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  • 1
    ISSN: 1432-2285
    Keywords: Allocation ; Defoliation ; Carbohydrate ; Herbivory ; Nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In three experiments, red pine (Pinus resinosa Ait.) seedlings and trees were subjected to artificial defoliations of varying intensities and subsequent growth, gas exchange and nutritional responses were monitored. In Experiment 1, 2-year-old seedlings received 0, 1 or 2 50% defoliations during a single growing season and were maintained in 1 of 3 low nutrient supply treatments. In Experiment 2, response of 4-year-old seedlings was monitored in the year following 0, 25, 50 or 75% defoliation, while in Experiment 3, response of 11-year-old trees was measured 1 year after being defoliated by 0, 33 or 66%. Regardless of intensity of defoliation, or plant size, clipped plants made qualitatively similar allocational and metabolic adjustments over time. First, leaf diffusive conductance and rates of net photosynthesis were stimulated, especially by light to intermediate defoliation. However, there was no effect of defoliation on foliar nitrogen concentration, and elevated gas exchange rates apparently resulted from altered root-shoot dynamics. Second, allocation of new biomass was preferentially shifted towards foliage at the expense of roots, gradually restoring (but undershooting or overshooting) the ratio of foliage: roots of control plants. During the period when foliage: root balance was being restored, the stimulation of needle gas exchange rates disappeared. Plants defoliated by 25% overcompensated in terms of whole plant growth (were larger at harvest than controls), due to shifts in allocation and enhanced photosynthesis. Defoliated plants also stored a proportionally greater share of their carbohydrate reserves in roots than did control plants, even 1 year after clipping.
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  • 2
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    Trees 7 (1993), S. 78-85 
    ISSN: 1432-2285
    Keywords: Betula pendula ; Dry matter distribution ; Leaf area ratio ; Leaf weight ratio ; Net assimilation rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Growth of hydroponically cultivated birch seedlings (Betula pendula Roth.) at sub- and supra-optimum potassium supply rates was investigated. Potassium was supplied either as a relative addition rate (r k = 5, 10, 15 and 20% increase day-1) or as fixed concentrations (0.2, 3, 6, 12 and 15 mM) in the culture solution. After an acclimation period the growth rate of the seedlings in the suboptimum treatments reached values close to the treatment variable, the relative rate of K-addition. Deficiency symptoms, in the form of chlorosis and necroses along the leaf margins, developed initially in all suboptimum treatments, but very few new symptoms appeared once the seedlings had reached the phase of steady-state nutrition and growth. At supra-optimum K-supply levels, i.e. at 0.2–15 mM K in the culture solution, no symptoms of deficiency or toxicity developed, and the relative growth rate of the seedlings remained maximum. The relative growth rate of the seedlings was linearly related to the plant K-status for K contents ranging from 0.2 to 1.0% of dry weight (DW). At higher internal K-concentrations, 1.0–3.0% DW, no further increase in relative growth rate was achieved. A shortage of K resulted in a decrease in the net assimilation rate. This effect was counterbalanced by the absence of shift in he leaf weight ratio as well as by the production of relatively thin leaves. The fraction of dry matter allocated to roots decreased in K-limited plants, as did the leaf contents of soluble carbohydrates and starch.
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  • 3
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    Trees 7 (1993), S. 86-91 
    ISSN: 1432-2285
    Keywords: Pinus radiata ; Stem deformation ; Nitrogen ; Stem form ; Elasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seedlings from nine families of Pinus radiata were grown in a glasshouse under conditions of high and low nitrate nitrogen availability to investigate effects on anatomical and strength characteristics of stems. Families were classified into groups dependent upon their previously determined susceptibility to stem deformation prevalent in plantations established on fertile ex-pasture. Nitrogen treatments significantly affected seedling form in terms of both branch production and stem slenderness. The high N treatment resulted in shorter seedlings, a proportion of which were obviously stunted. Stem strength of seedlings, physically supported throughout the experiment, was assessed as stem lean at harvest as well as the bending strength of the fresh stem at 50% stem height. These two variables were found not to be correlated. Stem lean at harvest was greatest in families known to be susceptible to stem deformation. These families produced stems that were also more slender than families of low susceptibility. Increased stem lean was associated mostly with increased stem slenderness while elasticity was more influenced by pith diameter, stem density and wood radius.
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  • 4
    ISSN: 1432-2285
    Keywords: Chalcone synthase ; Juglans sp. ; Rejuvenation ; Phenylalanine ammonia lyase ; Polyphenolic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary During the first growth phase of walnut (Juglans sp.) stump shoots, the concentrations of the two major phenolic compounds are not correlated with an increasing rate of shoot growth. The concentration of hydrojuglone glucoside (naphtoquinone) decreases as shoot growth rate increases, whereas the concentration of myricitrin (flavonol) remains constant. In contrast, phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity is proportional to the growth rate of shoots. Rejuvenation, which induces a higher growth rate and vegetative propagation ability, results in an increase of both PAL and chalcone synthase (CHS, EC 2.3.1.74) activities and hydrojuglone glucoside/myricitrin ratio. Moreover, physiological ageing is characterized by an accelerated functioning of polyphenolic metabolism. Fluctuations in PAL activity are associated with changes in shoot growth rate and with rejuvenation, but PAL does not directly control the accumulation of flavonoid compounds during rejuvenation. On the contrary, mathematical correlation of CHS activity and flavonoid accumulation during annual shoot growth of both adult and rejuvenated trees, indicates that CHS is the rate-limiting enzyme of the pathway.
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  • 5
    ISSN: 1432-2285
    Keywords: Air pollution ; Forest decline ; Photosynthesis ; Picea abies ; Sulfur dioxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Photosynthetic performance of several needle age classes of Norway spruce trees [Picea abies (L.) Karst.] in highly SO2-polluted and heavily damaged forest sites was measured at two different locations in the Ore Mountains (Erzgebirge, Krusne Hory) during early summer. The carboxylation efficiency showed a dramatic drop from current-year's needles to 1-year-old needles with only a slight further decrease with increased needle age. The light use efficiency also revealed these characteristics. For both parameters, no linear decrease with needle age could be found. In contrast, the maximum photosynthetic capacity (A2500) decreased linearly with time and revealed a good correlation with the total sulfur content of the needles. Absolute values measured for A2500 were approximately 50% lower than those of comparable trees in the nearby Fichtelgebirge. Mineral deficiencies or acute nutrient imbalances of the needles were not detected. In contrast to the situation in the forests of the Fichtelgebirge, a direct effect of gaseous SO2 on the trees in the Ore Mountains seems plausible.
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  • 6
    ISSN: 1432-2285
    Keywords: Ozone ; Betula pendula ; Leaf differentiation ; Leaf and bark decline ; Senescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Leaf and bark structure of a birch clone (Betula pendula Roth) continuously exposed to charcoal-filtered air or charcoal-filtered air plus ozone (0.05, 0.075, 0.1 μl 1-1) was investigated throughout one growing season. Increasing ozone dose influenced leaf differentiation by reducing leaf area and increasing inner leaf air space, density of cells developing into stomata, scales and hairs. When approximately the same ozone dose had been reached, macroscopical and microscopical symptoms appeared irrespective of the ozone concentration used during treatment. Structural decline began in mesophyll cells around stomatal cavities (droplet-like exudates on the cell walls), continued with disintegration of the cytoplasma and ended in cell collapse. Epidermal cells showed shrinkage of the mucilaginous layer (related to water loss). Their collapse marked the final stage of leaf decline. When subsidiary cells collapsed, guard cells passively opened for a transitory period before collapsing and closing. With increasing ozone dose starch remained accumulated along the small leaf veins and in guard cells. IIK-positive grains were formed in the epidermal cells. This contrasted with the senescent leaves, where starch was entirely retranslocated. Injury symptoms in stem and petiole proceeded from the epidermis to the cambium. Reduced tissue area indicated reduced cambial activity. In plants grown in filtered air and transferred into ozone on 20 August, injury symptoms developed faster than in leaves formed in the presence of ozone. Results are discussed with regard to O3-caused acclimation and injury mechanisms.
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  • 7
    ISSN: 1432-2285
    Keywords: Ectomycorrhizal types ; Classification ; Morphology ; Picea abies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In a 3-year study of ectomycorrhizal diversity in 2 Norway spruce stands in Switzerland the macroscopically classified ectomycorrhizal types were analyzed microscopically to compare the results of the 2 approaches. A total of 22 ectomycorrhizal types were macroscopically classified in the 2 stands. Microscopic investigations — particularly of mantle structures — resulted in the identification of 7 additional types to give a total of 29. These additional types resulted from separation of macroscopically identical types occurring on both stands (type-pairs) at the microscopic level. The problematic nature of characterization and classification of ectomycorrhizas is discussed.
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  • 8
    ISSN: 1432-2285
    Keywords: Pinus radiata ; Stem strength ; Elasticity ; Lignin ; Microfibril angle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Segments of living stems from 2-year-old, fast growing Pinus radiata, established on a fertile ex-pasture, were examined in terms of their bending strength parallel to the grain. Stem anatomical and structural variables were examined to identify variables that could explain variation in bending strength. Half of the seedlings were physically supported to minimise the confounding effects of compression wood production in response to environmental stresses. Differences between seedlings and cuttings were examined. Variation in microfibril angle and lignin content was sufficient to account for 81% of the variation in bending strength. A positive correlation between both of these variables and elasticity was evident. Few differences were found to be caused by the support treatment or between seedlings and cuttings. The support treatment resulted in significantly fewer branches in the top most whorl, while cuttings had less branches in this whorl than seedlings.
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  • 9
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    Trees 7 (1993), S. 144-147 
    ISSN: 1432-2285
    Keywords: Bark structure ; Cork formation ; Melia azedarach ; Periderm differentiation ; Shoot development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The bark texture of Melia azedarach L. changes from smooth to furrowed as trees age. In trees that were cut down, those with smooth bark sprouted below the cut from suppressed buds; trees with thick, furrowed bark sprouted at the edge of the cut surface from adventitious buds. The trees that had thin, furrowed bark sprouted mainly at the edge of the cut from adventitious buds, but sometimes also from suppressed buds in cracks. The relationship between sprouting pattern and tree architecture are discussed.
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  • 10
    ISSN: 1432-2285
    Keywords: Model of cambial domains ; Grain pattern in wood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The relationship between the arrangement of cell events occurring in cambium in a definite configuration and the grain pattern of wood was investigated. Taking into consideration the growth activity of fusiform cell ends, a model of a migrating morphogenetic wave determining an event configuration was made. Waves of length λ=1 m for the periods T=2 years and T=3 years and waves of lengths λ=l m and λ=0.04 m for the period T=10 years were considered. On the model, events from successive annual rings, conventionally comprising 10 cell layers each, were summed. In this way, event maps were obtained. For wave λ=4 mm, the domain pattern on the modelled map was compatible with the grain pattern. The domain pattern for the wave λ=1 m was impossible to recreate because the wave “migrated too fast”. In this case, the pattern of event configuration, incompatible with the grain pattern, formed microareas, which were not domains.
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  • 11
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    Trees 7 (1993), S. 156-159 
    ISSN: 1432-2285
    Keywords: Hydraulic conductivity ; Stem insertions ; Quercus velutina ; Acer saccharum ; Tsuga canadensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Hydraulic conductivities were measured in branch junctions and in the proximal segments of Quercus velutina Lam., Acer saccharum Marsh., and Tsuga canadensis (L.) Carr. In all three species, the basal proximal segment was more conductive than the junction by a factor of 1.1–1.5. There was no consistent pattern for the distal proximal segments, where the conductivities were higher, lower, or the same as the junction. These data are discussed in terms of Martin H. Zimmermann's concept of plant segmentation. It is concluded that junction constrictions to water flow contribute less to plant segmentation than the variation in leaf specific conductivity in the crown of these species.
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  • 12
    ISSN: 1432-2285
    Keywords: Shoot water relations ; Gas exchange ; Morphological development ; Establishment process
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Shoot water relations, summer gas exchange response and morphological development of western hemlock [Tsuga heterophylla (Raf.) Sarg.] and western red cedar (Thuja plicata Donn) seedlings were monitored over the first growing season on a coastal reforestation site in British Columbia. In March, osmotic potential (ψs) at saturation [ψs(sat)] was −1.98 MPa and turgor loss point [ψs(tlp)] −2.38 MPa for western hemlock, while western red cedar had −1.45 MPa ψs(sat) and −1.93 MPa ψs(tlp). Seasonally ψs increased through June and then decreased through September, with western hemlock −0.15 to −0.50 MPa lower than western red cedar. Maximum bulk modulus of elasticity (ɛmax) for western hemlock was 29.3 MPa in March, decreased to 15.0 MPa in June and increased to 25.0 MPa from July through September, while western red cedar ɛmax was 10.6 MPa in March and around 8.0 MPa thereafter. Utilized turgor (T util) for western hemlock was 〈40% from March through May, 69 to 78% from June through August and 96% in September, while western red cedar T util was 68 to 73% during March and April, 84 to 96% from May through August and 100% in September. Maximum CO2 assimilation rate (A) of western red cedar was more than double western hemlock, and for both species A declined in a linear fashion with increasing vapour pressure deficit (D). Maximum foliage conductance (g wv) declined in a concave manner as D increased in both species, with western red cedar values 50 to 67% greater than western hemlock. Maximum daily g wv declined in a concave manner as predawn shoot water potential (ψpd) decreased, with maximum daily g wv 1.8 to 3.6 times greater in western red cedar than western hemlock, when ψpd was −0.25 and −1.4 MPa, respectively. Western red cedar, compared to western hemlock, had a greater increase in A as g wv increased. Eight months after planting, western red cedar seedlings had twice the root growth, measured as root dry weight and root number, of western hemlock.
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  • 13
    ISSN: 1432-2285
    Keywords: Populus ; Pollution ; Copper ; Lead ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The patterns of radial distribution of copper, lead, zinc and cadmium in two species of poplar, growing under polluted conditions near a copper smelter, were investigated. Populus marilandica is very resistant to such pollution, but P. balsamifera is sensitive. Soils were examined for concentrations of these metals, and only a surface layer of soil was polluted with copper and lead. P. balsamifera absorbed much more cadmium than P. marilandica under the same conditions. P. marilandica shows a pattern of copper radial distribution with significantly increased concentration of the meral in the layers in the middle of the trunk compared to P. balsamifera. Zinc and cadmium have a pattern with increased metal concentration from the bark towards the pith of the tree. In the case of copper and lead the pattern indicates increased concentrations of these metals in the rings adjacent to the pith while the pattern in other parts of the tree remains unconfirmed due to poor precision. Poplar xylem seems to accumulate zinc and cadmium while the content of lead in xylem is much lower than in the adjacent soil.
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  • 14
    ISSN: 1432-2285
    Keywords: Photosynthesis ; Lightflecks ; Photosynthetic induction ; Leaf temperature ; Sun and shade leaves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Responses of leaf gas exchange in shade and half-shade grown seedlings of the European beech, Fagus sylvatica L., to constant light conditions indicate different phases of photosynthetic induction: an immediate, a fast and a subsequent slow phase. The slow phase has both biochemical and stomatal components. The higher the induction, the higher the lightfleck utilization efficiency (LUE) attributable to a lightfleck. LUE can be higher than 100% compared to a theoretical instantaneous response. Lightfleck quantum yield (total carbon gain attributable to a lightfleck per incident quantum density in the fleck) is highest in short pulses of light. Post-illumination carbon gain initially increases with fleck length, levelling off above 20 s. The lower the induction, the longer carbon is fixed post-illuminatively (up to 84 s) but the less carbon is gained. Shade leaves are induced much faster than partial shade leaves. They utilize series of lightflecks to become fully induced, while half-shade (and sun) leaves depend on continuous high light. Half-shade leaves lose induction faster in low light between lightflecks. High as well as low temperatures strongly delay induction in half-shade but not in shade leaves. In general, shade leaves are much better adapted to the dynamic light environment of the forest understorey; however, their water-use efficiency during induction is lower.
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  • 15
    ISSN: 1432-2285
    Keywords: Seed cone distribution ; Position along shoot length ; Position around shoot circumference ; Seed cone bearing shoots ; Shoot vigour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Patterns of distribution of seed cones along the length and around the circumference of shoots were determined for young black spruce [Picea mariana (Mill.) B.S.P.] trees aged 9–17 years. Seed cone production averaged 5, 30, 62, 95, and 112 per tree of ages 9, 11, 13, 15, and 17 years, respectively. Cone distribution was restricted to distal and medial 1-year-old branches at age 9 and spread to distal 3-year-old branches by age 17. Sequentially, shoots of 0–25, 26–100, 101–250, 251–325, and 326–375 mm bore more cones in terminal, distal, medial, proximal, and basal positions along shoots, respectively. The uppermost and longest distal 1-year-old shoots bore most of their cones proximally and medially. On the shortest and innermost proximal order 2 shoots, cones were often terminal. The percentages of cones borne on upper, lower, and each of the two side surfaces of shoots were 31, 22, and 21, respectively, and 5% of the cones were terminal. Cones on lower surfaces were most common on the longest shoots near the apex of trees. Cones on upper surfaces became prevalent downward and outward in the crown. On-shoot positioning therefore varied in a predictable manner with shoot length, and thus with pattern of shoot-length distribution in the crown.
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  • 16
    ISSN: 1432-2285
    Keywords: Abies alba ; Abscisic acid ; Damage ; Gas chromatography ; Needles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The amount of abscisic acid (ABA) in needles of silver fir from a natural location was investigated with regard to position in the crown, damage, seasonal variation, and needle age. Because of problems of quantification of ABA in coniferous needles, which contain numerous secondary plant products, a method for reliable determination of both isomers cis-trans-ABA (c-ABA) and transtrans-ABA (t-ABA) was developed. By means of gas chromatography (GC) using an electron capture detector (BCD) and a programmed temperature vaporizer (PTV) injector complete separation of both compounds was achieved. Two different pairs of fir were investigated — in each case a damaged and a healthy tree. Needles from both trees from the first and the second pair collected in September contained 500–1100 ng c-ABA/g fresh weight (FW), and the concentrations of t-ABA varied from 400 to 700 ng/g FW. Investigations from the second pair show highest amounts of 2900 ng/g Fw c-ABA and 1800 ng/g FW of t-ABA in May and June. For the first pair a higher c-ABA content was found in needles from the top of the crown than in those from the middle and the base. This difference could not be confirmed in the analysis of the second pair. Because of the strong natural deviation no statistically significant difference between the healthy and the damaged tree was found. The first pair of firs examined showed a higher t-ABA concentration than the second one. In this case the highest amount was found in the top of the crown. Methodical mistakes during the clean-up procedure and in quantification by gas chromatography could be excluded. The presence of c- and t-ABA in the purified extract was corroborated by mass spectrometry. With regard to the seasonal variation both isomers of ABA show an unequivocal trend. The maximum concentration is achieved in May to June, whereas the content is minimal in August/September. In any case the level of t-ABA is lower than that of c-ABA. No correlation between the amount of ABA and the needle age could be established.
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  • 17
    ISSN: 1432-2285
    Keywords: Amino acids ; Polyamines ; Dipterocarpaceae ; Dipterocarpus alatus ; Hopea odorata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Amino acid, polyamine and protein concentrations in seeds and their evolution during seed germination of two dipterocarp species, Hopea odorata and Dipterocarpus alatus, were determined with the help of a multianalytical system. Glutamic acid and glutamine were the major amino compounds present. Hopea seeds also contain high levels of aspartic acid/asparagine, serine, threonine, arginine and alanine, while those of Dipterocarpus contain high levels of alanine, arginine and threonine. These species were quite different in their germination behavior and thus in their protein and amine metabolism rates. In Hopea, polyamines increased during the first 3 days of germination and reached a maximum by the 3rd day, 1 day before maximum germination rate. In Dipterocarpus polyamines reached their maximum at the 6th day while maximum germination rate is observed by the 7th day. This suggests that polyamine compounds could play a role in the early part of the germination process in Hopea and Dipterocarpus seeds. The possibility that control of polyamine biosynthesis could be used for the establishment of biochemical methods to improve seed storage and to control germination of these recalcitrant seeds is discussed.
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  • 18
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    Trees 7 (1993), S. 195-201 
    ISSN: 1432-2285
    Keywords: Stomatal conductance ; Water potential ; Urban ; Nutrient deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Growth and water relations of 10-year-old sweet gum (Liquidambar styraciflua L.) street trees were studied in sites with low and high potential evapotranspiration to determine how these differences are integrated by growth and water relations over time. The trees were located in the parking strip between the curb and sidewalk at a partially vegetated urban park and an urban plaza in Seattle, Washington. Crown size, and seasonal and diurnal stomatal conductance and water potential, as well as diurnal air temperature and humidity, were measured over 2 growing seasons. Yearly trunk growth since transplanting was measured from increment cores. Vapor pressure deficits and air temperatures averaged 18% greater at the plaza, but whole-tree water loss appeared to be much lower than the park trees due to more restricted stomatal conductance and crown size. In addition, yearly diameter increment declined progressively once the plaza trees were established in the existing soil several years after transplanting. Lower water potential in the plaza trees indicated greater internal moisture deficits than the park trees, and tissue analysis revealed lower nutritional status, particularly nitrogen. A manipulative study of water and fertilizer to several additional plaza trees showed an interaction between water and nutrient deficiencies in the coarse and shallow soil that apparently limited growth. Furthermore, soil limitations probably interacted with paved surface conditions over time by reducing nutrient recycling from leaf litter, and generating higher vapor pressure deficits that would contribute to prolonged stomatal closure. Restricted growth and water relations status of the plaza trees represented an equilibrium between chronic high-resource demand above ground and limited below ground.
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  • 19
    ISSN: 1432-2285
    Keywords: Net photosynthesis ; Carbon allocation ; Pinus taeda
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Shade treatments were applied to the terminal portions of branches in loblolly pine trees to test whether portions of branches were autonomous with respect to carbohydrates. The shade treatments reduced light by 50% and 72% compared with full sun conditions resulting in significant reductions in net photosynthesis. Branch growth (branch diameter and length, branch and needle biomass) decreased significantly within the shaded portion of the branch. Branch and needle morphology were also affected by shading. Lateral branches subtending terminal shoots were labelled with 14C 2 times during the growing season. No movement of 14C into the terminal portions of the branch was evident during the first growth flush. However, during the second flush of growth small but statistically significant amounts of 14C were imported into the terminal portion of the shaded branches from subtending laterals. It was concluded that loblolly pine shoots were usually autonomous with respect to carbohydrate supply, but that carbohydrate movement into the terminal shoot from subtending foliage could occur under conditions of very high stress.
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  • 20
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    Trees 7 (1993), S. 202-207 
    ISSN: 1432-2285
    Keywords: Tropical deciduous forest ; Light dependency ; Growth analysis ; Tree-seedlings ; Allocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The growth responses of seedlings of Amphipterygium adstringens, Caesalpinia eriostachys, and C. platyloba, species associated with undisturbed parts of the tropical deciduous forest in México, and Apoplanesia paniculata and Heliocarpus pallidus, two gap-requiring pioneer species, were determined under contrasting light conditions in a growth chamber experiment. The high (400 μmol m−2 s−1) and low (80 μmol m−2 s−1) light treatments correspond to the light available in a medium size gap and underneath the vegetation canopy in the deciduous forest during the rainy season, respectively. Following four destructive harvests the biomass production, relative growth rate, root/shoot ratio, specific leaf area, net assimilation rate, leaf area ratio and light dependency were determined for all species. In the high light treatment all species achieved higher relative growth rates and net assimilation rates than when growing at low light intensity. However, the two pioneer species showed the highest light dependency and were the species more affected by the low light treatment in biomass production. The two Caesalpinia species showed similar growth responses, but C. platyloba was the most shade tolerant species. Plastic adjustments in terms of the specific leaf area were more evident in the two pioneer species.
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  • 21
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    Trees 7 (1993), S. 214-219 
    ISSN: 1432-2285
    Keywords: Pinus sylvestris ; Precipitation ; Temperature ; Wood formation (cambium, radial cell expansion, secondary wall thickening)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary To find the optimal conditions for growth and development of tracheid walls in Scots pine stems the effects of temperature and precipitation on xylem cell production by the cambium, radial cell expansion and secondary wall thickening have been studied. The observations were carried out on 10 specially chosen 50 to 60-year-old trees, growing in central Siberia, over 2 seasons. The data on the number of cells in differentiation zones and mature xylem along radial rows of tracheids, radial and tangential sizes of tracheids and their lumens were used for calculating cambial activity, the rates and durations of cell development in the zones, and both the thickness and cross sectional areas of tracheid walls. The mean day, mean maximal diurnal and mean minimal nocturnal temperatures have been shown by correlation and regression analyses to affect differentially separate stages of cytogenesis. The temperature influenced the initial division the side of xylem and radial cell expansion mainly in May–June, while the influence of precipitation increased in July–August. Throughout all seasons it was the temperature that had the main influence on the biomass accumulation in cell walls. Optimal values of temperature and precipitation for cell production by cambium, radial cell expansion and secondary wall thickening have been calculated. The data are discussed in connection with productivity and quality of wood.
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    Trees 7 (1993), S. 220-226 
    ISSN: 1432-2285
    Keywords: Picea abies ; Xylem ; Relative hydraulic conductivity ; Resistance to water flow ; Tracheid radius
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The relative hydraulic conductivity (k) of xylem and resistance (R) to water flow through trunk, primary roots and branches in Picea abies trees growing under contrasting light conditions were investigated. The xylem permeability to water was measured by forcing 10 mM water solution of KC1 through excised wood specimens. From the values of k, the sapwood transverse area and the length of conducting segments, R of the whole trunk, branches and roots was calculated. The relative conductivity of xylem in open-grown trees exceeded that of shade-grown trees by 1.4–3.1 times, while k was closely correlated with the hydraulically effective radius (R e) of the largest tracheids (R 2 was 0.85–0.94 for open- and 0.51–0.79 for shade-grown trees). Because of both a low k and a smaller sapwood area in shade-grown trees the resistance to water movement through their trunk, roots and branches was many times higher. The distribution of R between single segments of the water-conducting pathway differed considerably in trees from different sites. At high water status the largest share of the total resistance in open- as well as shade-grown trees resides in the apical part of the trunk. The contribution of the branches to total xylem resistance is supposed to increase with developing water deficit.
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  • 23
    ISSN: 1432-2285
    Keywords: Nitrate reductase ; Nitrogen deposition ; Forests ; Nitrate ; Seedlings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seedlings of red maple, white pine, pitch pine and red pine were fertilized with nutrient solutions containing 4 levels of nitrate or ammonium additions. These levels corresponded to approximately 0.5, 1, 2 and 4 times normal availability of nitrogen in northeastern forests. Nitrate reductase (NR) activity was assayed in roots and leaves. Red maples treated with nitrate showed much higher leaf activities and higher ratios of leaf NR activity to root NR activity than any other species. Ammonium additions to red maple and white pine appeared to inhibit NR activity in leaves. With high nitrate additions, NR activity was induced in roots and leaves of pine species, but activity in roots remained much higher than in leaves.
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  • 24
    ISSN: 1432-2285
    Keywords: Ozone uptake ; Stomatal conductance ; Spruce
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The uptake of air pollutants depends both on pollutant concentration and on stomatal conductance. This paper deals with the uptake of ozone (O3) from the air into the needles of Norway spruce [Picea abies (L.) Karst.] under ambient climatic conditions. Regulation of O3 uptake by the stomata is shown and also the difference between the “physiologically active O3 concentration” and the O3 concentration of the ambient air. Data from the sun and shade crown of spruce trees at 1000 m a.s.l. are presented. Analysis of data from three vegetation periods has shown that at low ambient O3 concentrations the O3 uptake is largely regulated by stomatal conductance. Water vapour pressure deficit (VPD) of the atmosphere is the climatic factor which showed the highest positive correlation with O3 concentration. However, a high leaf-air VDP led to stomatal closure, thus reducing the O3 uptake in the needles despite high O3 concentrations in the ambient air. The potential O3 stress caused by high O3 concentrations can be strongly mitigated by this natural closing of the stomata and the simultaneous occurrence of moderate drought stress.
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    Trees 8 (1993), S. 31-38 
    ISSN: 1432-2285
    Keywords: Biomass and carbon allocation ; Birch ; Iron limitation ; Nutrient proportions ; Steady-state growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Small birch plants (Betula pendula Roth.) were cultivated in a hydroponic spray solution where the relative addition rate of iron (RFe; g g−1 day−1), was the growth-controlling variable. All other elements were added in free access. An additional treatment was performed where all nutrients, including iron, were in free access (FA). The plants showed deficiency symptoms at steady-state growth and severe limitation of iron, RFe 0.05 and 0.10 day−1. There were few symptoms at RFe of 0.15 or above. Plant relative growth rate (RG; g g−1 day−1), equalled the relative rate of increase in iron supply, RFe. Internal iron concentration of the plants ranged from 40 to 70 μg g−1 dry weight (DW) over the range for which iron supply was limiting growth. At FA, the internal concentration was approximately 200 μg g−1 DW without further increase in RG, demonstrating that iron may be taken up in excess without affecting growth. Internal concentrations of macronutrients were stable at the different RFe, except for Ca and Mg in shoots which were higher at low iron supply. Uptake rates of iron, calculated per root growth rate (μmol g−1 root DW), were approximately twice as high at RFe 0.20 as at 0.05 day−1. The effect of iron limitation on dry matter allocation to leaves was small, with increases in the root fraction being largely at the expense of the stem. Leaf area ratio was constant regardless of RFe and the specific leaf area tended to increase with increasing iron limitation. Net assimilation rate decreased by a factor of 6 from free access to severe iron limitation, largely accounting for the differences in plant RG.
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    Trees 8 (1993), S. 61-66 
    ISSN: 1432-2285
    Keywords: Douglas-fir ; Rubisco ; Translocation of nutrients ; Chlorophyll a fluorescence ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A transient decline in photosynthetic rate and several correlates of photosynthetic function in year-old shade needles coincided with shoot elongation in 15 fullsib 8-year-old Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] saplings. In year-old needles and current year needles collected from May to November from branchlets with a single terminal bud and at least 4 needle age classes, chlorophyll (chl) content, photosynthetic rate and non-photochemical quenching of chl fluorescence declined during the period of flushing of the new shoots and recovered as shoot elongation slowed. Developing shade needles did not achieve the same oxygen evolution rate per unit area as the year-old needles, but did develop a higher quantum yield (estimated from chl a fluorescence). In short, in shade branchlets shoot development occurred at a cost of photosynthetic function in year-old needles. In year-old sun needles collected from the upper portions of the same trees, total protein concentration increased prior to, and decreased during, flushing. The concentration of ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco) rose and decreased more than chlorophyll-binding proteins. In general, protein concentration in needles reflected age class rather than sun or shade environment. A specific decline in Rubisco in year-old sun needles during the period of new shoot elongation strengthens the hypothesis that degradation of this photosynthetic protein contributes to development of the new shoot.
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  • 27
    ISSN: 1432-2285
    Keywords: Amyloplast ; Plastid initial ; Plastid proliferation ; Poplar cortical cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Electron microscopic studies revealed that “plastid initials”, presumed precursors of plastids, occur in cortical cells of the following plants studied in February and March: Betula ermanii Cham.; Prunus sargentii Rhed.; Pyrus communis L.; Ribes sinanense F. Maekawa; Salix matsudana Koidz. forma tortuosa Rhed.; and Sambucus sieboldiana var. miquelii Hara. Since “plastid initials” were found previously in Malus pumila Mill., Morus bombycis Koidz. and Populus euramericana cv. gelrica (Sagisaka 1991), “plastid initials” have been found in all woody plants examined to date. In P. euramericana cv. gelrica, at later stages of the development of the initials in March, the conglomerates of plastid initials became heterogeneous in terms of size, extent of thylakoid formation and ability to form starch granules. The formation of prolamellar structures was frequently observed in cells of Magnolia kobus var. borealis Sarg., which was sampled on April 19. These observations suggest the course of events in the development of the “plastid initial” and the continuity of the life of amyloplasts over a year in the life of woody plants.
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    Trees 8 (1993), S. 99-103 
    ISSN: 1432-2285
    Keywords: Robinia pseudoacacia L. ; Hydrogen uptake ; Hydrogenase ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Hydrogen uptake is thought to increase the efficiency of nitrogen fixation by recycling H2 produced by nitrogenase that would otherwise be lost by diffusion. Here we demonstrate the capacity of eight Rhizobium strains to take up molecular hydrogen. Uptake by nodule homogenates from Robinia pseudoacacia was measured amperometrically under nitrogenase repression. Markedly lower activities were found than in soybean nodules. In addition hydrogenase activity was detected by the ability of bacteroids to reduce methylene blue in the presence of hydrogen. It was demonstrated that hydrogenase structural genes are present in the black locust symbiont, Rhizobium sp. strain R1, using hybridization with a plasmid, which contained hydrogenase genes from R. leguminosarum bv. viceae.
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    Trees 8 (1993), S. 104-109 
    ISSN: 1432-2285
    Keywords: Legume ; Phloem ; Protein storage ; Vacuole proteins ; Xylem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Light- and electron-microscopic observations were made on the stem parenchyma cells of Dalbergia odorifera T. Chen (Papilionaceae), a tropical deciduous tree. In the secondary phloem of branchlet and trunk, all of the parenchyma cells except companion cells contain vacuole proteins. Only the outer secondary xylem of branchlets, but not trunk secondary xylem, has proteins in the ray parenchyma and the vasicentric parenchyma. The xylem vacuole proteins begin to accumulate at the end of the growing period and they disappear after the first flush of growth in spring. The vacuole proteins in phloem cells, particularly in the cells near the cambium, also show seasonal fluctuations. Under the electron microscope, the vacuole proteins appear as fibrous materials in aggregation or in more or less even dispersion, and they occur in the large central vacuoles during both the growth and dormant periods. According to the published studies, the stem storage proteins in the temperate trees appear as small protein-storage vacuoles or protein bodies, and the proteins in the tropical trees occur in large central vacuoles. This distinction is assumed to be related to the differences in the nature of dormancy between temperate and tropical trees.
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    ISSN: 1432-2285
    Keywords: Amyema miquelii ; Eucalyptus behriana ; Leaf conductance ; Porometry ; Xylem pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Over several days at permanently low plant water status in the field, where predawn xylem pressures (Ψ) were never higher (less negative) than −1.2 MPa even after extended rain, leaf conductances (g) and transpiration rates of host trees, Eucalyptus behriana F. Muell., were higher than in mistletoes, Amyema miquelii (Lehm. ex Miq.) Tiegh., which contrasts with most studies known from the literature. Mistletoes influenced Ψ but not g of host leaves distal to the haustorium. Releasing xylem tension by cutting a host stem under water raised Ψ from about −3.5 MPa to about −0.5 MPa in both plants indicating that factors in the root zone were responsible for the low Ψ in the host. In all cases, with a freely transpiring or non-transpiring parasite at low and at artificially raised Ψ, mistletoe xylem pressure was lower than that of the host. Possible reasons are discussed.
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    The visual computer 10 (1993), S. 101-115 
    ISSN: 1432-2315
    Keywords: Implicit surfaces ; Blend surfaces ; Geometric modeling ; Polygonization ; Visualization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A method for visualizing implicit surfaces is discussed. This method makes as few assumptions as possible concerning the surface and representation of its defining function. The surface may contain singularities, for instance, because it has self-intersections or it is reducible. A userdefined part of space is filled by a set of cubes, cutting pieces (called facets) off the surface. The set of cubes is controlled by an octree converging to the surface. The set of resulting facets can be taken as a piecewise linear approximation, which is sufficiently close to the given surface with respect to criteria specified by the user. Finally, some examples obtained with this method are presented.
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    The visual computer 10 (1993), S. 127-144 
    ISSN: 1432-2315
    Keywords: Display algorithms ; Three-dimensional graphics ; Stereoscopic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In this paper, we describe a method to create an approximate ray-traced stereoscopic pair by transforming a fully raytraced left-eye view into an inferred right-eye view. Performance results from evaluating several random scenes, which indicate that the second view in a stereoscopic image can be computed with as little as 5% of the effort required to fully ray-trace the first view, are presented. We also discuss worst-case performance of our algorithm and demonstrate that our technique is always at least as efficient as two passes of a standard ray-tracer.
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    The visual computer 10 (1993), S. 145-159 
    ISSN: 1432-2315
    Keywords: Visualization of multidimensional data ; Cluster analysis ; Vector quantization ; Topological ordering ; Neural networks ; Remote sensing ; Image classification ; Environmental protection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper describes the application of self-organizing neural networks on the analysis and visualization of multidimensional data sets. First, a mathematical description of cluster analysis, dimensionality reduction, and topological ordering is given taking these methods as problems of discrete optimization. Then, the Kohonen map is introduced, that orders its neurons according to topological features of the data sets to be trained with. For this reason, it can also be called a topology-preserving feature map. In order to visualize the results obtained during the self-organization process, the standard map has been extended to a three-dimensional cube of neurons, where each neuron represents a discrete entity in the red green blue color space (RGB). According to the ordering properties of the network neighbored neurons and thus similr colors refer to data vectors with similar features. The application of this technique on multidimensional Landsat-TM remotely sensed image data, namely, the analysis of the burning oil fields in Kuwait, demonstrates the capabilities of the introduced method. Moreover it can be used to solve general visualization problems of data mapping into a lower dimensional representation.
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    The visual computer 10 (1993), S. 54-61 
    ISSN: 1432-2315
    Keywords: Visual codings ; User interface ; Graph-coloring ; Optimization ; Connected components ; Color distance ; Graph theory ; Algorithms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A formal study of visual codings in user interface design is presented. Visual codings for maximum distinction of different objects in displayed images are formulated as a discrete optimization problem of maximum-distance graph-coloring. The formulation is a generalization of the classical coloring problem in graph theory. Having pointed out that maximum-distance graph-coloring is NP-complete, we develop new, fast approximation algorithms for optimal visual codings. The proposed algorthms run inO (M N) time, whereM is the number of visual codes used andN is the number of objects to be encoded. Besides being efficient, the algorithms are simple and easy to implement. Our experiments showed that geographic maps automatically colored by the new algorithms were preferred to those colored by the previous graph-theoretical approach and they are competitive, if not better, in terms of the visual distinction of different regions than those drawn by hand.
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    The visual computer 9 (1993), S. 227-229 
    ISSN: 1432-2315
    Keywords: Computer art ; Solid models ; Curves ; Surfaces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The goal of this article is to present an informal introduction and tutorial on the production of aesthetically pleasing solid models. The article is intended for the nonmathematical reader interested in computer art. Simple generating formulas and recipes are included.
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    Wood science and technology 27 (1993), S. 131-136 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Five series of nonisothermal diffusion experiments originally analyzed by two theoretical equations were reanalyzed using a model derived from irreversible thermodynamics.
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    Wood science and technology 27 (1993), S. 115-129 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Ozonation of kraft pulp and oxygen-delignified kraft pulp in acetic acid/water mixtures has been studied at different pulp consistencies with and without an inhibitor to obtain information about the limitations of the selectivity of the ozone treatment. The experiments have been performed according to a full factorial design and data have been analysed by stepwise regression analysis. The results show that a better delignification selectivity can be achieved when ozone is applied in acetic acid media instead of conventional aqueous media. By combining conventional oxygen delignification and ozonation in acetic acid, pulps with equal strength properties and better optical properties compared to those of conventional O(DC)E prebleached pulps can be obtained. This study has also revealed that the reagent is utilized far more efficiently in ozonation at high pulp consistency (35%) than in ozonation at low consistency (1%), and that a similar selectivity can be achieved in both types of ozonation by choosing appropriate conditions. The greater selectivity of ozonation in acetic acid than in water is interpreted in terms of different stabilities of the oxidant in these reaction media. The relation between the formation of hydroxyl radicals and the extent and selectivity of delignification during ozonation has been investigated. The final bleaching of pulps prebleached with ozone in acetic acid medium has been studied. Two final bleaching sequences are presented, by which pulps with ISO brightness levels of 79% and 90% can be produced.
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    Wood science and technology 27 (1993), S. 173-182 
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    Notes: Summary A process for the manufacture of cork powder particleboards is described, where the agglomeration of the particles and in some cases the gluing of surface layers, is achieved by using different kinds of thermoplastics such as polyethylene and polyproyplene. Boards obtained by this process possess physico-mechanical characteristics which allow for a wider spectrum of applications than those of currently marketed corkboards.
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    Wood science and technology 27 (1993), S. 161-172 
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    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary It is frequently the case that multiple strength properties of structural wood members are simultaneously needed in design or research. A method has been developed to predict the probability distribution of concomitant material properties of wood from a knowledge of some correlated, nondestructive material property. The method developed in this study is based on properties of the univariate SB distribution and the bivariate SBB distribution. The technique involves a priori knowledge of the correlation relationship between a nondestructive parameter and the strength parameter for the two concomitant properties in question. A relationship is developed between the two nondestructive parameters and a simulation procedure is presented to predict either concomitant property from a single nondestructive measurement. The results showed that when a single parameter was predicted directly from a correlated variable, the simulated and experimental distributions were very similar (average error ≤3–4%). This result confirms previous findings. For the prediction of the concomitant property from an indirect relationship with another parameter, the absolute value of the average error was about 13%.
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    Wood science and technology 27 (1993), S. 151-160 
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    Notes: Summary As a reagent source for the formalization of wood, trioxane was used instead of conventional paraformaldehyde. From preliminary experiments it became apparent that trioxane depolymerizes to formaldehyde by heating in the presence of some metallic salts. Formalization of wood with trioxane was carried out under the catalysis of sulfur dioxide (SO2) along with these salts. The hygroscopic and acoustic properties were considerably improved by the treatment. Especially when the reaction was catalyzed by a combination of SO2 and Fe2(SO4)3, the antiswelling efficiency (ASE) reached nearly 70%, the specific dynamic Young's modulus (E/ϱ) in the radial direction increased about 20%, and the loss tangent (tan δ) decreased about 30% and 50% in the longitudinal and radial directions, respectively. In this case, the modulus of rupture did not appreciably decrease in the radial direction. This is comparable to the most prominent results obtained so far by SO2 catalyzed formalization with tetraoxane. It can be concluded that trioxane is very effective as a reagent source for formalization. The increase in acoustic converting efficiency, $$\sqrt {(E/\varrho ^3 )} /\tan$$ δ, of about twofold in the radial direction and decrease in hygroscopicity of more than 60% should not only enrich the sound volume of musical instruments but also stabilize their tone quality against humidity changes.
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    Wood science and technology 27 (1993), S. 229-239 
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    Notes: Summary Below-crown radial and height variations in maximum crushing strength parallel to grain, relative density and tracheid length of an immature, 55 year old, red pine were studied. All properties showed pronounced trends with radial age and increased from pith to bark. A radial age of 16 years was estimated as the ‘age’ from which mature stem wood is formed. All properties studied varied with height above ground. Strong correlations were observed among properties. The study tree exhibited noticeably lower average crushing strength than is reported in the literature for wood from mature red pines.
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    Wood science and technology 27 (1993), S. 241-248 
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    Notes: Summary Spruce (Picea mariana) and birch (Betula verrucosa) milled wood lignins were depolymerized with dry hydrogen iodide. 13C NMR spectra of the initial and treated lignins were recorded. The data on chemical shifts of a set of model compounds treated with dry HI were used in the assignment of changes in the spectra of the lignins. The results obtained show that a cleavage of ether bonds in lignin and a substitution of α-hydroxy and α-alkoxygroups by iodine take place during the treatment.
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    Wood science and technology 27 (1993), S. 205-217 
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    Notes: Summary Preboiling and drying wood samples of Eucalyptus regnans has shown that while in the heartwood shrinkage before reconditioning increased as a linear function of the logarithm of boiling time (BL), in the sapwood it decreased. These changes were interpreted as reflecting changes in green permeability through extractive modification which, for the sapwood, were sufficient to overcome any weakening of the cell walls through heat effects; in the heartwood, however, cell wall degradation apparently overshadowed any collateral increase in permeability, thus causing an increase in collapse. Shrinkage after reconditioning described a cubic function with respect to BL and showed an overall reduction which was greatest after 16 minutes boiling time. Correspondingly, recoverable collapse was greatly increased through preboiling; it was shown that per cent collapse recovery in the heartwood could be increased by more than one third that of controls by preboiling for 8 minutes. The possibilities for industry application are considered. Moisture content after reconditioning (Mr) was greatest after about two minutes preboiling, then declined to be less than the control after 16 minutes. Change in shrinkage after reconditioning and collapse were shown to be significantly related to change in Mr. It was suggested that while Mr may reflect relative permeabilities after reconditioning, this may not apply to permeability in the green condition. Additional parameters derived from the data, viz. the intersection point, unit shrinkage, the R-ratio, ‘collapse-free’ shrinkage, total collapse and residual collapse described mostly significant, cubic relationships with the logarithm of the boiling time. Generally, the major inflection point of regression curves occurred after 8 or 16 minutes boiling.
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    Wood science and technology 27 (1993), S. 280-280 
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    Notes: Summary To advance the discussion on the evolution mechanism of tree growth stresses, the relation between released strain and the chemical components was investigated experimentally. The expansive released strain in the longitudinal direction assumed large values as the lignin content increased in the compression wood, but there was no relation between released strain and lignin content in the normal wood region. The contractive released strain assumed large values as the cellulose content and its crystallinity increased. Their correlation was very high and clear. From these facts, it is considered that the lignin deposition plays an important role in the generation of the growth stresses in compression wood but is not important in normal or tension wood regions. Cellulose microfibrils contract along their longitudinal axis during cell maturation, and the stress included by the contraction creates a longitudinal growth stress in normal and tension woods.
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    Wood science and technology 27 (1993), S. 271-279 
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    Notes: Summary Explosion pulping results in strong pulp with breaking length at 100 ml CSF (Canadian standard freeness) higher than 6.5 kg and burst index approaching 4 KPa m2/g. The real advantage of eucalyptus explosion pulp over conventional CMP (chemical-mechanical pulp) and CTMP (chemical-thermo-mechanical pulp) is observed when the impregnation solution contains less than 2% NaOH along with 8% Na2SO3, and when the liquor/chips ratio equals 3. The strength of eucalyptus explosion pulp obtained by using a pretreatment solution consisting of 8% Na2SO3 and 1% NaOH is comparable with that of eucalyptus kraft pulp. The concentration of NaOH present in the pretreatment solution has a very important effect on the specific refining energy of eucalyptus explosion pulp as well as of CMP and CTMP. The explosion pulp obtained from eucalyptus pretreated with a solution containing an appropriate quantity of caustic along with Na2SO3 not only requires a minimum specific refining energy but also provides the highest strength values in comparison to that of CMP and CTMP.
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    Wood science and technology 27 (1993), S. 287-293 
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    Notes: Summary A method to control the tone quality of wooden string instruments by chemical modification is proposed. Sitka spruce specimens impregnated with saligenin solutions of various concentrations were allowed to react with gaseous formaldehyde using SO2 as a catalyst. In the frequency range where shearing deformation is negligible, the values of specific dynamic Young's modulus (E/γ) in the radial direction increased with increasing saligenin concentration by up to 27%, whereas the values of dynamic loss tangent (tan δ) decreased as much as 40% in the longitudinal direction and 50% in the radial direction along with small increases in air-dry specific gravity. The degree of increase of tan δ with increasing frequency was inversely proportional to the saligenin content. The frequency dependence of E/γ did not change as a result of treatment. From these results, it is considered that the sound level radiated from wooden string instruments changes at high frequencies according to the saligenin content.
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    Wood science and technology 27 (1993), S. 308-308 
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  • 49
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    Wood science and technology 27 (1993), S. 321-335 
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    Notes: Summary The minute compression failures of the cell walls known as slip planes are quantified with respect to their occurrence in the compression side of beams subjected to mechano-sorptive creep. It is shown that slip planes occur at values of stress/strain lower than previously assumed. The slip plane intensity proves to be linearly related to creep and non-linearly related to stress. A permanent increase, ΔS, of longitudinal shrinkage /swelling results from slip plane formation, and this parameter therefore serves as a substitute for slip plane intensity, which is not easily measured. Slip plane intensity is considered a measure of accumulated damage, and the substitute parameter ΔS is used to quantify the accumulated damage of structural timber beams. The load level experienced by structural timber beams subjected to mechano-sorptive creep is shown to be reflected in the accumulated damage as assessed by ΔS.
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  • 50
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    Wood science and technology 27 (1993), S. 309-320 
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    Notes: Summary The energy characteristics of hybrid willow (Salix spp.) were evaluated to improve the selection and breeding program of this short-rotation species. The differential scanning calorimeter (DSC) has proven to be a valuable tool over the conventional adiabatic oxygen bomb calorimeter (AOB) based on its accounting for losses due to dissipated heat, incomplete combustion of pyrolysis and the loss of the heat of vaporization. The average heat content of the four unextracted hybrid willow determined by AOB and DSC was 4635 cal/g and 1609 cal/g respectively. Clone SP-3 is the superior tree based on its energy content per volume of biomass and energy content per square meter of land. Chemical composition of the wood was determined to elucidate its effects on the pyrolysis and combustion. Fuels with high extractive and lignin contents will not necessarily liberate the highest energy when burned. The ash, although representing only a minor proportion by weight, appears to be a major determinant in the combustion behaviour of a material.
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  • 51
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    Wood science and technology 27 (1993), S. 347-355 
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    Notes: Summary European Beech (Fagus silvatica L.) was impregnated with a dimethylol resin to improve its dimensional stability and durability. Different catalysts were evaluated in combination with the resin. Depending on the range of relative humidity, the resin improved the shrinkage and swelling by approximately 50%. The use of an acid (citric or tartaric) catalyst lead to improved resin curing. A curing temperature of 100 °C is necessary.
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  • 52
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    Wood science and technology 27 (1993), S. 373-380 
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    Notes: Summary Because wood is a natural material, the variability of its properties is very large. In order to use wood efficiently in building, it has to be stress graded. The ultrasonic stress grading was developped as an improved alternative to visual grading. This non destructive evaluative technique allows reliable higher strength values while working with new products. Corrected models were studied to reference the ultrasonic propagation speed at constant moisture content and temperature. Using a referential ultrasonic wave velocity, stress grading can be carried out on trees or logs before cutting, or on fresh beams. The correlation between conditioned beams and test specimens is very high, especially for the strongest material.
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  • 53
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    Notes: Summary In this study a quantitative analysis of the low molecular carbohydrates (predominantly sucrose, fructose and glucose) in a series of lumber samples of Pinus sylvestris and Picea abies taken at various distances from the surface has been made. The increase of nitrogenous compounds towards the surface had been shown in a previous study. Several of the lumber samples showed a marked sugar accumulation at the surface, which correlated quite well with a corresponding nitrogen accumulation. In one case, the total amount of the three sugars was as high as 4.9% of the dry matter content in the 0–1 mm layer. It was of special interest to note that samples with high nitrogen and sugar contents also had a yellow surface colour, which probably formed during the drying process by the well-known Maillard reaction — a complex of reactions occurring when sugars and amino acids, peptides and proteins are heat-treated together. Growth of the mould fungus Penicillium brevicompactum was well correlated with the content of nitrogen and low molecular carbohydrates in adjacent samples. The initial colonization was somewhat delayed in material from the outermost sapwood zone despite high nutrient contents indicating effects of antifungal compounds from the bark or toxic Maillard reaction products effective against germination. Growth of Aspergillus versicolor was likewise most elaborate on samples with the highest nitrogen and soluble carbohydrate content but the results also indicate a sensitivity to antifungal compounds present.
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  • 54
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    Wood science and technology 27 (1993), S. 391-395 
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    Notes: Summary Cell wall lignin distribution was assessed in Pinus radiata wood using quantitative interference microscopy. Three groups of trees were examined. Five trees, offspring of NZ clone 850-55, and five trees of NZ 850-55 crossed with several parents of the Guadelupe provenance, were compared with five trees of unselected P. radiata. Lignin concentration in the cell corner middle lamella region was significantly lower in both offspring groups of NZ 850-55 when compared with the unselected control trees. No difference in S2 lignin concentration was observed among the three groups. This result represents the first indication that variations in lignin distribution are genetically controlled in pines.
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    Wood science and technology 27 (1993), S. 401-408 
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    Notes: Summary It is demonstrated that there can be only one driving potential for the movement of water through wood and this will be a function of wood state. On the assumption that the driving potential is the partial pressure of water vapour, a theoretical expression is derived for the diffusion coefficient. Such expression is fitted to diffusion coefficients for Scots pine and a remarkably good fit is obtained.
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    Wood science and technology 27 (1993), S. 421-427 
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    Notes: Summary Water vapour diffusion characteristics and adsorption isotherms were determined for cell-lumen and cell-wall treated wood polymer composites (WPC). The diffusion coefficients of the cell-lumen WPC were lower than untreated wood and the cell-wall WPC coefficients were lower than cell-lumen. Using the Hailwood and Horrobin sorption model, it was found that the unimolecular layer is formed at lower moisture contents in WPC than in wood. The amount of free dissolved water was reduced only in the cell-wall WPC. The polymer reduces the water vapour accessibility in both types of WPC.
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  • 57
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    Wood science and technology 27 (1993), S. 409-420 
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    Notes: Summary Diffusion analysis can be used to estimate the time required to dry lumber. However, more accurate calculations require additional information on the relationship between the diffusion coefficient as a function of moisture content and on the effects of temperature, equilibrium moisture content, board thickness, and air velocity on drying time and moisture gradients. The primary objectives of this study were (1) to determine the diffusion coefficient of northern red oak (Quercus rubra) as a function of moisture content and (2) to compare experimentally determined sorption times and moisture content gradients with those calculated by the diffusion model. The diffusion coefficient was found to increase approximately exponentially with moisture content over a range of 6 to 30 percent at 43°C. This relationship was similar in both adsorption and desorption tests. Experimental adsorption and desorption times and desorption moisture content gradients were compared with finite difference solutions to the diffusion equation. Practical uses of solutions to the diffusion equation are illustrated for kiln drying wood that has first been predried to below the fiber saturation point. Drying time is also related to variable kiln conditions and board thickness.
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    Wood science and technology 27 (1993), S. 461-467 
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    Notes: Summary In an X-ray diffraction investigation, the recrystallization behavior of ball-milled Chinese southern pine wood was found to differ from that of cellulose. The crystallinity of lignocellulose milled for a very long time and recrystallized by wetting in water did not decrease with increasing milling time as was the case with milled cellulose. In addition, it appeared that the presence of lignin tended to restrict the amorphous cellulose produced by milling from recrystallizing into Cellulose II, whereas it had no influence on the recrystallization into Cellulose I. These results were discussed in the context of the mechanism of the conversion of Cellulose I to Cellulose II.
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    Wood science and technology 28 (1993), S. 1-8 
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    Notes: Summary The oxygen (1s) ESCA peak for aspen explosion pulp consists of two components, O1 and O2. A tentative assignment was made for them. O1 with lower binding energy is assigned to oxygen in lignin; while O2 comes mainly from the oxygen elements in carbohydrates. Thus, an O1 area percentage might be viewed as a measure of lignin exposed on the fiber surface. Sulfur (2p) spectra show that the sulfur on the fiber surface of the pulps studied here is in the form of sulfonate groups. Compared to conventional pulps, the lower percentage of O1 and higher sulfur-to-carbon ratio for explosion pulps imply higher number of hydrophilic groups exposed on their fiber surface.
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    Wood science and technology 28 (1993), S. 23-33 
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    Notes: Summary In terms of the problem of formaldehyde-releasing, glyoxal is one of the interesting dialdehydes as a crosslinking agent for wood. In the present report, the reaction of glyoxal and glyoxal/glycol with the wood of Japanese ash (Fraxinus mandshurica Rupr. var. japonica Maxim.) has been studied. Particular attention to the structure of the product (after treatment with glyoxal/glycol (glycol: ethylene glycol, diethylene glycol, triethylene glycol)) was made and the formation of crosslinking has been discussed. Reaction of only glyoxal with wood showed little reactivity, while that of glyoxal/glycol gave high weight increases for each glycol. The appropriate condition was at 100° to 130°C for 2 hrs. It was found that the product forms network structures, at least within itself. The crosslinking between the product and wood components, however, could not be confirmed, although it was assumed that the product was structurally linked to wood by its reactive sites.
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    Wood science and technology 28 (1993), S. 45-51 
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    Notes: Summary A rationale is presented for developing a mathematical model which describes a randomly packed, short-fibre-type wood composite. The model will utilize probability theory to insure random packing both in terms of flake position and orientation. Knowledge about the spatial relationship between wood elements will be used, in future, to predict a number of physical parameters associated with the composite structure. This will be accomplished by first developing a single-layer-flake model and subsequently proceeding to a multi-layer mat structure.
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    Wood science and technology 28 (1993), S. 59-65 
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    Notes: Summary Results from sorption measurements at 23 °C on Picea abies in the intervals 54 to 75% RH and 75 to 84% RH are reported. In the higher interval non-Fickian sorption is clearly seen.
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    Wood science and technology 28 (1993), S. 86-88 
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    Notes: Summary The activation energy of diffusion can be expressed in terms of thermodynamic quantities such as entropy and enthalpy of sorption. A substantial simplification to such a published expression is presented.
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  • 64
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    Notes: Summary The spermiogenesis of three species of the Parotoplaninae (Otoplanidae, Proseriata) is described based on electron-microscopical observations. Special reference is given to organelles which do not persist in mature male gametes. One of these organelles is a striated appendage of the intercentriolar body. This differentiation has not been reported from any other plathelminth taxa up to now. The striated appendage, which may serve as a strengthening element, is hypothesized to be an autapomorphic feature of the Parotoplaninae.
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  • 65
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    Notes: Summary The unpaired germarium of Dicrocoelium dendriticum contains many female germ cells at different stages of maturation and is enveloped by a fibrous basal lamina-like structure and a multilayered cytoplasmic sheath whose origins and functions are discussed. The maturation process of primary oocytes occurs completely within the prophase of the first meiotic division. It has been divided into three stages, as previously suggested for monogeneans. Stage I corresponds to oogonia and early oocytes which are located in the distal germinative area of the gonad. These cells are characterized by a high nucleo/cytoplasmic ratio and a poorly differentiated cytoplasm. Stage II corresponds to maturing oocytes grouped in the central area of the gonad and exhibiting long synaptonemal complexes and a prominent nucleolus. The main feature of cytoplasmic differentiation is the increase in the number of RER and Golgi complex which are involved in the production of small electron-dense granules. Stage III corresponds to mature oocytes located in the proximal area of the germarium near the origin of the oviduct. In this stage, the granules become regularly distributed in a monolayer in the peripheral ooplasm and make contact with the oolemma. They show a distinctive complex structure, are composed of proteins and glycoproteins and do not contain polyphenols. Their possible role as cortical granules is discussed in relation to chemical composition and previous studies on other Plathelminthes. Neither yolk globules nor glycogen are present in the oocytes.
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  • 66
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    Notes: Summary The Aristotle's lantern, or masticatory apparatus, of regular sea-urchins is a complex musculo-skeletal system which is thought to have contributed significantly to the evolutionary success of these animals. This paper gives an account of the antomical relationships and functional morphology of both skeletal and soft tissue components in the lantern and related structures of the sea-urchin Stylocidaris affinis (Cidaridae), and compares these features with their equivalent in the previously described lantern of the sea-urchin Paracentrotus lividus (Echinidae, Camarodonta). There are major differences in the skeletons of these lanterns which involve mostly the arrangement and morphology of elements participating in movement, i.e. joints and articular surfaces, and which highlight the generally heavier and less mobile nature of the lantern in the Cidaridae. There are remarkably few differences, however, in the microstructure of the skeletal stereom. Significant dissimilarities were found in the anatomical arrangement of muscles and ligamentous structures and in their macro- and microstructure. The implications of these morphological features for the functioning of the lantern of the Cidaridae are discussed in the context of an integrated model of lantern biomechanics.
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    Notes: Summary Pre-cloacal glands occur in some species of amphisbaenians. Although these glands are important in systematics, their biology and chemistry are little known. The pre-cloacal glands of Amphisbaena alba are of the holocrine type. They are made up of a glandular body and a duct. The glandular body is conical to elongate and is formed of clongatc lobules separated one from another by collagen septa. Each lobule is composed, at its periphery, of germinative cells, and within of polyhedral secretory cells, of different degrees of differentiation. The germinative cells, set on a basal lamina, are basophilic and their cytoplasm is fairly electron dense. The polyhedral cells display bulky cytoplasm, filled with spherical granules, wrapped in membranes and differing in their electron densities. Towards the lumen of the gland, these granules are increasingly eosinophilic and have an affinity for orange G. The secretion is discharged into the duct leading to the pore, which is situated in the central region of the scale. This secretion shows positive histochemical results for mucopolysaccharides and proteins. The similarity between the epidermal glands of lizards and those of A. alba raises the suggestion that the glands have equivalent functions, possibly in the course of intra- or interspecific communication.
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    Notes: Summary Long-term light deprivation of the royal pair of Neotermes jouteli during the phase of reproduction leads to a dramatic change in the organization within the compound eye. In a swarming alate, investigated with scanning and transmission electron microscopy, the eye consists of about 200 ommatidia. No differences between male and female eyes are observed. Each ommatidium is composed of a biconvex cornea, a cone of the eucone type, and a rhabdom which is located directly beneath the Semper cells. The rhabdom consists of eight rhabdomeres which are fused along the ommatidial axis. In the central part of the compound eye the rhabdom measures roughly 20 μm in length. Concealed life of the imagines causes a dismantling of the cone and the rhabdom until complete destruction. This is accompanied by an increase in the number of pigment granules and a decrease in the number of mitochondria.
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  • 69
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    Notes: Summary The route followed by food particles in Spongilla lacustris was clarified by light and electron microscopic examination of sponges fed with Chlamydomonas reinhardtii. The algal cells are phagocytosed by prosendopinacocytes and choanocytes. After some time they are transferred to archaeocytes, amoebocytes, and lophocytes. Changes in algal structure during digestion were observed and the egestion of algal remnants was documented in life for the first time. In light micrographs, digestion of the algal cells is manifest first in shrinkage of the cells, then in disintegration to form several spherical green fragments 2–3 μm in diameter, and finally, after 12–18 h, in a reddish brown discoloration of the fragments. Signs of the digestive process in electron micrographs include disappearance of the cell-wall layers, the flagella, and the pyrenoid and its starch sheath, as well as a progressive increase in the density of the cytoplasm and karyoplasm.
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  • 70
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    Notes: Summary The introvert, mouth cone, and nervous system of Echinoderes capitatus were examined by transmission and scanning electron microscopy. The introvert bears seven rings of primarily quincunxial sensory scalids, including type 1 and 2 spinoscalids as well as trichoscalids; the latter two types are additionally provided with glandular cells. The mouth cone bears one ring of decamerous sensory oral styles and three rings of quincunxial sensory pharyngeal styles. The intra- to basiepithelial, bilateral nervous system consists of a circumentric nerve ring in the introvert, a terminal and proximal nerve ring in the mouth cone, a ventral chain of ganglia, one in each trunk zonite, and a caudal ganglion. The introvert, the neck, and the trunk zonites are innervated from the forebrain; the mouth cone and the pharyngeal bulb are innervated from the hindbrain. The monophyly of the Kinorhyncha is based upon the following autapomorphic characters: (1) a mouth cone, (2) a neck with 16 placids, (3) a trunk with 11 zonites, (4) scalids of three types: type 1 and type 2 spinoscalids, and trichoscalids, (5) an anteriormost ring of ten type 1 spinoscalids (sensory organs divided into a basal and a terminal part), (6) a posteriormost ring of 14 trichoscalids (glandular sensory organs which are undivided), (7) rings in between the anteriormost and posteriormost are type 2 spinoscalids (glandular sensory organs divided into a basal and a terminal part), (8) a mouth cone with a terminal and a proximal nerve ring, (9) nine sensory oral styles with decamerous symmetry (the dorsal style is missing) and (10) three rings of sensory pharyngeal styles with, from anterior to posterior, ten, five, and five styles with quincunxial arrangement. The following characters are assumed to be autapomorphic for the taxon Nematoda+Gastrotricha+Kinorhyncha+Loricifera+Priapulida: (1) a basiepithelial circumentric brain and (2) a neuropileous nerve ring in a subterminal position. The following characters are assumed to be autapomorphic for the taxon Kinorhyncha+Loricifera+Priapulida: (1) a neuropileous nerve ring in a terminal position, (2) an introvert with scalids, (3) an eversible foregut and (4) tanycytes.
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    Zoomorphology 113 (1993), S. 245-251 
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    Notes: Summary Each of the two protonephridial systems of Seison annulatus consists of three sections which are separated by cell borders with septate junctions: (a) a terminal syncytium with eight terminal organs and a capillary canal, (b) a canal syncytium which is divided into a multiciliary canal region and a main canal region, and (c) a nephroporus cell. The terminal syncytium is branched and linked twice to the canal syncytium. The supporting structure of each filtration barrier is a hollow cylinder which is perforated by pores and lacks microvilli (pillars). A protonephridial spine is situated in the multiciliary canal region and stabilizes the neck region. The ored, hollow cylinder and the protonephridial spine are new characteristics for the Rotifera.
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    Wood science and technology 27 (1993), S. 81-94 
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    Notes: Summary A procedure has been developed to determine the cut-off frequency in an algorithm to evaluate the localized modulus of elasticity (MOE) in lumber. MOE profiles have been artificially generated to serve as input for evaluation of the procedure. A noise component has also been added to the input record to test the robustness and accuracy of the procedure. Good agreement between program predictions and the known localized MOE values has been obtained. The efficiency of the procedure has also been tested using MOE profiles collected from experiments. The program performed efficiently and program predictions seemed reasonable.
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    Wood science and technology 27 (1993), S. 95-114 
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    Notes: Summary A model of isothermal moisture movement in wood during drying using the gradient in water potential as the driving force is proposed. The moisture transport coefficient used in this model is the effective water conductivity. It is a function of moisture content, temperature, and direction of flow. The boundary desorption curve of the effective water conductivity function is established in the radial and tangential directions of aspen sapwood from nearly saturated to dry conditions at 20, 35, and 50 °C using the instantaneous profile method. The results show that the effective water conductivity increases exponentially with moisture content and temperature. The effect of temperature cannot be solely explained by the variation of the viscosity of water. The variation of the moisture content-water potential relationship with temperature would explain a large part of this effect. The effective water conductivity was generally higher in the radial direction than in the tangential direction in a ratio varying from 1/1 to 25/1 depending on moisture content and temperature. The flux-gradient relationship obtained at given moisture contents were found to be linear, confirming the validity of the model for the experimental conditions considered in the present work.
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    Wood science and technology 27 (1993), S. 137-150 
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    Notes: Summary The duration of load effect for the fracture thoughness in mode II loading (forward shearing mode) has experimentally been determined for wood. The end-cracked beam specimens used were exposed to a constant load which corresponds to a nominal load level between 60 and 85% of the short-term capacity. The relative humidity was kept constant at 65% for two experimental series and changed cyclically between 40 and 90% for six experimental series. The length of a whole cycle was two weeks. In contrast to constant humidity conditions the time to failure was drastically reduced. For an end-cracked spruce beam loaded to 75% of its short-term capacity the lifetime was reduced from 2.5 months to 4 days.
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    Wood science and technology 27 (1993), S. 183-193 
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    Notes: Summary The effects of an oxidative activation of some different wood surfaces by flame treatment has been studied. Flame treatment markedly increased the wettability and decreased the microbiological activity. No improvement in glue adhesion was discerned for a water-borne PVAc-glue. ESCA measurements showed a considerable increase in oxidation level as a result of the flame treatment. The duration of the activation varied between different wood species.
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    Wood science and technology 27 (1993), S. 195-203 
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    Notes: Summary Specially designed wood blocks from Norway spruce were used to study the nature of the fracture surfaces developed in shear using a tensile tester. In the case of the control (water-soaked blocks), the fracture in the latewood takes place mainly in the S1 layer while in the earlywood the fracture occurs across the double cell wall. After dilute alkali treatment, some earlywood cells also fracture in the S1 layer. For sulfite-treated samples, on the other hand, both earlywood and latewood fracture in the middle lamella.
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  • 77
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    Notes: Summary Murine monoclonal antibodies (mAbs) were produced to the extracellular β-1,4-xy-lanase fraction of the brown-rot fungus, Postia placenta. The immunizing antigen was derived from decayed southern yellow pine wood blocks extracted in phosphate-buffered saline and Triton X-100, and fractionated by column chromatography. Five IgG monoclonal antibodies were selected for characterization by enzyme-linked immunosorbent assay, (ELISA) and western blot. Each mAb exhibited binding to two major protein bands on western blot at 32 kDa and 36 kDa. Characterization by chemical and enzymatic modification of the antigen determined whether mAbs were protein specific or specific for the carbohydrate portion of the glycoprotein. Affinity chromatography with the protein specific mAbs demonstrated specific binding to β-1,4-xylanase and cross-reactivity with β-1,3-glucanase, β-1,4-glucanase, and β-1,4-mannanase. These mAbs were also immunoreactive with polysaccharidases from liquid culture filtrates when tested by ELISA.The mAbs have been utilized to successfully detected P. placenta by ELISA in decayed southern yellow pine at a weight loss of 3.6%.
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    Wood science and technology 27 (1993), S. 249-256 
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    Notes: Summary Regression analyses using the traditional, mean-based, least squares (LS) and the median-based, least absolute deviations method (LAD) were performed on twenty-five sets of bending strength and stiffness data. Comparisons of regression models were made to determine the effect of mathematical technique. In all cases, model coefficients demonstrated some degree of sensitivity to regression method. In cases where the residual data appeared to approximate a normal distribution, the models produced fairly similar results. However, the LS technique was found to be highly influenced by even a single extreme residual value. LAD regression proved to be far more stable in the presence of extreme residual values due to its more rational distance function.
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  • 79
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    Notes: Summary Lignincarbohydrate complexes (LCC) of poplar wood obtained by sulfate pulping and containing lignin in amounts of 0.9–8.3% have been studied by X-ray diffractometry. Heterogeneous hydrolysis methods have been used to determine their reactivity. The content of the crystalline fraction in LCC depends on the lignin removal and increases with the decrease of the lignin content. The degree of crystallinity of cellulose in sawdust and in LCC is fairly high and changes slightly with the lignin removal. The presence of lignin plays a blocking role in the heterogeneous hydrolysis and decreases the rate constant. It is suggested that lignin is bonded to cellulose on the outer surfaces of the crystalline part of the cellulose fibril. Some possible variants of these bonds are discussed.
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    Wood science and technology 27 (1993), S. 294-294 
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  • 81
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    Notes: Summary Stereochemical studies on the formation of the diastereomers of arylglycerol-β-aryl ether structures during lignin biosynthesis have been carried out with model compounds. The addition of water to quinone methides of the β-syringyl ether type gives arylglycerol β-syringyl ethers with a predominance of the erythro isomer when the pH of the medium is low. Since erythro forms of arylglycerol β-syringyl ethers are prevalent in hardwood lignins, this indicates that the pH of the medium in which lignin biosynthesis occurs is lower than has been assumed until now. Equilibration studies with non-phenolic model compounds of the arylglycerolβ-guaiacyl ether and β-syringyl ether types under acidolysis conditions indicate that the erythro predominance observed in the syringyl ethers in lignins does not correspond to equilibrium conditions. A remarkable resistance to acidolysis is observed in the model compounds of etherified syringylglycerol β-syringyl ether type.
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  • 82
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    Notes: Summary The in vitro decay of Aextoxicon punctatum and Fagus sylvatica wood by the fungi Trametes versicolor, Ganoderma australe, Phlebia chrysocrea and Lentinus cyathiformis was studied by the agar-block method, and then the decayed woods were analyzed by chemical and spectroscopic techniques. The results demonstrated the strong resistance of the A. punctatum wood to the brown-rot fungus L. cyathiformis; the resistance might be related to the low S/G lignin ratio in this Austral hardwood. Wood decay by the Austral white-rot fungi G. australe and P. chrysocrea was rather limited, and preferential degradation of lignin was not produced although all the fungi studied increased wood digestibility. The most characteristic white and brown-rot decay patterns were observed during the in vitro decay with T. versicolor and L. cyathiformis, respectively. Trametes versicolor caused high weight losses and reduced the lignin content of the wood, whereas L. cyathiformis produced a preferential removal of xylan. No important changes in the solid-state 13C NMR spectra were observed after wood degradation by T. versicolor, but this technique evidenced an increase in aromatic carbon by L. cyathiformis. This increase was higher than that found in the Klason lignin content, suggesting the presence of altered lignin fractions in the brown-rotted wood.
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    Wood science and technology 27 (1993), S. 337-345 
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    Notes: Summary Samples of nine tropical hardwoods from Peru and sugar maple wood from Quebec were selected to perform moisture sorption tests associated with swelling tests at 25 °C. The results demonstrate that, for a given equilibrium moisture content, tangential and radial dimensions, and hence the volume of wood, are greater after desorption than after adsorption. The importance of these differences, so-called second-order effects of moisture sorption, varied with the species and with the direction of swelling. These effects are proportionally greater in the tangential direction of wood than in its radial axis. Finally, two types of samples showed similar swellings for three equilibrium moisture contents.
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    Wood science and technology 27 (1993), S. 390-390 
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    Wood science and technology 27 (1993), S. 357-371 
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    Notes: Summary An electron microscope study of the behaviour of Dacrydium cupressinum Lamb. (rimu), Podocarpus dacrydioides A. Rich, (kahikatea) and Pinus radiata D. Don. (radiata pine); two endemic timbers of New Zealand and one exotic timber coated with a specially formulated TiO2 tagged long soya oil alkyd coating was made using both the scanning and transmission electron microscopes. The key elements present in the coating were detected by energy dispersive X-ray analysis and used to qualitatively trace coating penetration into wood. Quantitative information on the nature of the coating penetration was obtained by photographing the entire cross-sectional length of each weatherboard under the scanning electron microscope and counting the number of filled cells inwards from the coating interface. The performance of the coating and the three weatherboard taxa were tested using accelerated weathering techniques involving the Xenon-arc Weather-Ometer. Coated and uncoated boards were weathered for up to three thousand hours. Coating durability and substrate behaviour were qualitatively assessed microscopically. Fourier transform infrared and attenuated total reflectance methods were used to obtain quantitative information on coating performance and particular reference is made to these latter techniques.
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    Wood science and technology 27 (1993), S. 396-400 
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    Notes: Summary An apparatus for sorption measurements has been built and tested. Control of temperature, relative humidity and air velocity over long periods of time have been the main objectives. The article contains a description of the instrument and its performance characteristics.
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    Wood science and technology 27 (1993), S. 438-438 
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    Wood science and technology 27 (1993), S. 429-437 
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    Notes: Abstract A geometrical model was derived to describe knots in logs and on the surface of lumber beams sawn from those logs. Each knot is defined by 7 parameters related to the shape and position in the stem. A computer simulation program was written to study knot shapes on a variety of observation planes. An initial investigation on the shape of knots in Scots pine logs and lumber beams suggests that the model is sufficiently accurate to describe knottiness in this species. Potential applications of this model include automated lumber grading, computerized log reconstitution and yield optimization studies.
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    Wood science and technology 27 (1993), S. 439-448 
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    Notes: Summary The objectives of this research were to investigate the proportion of decayed wood in mature aspen stems, its chemical composition and its potential utility as a fuel or as a substrate for conversion to fine chemicals as part of an integrated utilization scheme. Three sound and ten decayed aspen stems were sampled from a boreal forest site. Stem analysis indicate that on average, 20% of the merchantable stem volume was in advanced decay and that considerable sound wood recovery was possible. Wood specific gravity and chemical composition were determined. The holocellulose content (volumetric basis) in advanced decayed wood was reduced by 67%. Thermal analysis of the wood using a differential scanning calorimeter provided graphical evidence of a different sequence of events occurring during the combustion of decayed wood and a resulting heat content per unit weight that was 40% higher than that of sound aspen wood. A higher degree of enzymatic hydrolysis was attainable with white-rotted aspen wood. Approximately 62% of the theoretical glucose yield was obtained from decayed aspen wood after alkali-peroxide pretreatment followed by a 12 hour hydrolysis using technical grade enzymes. The above information is used to elucidate future opportunities for wood recovery and energy production from decayed wood resources.
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    Wood science and technology 27 (1993), S. 468-474 
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    Notes: Summary In this work we characterized olive tree fellings, wheat straw, sunflower stalks, vine shoots and cotton plant stalks, as well as pulp and paper sheets obtained from them. Thus, we determined the 1% NaOH solubles, alcohol-benzene extractables, ash, holocellulose, lignin, α-cellulose and pentosans in the aforementioned agricultural residues and their pulps, as well as the breaking length, stretch, burst index, tear index, porosity and water absorption of the resulting paper sheets, which were also subjected to the concora medium, concora crush and rings crush tests. Wheat straw and vine shoots were found to be the most and least suitable raw material, respectively, for paper production.
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    Wood science and technology 27 (1993), S. 449-459 
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    Notes: Summary The surface composition of explosion pulp and conventional CMP and CTMP underwent ESCA spectroscopy. Explosion pulps exhibited a higher oxygen-to-carbon ratio and less C1 peak areas compared to conventional CMP/CTMP. Based on the theoretical O/C ratios and C1 contents for the main components of wood fibers (i.e., carbohydrates, lignin and extractives), a triangular graph was used to illustrate the relative amounts of the three components on the surface. This analysis indicated that explosion pulps had more carbohydrates exposed on their fiber surface, which may explain their high physical strength. A bulk analysis indicated that these differences could not depend on their bulk compositions, since the latter were similar.
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    Wood science and technology 28 (1993), S. 9-22 
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    Notes: Summary Finely ground spruce wood (Picea abies (L.) Karst.) was incubated with various commercial enzyme preparations; the incubation liquid was analysed for the presence and volume of uronic acids and neutral sugars. The tested enzyme preparations dissolved neutral and acid sugar from the woodpowder. The most effective enzyme preparations were cellulolytic enzymes with some hemicellulolytic activites. This applied to the decomposition of neutral polysaccharide as well as to polyuronide. The polysaccharides in the cell wall were almost completely broken down to low molecular weight sugars by these preparations. Pectinase preparations, on the other hand, had lower efficacy in decomposing neutral and acid polysaccharides. A difference in efficacy of the enzyme preparations in decomposing heart- or sapwood could not be ascertained.
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    Wood science and technology 28 (1993), S. 35-44 
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    Notes: Summary Rigidity of cabinet furniture and load carrying ability of different classes of surface constructions depend on stability of sheets used as sheathing or back walls of these structures. The process of loss of stability by large sheets of wood boards (fiber and plywood boards) has not been sufficiently studied. The aim of this study was to carry out laboratory investigations on the phenomenon of the loss of stability by fiber and pine plywood boards used as back walls differently mounted to bodies of cabinet furniture. Experimental results were verified by theoretical calculations which showed satisfactory consistency. They also confirmed possibility of checking dimensions of these boards in finished constructions.
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    Wood science and technology 28 (1993), S. 53-58 
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    Notes: Summary The opto-thermal transient emission radiometry measuring system has been improved by including a microscope as part of the signal detection system to achieve a higher degree of spatial resolution. This is illustrated with measurement of decay time of optothermal signal observed from the transverse cut of pine wood samples. Good correlations were found between opto-thermal decay time and colour within the pine growth rings.
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    Wood science and technology 28 (1993), S. 67-85 
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    Notes: Summary Several properties have been measured for pinewood samples, corresponding to the region within the heartwood or the sapwood, with the aim of treating wood as a heterogeneous medium when modelling the drying process. A two driving-force model is used to compare a homogeneous and a heterogeneous approach to the drying of a pinewood board. The main difference between the two theoretical descriptions is a specific boundary condition for the inter-region, which may generate jumps of the moisture content fields. Experimental and numerical results are presented and some comments are made concerning the use of the heterogeneous model.
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    Zoomorphology 113 (1993), S. 1-20 
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    Topics: Biology
    Notes: Summary The prostomial appendages and the central nervous system have been investigated by electron microscopy in Protodriloides chaetifer, P. symbioticus, Protodrilus haurakiensis, P. oculifer, P. ciliatus, P. helgolandicus, P. adhaerens, Saccocirrus krusadensis and S. papillocereus. The tentacles are highly developed, mobile sensory structures and consist of cuticle, epidermis, a different number of intraepithelial nerves, a small blind-ending blood vessel and a bundle of longitudinal muscle fibres. An internal canal is only present in Protodrilus and Saccocirrus species. On the tentacles seven types of sensory cells have been found including different multiciliated and uniciliated sensory cells with cilia penetrating the cuticle, sensory cells with non-penetrative cilia, phaosomes and basal ciliated sensory cells. The latter are described for the first time in polychaetes. From the specific pattern of innervation by up to five nerves originating close to the brain from the dorsal and ventral roots of the circumoesophageal connectives it is evident that the prostomial appendages represent palps. In the palps the nerve fibres form neuroneuronal, myoneuronal and epithelioneuronal synapses. The brain also gives rise to the stomatogastric nerves and various dorsal nerves. The palp canals are separated from the surrounding tissue by a prominent extracellular matrix. The wall is formed by muscle cells. The centre is usually completely filled with the cell bodies of these muscle fibres and large coelenchyme-like cells. These cells move freely in the canals and they are very likely the structural basis for the hydroskeletal function of the canals. The canals are completely separated from other body cavities and fluid is probably driven into the canals from the blood vascular system via podocytes located in a specific zone in the prostomium. In particular, the structure of the central nervous system with its nerves, the pattern of innervation of the palps and the palp canal system are compared with those of other polychaetes with special emphasis to the Spionida, the taxon presumed to include the sister group of the Protodrilida.
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    Zoomorphology 113 (1993), S. 33-45 
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    Topics: Biology
    Notes: Summary The fine structure of the integument of Myzostoma cirriferum is described with special attention to the integument sensory areas. Hypotheses about the function and a functional model of these are proposed. The integument consists of an external pseudostratified epithelium with cuticle (the epidermis) covering a parenchymo-muscular layer (the dermis). The dermis includes two types of cells: muscular fibers of the double obliquely striated type and parenchymal cells. Differences occur in the epidermis, which consists either of a large non-innervated myoepithelial area (viz. the regular epidermis). or of several rather localized sensory-secretory areas associated with discrete nerve proceses (viz. the sensory epidermis). The regular epidermis is made up of three types of cell: covering cells, ciliated cells and myoepithelial cells. The sensory epidermis shows small or marked structural variations from the regular epidermis. Small variations occur in the cirri, the buccal papilla, the body margin, the parapodia and the parapodial folds where nerve processes insinuate between epidermal cells. They are thought to be mechanoreceptor sites that could give information on the structural variations of the host's integument and participate in the recognition of individuals of the same species. The sensory epidermis differs markedly from the regular eidermis in the four pairs of lateral organs. Each lateral organ consists of a villous and ciliated dome-like central part, surrounded by a peripheral fold. The epidermis of the fold's inner part (viz. the part facing the central dome) is made up of secretory cells, while that of the fold's outer part is similar to the regular epidermis. The epidermis of the dome includes vacuolar cells, sensory cells and a different type of secretory cell. Lateral organs are presumed to be both chemoreceptors and mechanoreceptors. They could allow the myzostomids to recognize the host's integument and prevent them from shifting on the surrounding inhospitable substrate.
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  • 98
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    Notes: Summary Coronal podia of Sphaerechinus granularis are anchoring (adhering) appendages involved in either locomotion or capture of drift materials. Adhesion is not due to the presumed sucker action of the disc but relies entirely on secretions of the disc epidermis. Peristomeal podia function in wrapping together food particles or food fragments in an adhesive material thus facilitating their capture by the Aristotle's lantern. In both types of podia, the disc epidermis is made up of four cell types: non-ciliated secretory cells (NCS cells) that contain graules whose content is at least partly mucopolysaccharidic in nature, ciliated secretory cells (CS cells) containing granules of unknown nature, ciliated non-secretory cells (CNS cells) and support cells. The cilia of CS cells are subeuticular whereas those of CNS cells, although also short and rigid, traverse the cuticle and protrude in the outer medium. All these cells are presumably involved in an adhesive/de-adhesive process functioning as a duogland adhesive system. Adhesive secretion would be produced by NCS cells and de-adhesive secretion by CS cells. These secretions would be controlled through stimulations by the two types of ciliated cells (receptor cells) which presumably interact with the secretory cells by way of the nerve plexus. This model of adhesion/de-adhesion fits well with the activities of both coronal and peristomeal podia. The secretion of NCS cells would make up a bridge of adhesive material between a podium and the substratum (coronal podia) or would coat and gather food particles (peristomeal podia), respectively. The de-adhesive material enclosed in the granules of CS cells would allow the podia (either coronal or peristomeal) to easily become detached from the substratum and to always remain clear of any particles.
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    Zoomorphology 113 (1993), S. 129-136 
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    Topics: Biology
    Notes: Summary The ultrastructural comparison of spermatozoa from eight scleractinian coral species shows a cytological diversity similar to the one known for the entire Anthozoa. Scleractinian spermatozoa are of compact shape with no strong demarcation between the sperm head and the middle piece. A comparison of the nuclear shape, as well as of the anterior structures of the proximal centriole, allow the description of different types of sperms in this group. Sperms with a spherical, pentagonally shaped or a conical and hereof derived nucleus can be distinguished. While correlations between sperm morphology and sexual characteristics can be seen, with one exception, in gonochoristic corals with a single reproductive cycle per year, no common sperm morphology can be described for hermaphroditic corals with a yearly reproductive cycle. Besides the centriolar complex which seems to be similar in all Scleractinia, a taxon-specific morphology of spermatozoa was only observed at the specific and generic level. As far as phylogenetic aspects are concerned, the almost identical arrangement of the centrioles and the intercentriolar connective strand in all examined Scleractina and Corrallimorpharia underscores the sister-group relationship of these two groups. Spermatozoa with a conical nucleus, a single basal indentation and a basal plate are considered to characterize the stem species of the Madreporaria.
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    Electronic Resource
    Springer
    Zoomorphology 113 (1993), S. 137-151 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Comparative ultrastructural analyses of the muscles that work the lantern of Aristotle support the opinion that the muscles in question are myoepithelially organized or derivatives of myoepithelia. They are part of the epithelium of the peripharyngeal cavity (=lantern coelom). The coelom epithelium may become multiplelayered in certain regions and is composed of (1) a layer of muscle cells that vary in number and size, (2) nerve cells and their processes that are interspersed between the muscle layer and (3) monociliated adluminal cells that build a continuous cell lining and completely cover the muscle layer. According to their complexity, the lantern muscles exhibit consecutive stages of myoepithelial variations and may finally simulate subepithelial musculature. The results of this study support the hypothesis of a histological development of subepithelial musculature from simple myoepithelia, although both epithelial and mesenchymal musculature may occur in the Echinodermata. Detailed knowledge of the organization of the lantern's coelom space was a prerequisite for the present study. In contrast to previous examinations the lantern coelom is not a continuous space, but is subdivided into several cavities that are partially completely separated from each other. On the one hand, this subdivision is probably caused by the sophisticated arrangement of the lantern's ossicles and on the other by the septa that give rise to muscles that fulfill different functions. lanter's ossicles and on the other by the septa that give
    Type of Medium: Electronic Resource
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