLarix decidua x leptolepis were investigated with respect to the phenomenon of stem heterosis in hybrid larch; the first part of this study compares the gas exchange responses of leaves. CO2 assimilation per leaf area was similar in the three larch species, but on a dry weight basis the nitrogen content of the needles and maximum CO2 assimilation rate (Amax) were slightly higher in the hybrid. This increase was accompanied by a higher protein content than in the Japanese and a lower specific leaf weight than in the European larch. All three species were similar in terms of the photosynthetic “nitrogen use” and stomatal conductance atA max. The similar slopes of the area-related steady-state responses of gas exchange against irradiance, evaporative demand and internal CO2 concentration led to similar rates of CO2 uptake under ambient conditions. The natural combinations and variability of the environmental factors also reduced the small dry weight-related difference inA max between hybrid larch and the parent species, such that all trees achieved similar daily carbon gains. Thus, the ecological significance of small interspecific differences in the metabolism of leaves has very little effect under the natural habitat conditions of a temperate climate. The second part of the study will investigate the effect of growth characteristics on the heterosis of hybrid larch.
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    Root histology, and nutrient uptake and translocation in tissue culture plantlets and seedlings ofThuja occidentalis L. (1987)
    Springer
    Trees 1 (1987), S. 232-237 
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    ISSN: 1432-2285
    Keywords: Thuja occidentalis ; 32P and86Rb uptake and translocation ; Root histology ; Tissue culture plantlets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Histological studies of the vascular connection in the root-shoot junction of tissue culture-derived plantlets and seedlings ofThuja occidentalis L. (Eastern white cedar) showed that in both plant types the xylem was well developed, smooth and not disrupted. Uptake and translocation of32P and86Rb were also similar for plantlets and seedlings. However, approximately 50% more86Rb could be desorbed from the root Donnan free space of plantlets than from seedlings. Uptake and translocation to the shoot was higher for86Rb than for32P, but no differences were found between the plant types. Tracer translocation rates to the shoot seem to be positively correlated with shoot fresh weight.
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    Heterosis in hybrid larch (Larix decidua x leptolepis) (1987)
    Springer
    Trees 1 (1987), S. 225-231 
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    ISSN: 1432-2285
    Keywords: Larix ; Heterosis ; Growth ; Branching pattern ; Needle density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Among 33-year-old forest trees ofLarix decidua, L. leptolepis andL. decidua x leptolepis, the hybrid possessed an above-ground biomass which was three times greater, although all larches displayed similar relative distributions of biomass. At a “relative growth rate” slightly lower than in the parent species, hybrid larch achieved twice the annual carbon gain, increment in stem length and above-ground production, and its foliage-related stem growth was higher than in European (L. decidua) but similar to Japanese (L. leptolepis) larch. A similar “relative growth efficiency” and foliage-related total above-ground production in all trees did reflect the similarity of photosynthetic capacity of the hybrid found at the leaf level. While the lengths of lateral twigs on hybrid branches were intermediate between the European larch with short, and the Japanese larch with large, twigs the hybrid possessed the longest branches with the highest needle biomass. This resulted in a crown structure of the hybrid crown similar to the Japanese larch together with a high needle density on branches as in the European larch. In total, the foliage biomass per crown length was about 30% higher in hybrid larch than in both of the parent species. Thus, the high carbon input for the stem heterosis was based on a “complementation principle” of advantageous parent features at the crown level. Similar slopes of foliage against sapwood area of stem and branches did not indicate a special need for a thick hybrid stem with respect to water transport.
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    Crassulacean acid metabolism in tropical dicotyledonous trees of the genusClusia (1987)
    Springer
    Trees 1 (1987), S. 238-247 
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    ISSN: 1432-2285
    Keywords: Citric acid ; Clusia ; Crassulacean acid metabolism ; Malic acid ; Tropics ; Venezuela
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The performance of crassulacean acid metabolism (CAM) by dicotyledonous trees of the genusClusia sampled at three sites in the state of Falcon in northern Venezuela is characterized.Clusia leaves have a somewhat succulent appearance. Unlike leaves of many other CAM plants, which are uniformly built up of very large isodiametric cells, there are distinct layers of palisade and spongy mesophyll, with individual cells being smaller. There is no specialized water storage tissue. δ13C values indicate thatC. multiflora in the elfin-cloud forest on top of Cerro Santa Ana, at ∼800 m altitude, performs C3 photosynthesis (δ13 −27.1‰). However,C. rosea in the tall cloud forest on Cerro Santa Ana (∼600m altitude), andC. rosea andC. alata in the dry forest on Serrania San Luis (∼900 m altitude) perform CAM (δ13C −14.1 to −19.2‰). InC. alta andC. rosea there were large day-night changes in the levels of malic and citric acids ranging from 63 to 240 mmol 1−1 for malid acid and from 35 to 112 mmol 1−1 for citric acid. The sum of the changes in malate and citrate levels accounts for the changes of titratable protons measured. With a day-night change of titratable protons of 768 mmol 1−1 in one of the analyses,C. rosea showed the highest value yet encountered in a CAM plant. Oscillations of free sugars (fructose, glucose, sucrose) and of starch were also analysed in the CAM performingClusia species. Carbon skeletons of the precursors involved in nocturnal malate and citrate synthesis largely derive from free sugars and not from polyglucan. Unlike some other CAM plants, there is no clear and quantitative correlation between day-night changes of organic acid levels and cell sap osmolality.
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    Allometric analysis of Sitka spruce branches: mechanical versus hydraulic design principles (1995)
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    Trees 10 (1995), S. 1-12 
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    ISSN: 1432-2285
    Keywords: Sitka spruce ; Geometry ; Allometry ; Branch form ; Architecture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The geometry of tree branches can have considerable effect on their efficiency in terms of carbon export per unit carbon investment in structure. The purpose of this study was to evaluate different design criteria using data describing the form of Picea sitchensis branches. Allometric analysis of the data suggests that resources are distributed to favour shoots with the greatest opportunity for extension into new space, with priority to the extension of the leader. The distribution of allometric relations of links (branch elements) was tested against two models: the pipe model, based on hydraulic transport requirements, and a static load model based on the requirement of shoots to provide mechanical resistance to static loads. Static load resistance required the load parameter to be proportional to the link radius raised to the power of 4. This was shown to be true within a 95% statistical confidence limit. The pipe model would require total distal length to be proportional to link radius squared but the measured branches did not conform well to this model. The comparison suggests that the diameters of branch elements were more related to the requirements for mechanical load. The cost of following a hydraulic design principle (the pipe model) in terms of mechanical efficiency was estimated and suggested that the pipe model branch would not be mechanically compromised but would use structural resources inefficiently. Resource allocation among branch elements was found to be consistent with mechanical stability criteria but also indicated the possibility of allocation based on other criteria, such as potential light interception by shoots. The evidence suggests that whilst branch topology increments by reiteration of units of morphogenesis, the geometry follows a functional design pattern.
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    Anatomical studies of branchlet abscission related to crown modification in Quercus cerris L. (1995)
    Springer
    Trees 10 (1995), S. 20-23 
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    ISSN: 1432-2285
    Keywords: Crown modification ; Oak decline ; Quercus cerris L ; Twig abscission
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The basic anatomy of lateral twig insertion onto the main branch in both healthy and damaged Quercus cerris L. trees was studied. An abscission zone is always present: in healthy trees it is formed by a smaller number of cell layers than in damaged ones, where it is more evident with many layers of cells. Cells of the abscission zone are roundish, with many intercellular spaces between them; cell walls are thin, non-lignified and without secondary walls. No starch was found in cells of the abscission zone, where, instead, a few scattered calcium oxalate druses are seen.
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    Stem annual increments as ecobiological indicators in Turkey oak (Quercus cerris L.) (1995)
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    Trees 10 (1995), S. 13-19 
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    ISSN: 1432-2285
    Keywords: Volume increment ; Stem analysis ; Dendroclimatology ; Quercus cerris ; Southern Italy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In recent decades, the biostatistical analysis of relationships among tree growth and macroclimatic factors has developed remarkably. In this discipline, the parametrisation of tree growth is generally based on the records of annual ring widths measured on breast height transverse sections of tree stems (ARI). The present research enables the stem volume annual increment (AVI) to be evaluated as a dendroclimatic indicator in comparison with ARI. The research is a part of a broader investigation into the ecobiological characteristics of Turkey oak in the Gargano region (southern Italy). The results indicate that AVI is no better than ARI as a means of highlighting expressive relationships among the examined macroclimatic factors (monthly precipitation and monthly averages of temperature daily maxima and minima) and the Turkey oak annual stem growth. In the examined stands, the most growthinfluencing factors are the autumn and spring rainfalls. Regarding the stem breast height radial increment, the most effective temperature factors are the June averages of daily minima and maxima.
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    The concentration of Ca, Sr, Ba and Mn in successive needle age classes of Norway spruce [Picea abies (L.) Karst.] (1995)
    Springer
    Trees 10 (1995), S. 31-39 
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    ISSN: 1432-2285
    Keywords: Calcium ; Barium ; Manganese ; Strontium ; Picea abies needles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The concentrations of Ca, Sr, Ba and Mn were determined in up to five successive needle age classes from 54 individual Norway spruce trees [Picea abies (L.) Karst] from nine different sites. The accumulation behaviour was found to be very nonuniform, going from an increase with needle age to a decrease; irregular patterns were also found. The type of accumulation is largely site specific. The increasing behaviour can in most cases be approximated by a simple arithmetic function. All four elements usually show the same accumulation pattern, the similarities being closest between Ca and Mn and least between Ca and Ba. It is postulated that the similarity between the four elements is due to their precipitation and storage as oxalates. The similarity between Ca, Sr and Ba is observed at all concentrations, that with Mn only at concentrations larger than 300 μg/g. Mn at small concentrations (〈 50 μg/g) shows a decreasing pattern and no similarity at all with Ca, Sr and Ba, but behaves similar to mobile elements.
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    Daily dynamics in xylem cell radial growth of Scots pine (Pinus sylvestris L.) (1995)
    Springer
    Trees 10 (1995), S. 24-30 
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    ISSN: 1432-2285
    Keywords: Pinus sylvestris L. ; Wood formation ; Tracheid ; Radial cell expansion ; Daily growth dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Daily dynamics of radial cell expansion during wood formation within the stems of 25-year-old Scots pine trees (Pinus sylvestris L.), growing in field conditions, were studied. The samples of forming wood layers were extracted 4 times per day for 3 days. Possible variations in the growth on different sides of the stem, duration of cell development in radial cell expansion phase and dynamics of cell growth in this phase were taken into account. The perimeters of tracheid cross-sections as a reflection of primary cell wall growth were the criterion of growth in a radial direction. For the evaluation of growing cell perimeters a special system for digital processing and image analysis of tracheid cross-sections of the forming wood was used. Growth rate for certain time intervals was estimated by the change in the relation of the perimeter of each observed cell in each of ten tracheid rows in each of 12 trees to the perimeter of the xylem cell of the same row before the expansion. Temporal differences in average values of the relations were estimated by Analyses of Variance. The existence of daily dynamics of Scots pine xylem cell radial growth has been proved. Intensive growth of pine tracheids has been shown to occur at any time of the day and to depend on the temperature regime of the day and the night as well as water supply of stem tissues. Moreover, reliable differences (P = 0.95) in the increment of cell walls during tracheid radial expansion have been found. Pulsing changes of the water potentials both of the cell and the apoplast, as the reason for the fluctuations of radial cell growth rate, were discussed.
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    Quinate:NAP(P)+-oxidoreductase from Larix sibirica: purification, characterization and function (1995)
    Springer
    Trees 10 (1995), S. 46-51 
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    ISSN: 1432-2285
    Keywords: Larix sibirica ; Metabolism ; Quinate:NAD(P)+-oxidoreductase ; Quinic acid ; Shikimate pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Quinate:NAP(P)+-oxidoreductase (QORase, EC 1.1.1.24), which catalyzes the interconversion of quinic and 3-dehydroquinic acids, was purified from the needles and developing xylem cells of Larix sibirica. The enzymes from these two tissues were partially characterized and compared. QORase from needles had optimum pH at 9.0 and apparent Km values of 1.84 mM for quinic acid and 0.19 mM for NADP+. The enzyme was activated by phosphoenolpyruvate. Gallic and protocatechuic acids were formed in a reaction mixture of purified enzyme from needles as final products of quinic acid transformation. QORase from developing xylem cells showed pH optimum at 10.0 and had apparent Km values of 0.70 mM for quinic acid and 0.05 mM for NADP+. The enzyme was not affected by PEP. The divalent cations Co2+ and Mn2+ at least doubled activity of QORase from both sources but Mg2+ affected the enzyme from needles only. The spatial organization and regulation of quinic acid metabolism in the autotrophic and heterotrophic cells of conifers and the role of QORase in this process are discussed.
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    Triacylglycerols in the seeds of northern Scots pine, Pinus sylvestris L., and Norway spruce, Picea abies (L.) Karst. (1995)
    Springer
    Trees 10 (1995), S. 40-45 
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    ISSN: 1432-2285
    Keywords: Picea abies ; Pinus sylvestris ; Conifer seeds ; Fatty acids ; Triacylglycerols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The geographical variation in the composition of triacylglycerols in seeds of Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst.], grown in Finland, was analyzed. The total lipid content of pine seeds was slightly higher in the northernmost provenance (68 °50′N), whereas the lipid content of spruce seeds was not affected systematically by the geographical origin of the seeds. The species studied differed in the proportions of fatty acids in their triacylglycerols, though the three most abundant components were the same, i.e. oleic acid (18∶1 n9), linoleic acid (18∶2n-6) and 5,9,12-octadecatrienoic acid (18∶3 5c9c12c). These fatty acids corresponded to more than 80 mol% of the total fatty acids. According to mass spectrometric analyses, the triacylglycerols of both spruce and pine seeds consisted of the same molecular species with 52–56 acyl carbons, but in different proportions. Molecules with 54 acyl carbons represented approximately 75% of the pine and 85% of the spruce triacylglycerols, with the most abundant molecular species being 54∶5, 54∶6 and 54∶7. Some minor differences in the fatty acid composition of triacylglycerols of pine seeds from different seed collecting areas were found: the proportion of linoleic acid slightly increased whereas that of 5,11,14-eicosatrienoic acid decreased towards the northern origins. Similar differences were not found in the proportions of fatty acids in spruce seed lots. Furthermore, the proportions of triacylglycerols in both pine and spruce seeds from northern and southern collecting areas were not significantly different. The higher content of total lipids in spruce seeds compared with pine seeds may be due to the structure of the seed coat, and the lipophilic layers inside it, acting as a barrier to imbibition.
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    Micronutrient composition of xylem sap and needles as a result of P-fertilization in maritime pine (1995)
    Springer
    Trees 10 (1995), S. 52-54 
    Details
    ISSN: 1432-2285
    Keywords: Forest fertilization ; Micronutrient ; Mineral interaction ; Mineral uptake ; Xylem sap
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Xylem sap and foliar compositions (P, Cu, Zn, Mn) were examined over 4 months in control and P-fertilized maritime pine in a 7-year-old plantation. The absorption of copper, zinc, and boron appears to be reduced by phosphate fertilization. Manganese concentrations are positively related to P-supply increase. Foliar analysis and sap provides the same type of information in terms of antagonism or synergism between elements but the response to treatment is more often significant with sap throughout the seasons and is completely non-existent on a single classical autumn diagnosis with foliar concentration (i.e. Zn and Cu). In consequence foliar analysis is not sensitive enough for copper or zinc deficiency diagnoses in young plantations where nutritional growth disorders appear in a short period of spring, and xylem chemistry appears to be a convenient tool in monitoring micronutrient disorders in pine plantations.
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  • 39
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    Seasonal and annual variations of phosphorus, calcium, potassium and manganese contents in different cross-sections of Picea abies (L.) Karst. needles and Quercus rubra L leaves exposed to elevated CO2 (1995)
    Springer
    Trees 10 (1995), S. 55-62 
    Details
    ISSN: 1432-2285
    Keywords: Picea abies ; Quercus rubra ; Nutrients ; Carbon dioxide ; Seasonal variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Norway spruce and red oak trees were planted directly into the soil and enclosed in open-top chambers. For 2 years the trees were exposed to both ambient and elevated CO2 concentrations (700 μmol mol-1) and during this time variations in nutrient concentrations were studied. CO2-treated plants had decreases in global leaf concentrations of nitrogen, potassium, calcium and manganese for both species. When different areas of the foliage were analysed however, the response showed much variability between the respective sites and between species. Furthermore the nutrient concentrations changed differently as the plant material aged and this change showed inter-treatment differences. These results show how it may be important to analyse plant material of different ages and at different cell sites when studying nutrient levels.
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    URL: http://dx.doi.org/10.1007/BF00192184
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    Poor stomatal control of water balance and the abscission of green needles from a declining stand of spruce trees [Picea abies (L.) Karst.] from the northern Alps (1995)
    Springer
    Trees 10 (1995), S. 63-73 
    Details
    ISSN: 1432-2285
    Keywords: Forest decline ; Osmotic potential ; Picea abies ; Stomatal control ; Water potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract On a site on the west slope of the Wank in the northern Alps changes in water potential, osmotic potential and transpiration rate were measured in spruce trees during the dry summer months of 1991. The pattern of decrease in water potential and osmotic potential on days of varying evaporative demand from trees of widely different decline conditions was used to describe the relative ability of the trees to withstand drought stress. Stress diagrams served as a tool for interpreting the state of health of each tree. The criterion is independent of the water situation of the tree and the other external conditions of the respective experiment. These diagrams clearly show that the foliage of spruces with high needle losses reaches the limit of endurance relatively early. For equal evaporative demand much lower turgor levels were observed in spruces with high needle loss compared to undamaged trees. Associated with the occurrence of low turgor values was the shedding of green needles. The abscission zone was shown in sections. The accumulation of highly fluorescent substances in the bundle sheath cells of the same material was described. Incomplete to non-existent stomatal control over water loss was attributed to modifications in the cell walls of the stomata which appear to alter the ability of the guard cells to sense changes in either atmospheric or cellular hydration. Our studies point to the following situation: air pollution directly affects stomatal control, the loss of stomatal control changes the drought avoidance abilities of the foliage and, as a consequence, low turgor levels occur and premature needle abscission is induced. As site water balance decreases, either due to a dry year or to poor moisture holding abilities of the soil, these conditions become apparent.
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    Fatty acids, starch and biomass of Scots pine needles and roots in open-air ozone exposure (1995)
    Springer
    Trees 10 (1995), S. 74-82 
    Details
    ISSN: 1432-2285
    Keywords: Ozone ; Pinus sylvestris (L.) ; Lipids ; Starch ; Biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Scots pine (Pinus sylvestris L.) seedlings were fumigated with 1.2–1.5 x ambient ozone (cumulative exposure) over 2 seasons in an open-air experiment. Starch and fatty acid concentrations were analyzed in needle and root tissue in the summer, autumn and early winter. Seedling growth was determined by measuring the height of the stem and the total shoot and root biomass. Significant decreases in growth were found in exposed seedlings, even though visible symptoms were lacking. Almost significant reductions in needle and root starch concentrations were found. In the ozone treated foliage, significant increases in myristic acid (14∶0) were detected, but the major fatty acids remained unchanged. Fatty acid ratios showed that the degree of unsaturation decreased in treated needles in the summer. In the roots of ozone treated seedlings, changes in fatty acids were different from those in the foliage. Decreases of the main root fatty acids (16∶0, 18∶0, 18∶1, 18:2, 18∶3) were detected in the summer. These results show that Scots pine is susceptible to enhanced levels of ozone. If the tropospheric ozone levels continue to increase it may have deleterious effects on Scots pine forests in Finland.
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    Restricted lateral gas movement in Pinus strobus branches (1995)
    Springer
    Trees 10 (1995), S. 83-85 
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    ISSN: 1432-2285
    Keywords: Oxygen ; Sap-flow ; Respiration ; Carbon dioxide ; Cambium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Argon gas was incorporated into the sap flowing through xylem of cut branches, or added to the air in a sealed cuvette surrounding a needle-free portion of the branch to investigate lateral movement of gases in Pinus strobus. Microdialysis was used to sample air in the xylem and evacuated vials were used to collect samples of air from cuvettes attached to branches. Argon concentrations of samples of air were measured by GC-MS. When argon was added through the sap, concentrations of argon in the xylem and in air of chambers enclosing needle stumps was greater than that of controls, but argon concentrations of air in cuvettes enclosing a needle-free portion of the branch were not greater than controls. When argon was added to cuvettes enclosing a needle-free portion of the branch, the argon did not enter the xylem and it was not emitted by needle stumps.
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    Coniferyl alcohol oxidase — a catechol oxidase? (1995)
    Springer
    Trees 10 (1995), S. 102-107 
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    ISSN: 1432-2285
    Keywords: Pinus strobus L ; Polyphenol oxidase ; Tracheid differentiation ; Wood formation ; Cell wall ; Lignin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The physico-chemical properties of coniferyl alcohol oxidase (CAO), a copper containing glycoprotein spatiotemporally associated with lignification in conifers, is reported here. By electron paramagnetic resonance spectroscopy, only type 3 copper was indicated in CAO. CAO oxidizes several laccase substrates; however, it is not a blue-copper protein and monoclonal antibodies against both native and deglycosylated CAO did not recognize any of several laccases. The N-terminal sequence of CAO, H2N-X E L A Y S P P Y X P S, was non-homologous with known enzymes. Transparent copper, tetrameric structure, aminoacid composition, phenylhydrazine and tropolone inhibition, and SDS enhancement of CAO activity indicate that CAO is an o-diphenol oxidase.
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    Carbohydrate content of Eucalyptus gunnii leaves along an annual cycle in the field and during induced frost-hardening in controlled conditions (1995)
    Springer
    Trees 10 (1995), S. 86-93 
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    ISSN: 1432-2285
    Keywords: Carbohydrates ; Eucalyptus gunnii ; Frost resistance ; Hardening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The annual changes in frost hardiness were studied for three Eucalyptus gunnii genotypes. Frost resistance evaluated on leaf discs by the electrolyte leakage method reached a maximum in the coldest period and a minimum in summer demonstrating winter frost hardening. Genotype 634 exhibited a higher intrinsic resistance than the other genotypes both in the hardened and in the non-hardened stages. Plants of this genotype were also frost acclimated in controlled conditions by a progressive decrease of culture temperature (25 to 0 °C) but the degree of hardening appeared to be lower in these conditions. The carbohydrate patterns in leaves varied with acclimation. In controlled conditions the leaves of genotype 634 exhibited a rise in sucrose, fructose and raffinose concentration up to a temperature of 10 to 7 °C which subsequently decreased. In natural conditions a comparison of the three genotypes allowed us to correlate the higher intrinsic resistance of genotype 634 to a higher soluble sugar content. During acclimation fructose and raffinose changes were also correlated to an increase in cold resistance even though the kinetics of these changes differed in controlled and natural conditions. The starch content was very low in the various genotypes in the different conditions but oligosaccharides such as stachyose and possibly verbascose were detected. The results point out the relationships occurring between increased frost resistance and changes in fructose and raffinose concentration in E. gunnii leaves.
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    Diurnal changes in the radius of a subalpine Norway spruce stem: their relation to the sap flow and their use to estimate transpiration (1995)
    Springer
    Trees 10 (1995), S. 94-101 
    Details
    ISSN: 1432-2285
    Keywords: Stem radius variation ; Xylem sap flow ; Crown transpiration ; Picea abies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Diurnal changes in the stem radius of a subalpine mature Norway spruce were measured simultaneously with the flow of sap in xylem. Matric potentials in the soil were 〉 -35 kPa. The kinetics of the flow were closely related to the changes in the radius of the stem resulting from depletion of its extensible tissues. The radius of the stem oscillated daily and, fairly independently of this, fluctuated over several days. The daily shrinkage (Δd) was correlated with the daily flow through its base (Qd). When the crown transpired little and was nearly saturated during rainy days, ASd tended to increase relative to Qd. Using a linear relation, the estimates of flow by Δd deviated less than ± 10% from the values measured by heat balance, provided that the periods of calibration in their ratio of dry to rainy days were comparable to those estimated. If the two periods differed in this respect, the estimates of flow deviated up to 42%. A quadratic relation yielded estimates that depended less on weather. It reduced maximal deviations to ±22%. Since Δd additionally may represent the time pattern of the daily transpiration better than Qd, analysing changes in the radius of stems may supplement or partly replace measurements of sap flow in stems.
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    Growth patterns of early versus late successional multipurpose trees of the western Himalaya (1995)
    Springer
    Trees 10 (1995), S. 108-113 
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    ISSN: 1432-2285
    Keywords: Growth pattern ; Multipurpose ; Successional trees ; Western Himalaya
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In the mid-western Himalaya (altitude 1350 m, rainfall 1100 mm), multipurpose trees found as escapees in agricultural fields or naturally growing in the forests, play an important role in providing fuel, fooder and small timber to the farmers. Shoot elogation, and tree architecture of 4 year old trees of Grewia optiva, Robinia pseudoacacia and Celtis australis (early successionals), and Quercus leucotrichophora, Q. glauca and Ilex odorata (late successionals), were analyzed. All the late successional species showed a proleptic type of bud and branch production, while the early successional trees made growth through syllepsis. The shoot elongation differed significantly (P 〈0.05) with the crown position, and ranged from 11 to 30 cm in different species. Early successional species tended to maintain a comparatively narrow crown and showed a significantly (P 〈0.05) higher ramification ratio, and multilayered canopy. The late successionals, in contrast, showed a wide crown with monolayered canopy, adapted to the weak light intensity. There was only one flush of leaves in Q. leucotrichophora and Q. glauca while in the rest of the species there were two distinct flush periods. The results are important for the management of agroforestry trees.
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    Altered root growth and plant chemistry ofPinus sylvestris seedlings subjected to aluminum in nutrient solution (1996)
    Springer
    Trees 10 (1996), S. 135-144 
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    ISSN: 1432-2285
    Keywords: Scots pine ; Aluminum ; Pollution ; Photosynthesis ; Roots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract One-year-old Scots pine (Pinus sylvestris L.) seedlings were grown for 9 weeks in nutrient solutions containing 0, 0.5, 1, 2 and 4 mM aluminum nitrate (Al(NO3)3) at pH 4.2. Nine weeks exposure to Al significantly reduced total plant, shoot and root mass and caused a linear decline in proportional allocation of biomass to roots. Relative growth rate of roots declined to as low as zero. Aluminum treatment decreased calcium and magnesium uptake and increased Al content in roots and needles. After 3 weeks of exposure a 10–60% increase in total phenols in roots and a 20–40% increase in o-diphenols in roots and needles were noted. Roots affected by Al showed degeneration of meristematic cells, fewer cell divisions, deformation in cell walls and higher lignification and suberization. The majority of root apices were structurally similar to dormant roots, and a premature senescence of the entire root system was observed. Net photosynthetic rate after 6 weeks of treatment was negatively correlated with needle Al content and Al/Ca ratio (r 〈 -0.9, P 〈 0.1). The results suggest that Scots pine may be more susceptible to Al than was expected based on previous experiments.
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    Development of needle retention in Scots pine (Pinus sylvestris) in 1957–1991 in northern and southern Finland (1995)
    Springer
    Trees 10 (1995), S. 125-133 
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    ISSN: 1432-2285
    Keywords: Pinus sylvestris ; Needle trace method ; Needle retention ; Long-term variation ; Reindeer browsing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The needle trace method was used to study retrospectively the long-term latitudinal variation in needle retention in Scots pine (Pinus sylvestris L.) in Finland. The mean annual summer needle retention (ANR) along the main stem varied from 3.4 to 6.0 needle sets during the period 1957–1991. The lowest values were observed in southern and the highest in northern Finland. The length of the growing season, expressed as the thermal sum (threshold value +5 °C), was negatively correlated with the mean ANR (r=-0.96). The geographical needle retention pattern (NRP) for the period 1957–1991 showed a clearly increasing trend from 1957 to 1969 (southern Finland) and to 1975 (northern Finland); thereafter, the NRP tended to decrease close to its minimum value recorded in 1991. The general level of the NRP was approximately 5.0 needle sets in northern Finland and 3.5–4.0 needle sets in southern Finland. The NRP, with its 6–12 year cycle for southern Finland, was clearly periodical. Differences in the NRP among the ten stands in southern Finland were small, whereas the said periodicity was missing and the differences were high among the stands in northern Finland. The results indicate that variation in the number of needle sets, viz. defoliation of pines, is a normal phenomenon. The role of net carbon assimilation as a regulator of the number of needle sets is discussed.
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    Photosynthetic acclimation to light in juveniles of two cloud forest tree species (1995)
    Springer
    Trees 10 (1995), S. 114-124 
    Details
    ISSN: 1432-2285
    Keywords: Alchornea triplinervia ; Decussocarpus rospigliosii ; Photosynthetic acclimation ; Sun/shade adaptation ; Tropical cloud forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The photosynthetic response of juveniles of Decussocarpus rospigliosii, an emergent primary forest species and shade tolerant in its juvenile stages and Alchornea triplinervia, a gap-colonizing species of tropical cloud forest in Venezuela was studied. Daily courses of microenvironmental variables and gas exchange under contrasting light conditions (gap and understory) were carried out in their natural environment and transplanted to different light regimes (shade and sun) in the field. The photosynthetic response and some anatomical characteristics of plants from different treatments were analyzed in the laboratory. Photosynthetic rates were low for both species, and were negative during some diurnal periods, related to the low photosynthetically active radiation levels obtained at both gap (6% of total radiation) and understory (2%). A. triplinervia shows higher rates (1.5–3.0 μmolm-2 -1) than D. rospigliosii (0.7–1.1 μmolm-2s-1). Both species showed increased photosynthetic rates when grown in gaps. A. triplinervia did not adjust its maximum photosynthetic rates to the prevailing light conditions. In contrast, D. rospigliosii responded to increased light levels. Both species showed low light compensation points when grown under total shade. There was a partial stomatal closure generally during midday in D. rospigliosii. A. triplinervia presented lower leaf conductances, transpiration rates and lesser stomatal control. Some leaf anatomical characteristics, in both species, were affected by variations in the light regime (i.e. increased leaf thickness, leaf specific weight and stomatal density). These results suggest that both species have the ability to respond to variations in their natural light environments, therefore maintaining a favorable carbon balance during the day.
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    Acceleration of leaf senescence inFagus sylvatica L. by low levels of tropospheric ozone demonstrated by leaf colour, chlorophyll fluorescence and chloroplast ultrastructure (1996)
    Springer
    Trees 10 (1996), S. 145-156 
    Details
    ISSN: 1432-2285
    Keywords: Fagus sylvatica ; Open-top chamber ; Ozone ; Plastoglobuli ; Senescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract From April 1988 to October 1991 3-year-old seed propagated beech (Fagus sylvatica L.) trees were exposed in open-top chambers to four different levels of air pollution: (1) charcoal filtered air, (2) ambient air, (3) ambient air plus 30 nl 1-1 ozone during the summer, and (4) ambient air plus 30 nl 1-1 ozone during the summer and 20 nl 1-1 SO2 and NO2 during the winter. Leaf colour was studied in the autumns of 1989 and 1991 and a close relationship between ozone dose and premature senescence was found. A correlation also exists between the colour groups and chlorophyll fluorescence (Fv/Fm). Ozone fumigation increases the size and speeds up the development of the plastoglobules. This is described using an index based on the volume of plastoglobules as a percentage of chloroplast volume. The index was significantly higher for ozone fumigated plants than for control plants during August to November 1989. According to all three methods it is concluded that low levels of ozone accelerate leaf senescence processes inF. sylvatica. There are indications that leaves of the first and the second flush react differently to the ozone treatment. Irrespective of the ozone treatment a special cell wall structure, probably a local suberization, is confined to the subsidiary cells in leaves of the first flush.
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    Influence of UV-B radiation on photosynthetic activity and chlorophyll fluorescence kinetics in Norway spruce [Picea abies (L.) Karst.] seedlings (1996)
    Springer
    Trees 10 (1996), S. 172-176 
    Details
    ISSN: 1432-2285
    Keywords: Ultraviolet-B radiation ; Norway spruce ; Picea abies (L.) Karst. ; Photochemical activity ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Norway spruce [Picea abies (L.) Karst.] seedlings were grown in greenhouses with two supplemental levels of ultraviolet-B (UV-B) radiation. Photochemical efficiency of photosystem II and vitality index were determined monthly. At the end of the experiment, growth, chlorophyll content and photosynthetic rates were measured. The data indicate that low temperature in winter affected light dependent processes in experimental plants including control, while the rise of ambient temperatures, moderate this effect. The synergistic effects of UV-B radiation and low temperatures could only be observed in the second winter period. Measurements of net photosynthetic activity in the second winter period showed significant differences between treated and untreated plants.
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    Changes in dormancy levels ofFraxinus excelsior L. embryos at different stages of morphological and physiological maturity (1996)
    Springer
    Trees 10 (1996), S. 177-182 
    Details
    ISSN: 1432-2285
    Keywords: Embryo dormancy ; Fraxinus excelsior ; In vitro germination ; Seed development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The dormancy status ofFraxinus excelsior embryos at different developmental stages under environmental conditions was examined over a period of 2 years. For each sampling date the length of the fruit, of the seed, and of the embryo were measured, and the embryological stage determined. The depth of dormancy was assayed by the germination behaviour of isolated embryos under aseptic conditions on an agar medium without nutrients. As an approach towards a quantitative estimate of the dormancy status, the degree of inhibiton of germinative growth in the embryonic organs was evaluated on the basis of four categories from none to full germinative growth. From these ratings a dormancy index was calculated, expressing the mean dormancy status of the embryos at a given date. Embryo dormancy already became apparent during embryogenesis and reached its highest level during the later phase of reserve deposition in the seed. A marked loss of embryo dormancy occurred during the phase of maturation drying in autumn, followed by a moderate increase in winter. In hydrated seeds in spring the embryo was gradually released from dormancy and enlarged further. In maintaining the embryo ofF. excelsior in a developmental but not germinative mode, dormancy mechanisms within the embryo and the endosperm, combined with environmental factors, may be involved.
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    Effects of long-term open-air exposure to fluoride, nitrogen compounds and SO2 on visible symptoms, pollutant accumulation and ultrastructure of Scots pine and Norway spruce seedlings (1996)
    Springer
    Trees 10 (1996), S. 157-171 
    Details
    ISSN: 1432-2285
    Keywords: Conifer ; Fluoride ; Nitrogen ; Sulphur dioxide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Effects of SO2, aqueous fluoride (NaF) and a solution of nitrogen compounds (NH4NO3) on the visible symptoms, pollutant accumulation and ultrastructure of Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst.] seedlings were studied in an open-air experiment lasting for 3 consecutive years. Visible injury symptoms were most pronounced in combination exposures and whenever F was applied. Visible symptoms correlated well with needle pollutant concentrations. Exposure to NaF increased needle F contents particularly when F was applied with SO2 or NH4NO3. This suggests that a reduction in N or SO2 emissions, in F polluted areas, could improve the condition of conifers via decreased accumulation of phytotoxic F in the needles. Norway spruce needles accumulated 2–10 times as much S and F as those of Scots pine. Microscopic observations showed various changes in the needle mesophyll cell ultrastructure. In both species, exposure to SO2 increased significantly the amount of cytoplasmic vacuoles, suggesting detoxification of excess sulphate or low pH. F treatments resulted in a significant enlargement of plastoglobuli in Scots pine and a darkening of plastoglobuli in Norway spruce. All exposures enhanced the accumulation of lipid bodies. An increased portion of translucent plastoglobuli was most pronounced in N treatments. Many of the ultrastructural changes and visible symptoms appeared only as number of years exposed increased, indicating that long-term experiments are needed. Both visible symptoms and ultrastructural changes pointed to the more pronounced sensitivity of Norway spruce compared to Scots pine. Ultrastructural results mostly supported earlier qualitative observations of F, N and SO2 effects on needle mesophyll cell ultrastructure. However, no reduction of thylakoids in SO2 containing exposure or curling of thylakoids in F exposure could be detected in the present study.
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    Anaerobic induced ethanol synthesis in the stems of greenhouse-grown conifer seedlings (1996)
    Springer
    Trees 10 (1996), S. 183-188 
    Details
    ISSN: 1432-2285
    Keywords: Anaerobic respiration ; Fermentation ; Hypoxia ; Pseudotsuga menziesii ; Pinus ponderosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ethanol synthesis was induced in stem segments from greenhouse-grown conifer seedlings by placing them in a N2 atmosphere at 30 °C for 24 h. Stems from ponderosa pine,Pinus ponderosa Dougl. ex Laws., sugar pine,Pinus lambertiana Dougl., Pacific silver fir,Abies amabalis Dougl. ex Forbes, and lodgepole pine,Pinus contorta Dougl. ex Loud, produced the highest quantities of ethanol. This group also had the smallest and slowest growing stems. Within each of these species the amount of ethanol produced was inversely related to the stem volume. Stems from western hemlock,Tsuga heterophylla (Raf.) Sarg., grand fir, Abies grandis Dougl. ex Forbes, Douglas-fir,Pseudotsuga menziesii (Mirb.) Franco, and western redcedar,Thuja plicata Donn ex D. Don, all produced equivalent but low ethanol concentrations. These species had the largest and fastest growing stems. In this group only grand fir exhibited an inverse relationship between ethanol concentrations and stem volume. The relative amounts of ethanol synthesized by stems from Douglas-fir, western hemlock and western redcedar seedlings were not the same as subsequently observed in logs from mature trees of the same species under field conditions. Differences in the anaerobic environments for the two stem types could have affected the quantities of ethanol produced. The observed high amounts of ethanol produced by the stems from pine species were discussed in terms of their ability to handle periods of anaerobic stress or hypoxia.
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    Effects of N addition rates on the productivity ofPicea sitchensis,Thuja plicata, andTsuga heterophylla seedlings (1996)
    Springer
    Trees 10 (1996), S. 189-197 
    Details
    ISSN: 1432-2285
    Keywords: Nitrogen ; Picea sitchensis ; Relative growth rates ; Thuja plicata ; Tsuga heterophylla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seedlings ofPicea sitchensis, Thuja plicata andTsuga heterophylla were supplied N hydroponically at one of four exponentially increasing rates of addition (0.09, 0.07, 0.05, or 0.025 gN-1 day-1) for up to 3 months in a naturally illuminated glasshouse. Relative growth rates (RGR) were analyzed as a function of N uptake, the allocation of assimilated N to foliage (LNFR), foliar N concentrations (Nla) and met assimilation rates (NAR), which were combined to estimate N productivity (RGR per unit whole-plant N concentration). Nitrogen accumulation, biomass and N partitioning and RGR and its components varied with species in response to the different N regimes.T. heterophylla had the lowest maximum wholeplant N concentrations (wpN) and specific absorption rates for N and exhibited the least plasticity in root: shoot ratios as wpN increased from 11–21 mg g-1. In all species, RGR increased linearly with wpN, while LNFR increased curvilinearly. Foliar N (Nla) increased linearly with wpN and NAR increased linearly with Nla. The RGRs ofT. heterophylla were highest at wpNs up to 18 mg g-1, a result of higher foliar N use efficiencies (NAR/Nla). However, RGR increased more with wpN inT. plicata andP. sitchensis. Although LNFR increased with wpN in all species, foliar N use efficiency declined, possibly due to an increased partitioning of foliar soluble N to non-photosynthetic compounds. Thus, in each species, N productivity did not increase above intermediate levels of wpN: 14 mg g-1 inT. heterophylla, 16 mg g-1 inP. sitchensis and 17 mg g-1 inT. plicata.
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    Assessing the impact of ozone on photosynthesis of European beech (Fergus sylvatica L.) in environmental chambers (1996)
    Springer
    Trees 10 (1996), S. 268-275 
    Details
    ISSN: 1432-2285
    Keywords: Beech ; Ozone ; Photosynthesis ; Closed chambers ; Critical Levels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An exposure — response study with proportionalto-ambient ozone levels was conducted in closed chambers on 3-year-old European beech (Fagus sylvatica L.) of montane origin. The fumigation started in April 1990 and lasted for a single growing season. Climate data and ozone concentrations monitored at an experimental station of the Institute for Applied Plant Biology, Schönenbuch, Switzerland were simulated in the exposure chambers 12 days later (1*O3). To test exposure-response relations three additional treatments were applied, subambient (0.2*O3) and two proportionally increased ozone treatments (1.5*O3 and 2*O3). The photosynthetic behaviour of the trees in August revealed the light reactions to be less affected than parameters which are related to the dark reactions of photosynthesis. Assimilation (A350), apparent carboxylation efficiency (CE), and maximum photosynthetic capacity (A2500) were reduced with increasing ozone concentration. For the ozone response of CE and A2500 ‘Critical Levels’ were calculated.
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    Effects of N addition rates on the productivity ofPicea Sitchensis,Thuja plicata, andTsuga heterophylla seedlings (1996)
    Springer
    Trees 10 (1996), S. 198-205 
    Details
    ISSN: 1432-2285
    Keywords: Nitrogen ; Photosynthesis ; Picea sitchensis ; Thuja plicata ; Tsuga heterophylla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of differing, exponentially increasing rates of N addition (0.025, 0.05, 0.07 and 0.09 gN gN-1day-1) on photosynthesis, discrimination against13C and partitioning of foliar N to chlorophyll and major photosynthetic proteins were compared in seedlings of the evergreen conifersPicea sitchensis, Thuja plicata andTsuga heterophylla. T. heterophylla had the lowest range of foliar N concentrations (Nlm). Across species, photosynthetic rates (A) increased linearly with Nlm to a maximum at 21 mg g-1 and declined at higher Nlms. Species differences inA resulted from differences in Nlm, not from differences in photosynthetic N use efficiency. Self-shading may have causedA to decline at a high Nlm inP. sitchensis andT. plicata. Measurements of gas exchange and δ13C suggested that carboxylation capacity increased more than did stomatal conductance as Nlm increased. The responses were small and confined to Nlms associated with the lesser rates of N addition. Concentrations of total protein, ribulose 1,5-bisphosphate carboxylase (RUBISCO) and the light harvesting chlorophyll a/b protein complex (LHC) increased with Nlm, but the fraction of foliar N allocated to RUBISCO and LHC increased with Nlm only inP. sitchensis and only between the 0.025 and 0.05N regimes. The responsiveness ofA and concentrations of RUBISCO to Nlm were less than reported for deciduous C3 species.
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    Slightly elevated ozone exposure causes cell structural changes in needles and roots of Scots pine (1996)
    Springer
    Trees 10 (1996), S. 207-217 
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    ISSN: 1432-2285
    Keywords: Ozone ; Pine ; Fine structure ; Needles ; Roots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Scots pine (Pinus sylvestris L.) seedlings were fumigated with 1.2–1.5 x ambient ozone over 2 seasons in an open-air experiment. Fumigation started in the early spring and continued into late autumn during both years. Needle and root cell structures were analyzed in the summer, autumn and early winter following the second fumigation period. Under the light microscope an increase in the intercellular space and disintegrating cells in the mesophyll tissue near the stomata and stomatal cavities were observed in the ozone-exposed needles. Darkening of chloroplast stroma, increased plastoglobulus size and decreased chloroplast size were characteristic ultrastructural changes associated with ozone exposure. In addition, less dense grouping of the chloroplasts in the needles of elevated ozone-exposed seedlings as compared to the controls (background ozone) was observed in the early winter. Fewer starch grains and an increased accumulation of tannin-like substances were detected in both mycorrhizal and uninfected roots of ozone-exposed seedlings as compared to the control seedlings. For the first time, we were able to show that the ozone-induced darkening of needle chloroplast stroma is a reversible symptom. An increased frequency of frost injury symptoms indicated that the winter hardening process was disturbed in the needles of ozone-treated seedlings.
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    Estimation of canopy density and irradiance in 20- to 40-year-old birch stands (Betula pubescens Ehrh. andBetula pendula Roth) (1996)
    Springer
    Trees 10 (1996), S. 223-230 
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    ISSN: 1432-2285
    Keywords: Betula pubescens Ehrh ; Betula pendula Roth ; Birch ; LAI ; Crown free projection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Three different experiments in birch (Betula pubescens Ehrh. andBetula pendula Roth) stands were conducted during summer 1991: an evaluation of the accuracy of the vertical tube method measuring crown free projection (CFP) in four birch stands; a study of relative irradiance (RI; photosynthetically active radiation, PAR), in birch stands differing in stem density and basal area; and an estimation of the CFP in different types of birch stands and the correlation between RI and CFP. The results indicate that the number of observation points well distributed over an area of 0.1 ha can vary between 50 and 200 to achieve sufficient accuracy. There were no significant differences in the CFP estimates made on the same plot by different observers including an untrained observer. CFP was related to basal area, stem number and diameter sum in a non-linear regression, CFP = A*e-BX. The correlations between RI and basal area, density and diameter sum, respectively, were 0.54, 0.57 and 0.67 for PAR. The coefficients of determination for RI (PAR) and CFP were high (0.86).
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    Carbon and water balance in Polylepis sericea, a tropical treeline species (1996)
    Springer
    Trees 10 (1996), S. 218-222 
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    ISSN: 1432-2285
    Keywords: Carbon balance ; Polylepis sericea ; Treeline ; Tropical Andes ; Water balance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Polylepis sericea trees grow well above the continuous forest line in the Venezuelan Andes. In these environments, extreme daily temperature ranges can occur at any time of the year and trees experience a 4 month dry period. The purpose of this work was to study carbon and water relations of this species in the field during wet and dry seasons in order to understand this species' success at such high altitudes. Leaf gas exchange (portable system in open mode) and leaf water potential (pressure chamber) were measured at 1–2 h intervals during several daily courses at 4000 m elevation in the Páramo de Piedras Blancas. CO2 assimilation versus leaf temperature curves were also obtained for this species in the laboratory. Clear differences in the measured parameters were observed between seasons. For a wet season day, maximum CO2 assimilation rate was 7.4 μmol m-2 s-1 and leaf conductance was relatively constant (approximately 100 mmol m-2 s-1)In the dry season day, maximum CO2 assimilation rate was 5.8 μmolm-2 s-1 and leaf conductance was close to 60 mmolm-2 s-1. Minimum leaf water potentials measured were -1.3 MPa for the wet and -2.2 MPa for the dry season. The CO2 assimilation-leaf temperature relationship showed a 13.4°C leaf temperature optimum for photosynthesis with maximum and minimum compensation points of 29.5 and -2.8°C, respectively. Maximum night-time respiration was relatively high (2.7 (imol) m-2 s-1)Our results show thatP. sericea maintains a highly positive carbon balance through all daily courses, even though there is a slight water stress effect during the dry season; this suggests that its carbon assimilation machinery is well adapted to the low temperatures and seasonal water stress found in the high tropical mountains.
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    Effects of age and site quality on the distribution of biomass in Scots pine (Pinus sylvestris L.) (1996)
    Springer
    Trees 10 (1996), S. 231-238 
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    ISSN: 1432-2285
    Keywords: Scots pine ; Biomass ; Allocation ; Age ; Single tree
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The distribution of the above-ground and below-ground biomass of Scots pine in southern Finland were investigated in trees of different ages (18–212 years) from two types of growth site. Secondly, some structural regularities were tested for their independence of age and growth site. Trees were sampled from dominant trees which could be expected to have a comparable position in stands of all ages. All stands were on sorted sediments. The biomass of the sample trees (18 trees) was divided into needles, branch sapwood and heartwood, stem sapwood and heartwood, stem bark, stump, large roots (diameter 〉20 cm), coarse roots (five classes) and fine roots. The amount of sapwood and heartwood was also estimated from the below-ground compartments. Trees on both types of growth site followed the same pattern of development of the relative shares of biomass compartments, although the growth rates were faster on the more fertile site. The relative amount of sapwood peaked after canopy closure, coinciding with the start of considerable heartwood accumulation. The relative amount of needles and fine roots decreased with age. The same was true of branches but to a lesser degree. The relative share of the below-ground section was independent of tree age. Foliage biomass and sapwood cross-sectional area were linearly correlated, but there were differences between the growth sites. Needle biomass was linearly correlated with crown surface area. The fine root to foliage biomass ratio showed an increasing trend with tree age.
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    Effects of bending stress on taper and growth of stems of youngEucalyptus regnans trees (1996)
    Springer
    Trees 10 (1996), S. 239-246 
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    ISSN: 1432-2285
    Keywords: Bending stress ; Stem shape ; Radial growth rate ; Eucalyptus regnans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A glasshouse experiment investigated the effect of bending stress on stem radial and height growth and stem taper ofEucalyptus regnans seedlings. Eighteen-week-old, potted seedlings were bent continuously for 8 weeks with a static bending stress. The bending treatment was then removed and the seedlings grown for another 12 weeks. Other seedlings were stayed vertically throughout the experiment whilst control seedlings were neither bent nor stayed. Seedlings were rotated every 2 days to prevent reaction wood developing asymmetrically in the stems of bent trees. Bent trees had higher radial growth rates, developed more tapered stems and had higher safety factors (the ratio of stem radius to the minimum radius required to prevent the tree toppling over) than unbent seedlings. They produced a band of tension wood in their stems and ceased height growth whilst bent. When bending ceased, they resumed normal radial and height growth. Unbent trees developed more cylindrical stems. There were no differences in growth behaviour between stayed and control trees. Bent and unbent trees all developed a butt swell, the taper of which was not affected by treatment. It was concluded that bending stress has substantial effects on both the size and taper of tree stems. However, the development of butt swell is independent of the bending stress applied. The results were considered in relation to biomechanical theories of tree stem development.
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    Nutrient dynamics in crown tissues of cork-oak (Quercus suber L.) (1996)
    Springer
    Trees 10 (1996), S. 247-254 
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    ISSN: 1432-2285
    Keywords: Evergreen oaks ; Macronutrients ; “Montado” ; Seasonal patterns ; Tissue nutrient contents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The seasonal fluctuation of N, P, K, Ca and Mg in leaves, young stems and fruits of young and matureQuercus suber trees growing at the same site was studied. Nutrient dynamics within the tree appeared to be linked to phenological events. Leaves maximized their nutrient contents throughout summer whereas stems maintained rather constant values during most of the year. Before the spring growth flush they apparently acted as temporary reservoirs for some nutrients, translocated from leaves or other organs, so that such nutrients would be easily invested in the new tissues. A significant investment was made in sink organs like flowers and fruits. The tree probably relies not only on leaves but also on other nutrient reservoirs like older branches and roots for an adequate supply to those sinks and to the spring growth. The importance of the sampling dates and the basis of expression used for nutrient concentrations has also been emphasized. Nutrient contents and seasonal trends of the studied trees were similar to those of other evergreen oaks, although somewhat higher values for N, K, and Mg were found. Moreover, soil nutrient contents in the studied “montado” were much lower than in other Iberic oak stands. However the nutrient status and requirements of cork-oak suggest high (or at least adequate) nutrient availability to the trees. The mechanisms by which this could be achieved are discussed.
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    Microautoradiographic detection of CO2 fixation in lenticel chlorenchyma of youngFraxinus excelsior L. stems in early spring (1996)
    Springer
    Trees 10 (1996), S. 255-260 
    Details
    ISSN: 1432-2285
    Keywords: CO2 fixation ; Fraxinus excelsior L. ; Lenticels ; Microautoradiography ; Stem chlorenchyma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Microautoradiography indicated that 1-year-oldFraxinus excelsior L. stem chlorenchyma assimilated external14CO2 in mid-April, when buds were swollen, but before bud-break. The lenticel regions showed the highest amount of radioactively labeled assimilates. Labeled assimilates declined in the tangential direction with increasing distance from lenticels, suggesting that14CO2 entered the stem through the open intercellular spaces of lenticels. In the radial direction, the amount of radioactively labeled assimilates did not constantly decline with growing distance from the lenticel entrance. It was high in all lenticel phelloderm cells, which had high chlorophyll autofluorescence and very small starch grains, highest in the adjacent 4–6 rows of chlorenchyma, which had larger starch grains that increased in size towards the interior rows, and much lower in the inner cortex chlorenchyma, which had large starch grains. We suggest that the main function of the lenticel chlorenchyma (lenticel phelloderm plus 4–6 rows of adjacent cortex chlorenchyma) is the refixation of respiratory CO2 which could easily leave the stem intercellular spaces, rather than the fixation of external CO2. The lenticel chlorenchyma could reduce the loss of respiratory CO2 by its photosynthetic activity.
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    Uptake of ammonium and nitrate ions from acid mist applied to Sitka spruce [Picea sitchensis (Bong.) Carr.] grafts over the course of one growing season (1996)
    Springer
    Trees 10 (1996), S. 261-267 
    Details
    ISSN: 1432-2285
    Keywords: Wet N inputs ; Labelled N ; N partitioning ; N accumulation ; Per cent incorporation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Cloned Sitka spruce grafts were subjected to NH4NO3 mist (1 mm day-1 equivalent) acidified with H2SO4, for 4 days a week, from April until November. Three N treatments at pH 5.0 used 0.01 mol m-3 15NH4 15NH3, 1.6 mol m-3 15NH4 NO3 or 1.6 mol m-3 NH4 15NO3. At pH 2.5, the treatments were15NH4 15NO3,15NH4NO3 and NH4 15NO3 all at 1.6 mol m-3. At the end of the growing season,15N was found in every part of the trees, even when NH4NO3 was supplied at 0.01 mol m-3. It was shown that both $$NH_{4^ + } $$ and $$NO_{3^ - } $$ could enter needles to a similar degree and be transported to the roots. No differences between pH treatments or clones could be demonstrated. Entry of labelled N via the roots, in those trees with unprotected compost, was reflected in higher fine root15N content, but no change in shoot15N levels. Per cent incorporation expressed as labelled N as a percentage of total N, was generally at its highest in bark, and in older needles in all treatments, values ranging from 5 to 11%. When15N content was expressed as total content for each tree part on a per tree basis, 25–36% was found in current year needles, with a further 12% in current year bark. The most reproducible data was that for dry weight of tree parts as per cent of the whole tree, where proportions compared closely between treatments and the two clones used. The implications of the results for cuticular transport mechanisms, N storage and internal cycling are discussed.
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    The effect of crown position and date of sampling on biomass, nutrient concentrations and contents of needles and shoots in European larch (1996)
    Springer
    Trees 10 (1996), S. 339-350 
    Details
    ISSN: 1432-2285
    Keywords: European larch ; Nutrient ; Biomass ; Needle ; Shoot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The nutrient concentrations and contents of needles and shoots of 22-year-old European larch (Larix decidua Mill.) were evaluated with respect to crown position, age of tissues and sampling date during a complete growing season. Concentrations of N, P, K, Ca, Mg and Zn in the needles and of N, P and K in the shoots differed significantly among the dates of sampling. The concentrations of N and Mn in the needles and all nutrients in the shoots (except Mg) also differed significantly with crown position. Maximum needle biomass was observed in the middle crown position (55% of the total) and maximum shoot biomass, in the lower crown position (52% of the total). Maximum needle and shoot nutrient contents were observed in the middle position of the living crown for long shoot, short shoot-1, short shoot-2, short shoot-3 and, short shoot-4 age classes while highest contents for short shoot-5 and short shoot-6 age classes were observed in the lower crown position. Biases up to 42% for Mg in the needles and 200% for K in the shoots were obtained when only long shoot tissues are used for content evaluation. For needles and shoots, Mg and K are more difficult nutrients to evaluate. A sampling methodology is proposed for evaluating nutrient contents of the living crown.
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    A model of the gas exchange response ofPicea abies to habitat conditions (1996)
    Springer
    Trees 10 (1996), S. 277-287 
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    ISSN: 1432-2285
    Keywords: Picea abies ; Norway spruce ; Leaf gas exchange ; Net photosynthesis ; Stomatal conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Databases describing branch gas exchange ofPicea abies L. at two montane forest sites, Lägeren, Switzerland (National Forschungsprojekt 14 of the Schweizerische Nationalfonds) and Oberwarmensteinach, Germany (Bayerische Forschungsgruppe Forsttoxikologie), were analyzed in conjunction with a physiologically based model. Parameter estimates for describing carboxylase kinetics, electron transport, and stomatal function were derived, utilizing information from both single factor dependencies and diurnal time course measurements of gas exchange. Data subsets were used for testing the model at the branch level. Most of the observed variation in gas exchange characteristics can be explained with the model, while a number of systematic errors remain unexplained. Factors seen as contributing to the unexplained residual variation and not included in the model are light acclimation, degree of damage in adjustment to pollutant deposition, needle age, and cold stress effects. Nevertheless, a set of parameter values has been obtained for general application with spruce, e.g., for use in calculating canopy flux rates and to aid in planning of focused leaf and canopy level experiments. The value of the model for estimating fluxes between the forest and the atmosphere must be evaluated together with measurements at the stand level.
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    Photoinhibition in cork-oak leaves under stress: influence of the bark-stripping on the chlorophyll fluorescence emission inQuercus suber L. (1996)
    Springer
    Trees 10 (1996), S. 288-292 
    Details
    ISSN: 1432-2285
    Keywords: Bark-stripping ; Fluorescence emission ; Quercus suber L. ; Water relations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Quercus suber is the primary source for industrial cork and becomes bark-stripped every 9–10 years. Recurring cork extraction is a major stress factor and the large water loss from the stripped trunk surface may affect the water balance and tree productivity. To evaluate the effect of bark-stripping, fluorescence emission and stomatal conductance of leaves were determined in groups of bark-stripped and control trees. Fv/Fm ratio was found to be significantly lower in bark-stripped trees indicating a reduced photosynthetic efficiency of PSII. Photosynthesis was not found to be stomata limited. The reduction in Fv/Fm resulted from a decline in maximum and variable fluorescence while the initial fluorescence of the dark-adapted state (Fo) remained constant. A general decline in photosynthetic efficiency of PSII was found in all trees during the summer, probably reflecting the prolonged environmental stresses during a hot and dry season. Additional stress caused by the bark-stripping seems to enhance the susceptibility to photoinhibition of the trees.
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    Magnesium deficiency treatment causes reductions in photosynthesis of well-nourished Norway spruce (1996)
    Springer
    Trees 10 (1996), S. 293-300 
    Details
    ISSN: 1432-2285
    Keywords: Norway spruce ; Magnesium deficiency ; Photosynthesis ; Carboxylation efficiency ; Starch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In order to investigate effects of magnesium deficiency on Norway spruce [Picea abies (L.) Karst.] photosynthesis, 100 well-nourished 5-year-old spruce trees were grown in sand culture, individually supplied with circulating nutrient solutions. Mineral nutrients were added to the nutrient solutions in optimal quantities and optimal relations to nitrogen. Magnesium was supplied at 0.203, 0.041 and 0.005 mM in order to simulate optimal nutrition, moderate deficiency and severe deficiency. Parameters of photosynthetic gas exchange, chlorophyll, magnesium and starch concentrations were determined in current-year and 1-year-old needles during one growing season. By mid May — 6 months after onset of the Mg deficiency treatments in late autumn — CO2-assimilation rates of 1-year-old needles were significantly decreased independent of the severity of the deficiency treatment, whereas the chlorophyll concentrations did not differ from the controls. The occurrence of yellowing symptoms during July did not further influence the Mg deficiency effect on photosynthesis. In contrast to 1-year-old needles, significant reductions of photosynthesis and chlorophyll in current-year needles were only caused by severely deficient Mg supply. Mg deficiency affected carboxylation efficiency but not light use efficiency. From the accumulation of starch in the needles, up to 30-fold of the controls, the conclusion has been drawn that reactions of CO2-fixation were affected by reduced carbohydrate export. The light-dependent pigment reduction, leading to the typical tipyellowing of needles, clearly reflects a secondary effect of Mg deficiency.
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    Transpiration and drought resistance of Douglas-fir seedlings exposed to excess ammonium (1996)
    Springer
    Trees 10 (1996), S. 301-307 
    Details
    ISSN: 1432-2285
    Keywords: K ; P ; Pseudotsuga menziesii ; Root/shoot ratio ; Soil acidification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In a pot trial growth and transpiration of 3-year-old Douglas-fir seedlings on an acid, sandy soil was examined at a deficient (30 kg N ha-1 year-1) and an excessive level (120 kg N ha-1 year-1 of NH4 application. Dissolved ammonium sulphate was applied to the pots weekly for two growing seasons. In half of the pots a complete set of other nutrients was applied in optimal proportions to the applied nitrogen. Water supply was optimal and transpiration was recorded. At the end of the second treatment season irrigation was stopped for 2 weeks during dry and sunny weather. Both high application of NH4 and additional nutrients increased shoot growth and transpiration demand in the first treatment year. The root system was smaller at higher N level and this reduced water uptake accordingly. In the second year the combination of high NH4 + and additional nutrients affected root functioning predominantly due to salinity effects and this seriously decreased water uptake capacity and shoot water potentials, finally resulting in tree death. Without addition of other nutrients the high NH4 + application resulted in a high degree of soil acidification, which damaged the roots, that showed a decrease in water uptake capacity. At the low NH4 supply level soil acidification was lower, and root functioning was not affected, and the trees recovered quickly from the imposed drought. Higher needle K and P status depressed transpiration rates at the low NH4 application rate.
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    URL: http://dx.doi.org/10.1007/BF02340776
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    Differential growth and recovery rates following defoliation in related deciduous and evergreen trees (1996)
    Springer
    Trees 10 (1996), S. 308-316 
    Details
    ISSN: 1432-2285
    Keywords: Herbivory ; Plant-insect interactions ; Leaf lifespan ; Pinus ; Larix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Deciduous larches,Larix spp., and evergreen pines,Pinus spp., are sympatric Pinaceae conifers. Adjacent monocultures of 10-year-oldLarix decidua Mill, andPinus resinosa Ait. were subjected to single-season artificial defoliation by clipping from 0% to 99% of each needle. Survival, above-ground productivity, and architecture were measured for 36 months.P. resinosa andL. decidua exhibited differential relationships with defoliation intensity and recovery time. Two months after treatment, defoliation reduced larch height growth but had no effect on radial growth. By contrast,P. resinosa stem radial growth was reduced immediately, but height growth was not decreased until the following year. Pine leader growth and above-ground biomass following 66% defoliation never recovered to control values or 33% defoliated pines. Conversely, defoliated larch quickly recovered from an initial growth loss to eliminate all treatment effects on biomass. The plasticity in architectural response found in larch, but not pine, might partially account for defoliation tolerance. BothP. resinosa andL. decidua exhibited non-linear responses to defoliation. These patterns may be caused partially by the uneven distribution of nutrients within needles, rather than a simple function of leaf area lost to defoliators. Concentrations of 13 nutrients inP. resinosa were highest either in the mid-(Ca, Mg, S, Zn, B, Mn, Fe, Al and Na) or basal-(N, P, K, and Cu) section. The relatively low nutrient content in needle tips may contribute to similar biomass productivity between trees defoliated 33% and controls. Removal of needle mid-sections significantly reduced whole-plant productivity. In contrast,L. decidua nutrients are concentrated in the distal sections. Nutrient concentrations were generally highest in larch. Our results agree with an emergent prediction of the carbon/ nutrient balance theory that defoliation more severely reduces growth of evergreen than deciduous species. These results are discussed within the physiological, ecological and evolutionary context of allocation theory, with implications for natural resource management and plant-insect interaction theory.
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    URL: http://dx.doi.org/10.1007/BF02340777
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    Effects of pre-severance light quality on the vegetative propagation ofEucalyptus grandis W. Hill ex Maiden (1996)
    Springer
    Trees 10 (1996), S. 317-324 
    Details
    ISSN: 1432-2285
    Keywords: Carbohydrates ; Eucalyptus grandis ; Photosynthesis ; Propagation ; Red to far-red ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two-leaf, two-node cuttings were taken fromEucalyptus grandis stockplants grown under different light qualities (red to far-red ratios of 0.4, 0.7, 1.3, 3.5 and 6.5) at a constant photon flux density (200 μmol m-2 s-1). Two experiments tested effects of pre-severance light quality on cutting morphology, post-severance gas exchange, carbohydrate status and rooting of cuttings. The best rooting percentage was achieved by cuttings with longer stems and greater stem volume from stockplants grown at lower red to far-red (R∶FR) ratios. Generally, rooting success was associated with low pre-severance starch and water-soluble sugar concentrations, and a greater total water-soluble carbohydrate (TWSC) content per cutting. Rooting was associated with well maintained stem starch and an increase in stem TWSC during the propagation period. Gas exchange of cuttings was measured between 28 and 33 days after severance. Rooting percentages at 35 days after severance were positively and linearly related to net photosynthetic rate and stomatal conductance. In unrooted cuttings there was a net release of CO2 which increased significantly with an increase in pre-severance R∶FR ratio. These results demonstrate that stockplant environment may significantly modify the morphology and physiology of subsequent cuttings, and that cutting morphology, and stored and current photosynthates have a significant influence on rooting.
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    URL: http://dx.doi.org/10.1007/BF02340778
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    Pyridine nucleotide levels and activities of dehydrogenases in cambial derivatives ofRobinia pseudoacacia L. (1996)
    Springer
    Trees 10 (1996), S. 325-330 
    Details
    ISSN: 1432-2285
    Keywords: Cambial differentiation ; Glucose-6-phosphate dehydrogenase ; 6-Phosphogluconate dehydrogenase ; NAD kinase ; Pyridine nucleotides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Despite the importance of the vascular cambial differentiation, little is known about its regulation. In order to address this problem we attempted to biochemically characterize differentiating xylem and phloem elements during the early stages of development. By applying techniques of quantitative histochemistry we show that the total pool size of pyridine nucleotides is similar in the phloem (PD) and xylem (XD) oriented derivatives of the cambial zone of trees ofRobinia pseudoacacia L. Within the PD zone, the amount of NAD + NADH exceeded that of NADP + NADPH [around 600 versus 200 pmol (mg dry weight)-1], possibly indicative of a preponderance of catabolic pathways (ratio of NADH∶NAD about 1). In contrast, the NADP(H) system dominated in the XD zone. This coincided with a high activity of NAD kinase. In addition, the extractable activities of the key enzymes of the oxidative pentose phosphate pathway, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, were greatly increased. At a ratio of NADPH∶NADP of approximately 1, this could be indicative of increased rates of reductive biosyntheses, and could thus well be involved in early steps of the formation of phenols and lignin monomers. Taken together, this first approach clearly shows that phloem-oriented and xylem-oriented cambial descendents exhibit distinct differences in their biochemical patterns even in early stages of differentiation.
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    URL: http://dx.doi.org/10.1007/BF02340779
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    Phytohormones in needles of healthy and declining silver fir (Abies alba Mill.): I. Indole-3-acetic acid (1996)
    Springer
    Trees 10 (1996), S. 331-338 
    Details
    ISSN: 1432-2285
    Keywords: Indole-3-acetic acid ; Abies ; Needle senescence ; Forest decline ; SO2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Levels of indole-3-acetic acid (IAA) were determined in needles from silver fir (Abies alba Mill.) trees in the northern Black Forest. IAA was quantified by gas chromatography (GC) as 1-heptafluorobutyryl-IAA-methylester (HFB-IAA-ME) using electron capture detection. Prior to GC analysis, extensive purification of needle extracts was performed employing two HPLC steps. Peak identity of HFB-IAA-ME was confirmed by combined gas chromatography-mass spectrometry in selected samples. Levels of IAA in needles belonging to different needle age-classes exhibited a cyclic seasonal pattern with highest concentrations in winter and lowest levels in spring when bud-break occurred. Such a cyclic seasonal pattern of IAA levels was also observed in needles from declining fir trees or fir trees suffering from a strong sulfur impact (S-impact) in the field due to a local SO2 source. Levels of IAA increased with increasing needle age. This age dependency of IAA concentrations was most pronounced in late autumn when IAA levels were high and nearly disappeared in spring when IAA levels reached their minimum. In needles from declining fir trees or fir trees suffering from a strong S-impact in the field, IAA levels hardly increased with increasing needle age. It is suggested that in healthy trees high levels of IAA protect older needles from abscission and that the considerable losses of older needles of declining fir trees or of fir trees under S-impact are a consequence of the low levels of IAA found in older needles of such trees.
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    URL: http://dx.doi.org/10.1007/BF02340780
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    Relationships between carbon and hydrogen isotope ratios and nitrogen levels in leaves ofClusia species and two other Clusiaceae genera at various sites and different altitudes in Venezuela (1996)
    Springer
    Trees 10 (1996), S. 351-358 
    Details
    ISSN: 1432-2285
    Keywords: Altitude ; Carbon isotope ratio ; Clusiaceae ; Crassulacean acid metabolism ; Deuterium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Samples of the Clusiaceae generaClusia, Oedematopus andDystovomita were collected at various sites and different altitudes in northern and south-western Venezuela. Analyses of stable isotopes of carbon and hydrogen and of leaf-nitrogen levels were performed on the dried samples. Correlations among these variables, i.e. carbon isotope discrimination (Δ), hydrogen isotope ratio (δD) and N-levels, and with altitude were assessed. In the samples, where values of Δ above 15‰ indicate predominant performance of C3 photosynthesis, there were slight tendencies of increasing Δ, δD and N-levels with increasing altitude and of increasing Δ with increasing N. Although these correlations taken separately were not statistically significant, they support each other and indicate increasing transpiration and increased leaf-nutrient supply at increasing altitude. Performance of crassulacean acid metabolism (CAM) in species ofClusia appears to be restricted to altitudes below 1500 m a.s.l. There was a significant negative correlation of Δ with altitude in the samples, where values of Δ below 10‰ indicated predominant performance of CAM. This suggests that phases II and IV of CAM are progressively suppressed towards the upper altitudinal limit of CAM inClusia in northern Venezuela. It is concluded that among the large number of environmental factors and combinations thereof, which determine the expression of CAM inClusia and trigger C3-CAM transitions in C3/CAM intermediate species, low availability of water is the most important.
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    URL: http://dx.doi.org/10.1007/BF02185638
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    The effect of light levels on daily patterns of chlorophyll fluorescence and organic acid accumulation in the tropical CAM treeClusia hilariana (1996)
    Springer
    Trees 10 (1996), S. 359-365 
    Details
    ISSN: 1432-2285
    Keywords: Chlorophylla fluorescence quenching ; Citric acid ; Malic acid ; Photochemistry ; Photosynthetic electron transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Sandy plains are characteristic of the coastal region of Brazil. We investigated the diel patterns of changes in organic acid levels, leaf conductance and chlorophylla fluorescence for sun-exposed and shaded plants ofClusia hilariana, one of the dominant woody species in the sandy coastal plains of northern Rio de Janeiro state. Both exposed and shaded plants showed a typical CAM pattern with considerable diel oscillations in organic acid levels. The degradation of both malic and citric acids during the midday stomatal closure period could lead to potential CO2 fixation rates of 28 μmol m-2 s-1 in exposed leaves. Moreover, exposed leaves exhibited large increases in total non-photochemical quenching (qN) accompanied by a substantial decrease in effective quantum yield during the course of the day. However, these potential high rates of CO2 fixation and the increases inqn of exposed plants were not enough to maintain the primary electron acceptor of photosystem II (qA) in a low reduction state, similar to that of shaded plants. As a result, there was a moderate increase in the reduction state of qA throughout the day. Most of the decline in photochemical efficiency of exposed leaves ofC. hilariana was reversible, as evidenced by the high levels of pre-dawn potential quantum yields (Fv/Fm) and their rapid recovery after sunset. However, the depletion of the organic acid pool in the afternoon resulted in an accentuated subsequent drop in Fv/Fm, suggesting that prolonged periods of water stress accompanied by high irradiance levels may expose plants ofC. hilariana in unprotected habitats to the danger of photoinhibition.
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    URL: http://dx.doi.org/10.1007/BF02185639
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    Lipids and lipolytic enzymes in the trunkwood ofRobinia pseudoacacia L. during heartwood formation (1996)
    Springer
    Trees 10 (1996), S. 366-375 
    Details
    ISSN: 1432-2285
    Keywords: Acyllipids ; Heartwood formation ; Phospholipids ; Robinia pseudoacacia L. ; Sterols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The radial distribution of membrane and storage lipids was determined in the trunkwood ofRobinia pseudoacacia L. The trees were felled in November at the time of heartwood formation and fluctuations in the amount and composition of phospholipids, free sterols, steryl esters, diand triacylglycerols, and free fatty acids were investigated across the sapwood-heartwood boundary. The individual compounds were identified and quantified by thin layer chromatography, enzymatic and colorimetric assays, and by capillary gas chromatography. Phospholipids show a significant decrease towards the boundary area, and in the heartwood only trace amounts can be detected. The same pattern is observed for free sterols in the sapwood; in the heartwood, however, they reach maximum values with increasing depth of the trunk. Steryl esters exhibit a complementary behaviour by accumulating at the periphery of the heartwood. No concentration changes are found in the total amounts of diacylglycerols and free fatty acids. In contrast, the triacylglycerol concentration declines steadily across the trunk. With regard to qualitative composition, free fatty acids and the fatty acid moieties of the esterified constituents vary in their chain length from 14 to 24 carbon atoms and have up to three double bonds. A radial gradient in the ratio saturated/unsaturated fatty acids can be observed: except for the phospholipid fraction the relative amounts of unsaturated fatty acids increase in centripetal direction. Seven phospholipids were identified: phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, diphosphatidylglycerol, and phosphatidic acid, which constitutes the major proportion. In the sterol group, sitosterol is the most abundant component. The composition of the esterified sterols remains constant across the trunk cross-section, whereas the relative frequencies of individual free sterols change markedly.
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    Lipids and lipolytic enzymes in the trunkwood ofRobinia pseudoacacia L. during heartwood formation (1996)
    Springer
    Trees 10 (1996), S. 376-381 
    Details
    ISSN: 1432-2285
    Keywords: Acylesterhydrolase ; Heartwood formation ; Lipase ; Robinia pseudoacacia L. ; Phospholipases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The radial profile of lipase and phospholipase activities was determined in the trunkwood ofRobinia pseudoacacia L. The trees were felled in November at the time of heartwood formation and alterations in the enzymatic activities were investigated across the sapwood and heartwood. Methods employed include gaschromatographic, colorimetric and enzymatic assays. On a dry weight basis, the hydrolysis of the artificial substrate pnitrophenylpalmitate shows a maximum activity in growth ring 4; however, the assay has proved not to be specific for lipase. In contrast, lipase analyses (triacylglycerol acylhydrolase; E.C. 3.1.1.3) with an authentic substrate show activity peaks in growth rings 1 and 4. With protein as a reference the highest activity is found in growth ring 5. A similar tendency is observed for phospholipase A1 (E.C. 3.1.1.32) and phospholipase A2 (E.C. 3.1.1.4). Phospholipase C (E.C. 3.1.4.3) activity decreases towards the sapwood-heartwood boundary; negligible traces of activity are detected in the heartwood, whereas, based on the protein content, growth ring 4 yields maximal activity. Phospholipase D (3.1.4.4) exhibits the same radial pattern with regard to protein content as a reference. On a dry weight basis there is a significant increase within the sapwood area, while in the heartwood the activity drastically decreases. The enzyme activities are discussed in relation to degradative processes within the plasma membranes and the hydrolysis of reserve lipids during heartwood formation.
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    Interactive effects of elevated CO2 and O3 on photosynthesis and biomass production of clonal 5-year-old Norway spruce [Picea abies (L.) Karst.] under different nitrogen nutrition and irrigation treatments (1996)
    Springer
    Trees 10 (1996), S. 382-392 
    Details
    ISSN: 1432-2285
    Keywords: CO2 ; Ozone ; Norway spruce ; Gas exchange ; Biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract To study the single and combined effects of elevated carbon dioxide (CO2), ozone (O3), nitrogen nutrition, and water supply on photosynthetic gas exchange and biomass accumulation of Norway spruce, a four-factorial experiment was conducted in closed environmental chambers. Each factor was applied at two levels: (i) ambient and elevated (ambient + 200 μl 1-1) CO2, (ii) 20 and 80 nl 1-1 O3, (iii) low and high nitrogen fertilization, and (iv) a well watered and a drought treatment. Neither elevated O3 nor CO2 significantly changed stomatal conductances of spruce needles. Adverse effects of elevated O3 on photosynthetic parameters such as net assimilation rate and carboxylation efficiency occurred only when the plants were well watered and in a good nutritional status. After 6 weeks enhanced atmospheric CO2 resulted in increased net assimilation rates provided that nutrition was well balanced and plants were well watered. Acclimation processes became apparent and are interpreted as a consequence of sink regulation. While O3-effects were apparent only in biomass of 1-year-old plant material, elevated CO2 resulted in higher biomass of the buds expanding during the exposure and increased root biomass significantly. Above and below-ground biomass were strongly influenced by the water and nutrition treatments.
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    The effect of long term CO2 enrichment on the growth, biomass partitioning and mineral nutrition of Sitka spruce (Picea sitchensis (Bong.) Carr.) (1996)
    Springer
    Trees 10 (1996), S. 393-402 
    Details
    ISSN: 1432-2285
    Keywords: Elevated CO2 ; Sitka spruce ; Growth ; Allocation ; Nutrients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Sitka spruce [Picea sitchensis (Bong.) Carr.] seedlings were grown for 3 years in an outside control plot or in ambient (∼355 μmol mol-1) or elevated (ambient + 350 μmol mol-1) atmospheric CO2 environments, within open top chambers (OTCs) at the Institute of Terrestrial Ecology, Edinburgh. Sequential harvests were carried out at the end of each growing season and throughout the 1991 growing season, five in all. Plants grown in elevated CO2 had, (i) 35 and 10% larger root/shoot ratios at the end of the first and third season, respectively, (ii) significantly higher summer leader extension relative growth rates, which declined more rapidly in early autumn than ambient grown plants, (iii) after three growing seasons a significantly increased mean annual relative growth rate, (iv) consistently lower foliar nutrient concentrations, and (v) after two growing seasons smaller total projected needle areas. Plants grown inside OTCs were taller, heavier and had a smaller root/shoot ratio than those grown outside the chambers. There was no effect of CO2 concentration on Sitka spruce leaf characteristics, although leaf area ratio, specific leaf area and leaf weight ratio all fell throughout the course of the 3 year experiment.
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    Changes in root growth patterns of (Picea abies) spruce roots by inoculation with an ectomycorrhizal fungusPisolithus tinctorius and jasmonic acid treatment (1996)
    Springer
    Trees 10 (1996), S. 410-414 
    Details
    ISSN: 1432-2285
    Keywords: Ectomycorrhiza ; Jasmonic acid ; Picea abies ; Pisolithus tinctorius ; Spruce
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Symbiosis between fungi and plant roots forming a mycorrhiza involves extensive interactions at the molecular level between both partners. The role of plant hormones in the regulation of mycorrhizal infection is not known to involve jasmonates. Their endogenous levels increase during pathogen attack; however, little has been done on their involvement in mycorrhizae. In our recent work, root growth patterns of 2-month-old spruce seedlings after inoculation withPisolithus tinctorius and/or jasmonic acid (JA) treatment were studied using a paper-sandwich technique. Changes in root length, the degree of branching, presence and length of root hairs, and infection parameters were followed using a stereomicroscope. The first mycorrhizal contact of hyphae with roots was significantly accelerated upon treatment with 0.5 μM JA. Interactions between root hairs and fungal hyphae were seen by scanning electron microscopy. The multiplication of root hairs of non-mycorrhized seedlings treated with 5.0 μM JA and changes of the root surface were observed by the same technique.
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    Early season cuticular conductance and gas exchange in two oaks near the western edge of their range (1996)
    Springer
    Trees 10 (1996), S. 403-409 
    Details
    ISSN: 1432-2285
    Keywords: Cuticular conductance ; Gallery forests ; Leaf development ; Photosynthesis ; Quercus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seasonal changes in minimum leaf conductance to water vapor (gmin), an estimate of cuticular conductance, and photosynthetic gas exchange in two co-occurring oak species in north-east Kansas (USA) were examined to determine if leaf gas exchange characteristics correlated with differences in tree distribution. Bur oak (Quercus macrocarpa Michx.) is more abundant in mesic gallery forest sites, whereas chinquapin oak (Quercus muehlenbergii Englm.) is more abundant in xeric sites. Early, during leaf expansion, gmin was significantly lower in chinquapin oak than in bur oak, though midday water potentials were similar. After leaves had fully expanded, gmin decreased to seasonal minimum values of 4.57 (±0.274) mmol m-2 s-1 in bur oak, and 2.66 (±0.156) mmol m-2 s-1 in chinquapin oak. Water potentials at these times were significantly higher in chinquapin oak. As leaves were expanding, photosynthesis (Anet) was significantly higher in chinquapin oak than in bur oak. Later in the growing season, Anet and gleaf increased dramatically in both species, and were significantly higher in bur oak relative to chinquapin oak. We concluded that bur and chinquapin oak have a number of leaf gas exchange characteristics that minimize seasonal water loss. These characteristics are distinct from trees from more mesic sites, and are consistent with the distribution patterns of these trees in tall-grass prairie gallery forests.
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    The effect of industrial pollution on Zinc, Cadmium and Copper concentration in the xylem rings of Scot's pine (Pinus sylvestris L.) and in the soil (1988)
    Springer
    Trees 2 (1988), S. 1-6 
    Details
    ISSN: 1432-2285
    Keywords: Tree-rings ; Pine ; Zinc ; Cadmium ; Copper
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The concentrations of heavy metals, including zinc, cadmium, and copper were studied in the xylem rings of Pinus sylvestris trees and in the soil of three heavily polluted sites and one non-polluted site. There was a high correlation between the concentration of heavy metals in the soil and recently produced xylem rings. However, the initiation of industrial pollution did not abruptly increase heavy metal concentrations in the xylem rings. There was a high correlation between the zinc content of trees growing near a zinc smelter and the values obtained by other investigators for pine trees growing on the same site.
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    The effect of vessel element structure on element conductivity (1988)
    Springer
    Trees 2 (1988), S. 25-31 
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    ISSN: 1432-2285
    Keywords: Vessel elements ; Conductivity ; Perforation plates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A number of structural variables influence the conductivity of simple and scalariform perforation plates, and of vessel lumina. Using a previously developed computer model, the effects on conductivity of over 8,000 permutations of different lumen radii, perforation plate angles, perforation plate rim widths, scalariform slit pore heights, and scalariform bar thicknesses are considered. By taking advantage of basic patterns of similarity in the data, and by using scaling techniques, it has proved possible to calculate a series of factors which may be used to predict the conductivity of a vessel element or perforation plate of known dimensions. A number of previous workers have sought relationships between element structure and evolutionary or adaptive trends. Some important variables have been ignored in these studies in the past.
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    Transport processes in stimulated and non-stimulated leaves of Mimosa pudica (1988)
    Springer
    Trees 2 (1988), S. 7-17 
    Details
    ISSN: 1432-2285
    Keywords: Leaf movements ; Mimosa ; Osmotic mechanisms ; Phloem translocation ; Sucrose unloading ; Turgor release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Mature leaves of Mimosa pudica L. or parts of them were exposed to 14CO2, and translocation was recorded by macroautoradiography. It was observed that considerable amounts of labelled photoassimilates were accumulated in pulvini when the leaf was stimulated. In non-stimulated leaves, no such accumulation of label was observed. Microautoradiographs of pulvinar regions of the non-stimulated leaf showed 14C- label restricted to the phloem. When stimulated, the 14C- label was unloaded from the phloem of the pulvini. Labelled photoassimilates appeared most concentrated in the walls of the collenchymatous cells and beyond in the extensor region of the motor cortex. There, label was accumulated in the apoplastic compartments. Stimulation causes a sudden phloem unloading of sucrose, and its accumulation in the apoplast lowers the water potential which eventually exceeds the osmotic potential of the extensor cells of the motor cortex. By removal of cytoplasmic water the motor cells lose turgidity which results in the closing movement of the leaflets, and — some seconds later — in the bending down of the petiole. In late afternoon night-stimulation triggers sucrose unloading in secondary pulvini. During phases of relaxation, labelled material is taken up by motor cells of the extensor, which concomitantly gain turgor.
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    Transport processes in stimulated and non-stimulated leaves of Mimosa pudica (1988)
    Springer
    Trees 2 (1988), S. 18-24 
    Details
    ISSN: 1432-2285
    Keywords: Action potential ; Adenine nucleotides ; Aphid stylet ; Mimosa ; Orthophosphate ; Phloem ; Sucrose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Adenosine diphosphate (ADP), adenosine triphosphate (ATP) and orthophosphate were determined in non-stimulated, stimulated and relaxed pulvini of mature Mimosa pudica L. leaves. Additional determinations were made with leaflets, rhachillae, petiole and the stem in the stimulated condition. Results show that the content of adenine nucleotides is approximately twice as high in the pulvini as in the tissues between the pulvini. Orthophosphate, in contrast, occurs at higher concentrations in the connecting tissues than in the pulvini. ATP content is highest in the primary pulvini (0.8 μmol/mg dry wt.) and lowest in the tertiary pulvini. Stimulation causes consumption of ATP with a simultaneous increase in ADP content; however, the response is different in each type of pulvinus. This difference is best expressed in the ATP∶ADP ratio. Stimulation causes the most marked reduction of the ratio (9.5-1.4) in the secondary pulvini which react nyctinastically. Orthophosphate content is reduced by stimulation in all types of pulvini, and is increased during the recovery phase. By using a stylet bundle severed from a feeding aphid by a laser shot as tip for the microelectrode, changes of sieve tube membrane potentials were recorded. The changes of the electropotentials following stimulation show that the sieve tube is the pathway for the transmission of the excitation signal in the form of an action potential.
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    URL: http://dx.doi.org/10.1007/BF00196975
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  • 87
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    Adventitious bud development in embryonic tissue of Pinus caribaea and Pseudotsuga menziesii (1988)
    Springer
    Trees 2 (1988), S. 32-38 
    Details
    ISSN: 1432-2285
    Keywords: Auxin ; Cytokinin ; Gymnosperm ; Micropropagation ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Adventitious bud formation was induced on detached cotyledons and on cotyledons attached to excised embryos of Pinus caribaea and Pseudotsuga menziesii. The embryonic tissue was exposed to the cytokinin 6-benzyl amino purine contained within an agar medium. This exposure resulted in the formation of a meristematic zone, involving both epidermal and sub-epidermal cells, and then nodules on the tissue surface. Some of these nodules were induced to differentiate into bud primordia, and thence shoots, following exposure to a combination of auxin (IAA) and cytokinin. Shoots were produced over the entire surface of detached cotyledons of Ps. menziesii but predominantly on the adaxial surfaces of detached cotyledons of Pi. caribaea and the tips and adaxial surfaces of the cotyledons on the entire embryos of both species. Thus, inter-specific differences in the distribution of competent areas for adventitious bud production were detected in embryos.
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    URL: http://dx.doi.org/10.1007/BF00196977
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  • 88
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    Cytokinin activity in Citrus jambhiri Lush. seedlings colonized by vesicular-arbuscular mycorrhizal fungi (1988)
    Springer
    Trees 2 (1988), S. 39-44 
    Details
    ISSN: 1432-2285
    Keywords: Citrus jambhiri ; Dihydroeatin ; Symbiosis ; Zeatin ; Zeatin riboside
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The influence of vesicular-arbuscular mycorrhizal symbiosis on cytokinin activity in Citrus jambhiri Lush, seedlings was investigated. C. jambhiri inoculated with cultures of Glomus caledonium (Nicol. and Gerd.), G. epigaeum (Dan. and Trappe), G. etunicatum (Becker and Gerd.), G. fasciculatum Thaxt. (Gerd, and Trappe) or G. mosseae (Nicol and Gerd.) was grown from seed for 105 days in a glasshouse. Cytokinin activity in roots and leaves of seedlings was analyzed using high-performance liquid chromatography, mass spectrometry and a bioassay. Seedling leaf tissue had greater cytokinin activity than root tissue. Zeatin, zeatin riboside, and their dihydro- and glucoside derivatives were isolated from leaves of 105-day-old seedlings inoculated with G. fasciculatum and G. mosseae. Cytokinin activity in roots and leaves was associated with differences in seedling total dry weight and vesicular-arbuscular mycorrhizal colonization. The ribose moiety and the saturated side chain apparently influence cytokinin transport and physiological activity in Citrus seedlings.
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    URL: http://dx.doi.org/10.1007/BF00196978
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  • 89
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    Influence of various factors on quantitative composition of leaf monoterpenes of Picea abies (L.) Karst (1988)
    Springer
    Trees 2 (1988), S. 45-51 
    Details
    ISSN: 1432-2285
    Keywords: Picea abies ; (Mono) terpenes ; Needle ; Variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The extractable monoterpenes from needles of two groups of trees — 4-year-old clonal and 20-year-old wild trees — were studied with respect to the influence of individual constitution, needle age, whorl position, and position on branch. Leaf terpene amounts from clonal trees are significantly affected by age and position of the whorl, whereas position on the branch is of minor importance. Developing needles of clonal trees are most strongly affected by age and whorl position and they differ markedly from mature needles in quantitative terpene composition. Wild trees exhibit a very high variation from tree to tree, which obscures the influence of needle age and position. For this reason meaningful tree leaf terpene data will only be derived if large samples of needles of different ages are collected from distinct positions. When comparing different trees, needles should be selected that not only have the same state of development, but also originate from identical positions and have been subjected to the same light treatment.
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    URL: http://dx.doi.org/10.1007/BF00196979
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  • 90
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    Electronic Resource
    The seasonal variation of 20 elements in 1st and 2nd year needles of Norway spruce, Picea abies (L.) Karst (1988)
    Springer
    Trees 2 (1988), S. 52-64 
    Details
    ISSN: 1432-2285
    Keywords: Picea abies ; Seasonal variation ; Correlations ; Elemental concentrations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The concentration of 20 elements (including eight nutritional elements) in spruce needles was monitored by taking samples at nine different dates in a single year. On each date the youngest and the 1-year-old needles were collected at four different sites. The needles were washed with an organic solvent to remove surface contamination before analysis by instrumental neutron activation. Although the sites showed widely different concentrations for the same element, they could be treated as a uniform population using normalized concentration values. Taking the time dependence of the concentration and the ratio of the concentrations in new and old needles as criteria, the following three groups of elements could be distinguished: 9 group I —Ca, Sr, Ba, and Mn; group II — Al, Br, Co, Fe, Hg, La, Sc, Sb, and Zn; group III — K, Rb, Cs, P, and Cl. Mg and Na did not fit into any of these groups. Within group I and III elements the strongest variations occur during the growing season (late spring and early summer) and the weakest during the dormant season; the variation is greater in the younger needles. Group II elements show an approximately linear increase throughout the year in both the younger and older needles. The concentrations of elements of groups I and II increase with time, while those of group III decrease. Na is unique insofar as its concentration is influenced by foliar uptake of road de-icing salt. The concentration of elements belonging to the same group shows strong inter-element correlations. The grouping of elements deduced here shows similarities with the chemical nature of the elements and with their transportability within the plant.
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    URL: http://dx.doi.org/10.1007/BF00196980
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  • 91
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    The effect of industrial pollution on Zinc, Cadmium and Copper concentration in the xylem rings of Scot's pine (Pinus sylvestris L.) and in the soil (1988)
    Springer
    Trees 2 (1988), S. 1-6 
    Details
    ISSN: 1432-2285
    Keywords: Tree-rings ; Pine ; Zinc ; Cadmium ; Copper
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The concentrations of heavy metals, including zinc, cadmium, and copper were studied in the xylem rings ofPinus sylvestris trees and in the soil of three heavily polluted sites and one non-polluted site. There was a high correlation between the concentration of heavy metals in the soil and recently produced xylem rings. However, the initiation of industrial pollution did not abruptly increase heavy metal concentrations in the xylem rings. There was a high correlation between the zinc content of trees growing near a zinc smelter and the values obtained by other investigators for pine trees growing on the same site.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01196338
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  • 92
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    Electronic Resource
    Transport processes in stimulated and non-stimulated leaves ofMimosa pudica (1988)
    Springer
    Trees 2 (1988), S. 7-17 
    Details
    ISSN: 1432-2285
    Keywords: Leaf movements ; Mimosa ; Osmotic mechanisms ; Phloem translocation ; Sucrose unloading ; Turgor release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Mature leaves ofMimosa pudica L. or parts of them were exposed to14CO2, and translocation was recorded by macroautoradiography. It was observed that considerable amounts of labelled photoassimilates were accumulated in pulvini when the leaf was stimulated. In non-stimulated leaves, no such accumulation of label was observed. Microautoradiographs of pulvinar regions of the non-stimulated leaf showed14C- label restricted to the phloem. When stimulated, the14C- label was unloaded from the phloem of the pulvini. Labelled photoassimilates appeared most concentrated in the walls of the collenchymatous cells and beyond in the extensor region of the motor cortex. There, label was accumulated in the apoplastic compartments. Stimulation causes a sudden phloem unloading of sucrose, and its accumulation in the apoplast lowers the water potential which eventually exceeds the osmotic potential of the extensor cells of the motor cortex. By removal of cytoplasmic water the motor cells lose turgidity which results in the closing movement of the leaflets, and — some seconds later — in the bending down of the petiole. In late afternoon night-stimulation triggers sucrose unloading in secondary pulvini. During phases of relaxation, labelled material is taken up by motor cells of the extensor, which concomitantly gain turgor.
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    URL: http://dx.doi.org/10.1007/BF01196339
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  • 93
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    The effect of vessel element structure on element conductivity (1988)
    Springer
    Trees 2 (1988), S. 25-31 
    Details
    ISSN: 1432-2285
    Keywords: Vessel elements ; Conductivity ; Perforation plates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A number of structural variables influence the conductivity of simple and scalariform perforation plates, and of vessel lumina. Using a previously developed computer model, the effects on conductivity of over 8,000 permutations of different lumen radii, perforation plate angles, perforation plate rim widths, scalariform slit pore heights, and scalariform bar thicknesses are considered. By taking advantage of basic patterns of similarity in the data, and by using scaling techniques, it has proved possible to calculate a series of factors which may be used to predict the conductivity of a vessel element or perforation plate of known dimensions. A number of previous workers have sought relationships between element structure and evolutionary or adaptive trends. Some important variables have been ignored in these studies in the past.
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    URL: http://dx.doi.org/10.1007/BF01196341
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  • 94
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    Adventitious bud development in embryonic tissue ofPinus caribaea andPseudotsuga menziesii (1988)
    Springer
    Trees 2 (1988), S. 32-38 
    Details
    ISSN: 1432-2285
    Keywords: Auxin ; Cytokinin ; Gymnosperm ; Micropropagation ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Adventitious bud formation was induced on detached cotyledons and on cotyledons attached to excised embryos ofPinus caribaea andPseudotsuga menziesii. The embryonic tissue was exposed to the cytokinin 6-benzyl amino purine contained within an agar medium. This exposure resulted in the formation of a meristematic zone, involving both epidermal and sub-epidermal cells, and then nodules on the tissue surface. Some of these nodules were induced to differentiate into bud primordia, and thence shoots, following exposure to a combination of auxin (IAA) and cytokinin. Shoots were produced over the entire surface of detached cotyledons ofPs. menziesii but predominantly on the adaxial surfaces of detached cotyledons ofPi. caribaea and the tips and adaxial surfaces of the cotyledons on the entire embryos of both species. Thus, inter-specific differences in the distribution of competent areas for adventitious bud production were detected in embryos.
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  • 95
    Electronic Resource
    Electronic Resource
    Transport processes in stimulated and non-stimulated leaves ofMimosa pudica (1988)
    Springer
    Trees 2 (1988), S. 18-24 
    Details
    ISSN: 1432-2285
    Keywords: Action potential ; Adenine nucleotides ; Aphid stylet ; Mimosa ; Orthophosphate ; Phloem ; Sucrose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Adenosine diphosphate (ADP), adenosine triphosphate (ATP) and orthophosphate were determined in non-stimulated, stimulated and relaxed pulvini of matureMimosa pudica L. leaves. Additional determinations were made with leaflets, rhachillae, petiole and the stem in the stimulated condition. Results show that the content of adenine nucleotides is approximately twice as high in the pulvini as in the tissues between the pulvini. Orthophosphate, in contrast, occurs at higher concentrations in the connecting tissues than in the pulvini. ATP content is highest in the primary pulvini (0.8 μmol/mg dry wt.) and lowest in the tertiary pulvini. Stimulation causes consumption of ATP with a simultaneous increase in ADP content; however, the response is different in each type of pulvinus. This difference is best expressed in the ATP∶ADP ratio. Stimulation causes the most marked reduction of the ratio (9.5-1.4) in the secondary pulvini which react nyctinastically. Orthophosphate content is reduced by stimulation in all types of pulvini, and is increased during the recovery phase. By using a stylet bundle severed from a feeding aphid by a laser shot as tip for the microelectrode, changes of sieve tube membrane potentials were recorded. The changes of the electropotentials following stimulation show that the sieve tube is the pathway for the transmission of the excitation signal in the form of an action potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01196340
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  • 96
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    Cytokinin activity inCitrus jambhiri Lush. seedlings colonized by vesicular-arbuscular mycorrhizal fungi (1988)
    Springer
    Trees 2 (1988), S. 39-44 
    Details
    ISSN: 1432-2285
    Keywords: Citrus jambhiri ; Dihydroeatin ; Symbiosis ; Zeatin ; Zeatin riboside
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The influence of vesicular-arbuscular mycorrhizal symbiosis on cytokinin activity inCitrus jambhiri Lush, seedlings was investigated.C. jambhiri inoculated with cultures ofGlomus caledonium (Nicol. and Gerd.),G. epigaeum (Dan. and Trappe),G. etunicatum (Becker and Gerd.),G. fasciculatum Thaxt. (Gerd, and Trappe) orG. mosseae (Nicol and Gerd.) was grown from seed for 105 days in a glasshouse. Cytokinin activity in roots and leaves of seedlings was analyzed using high-performance liquid chromatography, mass spectrometry and a bioassay. Seedling leaf tissue had greater cytokinin activity than root tissue. Zeatin, zeatin riboside, and their dihydro- and glucoside derivatives were isolated from leaves of 105-day-old seedlings inoculated withG. fasciculatum andG. mosseae. Cytokinin activity in roots and leaves was associated with differences in seedling total dry weight and vesicular-arbuscular mycorrhizal colonization. The ribose moiety and the saturated side chain apparently influence cytokinin transport and physiological activity inCitrus seedlings.
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  • 97
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    Influence of various factors on quantitative composition of leaf monoterpenes ofPicea abies (L.) Karst (1988)
    Springer
    Trees 2 (1988), S. 45-51 
    Details
    ISSN: 1432-2285
    Keywords: Picea abies ; (Mono) terpenes ; Needle ; Variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The extractable monoterpenes from needles of two groups of trees — 4-year-old clonal and 20-year-old wild trees — were studied with respect to the influence of individual constitution, needle age, whorl position, and position on branch. Leaf terpene amounts from clonal trees are significantly affected by age and position of the whorl, whereas position on the branch is of minor importance. Developing needles of clonal trees are most strongly affected by age and whorl position and they differ markedly from mature needles in quantitative terpene composition. Wild trees exhibit a very high variation from tree to tree, which obscures the influence of needle age and position. For this reason meaningful tree leaf terpene data will only be derived if large samples of needles of different ages are collected from distinct positions. When comparing different trees, needles should be selected that not only have the same state of development, but also originate from identical positions and have been subjected to the same light treatment.
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    URL: http://dx.doi.org/10.1007/BF01196344
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  • 98
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    Electronic Resource
    The seasonal variation of 20 elements in 1st and 2nd year needles of Norway spruce,Picea abies (L.) Karst (1988)
    Springer
    Trees 2 (1988), S. 52-64 
    Details
    ISSN: 1432-2285
    Keywords: Picea abies ; Seasonal variation ; Correlations ; Elemental concentrations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The concentration of 20 elements (including eight nutritional elements) in spruce needles was monitored by taking samples at nine different dates in a single year. On each date the youngest and the 1-year-old needles were collected at four different sites. The needles were washed with an organic solvent to remove surface contamination before analysis by instrumental neutron activation. Although the sites showed widely different concentrations for the same element, they could be treated as a uniform population using normalized concentration values. Taking the time dependence of the concentration and the ratio of the concentrations in new and old needles as criteria, the following three groups of elements could be distinguished: 9 group I —Ca, Sr, Ba, and Mn; group II — Al, Br, Co, Fe, Hg, La, Sc, Sb, and Zn; group III — K, Rb, Cs, P, and Cl. Mg and Na did not fit into any of these groups. Within group I and III elements the strongest variations occur during the growing season (late spring and early summer) and the weakest during the dormant season; the variation is greater in the younger needles. Group II elements show an approximately linear increase throughout the year in both the younger and older needles. The concentrations of elements of groups I and II increase with time, while those of group III decrease. Na is unique insofar as its concentration is influenced by foliar uptake of road de-icing salt. The concentration of elements belonging to the same group shows strong inter-element correlations. The grouping of elements deduced here shows similarities with the chemical nature of the elements and with their transportability within the plant.
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    URL: http://dx.doi.org/10.1007/BF01196345
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  • 99
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    Electronic Resource
    Transport processes in stimulated and non-stimulated leaves of Mimosa pudica (1988)
    Springer
    Trees 2 (1988), S. 65-72 
    Details
    ISSN: 1432-2285
    Keywords: Calcium ; Chlorine ; Ion shifts ; Mimosa pudica ; Potassium ; Seismonastic movements ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Using energy-dispersive X-ray microanalysis, the concentrations of ions, especially potassium and chlorine, were determined in different tissues of primary and tertiary pulvini of Mimosa pudica. It was shown that stimulating the leaf was followed by ion displacements which were most striking in the outer extensor cells, resulting in turgor loss. Since Ca concentration remains relatively constant in cell walls of collapsed cells, the changes of K concentration are best described by the K:Ca ratio. After stimulation the K:Ca ratio dropped in the outer extensor of the primary pulvinus from 775.3 to 2.37 in the cytoplasm, and from 542.2 to 9.25 in the cell wall. Changes in chlorine content were less striking in the primary pulvinus. The K∶Cl ratios in some cases were lower than 1.0, which indicates that Cl content can increase, while K content is diminished. In the non-stimulated tertiary pulvini the outer extensor cells show high concentrations of Cl, but much lower Cl concentrations were found after stimulation. In contrast to the primary pulvinus the K content of the tertiary pulvini is very low. In the vascular tissues of both primary and tertiary pulvini stimulation is followed by a release of K and Cl out of the sieve element cytoplasm into the apoplast. K then appears accumulated in the cell walls of the collenchymatous tissue. These displacements lead to the assumption that the collenchymatous apoplast temporarily functions as a reservoir for K and to a lesser extent for Cl. With regard to the mechanism of leaf movement after stimulation, the accumulation of ions in the apoplast seems to be initiated by the decrease of water potential triggered by an apoplastic accumulation of unloaded sucrose (Fromm and Eschrich 1988a). The resulting turgor release in the outer extensor is accompanied by an efflux of ions.
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    URL: http://dx.doi.org/10.1007/BF00196751
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  • 100
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    Mineral partitioning in the phloem during autumn senescence of beech leaves (1988)
    Springer
    Trees 2 (1988), S. 73-83 
    Details
    ISSN: 1432-2285
    Keywords: Autumn leaves ; Fagus sylvatica ; Mineral retrieval ; Phloem transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary During the period of leaf senescence in fall, the minerals Mg, Ca, K, P, Cl, S, and Si were compared for occurrence and density in tissue compartments of leaf blade, petiole, and subtending stem of beech (Fagus sylvatica L.). Measurements were made by energy-dispersive X-ray microanalysis. The plant material was collected on 2,9, 16 and 23 October, and showed green, greenyellow, yellow, and red-brown autumn leaf coloration. Mg, K, and P were retrieved from the leaf blade prior to shedding, and deposited mainly in cortex and pith tissues of the stem. S and Ca remained in the leaf, and Si and Cl appeared to accumulate in the leaf prior to shedding. During the four stages of leaf senescence, the phloem compartments of the petiole showed considerable changes in mineral content. In addition, leaf senescence in several cases was accompanied by ion shifting from symplastic to apoplastic compartments and vice versa.
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