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  • 1
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    Gold metallogeny in the Sino-Korean Platform: examples from Hebei province, NE China. (1992)
    Springer
    Details
    Publication Date: 2020-02-12
    Keywords: 550 - Earth sciences
    Type: info:eu-repo/semantics/book
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    PAPER (OA)
  • 2
    Electronic Resource
    Electronic Resource
    Net assimilation rate and shoot area development in birch (Betula pendula Roth.) at different steady-state values of nutrition and photon flux density (1992)
    Springer
    Trees 6 (1992), S. 1-6 
    Details
    ISSN: 1432-2285
    Keywords: Nitrogen ; Photon flux density ; Growth ; Betula
    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 grown in a climate chamber at different, exponentially increasing rates of nitrogen supply and at different photon flux densities. This resulted in treatments with relative growth rate equal to the relative rate of increase in nitrogen supply and with different equilibrium values of plant nitrogen concentration. Nitrogen productivity (rate of dry matter increase per plant nitrogen) was largely independent of nitrogen supply and was greater at higher photon flux density. Leaf weight ratio, average specific leaf area (and thus leaf area ratio) were all greater at better nitrogen supply and at lower values of photon flux density. The dependencies were such that the ratio of total projected leaf area to plant nitrogen at a given photon flux density was similar at all rates of nitrogen supply. The ratio was greater at lower values of photon flux density. At a given value of photon flux density, net assimilation rate and net photosynthetic rate per shoot area (measured at the growth climate) were only slightly greater at better rates of nitrogen supply. Values were greater at higher photon flux densities. Acclimation of the total leaf area to plant nitrogen ratio and of net assimilation rate was such that nitrogen productivity was largely saturated with respect to photon flux density at values greater than 230 μmol m-2 s-1. At higher photon flux densities, any potential gain in nitrogen productivity associated with higher net assimilation rates was apparently offset by lower ratios of total leaf area to plant nitrogen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224491
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  • 3
    Electronic Resource
    Electronic Resource
    The effects of water and multi-nutrient stress on xylem sap chemistry, photosynthesis and transpiration of seedlings of two Eucalypts (1992)
    Springer
    Trees 6 (1992), S. 7-12 
    Details
    ISSN: 1432-2285
    Keywords: Eucalyptus ; Nutrients ; Photosynthesis ; Transpiration ; Xylem sap
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ten seedlings each of Eucalyptus kitsoniana Maiden and Eucalyptus globulus Labill. were subjected to two levels of water stress and two levels of nutrient stress (macro and micro-nutrients) in a greenhouse for 3 weeks. The objectives were to determine the degree to which seedlings show differences in sap chemistry, photosynthesis and transpiration that relate to the environments in which these two species live. Whole plants were then extracted for xylem sap using a pressure chamber and the sap was analyzed for 14 elements using an inductively coupled plasma spectrometer and a nitrometer. For E. kitsoniana water and nutrient stress, applied separately or in combination, significantly reduced leaf conductance, transpiration, photosynthesis and midday water potential. Nutrient stress alone had less effect than water stress on most functions measured. Water stress alone reduced the root/shoot ratio; the combination of water and nutrient stress increased the root/shoot ratio, primarily because of reduced shoot weight. In E. kitsoniana, water stress alone or in combination with nutrient stress increased the xylem sap concentrations of B and Si. Multi-nutrient stress alone, or in combination with water stress, significantly decreased sap Zn and K. For this species, sap N was decreased by nutrient stress, but increased by water stress. E. globulus had significantly lower transpiration rates and less root mass than E. kitsoniana. Slightly lower leaf conductance and photosynthesis were not significant in E. globulus compared to E. kitsoniana. Water and nutrient stress reduced conductance, transpiration (except for nutrient stress) and photosynthesis, and the effects of water stress on E. globulus were greater than the effects of nutrient stress. Midday water potential was reduced by water stress. Water or nutrient stress alone did not alter seedling root/shoot ratio, but the combination of water and nutrient stress significantly increased the root/shoot ratio for both species. For E. globulus, sap concentrations of Mn, Na, Si and K were increased by water stress (alone or in combination with nutrient stress). Sap N increased with water stress or combined stresses, but decreased under nutrient stress alone. When the two species were compared, E. globulus generally had lower or similar nutrient concentrations in the sap, with Ca, Mg, Mn and P significantly lower than in E. kitsoniana. Seedlings of these two species show strong site adaptations to water and nutrient availability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224492
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  • 4
    Electronic Resource
    Electronic Resource
    In vivo pH measurement in the xylem of broad-leaved trees using ion-sensitive field-effect transistors (1992)
    Springer
    Trees 6 (1992), S. 13-18 
    Details
    ISSN: 1432-2285
    Keywords: pH value ; Broad-leaved trees ; Xylem ; ISFET ; Sensor ; pH measurement ; Long-term measurement ; In vivo measurement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A new method of in vivo pH determination in the xylem of broad-leaved trees using ion-sensitive field effect transistors is developed and its suitability for use is studied. In the first few hours after the sensor had been implanted in the xylem signals could be detected which were generated in response to mechanical damage; particularly strong signal changes are detectable in Populus balsamifera L., Tilia cordata Mill, and Aesculus hippocastanum L. The pH values of the xylem sap extracted from branches corresponded to the values measured by the in vivo method only at certain times. Due to sensor drift the measuring accuracy of long-term experiments lasting up to 3 weeks is restricted. The in vivo measurement of pH in the xylem of poplar branches revealed the ability of the living xylem to buffer the pH of the sap to its own characteristic value.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224493
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  • 5
    Electronic Resource
    Electronic Resource
    Water holdup capacity and residence time of red spruce and balsam fir branches (1992)
    Springer
    Trees 6 (1992), S. 10-27 
    Details
    ISSN: 1432-2285
    Keywords: Throughfall ; Red spruce ; Balsam fir ; Wettability ; Acid precipitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary This study examined the throughfall dynamics of high-elevation red spruce (Picea rubens Sarg.) and balsam fir [Abies balsamea (L.) Mill.] branches. A site was established at an elevation of 1160 m on Mt. Washington, New Hampshire, USA, and branches were collected from the canopies of mature trees. Throughfall water dynamics of branches collected in September 1988 and March 1989 were determined using a fluorescent tracer in an artificial precipitation apparatus. Water holdup capacities of spruce and fir branches from different canopy positions were similar. Spruce retained more water per unit area than fir. For rain, a three-compartment model that was used to analyze water dynamics showed that the bulk of water initially on the branch experienced very slow turnover, while intercepted water left the branch quickly. There did not appear to be any difference in throughfall dynamics between spruce and fir. Our results suggest that the initial composition of rain and mobilized dry deposition will influence the composition of water in contact with the branch for a relatively long time, as branch water composition will respond slowly to changes in precipitation composition. These predictions require field testing where sequential sampling of throughfall and precipitation occurs on a time scale equivalent to 0.1–0.2 mm of precipitation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224494
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  • 6
    Electronic Resource
    Electronic Resource
    Gas exchange and canopy structure of 9-year-old loblolly pine, pitch pine and pitch x loblolly hybrids (1992)
    Springer
    Trees 6 (1992), S. 28-31 
    Details
    ISSN: 1432-2285
    Keywords: Canopy leaf surface area ; Gas exchange ; Pinus rigida x taeda ; Silhouette area ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seasonal gas exchange and canopy structure were compared among 9-year-old loblolly pine (Pinus taeda L.), pitch pine (Pinus rigida Mill.), and pitch x loblolly hybrids (Pinus rigida x taeda) growing in an F2 plantation located in Critz, Va., USA. Leaf net photosynthesis, conductance, internal CO2 concentration (ci), water use efficiency (WUE; photosynthesis/conductance), dark respiration and the ratio of net photosynthesis/respiration did not vary among or within the three taxa. Significant differences in volume production, crown length, total crown leaf surface area and the silhouette area of shade shoots among the taxa were observed. The loblolly-South Carolina source had greater volume and crown surface area than the pitch pine, and the hybrid taxa were intermediate between the two. Although the silhouette area ratio of shade foliage varied among taxa, it was not related to volume. A strong relationship between total leaf surface area and volume was observed. Leaf conductance, ci, WUE and leaf water potential were the physiological parameters significantly and positively correlated with volume. This study suggests that the amount of needle surface in the canopy is more important in early stand volume growth than the leaf carbon exchange rate and the degree of needle self-shading in the lower canopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224495
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  • 7
    Electronic Resource
    Electronic Resource
    Partition coefficients of plant cuticles for monoterpenes (1992)
    Springer
    Trees 6 (1992), S. 32-36 
    Details
    ISSN: 1432-2285
    Keywords: Abies ; Cuticle ; Monoterpene ; Octanol/water partition coefficient ; Picea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Cuticle/water partition coefficients (Kc/w) for d-limonene, α-pinene and β-pinene were determined by an extrapolation and a desorption method. The sorption experiments were carried out with isolated angiosperm and gymnosperm cuticles and with [14C]-labelled monoterpenes, which were obtained biosynthetically. Both methods were suitable for the determination of the Kc/w of volatile hydrophobic compounds. For the angiosperm cuticles the partition coefficients are of the order of 104, which indicates a high accumulation of monoterpenes in the cuticle. The values of the conifer cuticles of Picea abies (L.) Karst. and Abies alba Mill., however, are lower due to their high lignin content. This is proved by the increase of the partition coefficients after removal of polar and phenolic components. The Kc/w can be estimated with good accuracy from the octanol/water partition coefficient, which was determined experimentally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224496
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  • 8
    Electronic Resource
    Electronic Resource
    Localization of a storage protein in the wood ray parenchyma cells of Taxodium distichum (L.) L. C. Rich. by immunogold labeling (1992)
    Springer
    Trees 6 (1992), S. 37-40 
    Details
    ISSN: 1432-2285
    Keywords: Taxodium distichum ; Immunoblotting ; Immunogold labeling ; Ultrastructure of wood ray cells ; Protein storing vacuoles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ultrastructural investigations showed the occurrence of electron-dense intravacuolar aggregations in wood ray cells of Taxodium distichum (L.) L. C. Rich, during the dormant season. Such aggregations were missing in summer. By SDS-PAGE of the crude protein extract of Taxodium, a prominent protein of about 35 kDa was detected before budbreak. This protein disappeared at the time when the new shoots had fully grown out. An antibody was raised against this “storage protein”. In the immunoblot the antibody reacted specifically with the 35 kDa protein. At the electron-microscope level, by immunogold labeling, the electron-dense intravacuolar aggregations were identified as the specific storage sites for the 35 kDa protein. Thus, these vacuoles proved to be “protein storing vacuoles”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224497
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  • 9
    Electronic Resource
    Electronic Resource
    Physiological responses of Pinus sylvestris to atmospheric ammonia (1992)
    Springer
    Trees 6 (1992), S. 48-53 
    Details
    ISSN: 1432-2285
    Keywords: Air pollution ; Ammonia ; Assimilation of carbon dioxide ; Transpiration ; Drought stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Young saplings of Pinus sylvestris were fumigated for 3 months with ammonia in concentrations ranging from 0 to 240 μg m-3. Despite the much higher concentrations than normal in the field, no visible damage occurred. Photosynthesis, dark respiration, transpiration and biomass production were stimulated. At 240 μg m-3 with high irradiance (PAR: 950 μmol m-2 s-1), net photosynthesis was stimulated by 24% and dark respiration by 76%. Intitial light use efficiency was not significantly affected. Transpiration increased, both in the dark and at 950 μmol m-2 s-1 by 40% and 57%, respectively. In the presence of ammonia, stomatal control was less efficient. Though growth of roots was not affected by NH3, that of current year needles was stimulated, resulting in an increased mass ratio of needles to roots. The nitrogen content of the needles increased, but the contents of other mineral components did not change significantly. Due to increased transpiration per unit of needle area and increased mass of needles per tree, water loss per tree was about twice as high in the treatment with 240 μg m-3 as in the control. Towards the end of fumigation, a 10-day period without water supply followed and then the water potential of the shoots was measured as an indicator of water demand. This demand was higher with higher concentrations of NH3, suggesting a higher risk of injury from drought.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224499
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  • 10
    Electronic Resource
    Electronic Resource
    Changes in chlorophyll fluorescence and chlorophyll content in suppressed Norway spruce [Picea abies (L.) Karst.] in response to release cutting (1992)
    Springer
    Trees 6 (1992), S. 41-47 
    Details
    ISSN: 1432-2285
    Keywords: Release cutting ; Chlorophyll fluorescence ; Chlorophyll ; Stress reactions ; Picea abies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In order to study physiological strain caused by release cutting, suppressed Norway spruce on mesic and moist sites was completely released from overstory birch, or 500 birches per hectare were left as a shelter. The treatments were conducted in late June in 1988 and in 1989. The spruce's reaction to the environmental change was monitored by measurements of fast chlorophyll fluorescence kinetics and analysis of chlorophyll content. This was done before treatment, 1 week after treatment, 2 months after treatment, and twice during the following growth period. Complete release resulted in a more pronounced decrease in the ratio of variable fluorescence to maximal fluorescence (Fv/Fm) than partial release. There was also a tendency for the build-up of chlorophyll content in needles to be more affected when the spruce was completely released. Released spruces on moist sites tended to be more affected by the release than released spruces on mesic sites. The results suggest that in this kind of stand the risk of damage to the spruces is greatest when the spruces are completely released on moist sites. Furthermore, it is shown that the weather conditions prevailing shortly before and after the release have a large influence on the spruce's reaction to the release. The results also indicate some adjustment to the new environment in mature needles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224498
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  • 11
    Electronic Resource
    Electronic Resource
    Phytoalexins of woody plants (1992)
    Springer
    Trees 6 (1992), S. 55-68 
    Details
    ISSN: 1432-2285
    Keywords: Woody plants ; Host-pathogen systems ; Phytoalexins ; Stress metabolites ; Antimicrobial activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Phytoalexins accumulated in selected woody plants in response to microbial attack or stress are reviewed and listed with respect to their chemical structure and probable biogenetic origin. The host-pathogen systems from which they have been isolated are described. The review also considers the antimicrobial activity of the phytoalexins to the causal pathogens and other microorganisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226582
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  • 12
    Electronic Resource
    Electronic Resource
    Seasonal growth, δ13C in leaves and stem, and phloem structure of birch (Betula pendula) under low ozone concentrations (1992)
    Springer
    Trees 6 (1992), S. 69-76 
    Details
    ISSN: 1432-2285
    Keywords: Ozone ; Betula pendula ; Growth analysis ; δ13C ; Phloem structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The growth of potted birch cuttings (one clone of Betula pendula) was studied under low O3 concentrations (0, 0.050, 0.075, 0.100 μl l-1) throughout an entire growing season. With increasing O3 dose, 20–50% of all leaves formed were prematurely shed, while 40–70% of the remaining foliage displayed advanced discoloration by the end of the season. Ozonation affected the S, P and N concentration of leaves and increased δ13C in leaves and stem, while the CO2 assimilation rate declined with increasing CO2 concentration in mesophyll intercellulars. While whole-plant production correlated negatively with the O3 dose, ozone increased the specific leaf weight (i.e. leaf weight/leaf area, SLW) but decreased the ratios of stem weight/stem length and root/shoot biomass. Neither the latter ratio nor SLW changed in experimentally defoliated control plants, whereas in ozonated plants starch accumulated along leaf veins and phloem tissue was deformed in the leaf petioles and the stem. Only in early summer was the relative growth rate higher in the ozonated than in the control plants. The ratio of whole-plant biomass production versus total foliage area formed was lowered under O3 stress. However, when relating biomass to the actual foliage area present due to leaf loss, this ratio did not differ between treatments. Similarly the ratio of actual foliage area versus basal stem area in cross-section did not differ. Overall, whole-plant production was strongly determined by O3-caused changes in crown structure and began to be limited at O3 doses (approximately 180 μl l-1 h) similar to those of rural sites in Central Europe.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226583
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  • 13
    Electronic Resource
    Electronic Resource
    Root system analysis of seedlings of seven tree species from a tropical dry forest in Mexico (1992)
    Springer
    Trees 6 (1992), S. 77-82 
    Details
    ISSN: 1432-2285
    Keywords: Tropical deciduous forest ; Tree seedlings ; Root morphology ; Growth analysis ; Legumes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Root attributes of tree seedlings of seven species from the tropical deciduous forest along the Pacific Coast of Mexico are described using morphometirc root system analysis. Mean relative growth rate, root/shoot ratios, specific root length, root density, mean number of roots tips and root length/leaf area ratio were determined in seedlings grown for 35 days inside growth chambers. All the species had low relative growth rates, low root/shoot ratios and low root densities (〈0.5 cm/cm3). The species associated with disturbed habitats, in contrast to the species characteristic of undisturbed areas, presented small seeds, a dichotomous root branching pattern and large specific root length. No relationship was found between seed size and mean relative growth rate among the species studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226584
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  • 14
    Electronic Resource
    Electronic Resource
    Interactions between Cylindrocarpon destructans and ectomycorrhizas of Picea abies with Laccaria laccata and Paxillus involutes (1992)
    Springer
    Trees 6 (1992), S. 83-90 
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    ISSN: 1432-2285
    Keywords: Cylindrocarpon destructans ; Picea abies ; Laccaria laccata ; Paxillus involutus ; Protection by mycorrhizas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In paired cultures with two mycorrhizal fungi, the root pathogen Cylindrocarpon destructans (Zinsm.) Scholten had an inhibitional effect on mycelial growth of Laccaria laccata (Scop, ex Fr.) Bk. & Br. but was inhibited itself by Paxillus involutes (Batsch.) Fr. A similar pathogen-symbiont interaction scheme was observed in triaxenic cultures with Picea abies Karst. seedlings but only in the vicinity of the mycorrhizal root tips. Both mycorrhizas similarly increased the endogenous plant resistance against the infection of C. destructans. This suggests that direct pathogen-symbiont interactions are an important factor for population dynamics in the mycorrhizo sphere. Moreover, endogenous plant resistance constitutes one of the key factors for an effective defence against pathogenic fungi.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226585
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  • 15
    Electronic Resource
    Electronic Resource
    Changes in photosynthetic activity of buds and stem tissues of Fagus sylvatica during winter (1992)
    Springer
    Trees 6 (1992), S. 91-95 
    Details
    ISSN: 1432-2285
    Keywords: Fagus sylvatica ; Chlorophyll fluorescence ; Dormancy ; Photosynthesis ; Seasonal variations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The photosynthetic activity of leafless twigs and buds of Fagus sylvatica was determined by in vivo chlorophyll fluorescence from November to May. Measurements were made on the day of sampling, and during exposure to warm temperatures until reactivation was attained. Under the same conditions, bud development and growth were forced by exposure of cut twigs to 25/18° C at long-day conditions, and bud swelling and bud burst were monitored. Winter inactivation of photosynthesis results in a reduction of the photochemical efficiency of PS II, as indicated by lowering of FV/FM, from January through March. The greatest reduction is in cortical chlorenchyma, the least in folded leaflets and primordia of buds. Restoration of photosynthetic activity, brought about by warming, needed 3–4 weeks in cortex and 1–2 weeks in buds during the coldest period of winter. Frequency distributions based on three types of chlorophyll fluorescence transients, defined by quantitative fluorescence parameters, have proved to be a valuable method for a differentiated expression of the unequal functional activation states of parallel samples. The seasonal course of winter inactivation of photosynthesis did not correspond entirely with the depth of bud dormancy as revealed by the forcing treatments; inactivation of photosynthesis may be more closely synchronized with changes in frost hardiness; possible causes are discussed. We suggest, therefore, that a distinction should be made between inactivation of metabolic processes and depth of dormancy, even though these processes are inherently interrelated.
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    URL: http://dx.doi.org/10.1007/BF00226586
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  • 16
    Electronic Resource
    Electronic Resource
    Seasonal changes in CO2 and H2O gas exchange of young European beech (Fagus sylvatica L.) (1992)
    Springer
    Trees 6 (1992), S. 96-102 
    Details
    ISSN: 1432-2285
    Keywords: Fagus sylvatica L ; Photosynthesis ; Transpiration ; Diurnal and annual courses ; Quantum yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The CO2 and H2O gas exchange of young beech trees (Fagus sylvatica L.) were measured over a growing season. Of particular interest was the adaptation of gas exchange to the low level of photon flux density in the understorey of the old beech. The recorded diurnal courses were subdivided into several classes of irradiance. The most frequent class was from only 30–40 μE * m-2 * s-1. Even at the highest irradiance values, no light saturation in assimilation occurred. The light compensation point lies below 3 μE * m-2 * s-1, because net dark respiration values are very low. Calculated from the initial slope of the light response curves a mean value of 0.02 mol CO2 * mol photons-1 shows a very efficient use of light be the young trees. At the optimal phase of assimilation, the relationship between the daily sum of irradiance and net photosynthesis is highly significantly correlated. Under the local climatic situation, the stomatal opening primarily depends on irradiance. In response to a change in irradiance, stomatal opening also changes rapidly. Therefore, there is only a loose relationship between transpiration rate and vapour pressure saturation deficit. Towards autumn, the transpiration coefficient (E/A-ratio, estimated under light saturation) increases strongly because net photosynthesis decreases simultaneously.
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    URL: http://dx.doi.org/10.1007/BF00226587
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  • 17
    Electronic Resource
    Electronic Resource
    Determination of water sorption by cuticles isolated from fir tree needles (1992)
    Springer
    Trees 6 (1992), S. 109-114 
    Details
    ISSN: 1432-2285
    Keywords: Water content ; Water permeability ; Partition coefficient ; Sorption isotherm ; Plant cuticle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The water sorption by isolated cuticles from needles of Abies alba was measured between 4% and 80% relative humidity using a magnetic suspension microbalance. The sorption isotherms were not linear and sorption increased more rapidly at the lowest and highest values of relative humidity. The mean values, calculated for 1- to 5-year-old adaxial cuticles developed from 1984 to 1988, increased from 2.9% to 17.1% of the dehydrated weight, and from 4% to 80% relative humidity. Results did not depend on the age of needles and the comparison between healthy and declining trees revealed no major difference in water sorption by cuticles isolated from these two types of trees. Data are discussed in relation to cuticular permeability and one determinant of water permeability, the partition coefficient relating the equilibrium water concentration of the cuticle to that of the surrounding atmosphere, was calculated.
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    URL: http://dx.doi.org/10.1007/BF00226589
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  • 18
    Electronic Resource
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    Tree-ring element analysis of Korean pine (Pinus koraiensis Sieb. et Zucc.) and Mongolian oak (Quercus mongolica Fisch. ex Turcz.) from Changbai Mountain, north-east China (1992)
    Springer
    Trees 6 (1992), S. 103-108 
    Details
    ISSN: 1432-2285
    Keywords: Nutrient elements ; Pinus koraiensis Sieb. et Zucc ; Quercus Mongolica Fisch. ex Turcz ; Trace elements ; Tree rings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Tree-ring analysis of 17 elements (Pb, Cd, Cu, Zn, As, Cr, Ti, Ni, V, Mn, Fe, Al, Ca, Mg, K, Na and P) was performed on Korean pine (Pinus koraiensis Sieb. et Zucc.) and Mongolian oak (Quercus mongolica Fisch. ex Turcz.) specimens from Changbai Mountain, a remote nature reserve in north-east China. The radial distribution patterns of Pb, Cu, Cr, Ti, Ni, V, As and Fe for both Korean pine and Mongolian oak were similar: concentrations remained generally constant in tree-ring intervals spanning approximately 200 years. These temporal patterns were in accordance with the known stability of the local ecological environment during this period. However, the other elements showed characteristic distribution patterns that differed between Korean pine and Mongolian oak. These patterns can only be interpreted in terms of physiological results; specifically they appeared to be related to the sapwood-heartwood conversion.
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    URL: http://dx.doi.org/10.1007/BF00226588
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  • 19
    Electronic Resource
    Electronic Resource
    The effects of ultraviolet-B radiation on loblolly pine (1992)
    Springer
    Trees 6 (1992), S. 115-120 
    Details
    ISSN: 1432-2285
    Keywords: Growth ; Loblolly pine ; Ozone depletion ; Pinus taeda ; Ultraviolet-B radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Depletion of stratospheric ozone and the resulting increase in ultraviolet-B (UV-B) radiation may negatively impact the productivity of terrestrial ecosystems. This concern has led to a number of studies that report the influence of supplementing UV-B radiation on plant growth and development. However, only two of these field studies have included tree species and both were singleseason experiments. In this study, loblolly pine (Pinus taeda L.) from seven seed sources was grown under natural and supplemental levels of UV-B radiation. Irradiation treatments were continued for three seasons on plants from four of the seven groups and for 1 year only for three groups. The supplemental irradiances simulated those that would be anticipated with stratospheric ozone reductions of 16% and 25% over Beltsville, Md. The effects of UV-B radiation during the 1st year on plant growth varied among the seed sources. The growth of plants from two of the seven seed sources tested showed significant reductions following a single irradiation season and plants from one group tended to be larger under increased UV-B radiation. However, after 3 years of supplemental irradiation, plant biomass was reduced in all four groups by 12–20% at the highest simulated ozone depletion. These results suggest that the effects of UV-B radiation may accumulate in trees and that increased UV-B radiation could significantly reduce the growth of loblolly pine over its lifetime. However, they also point to a need for multiple season research in any analysis of potential consequences of global change on the long-term growth of trees.
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    URL: http://dx.doi.org/10.1007/BF00202426
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    Structural aspects of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] tuberculate ectomycorrhizae (1992)
    Springer
    Trees 6 (1992), S. 137-146 
    Details
    ISSN: 1432-2285
    Keywords: Pseudotsuga ; Tubercles ; Ectomycorrhiza ; Calcium oxalate ; Bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Tubercles of Pseudotsuga menziesii consisted of clusters of ectomycorrhizae surrounded by a peridiumlike rind. Energy dispersive spectroscopy demonstrated that crystals found in the zone of loose hyphae extending from the inner rind to the mantle of each root probably contain calcium oxalate. Inner mantle and Hartig net hyphae showed a labyrinthine branching pattern and stored carbohydrates and protein. The Hartig net formed up to inner cortical cells which had thickened, darkly stained walls. Bacteria were located either along with hyphae within the rind or as colonies on the surface of the tubercle.
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    URL: http://dx.doi.org/10.1007/BF00202429
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    Assessment of transpiration estimates for Picea abies trees during a growing season (1992)
    Springer
    Trees 6 (1992), S. 121-127 
    Details
    ISSN: 1432-2285
    Keywords: Heat balance method ; Canopy conductance ; Sap-flow rate ; Penman-Monteith equation ; Scaling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The tree-trunk heat balance method with internal heating and sensing of temperature was used to estimate sap-flow rate of spruce trees in a stand in southern Sweden. Sap-flow rate values were scaled up to stand transpiration and utilised for calculation of canopy conductance. The calculated values provided the basis for a function relating canopy conductance to vapour pressure deficit, which was implemented in the Penman-Monteith equation. The stand was mostly growing in non-limiting soil water conditions (irrigation regime applied during dry periods). The whole-season transpiration was assessed by two different approaches and then compared: the sap-flow rate measurements were scaled to stand transpiration and the adapted Penman-Monteith estimate. They gave similar results: the transpiration totals differed by 3% and the coefficient of determination of the linear regression was r2 = 0.89. Similarly good was the assessment for a set of rainy days. The Penman-Monteith estimate adapted in this way proved to be reasonably precise and reliable in this forest stand and usable even in wet conditions. The seasonal transpiration of the spruce stand was 392 mm according to the adapted Penman-Monteith equation. Mean daily transpiration was 1.8 mm and daily maximum transpiration was 4.8–4.9 mm as estimated by sap-flow rate measurements.
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    URL: http://dx.doi.org/10.1007/BF00202427
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    The influence of ozone on the stomatal and non-stomatal limitation of photosynthesis in Norway spruce, Picea abies (L.) Karst, exposed to soil moisture deficit (1992)
    Springer
    Trees 6 (1992), S. 128-136 
    Details
    ISSN: 1432-2285
    Keywords: Norway spruce ; Ozone ; Photosynthesis ; Stomatal limitation of photosynthesis ; Drought stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Norway spruce, Picea abies (L.) Karst., was exposed to charcoal-filtered air (CF) and non-filtered air + ozone (NF+) and periods of soil moisture deficit from 1985 to 1988 in open-top chambers. Net photosynthesis, stomatal conductance, needle water potential and various shoot properties were measured on 1-year-old shoots during a period of soil moisture deficit. The gas exchange was measured at saturating photosynthetic photon flux density and across a range of CO2 concentrations. The soil moisture deficit induced a mild drought stress in the plants, expressed by a pre-dawn needle water potential of approximately-0.9 MPa and a substantial reduction in net photosynthesis and gas phase conductance. In the CF treatment, intercellular CO2 concentration was reduced, but was unaffected in the NF+ treatment. Furthermore, net photosynthesis declined more in response to the soil moisture deficit in the NF+ treatment than in the CF treatment. This is suggested to be attributed to the carboxylation efficiency at the operating point, which was decreased by 47% and 64% in shoots from the CF and the NF+ treatments, respectively. Stomatal limitation of net photosynthesis was increased by drought by 24–45% in the CF treatment, while it was unaffected in the NF+ treatment. Thus, our results imply that the coupling between the stomatal conductance and the photosynthetic rate was changed and that the marginal cost of water per given amount of carbon gain will increase in trees exposed to ozone, during periods of drought.
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    URL: http://dx.doi.org/10.1007/BF00202428
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    Longevity and senescence of needles in Pinus cembra L. (1992)
    Springer
    Trees 6 (1992), S. 156-161 
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    ISSN: 1432-2285
    Keywords: Pinus cembra ; Needle longevity ; Needle senescence ; Nutrient elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Needle development has been investigated in Pinus cembra at several locations in the Grisons. Special attention has been paid to longevity and senescence. Despite large variations from one tree to another, longevity (up to 12 years) appeared to increase with increasing altitude. With increasing age, contents of nutrients such as N, P, K and, to a lesser extent, Mg and S tend to decrease. Photosynthetic activity did not decline with increasing age of short shoots. Senescence begins in mid-August in needles of the oldest age classes. It is associated with the mobilization and withdrawal of large proportions of N, P, K and also Mg and S, but Ca appears to be immobile. The extent of yellowing is irregular in individual trees but needle losses on a large scale are followed by reduced losses in subsequent years.
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    URL: http://dx.doi.org/10.1007/BF00202431
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    Food reserves of scots pine (Pinus sylvestris L.) (1992)
    Springer
    Trees 6 (1992), S. 147-155 
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    ISSN: 1432-2285
    Keywords: Pinus sylvestris ; Starch ; Sugars ; Triacylglycerols ; Xylem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Starch, soluble sugars, triacylglycerols, diacylglycerols and free fatty acids were measured in 30-year-old Scots pine (Pinus sylvestris L.) trees during an annual cycle in the sapwood (youngest ten xylem rings). The radial distribution of carbohydrates and lipids was studied in the trunkwood of 90 -to 150-year-old Scots pine trees collected at the end of the growing season. Determination of the compounds was performed using specific enzymatic assays, capillary gas chromatography and thin layer chromatography. The amounts of glucose, fructose, sucrose, and galactose/arabinose in the sapwood were slightly higher in winter than in summer. Raffinose/stachyose increased up to 5-fold during the cold period. At the beginning of the growing season starch amounts rose, and then decreased in summer and autumn. No concentration changes were observed in the total amounts of diacylglycerols and fatty acids throughout the year. Triacylglycerol levels were slightly higher in February than in summer and autumn. Relative frequencies of individual fatty acids were similar in all lipid fractions. Glucose, fructose, sucrose, starch and triacylglycerols disappeared almost entirely at the transition zone from sapwood to heartwood. In contrast, free fatty acids and galactose/arabinose rose in centripetal direction, and diacylglycerols remained constant across trunk cross-sections. The relative amounts of individual fatty acids changed markedly in the free fatty acid fraction and in the triacylglycerols when crossing the sapwood-heartwood boundary. Concentration changes of reserve materials are discussed in relation to season, mobilization and translocation processes, dormancy, frost resistance, and heartwood formation. The results are compared to those found in needles.
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    URL: http://dx.doi.org/10.1007/BF00202430
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    Geographic variability of terpene composition in Abies cephalonica Loudon and Abies species around the Aegean: hypotheses for their possible phylogeny from the Miocene (1992)
    Springer
    Trees 6 (1992), S. 162-171 
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    ISSN: 1432-2285
    Keywords: Abies cephalonica ; Monoterpenes ; Sesquiterpenes ; Geographic variability ; Phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Cortical oleoresin composition of lateral shoots (mono- and sesquiterpenes) was analysed by gas chromatography on 18 Mediterranean fir populations grown in experimental fields in southern France: 13 Abies cephalonica Loudon provenances and one A. borisii regis Mattfeld provenance from Greece, 2 A. alba Miller provenances from Romania and Bulgaria, 1 Abies bornmuelleriana Mattfeld provenance and 1 A. equi trojani Ascherson and Sintenis provenances from Turkey. Terpenes with the highest between-provenance variability were limonene, β-pinene, longifolene, δ-cadinene and α-humulene. Both similarity in terpene composition of all the firs studied and paleogeographical data demonstrated the possible existence of a unique Eastern Mediterranean tertiary ancestor for present-day Aegean species. The Pliocene marine transgression of the Aegean basin could have caused this geographical disjunction. According to this hypothesis, A. alba would have appeared in the Northern part of the Aegean and then colonized all of Europe while A. bornmuelleriana would have appeared in its Eastern part. Frequent Pleistocene contacts between the two species could have contributed to the individualization of A. equi trojani and given rise to the particular morphology of the south-eastern ecotypes of A. alba. In the western part of the basin, A. cephalonica populations would have appeared. Southern migrations of A. alba during the Ice Age and contact with A. cephalonica in refugia probably led to the development of A. borisii regis hybrid populations. Evidence for an A. alba gene flow can be found in the southernmost A. cephalonica populations.
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    URL: http://dx.doi.org/10.1007/BF00202432
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    Permeation characteristics of isolated cuticles of Citrus aurantium L. for monoterpenes (1992)
    Springer
    Trees 6 (1992), S. 172-177 
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    ISSN: 1432-2285
    Keywords: Citrus ; Cuticle ; Diffusion coefficient ; Limonene ; Monoterpene ; Ozone ; Permeability coefficient ; Permeation ; α-Pinene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Permeation parameters of isolated cuticular membranes of Citrus aurantium L. for gaseous monoterpenes were determined by an isostatic system. For α-pinene and d-limonene permeability coefficients range from 4.3 × 10−11 m−2 s−1 to 7.3 × 10−11 m−2 s−1. These values can be compared to that measured for benzene gas at the cuticle of Citrus. The permeability coefficients of the two monoterpenes did not differ significantly, in contrast to their diffusioin coefficients. The diffusion coefficient values are 3.7 × 10−15 m−2 s−1 for limonene and 15.5 × 10−15 m−2 s−1 for α-pinene. The reason for this difference is still unclear. A dependence of the permeation parameters on the direction of the monoterpene transport could not be observed. Moreover, there are some indications that, in spite of its heterogeneous character, the cuticular membrane of Citrus is homogeneous in respect to the transport of small gaseous molecules. An exposure to environmentally relevant ozone concentrations for 6 months did not change the permeation characteristics of the membrane. Due to the high variability of the samples only a tendency towards higher permeability coefficients of cuticles treated with 80 ppb ozone was observed. This may be attributed to a reduced tension of the membrane caused by chain fractions.
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    Extrinsic and intrinsic influences on tree growth — anatomical analysis of spruce branches (1992)
    Springer
    Trees 6 (1992), S. 179-185 
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    ISSN: 1432-2285
    Keywords: Cambial activity ; Gross anatomy ; Picea abies ; Weather conditions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In order to differentiate between environmental (extrinsic) influences affecting tree growth, and those causing (intrinsic) temporary irregularities in a single tree, we investigated the anatomy of three branches of comparable size and age, taken from two 60-year-old European spruces [Picea abies (L.) Karst]. Wood depositions in five consecutive internodes (4–8) along the branches were analysed. Internodal cross-sections were evaluated to discover whether extrinsic factors may have influenced the structure of the cambial xylogenic derivatives, or whether structural variations were caused by intrinsic events. Features occurring in all three branches were evaluated as extrinsically influenced. Observations like earlywood disturbances, distribution of resin ducts, duplication of radial files, and increments with narrow or broad latewood bands were considered. The ratio of radial cell number to ring width was used to define the vigour of cambial growth during the years covered. Meteorological data of the growing periods (May–September 1981–1988) representing mean values of temperature, cloudiness, sunshine and precipitation were used to characterize weather conditions. They were considered as extrinsic influences, possibly affecting anatomical structures.
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    URL: http://dx.doi.org/10.1007/BF00224333
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    Histological examination of spruce needles from a long-term gas exchange experiment in pure and polluted air in the field (1992)
    Springer
    Trees 6 (1992), S. 186-194 
    Details
    ISSN: 1432-2285
    Keywords: Air pollutants ; Bundle sheath ; Picea abies ; Stomata ; UV absorbance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary At the end of a 4-year period of gas exchange measurements in a natural stand in the Lower Bavarian Forest, needles of an adult spruce [Picea abies (L.) Karst.] were harvested from two chambers, one with pure air and the other with ambient air. The needles were examined as to their histological properties in the stomatal apparatus and in the bundle sheath. In needles from the polluted air UV absorbance at 280 nm was decreased in the walls of the stomatal apparatus. Simultaneously, the deposition of compounds with an absorption maximum at 310 nm increased within the encrusted plate-like thickenings of the subsidiary cells. The contents of the lumina of hypodermal cells and of the bundle sheath exhibited a greater degree of autofluorescence in ambient-air material than in pure-air leaf organs. Differences between needles exposed to pure and polluted air are gradual. The “damaged” condition is rare in pure air, common in polluted air. The needles from outside the chambers occupied an intermediate position between pure-air and ambient-air needles. This fact is traced to an unnaturally high pollutant load in the liquid phase of the needle surfaces within the ambient-air chamber because in order to compensate pollutant losses within the system, SO2 and O3 were added even during periods of irrigation. The reduction of absorption capacity at 280 nm in the walls of the stomatal apparatus is attributed to destruction of lignin due to the high reactivity of the pollutants in the liquid phase on the damp needle surface. The importance of delignification with regard to hydroregulation is discussed.
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    Growth rates in diameter, basal area, and height of Pilgerodendron uviferum; relationship between growth index and germination (1992)
    Springer
    Trees 6 (1992), S. 199-203 
    Details
    ISSN: 1432-2285
    Keywords: Dendrochronology ; Growth rate ; Pilgerodendron uviferum ; Chile
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Increment borer samples taken at breast height in Pilgerodendron uviferum (Cupressaceae) trees growing in two Chilean forest stands near latitude 42° south were used to study growth rates in diameter, basal area, and height. Radial average growth is 0.51 mm/year in Santa Luciă 0.44 mm/year in the Piuchué stand; the correlation between diameter and age is 0.79 in Santa Lucía and 0.64 in Piuchué. Similar results were obtained in the basal area/age relationship. Both groups of trees have a low rate of growth compared to rates obtained in other studies. Maximum values for radial growth (culmination age) are reached at 110 years of age in Santa Lucia and 50 years in Piuchue. Growth in height, averaging 5.8 cm/year, appears to be similar in all trees analyzed; occasional differences can be attributed to understory position of some trees. Comparison of radial growth and germination of Pilgerodendron plants shows a synchronous relationship, suggesting an influence of climate on the pattern of forest regeneration.
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    Ethylene production by different age class ponderosa and Jeffery pine needles as related to ozone exposure and visible injury (1992)
    Springer
    Trees 6 (1992), S. 195-198 
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    ISSN: 1432-2285
    Keywords: Ethylene production ; Ozone ; Pinus jeffreyi ; Pinus ponderosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ethylene produced by different needle age classes representing natural populations of two ponderosa pine varieties [Pinus ponderosa var. arizonica (Engelm.) Shaw and var. ponderosa Dougl. ex Laws.] and Jeffery pine (Pinus jeffreyi Grev. and Balf.) was characterized using mercuric perchlorate traps. All populations contained individual trees which were either symptomatic or asymptomatic with respect to visible ozone injury. Ethylene production by different needle age classes was also characterized in P. ponderosa var. ponderosa seedlings grown in open top ozone fumigation chambers. Older age class needles produce significantly (P〉0.05) more ethylene than younger age class needles. Needles of both P. ponderosa var. ponderosa and P. jeffreyi exhibiting ozone injury in the field produced significantly (P〉0.05) higher levels of ethylene than asymptomatic conspecific trees. Seedlings exposed to the highest level of ozone in the fumigation study produced the highest levels of ethylene, followed by fumigation with medium and low ozone concentrations and carbon filtered air. These data indicate that the measurement of ethylene in conifer needles, as a measure of stress, needs to be calibrated for needle age class. It also suggests that the sensitivity of a tree to ozone injury may be regulated by the inherent ability of the individual to produce ethylene.
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    Germination and phenology of 1-year-old maritime pine (Pinus pinaster Aït.) seedlings under continuous light (1992)
    Springer
    Trees 7 (1992), S. 48-58 
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    ISSN: 1432-2285
    Keywords: Budset ; Early selection ; Germination ; Pinus pinaster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nine half-sib families of maritime pine (Pinus pinaster Aït.), of known vigor and growth pattern (monocyclic vs polycyclic), were grown under continuous light in two temperature regimes. Results of germination and development to the beginning of the second flush are reported here. Families significantly differed for mean date of germination and date of first budset. After 18 weeks of continuous light most of the seedlings had set a bud. High temperature (25° C vs 25° C/20°C) hastened first budset by approximately 5 days. However, 3 families had not reached 75% budset at the end of the experiment. Variation in date of first budset was almost exclusively explained by variation in the period between initiation of primary needles and budset. Further, 2 developmental stages could be distinguished within this period, the boundary between them being the emergence of the first secondary needles. Variation in height at first budset was mostly due to variation in growth rate, not in duration. Possible causes of early budset and implication for selection are discussed.
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    Patterns of leaf size and morphology in relation to shoot length in Tsuga canadensis (1992)
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    Trees 7 (1992), S. 59-66 
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    ISSN: 1432-2285
    Keywords: Eastern hemlock ; Morphogenesis ; Neoformed (late) leaves ; Pattern along shoots ; Preformed (early) leaves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Pattern of change in leaf character was assessed along the length and around the circumference of Tsuga canadensis (L.) Carr. shoots of different length classes. Leaf size decreased, and number of leaves per unit length of shoot increased, with decrease in shoot length. Acropetally along the shoots, lamina length and width decreased, relative petiole length increased, apices became more pointed, and leaf margins bore more teeth. Around the shoot, from upper to side, and to lower surfaces, leaf size and number of marginal teeth in the proximal halves of leaves increased. These patterns were related both to production of preformed versus neoformed leaves, though their separation was indistinct, and to secondary orientation of leaves by twisting in their petiolar regions into two major bi-lateral ranks. An additional minor rank occurred along the upper surfaces of the shoots where secondary orientation of the leaves was minimal. Surface features of leaves did not differ in any obvious manner. Leaves on sylleptic shoots, which by definition were all neoformed, exhibited similar patterns, but were generally smaller than those on their parent shoots.
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    Events (1992)
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    The visual computer 8 (1992), S. 260-261 
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    ISSN: 1432-2315
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
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    URL: http://dx.doi.org/10.1007/BF01900661
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    Normal estimation in 3 D discrete space (1992)
    Springer
    The visual computer 8 (1992), S. 278-291 
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    ISSN: 1432-2315
    Keywords: Discrete shading ; Volume rendering ; Filtering ; Segmentation ; Volume visualization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Three-dimensional voxel-based objects are inherently discrete and do not maintain any notion of a continuous surface or normal values, which are crucial for the simulation of light behavior. Thus, in volume rendering, the normal vector of the displayed surfaces must be estimated prior to rendering. We survey several methods for normal estimation and analyze their performance. One unique method, the context-sensitive approach, employs segmentation and segment-bounded operators that are based on object and slope discontinuities in order to achieve high fidelity normal estimation for rendering volumetric objects.
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    URL: http://dx.doi.org/10.1007/BF01897115
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    Precise rendering method for exact anti-aliasing and highlighting (1992)
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    The visual computer 8 (1992), S. 315-326 
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    ISSN: 1432-2315
    Keywords: Rendering ; Anti-aliasing ; Highlighting and shading ; Exact polygon area calculation ; Analytical integration of reflection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This paper introduces the Precise Rendering Method, which generates accurately anti-aliased and highlighted images from tessellated polygons. The Precise Rendering Method first solves the aliasing problems of hidden surface removal by using the Cross Scanline Algorithm. This algorithm can exactly calculate polygon areas projected onto each pixel by using horizontal and vertical scanlines. Aliasing artifacts in shading are then prevented by the Reflection Intergration Method, which analytically integrates the intensity of reflection in the solid angle defined by surface normals at vertices of the projected area. Several synthesized images are created to show the efficiency of the Precise Rendering Method.
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    Computer art forum (1992)
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    The visual computer 9 (1992), S. 57-58 
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    ISSN: 1432-2315
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01901029
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    A visual environment to define composition of interacting graphical objects (1992)
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    The visual computer 9 (1992), S. 73-83 
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    ISSN: 1432-2315
    Keywords: Graphical interaction ; User interface management systems ; Visual languages
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract This work presents the FP visual language that specifies the components of a user interface and their relationship. Each component is an instance of an interactor that is a general description of a basic graphical interaction. By a visual language, it is possible to specify in a flexible way the logical structure of a user interface defined as a composition of interacting graphical objects. The graphical tool allows the designer to investigate the correctness of user interfaces and their properties.
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    URL: http://dx.doi.org/10.1007/BF01901272
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    Canopy surface technique for parametric blending (1992)
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    The visual computer 9 (1992), S. 84-90 
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    ISSN: 1432-2315
    Keywords: Parametric surfaces ; Blend surfaces ; Contact curves ; End-tangents ; Boundary data interpolation ; Cross-sectional curves ; Canopy surfaces ; Interpatch continuity of iso-parametric curves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A method based on canopy surfaces is presented for blending parametric surfaces. The blend designed using this method gives freedom to the designer in selecting i) the primitive surfaces to be blended, ii) the contact curves lying on them (in which the blend meets the primitives), iii) the endtangent directions along the contact curves (which are used to ensure tangentplane continuity), and iv) the shape of the cross-sectional curve. An important feature of this method, which is not seen in earlier methods, is the use of end tangents to ensure theC 1 continuity of iso-parametric curves across the junctions between the blend and the primitives in addition to the tangent-plane continuity.
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    Images of the rose (1992)
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    The visual computer 9 (1992), S. 109-113 
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    ISSN: 1432-2315
    Keywords: Visualization ; Rose equation ; Geometrical surfaces ; Solid textures ; Visual exploration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The surprisingly simple rose equation can provide a fertile basis for generating many visually intriguing 3D forms. This equation was originally investigated in 2D in the 18th century. However, today, using modern computer graphics techniques, full 3D versions can be visualized. The geometrical surfaces of the rose functions correspond to the zeros of the equations and are visualized as the isosurfaces of 3D fields. Despite their apparent complexity, the surfaces are not generated by iteration nor by the intersection of primitives, and it is encouraging that such simple functions can produce a wealth of interesting geometrical shapes. Solid textures and colour maps are designed using equations in a simular way. These can be used to further enhance the aesthetic sense and visual appearance of the geometrical forms.
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    URL: http://dx.doi.org/10.1007/BF01901276
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    Events (1992)
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    The visual computer 9 (1992), S. 170-170 
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    ISSN: 1432-2315
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01902556
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    The filtration apparatus for food collection in freshwater sponges (Porifera, Spongillidae) (1992)
    Springer
    Zoomorphology 112 (1992), S. 51-55 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The freshwater sponges (Spongillidae) feed by filtering out small particles from the water passing through them by means of strainer devices in the flagellated chambers. These are filamentous, fine-meshed structures at the distal ends of the choanocyte collars formed of a mucous material similar to that in the glycocalyx. Each strainer separates its flagellated chamber into an outer and an inner zone. The strainers are an extremely efficient filtering mechanism.
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    URL: http://dx.doi.org/10.1007/BF01632994
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    Functional morphology of the female reproductive tract ofPseudoterranova decipiens (Nematoda) raised in vivo and in vitro (1992)
    Springer
    Zoomorphology 112 (1992), S. 237-245 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Entire reproductive tracts dissected from live femalePseudoterranova decipiens, some collected from grey seals (Halichoerus grypus) and some raised in vitro, were examined using light and electron microscopy. The reproductive tracts from both samples are similar in that the oogonia accumulate cytoplasmic inclusion granules and remain attached to the rachis until just before entering the oviduct. Sperm stored in the oviduct fertilize the oocytes, which then pass into the uterus where elaboration of the shell occurs. Two polar bodies are evident in recently fertilized eggs, suggesting that reduction division proceeds as in most nematode eggs. The epithelial cells of the oviduct appear to secrete material that surrounds the oocytes, and the epithelial cells of the uterus secrete a fibrous material that adheres to the outside of the egg shell. The two samples differ in that the oocytes of in vivo-raised nematodes contain curious conglomerates of organelles: areas of membranous whorls in association with electron-dense inclusion granules and glycogen granules. The samples differ also in that the ovarian epithelial cells in the in vitro-raised specimens phagocytose necrotic oogonia at the tip of the ovary.
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    The acoustic response of three species of wood while immersed in three different liquids (1992)
    Springer
    Wood science and technology 26 (1992), S. 131-137 
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    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 The interaction of small, dried samples of pine, redwood and yellow-poplar with toluene, water and formic acid was measured using acoustic emission (AE) sensors. The purpose of these experiments was to determine if the level of acoustic emissions could be correlated with the amount of swelling. The results indicate that acoustic emissions are well correlated with swelling. The level of AE was low when using a non-swelling solvent, toluene, and high with water and the super-swelling solvent, formic acid. Also, it is evident that both a species effect and a solvent effect exists when the solvent/wood interaction is measured using AE.
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    Proton magnetic resonance techniques for characterization of water in wood: application to white spruce (1992)
    Springer
    Wood science and technology 26 (1992), S. 101-113 
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    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 Two new proton magnetic resonance techniques, relaxation spectra and relaxation selective imaging, have been used to investigate the distribution of water in samples of normal white spruce sapwood, heartwood, and juvenile wood as well as two rehydrated heartwood samples containing incipient decay and compression wood respectively. It is demonstrated that the spin-spin (T2) relaxation behavior in wood is best presented as a continuous spectrum of relaxation times. Spectra of T2 for white spruce show separate peaks corresponding to the different water environments. Bound water gives a peak with an T2 time of about 1 ms and lumen water gives a distribution of T2 times in the range of 10 to 100 ms. The lumen water T2 time is a function of the wood cell radius. Consequently, the different cell lumen radii distributions for spruce sapwood, juvenile wood, and compression wood are readily distinguishable by the shape of their T2 spectra. Water environments which are separable on a T2 spectrum may be imaged separately. Imaging has been carried out in one dimension for bound water and lumen water of a spruce sapwood sample at four different moisture contents ranging from 100% to 17%. For the first time, we demonstrate that above the fibre saturation point the moisture density profile of the bound water is largely independent of moisture content. The feasibility and utility of using these techniques for internal scanning of logs and lumber is discussed. These techniques should provide new insights into the wood drying process.
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    Book reviews (1992)
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    Wood science and technology 26 (1992), S. 164-164 
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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
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    URL: http://dx.doi.org/10.1007/BF00194472
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    Collapse phenomena in eucalypts (1992)
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    Wood science and technology 26 (1992), S. 165-179 
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    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 Trees belonging to the genus Eucalyptus are specifically prone to developing damage due to collapse soon after felling. Observations on 150 trees of five Eucalyptus species from two growth sites, indicate that collapse occurs in the wake of the receding liquid water supposedly moving from the heartwood fibres into the rays, and from there to the vessels of sapwood and to the pith (heart shakes), respectively from where it evaporates. Collapse was observed over the entire cross section of stems. Anatomical evidences suggest a collapse modifying process across the stem from the pith to the cambium. Generally, the stresses generated cause tangential flattening of fibres and open radial/longitudinal splits in the tissue. Fibres seem to collapse in radial strings and also in small lumps scattered over the xylem. Based on their effect, the level of collapse stresses must be greater than the cross-grain tension strength but smaller than the longitudinal compression strength of the wet wood. The results suggest that the prediction of collapse susceptibility of standing trees is possible.
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    Shrinkage and collapse in thin sections and blocks of Tasmanian mountain ash regrowth (1992)
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    Wood science and technology 26 (1992), S. 181-187 
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    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 The relationship between the R-ratio (the change in external volume per change in associated volume of water) and specific gravity in the wood of E. regnans was shown to be negatively significant for blocks but not significant for sections. The difference arose because of disproportionately high shrinkage in blocks, especially at low specific gravity, and only relatively small differences in fibre saturation point between the two groups. Estimates of progressive lumen change, based on green volume, were calculated using R. It was shown that, for sections, lumen volume increased from green to 5% EMC and then decreased to 0% moisture content; conversely, in blocks, lumen volume decreased to 5% EMC and then increased substantially to 0%. It was suggested that, in blocks, a recovery in the final stages of drying may have caused the reversal in lumen shrinkage. Correspondingly, it was suggested that such changes may be related to the general, non-linear behaviour of external shrinkage near 0% moisture content. Because reconditioned wood may generally contain residual collapse, or may be otherwise modified by the reconditioning process, it was suggested that care should be exercised in the interpretation of results so derived.
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    Cluster theory for water sorption in wood (1992)
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    Wood science and technology 26 (1992), S. 83-99 
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    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 A review of water interaction in cellulosic-systems, particularly wood, is presented. Discussed are the different states of water in these systems according to Nuclear Magnetic Resonance results, the BET, Dent, and Hailwood and Horrobin sorption isotherm models. The discussion includes details of water structure, and, conformational analysis of cellulose crystals and amorphous cellulose. The water cluster theory is used to more adequately explain the sigmoid curve of the wood isotherm.
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    Structure-property relationship of wood in East-Liaoning oak (1992)
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    Wood science and technology 26 (1992), S. 139-149 
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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 Relationships between various anatomical parameters and selected physico-mechanical properties of wood were examined statistically in East-Liaoning Oak. Path analysis revealed that the key anatomical factors influencing wood shrinkage vary with the type of shrinkage: both radial and tangential shrinkage are mainly controlled by fiber diameter, differential shrinkage mainly by microfibrillar angle and volumetric shrinkage by tissue proportions; specific gravity is determined directly by percentage of cell wall material, while the percentage, in turn, is closely related to tissue proportions, among which vessel proportion is the most important; tensile strength is closely related to microfibrillar angle and specific gravity is not always a good estimator of strength.
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    Shrinkage and collapse in thin sections and blocks of Tasmanian mountain ash regrowth (1992)
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    Wood science and technology 26 (1992), S. 115-129 
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    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 Shrinkage and moisture content measurements for thin sections of Eucalyptus regnans have shown that although total volumetric shrinkage was positively correlated with specific gravity, the relationship did not conform to the general equation s = ϱ f (Stamm 1935, 1952) in that the straight regression line was significantly different from a line passing through the origin. This contrasted with the relationship between shrinkage from 17% EMC to 0% moisture content and specific gravity which, in principle, complied with the Stamm formula. The discrepancy arose because shrinkage from the green condition to 17% EMC was negatively related to specific gravity owing to the high variability of the measured fibre saturation point and its negative correlation with specific gravity. These observations were affirmed in a comparison of unit shrinkage-specific gravity regressions where relationships were positively significant but the regression constants were not. Shrinkage behaviour in blocks of E. regnans did not comply with the Stamm formula although the average fibre saturation point (41.8%) was not significantly different from that for sections (38.2%). The near similarity derived from a significantly greater unit shrinkage in blocks (0.49) than that in sections (0.30). It was suggested that the much greater external shrinkage in blocks contained a significant increment of cell collapse induced by drying stress below the fibre saturation point.
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    Wood science and technology 26 (1992), S. 150-150 
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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
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    URL: http://dx.doi.org/10.1007/BF00194470
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    Studies of the degradation and protection of wood surfaces (1992)
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    Wood science and technology 26 (1992), S. 151-163 
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    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 Large weight losses occurred in thin veneers of radiata pine (P. radiata) during natural weathering due mainly to loss of lignin and hemicelluloses. This was demonstrated by direct chemical analysis and by spectrocopic techniques. Treatment of veneers with dilute aqueous solutions of the recognized surface stabilizing compound chromium trioxide was found to dramatically restrict weight loss during weathering, but similar applications of ferric compound were less effective (Evans, Schmalzl 1989). In order to rationalize these protective effects FTIR internal reflectance spectroscopy was used to study chemical changes taking place at the wood surface upon treatment and during weathering. The spectra obtained provide direct evidence for the modification and stabilization of the lignin aromatic system with aqueous chromium trioxide and to a lesser extent with ferric salts. It is postulated that photostable lignin complexes are formed. The implications of these findings for the development of improved surface stabilizing compounds for wood are discussed briefly.
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    Kinetic study of dilute-acid prehydrolysis of xylan-containing biomass (1992)
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    Wood science and technology 26 (1992), S. 189-208 
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    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 With the current interest in chemicals production from biomas and in view of the emerging pulping processes, the hydrolysis of lignocellulosics is being considered as a promising industrial approach. Since hemicellulose is more readily hydrolyzed than cellulose, most processes include a prehydrolysis step to remove pentosans prior to the main hydrolysis of cellulose to glucose. However, the mechanism of solid-phase acid-catalyzed hydrolysis has not been elucidated and it is impossible to predict the extent of reaction a priori. Having the goal to design reactors, engineers need empirical rate equations. A series of kinetic data available in the literature have been compiled and different kinetic empirical models were analyzed in order to simulate the dilute-acid prehydrolysis of xylan-containing materials. The objective of this paper is to provide profiles of xylan removal and xylose production as a function of a few process variables such as: preheating time, heating rate, acid concentration, reaction temperature and reaction time. Moreover, the influence of biomass species as well as the type of reactor were studied to understand the different solubilization profiles obtained. Other variables such as biomass concentration and particle size were also analyzed. The cellulose dissolved during the prehydrolytic stage was calculated to determine the prehydrolysis selectivity.
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    Growth stresses and strains in cork (1992)
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    Wood science and technology 26 (1992), S. 241-258 
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    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 A detailed study of the growth stresses and strains in the cork shell of the cork-oak was undertaken based on experimentally determined constitutive relations for cork in tension and compression. The stresses depend on the thicknesses of the cork shell and of the back layer around the cork shell, on the radius of the trunk and on its increase due to growth. The circumferential stresses in the cork shell and back layer are tensile and increase with increasing distance to the tree axis. The radial stresses are compressive and decrease with increasing distance to the tree axis. The strains due to growth are not recovered when the cork boards are removed, unless the boards are heated, for example, by immersion in boiling water. Other consequences of the growth stresses are analysed, such as the occurrence of corrugations in the lateral cell walls of cork, the variation of width of the successive growth rings and the occurrence of cracks in the back layer and outer cork layers.
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    The effect of high-temperature drying on the antisplitting properties of makino bamboo culm (Phyllostachys makinoi Hay.) (1992)
    Springer
    Wood science and technology 26 (1992), S. 271-277 
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    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 The anatomical structure of bamboo culm is governed by the number, arrangement, shape and size of the vascular bundles. The vascular bundles at the peripheral zone of the culm are small and numerous, while those of the inner part are larger in size and smaller in number. No radial cell elements are present in the culm. Due to these peculiar structures, bamboo culms are susceptible to splitting during seasoning. This problem has been overcome by applying a high-temperature drying technique.When makino bamboo (Phyllostachys makinoi Hay.) culms were dried under elevated temperatures (from 60 °C up to 120 °C), no splits occurred on the culm surface. This phenomenon is explained by chemical composition analysis, mechanical properties associated with physical changes, scanning electron microscope and x-ray diffractometer observations.
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    The thermoosmotic effect in wood (1992)
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    Wood science and technology 26 (1992), S. 289-294 
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    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 Water vapor pressures computed from stationary state data for moist wood (Choong 1963) are used to infer changes in the logarithm of vapor pressure per unit change in Kelvin temperature, d ln p/dT, for comparison with corresponding values from a thermodynamic model. The model evaluates the overall heat of transfer associated with passage of vapor through wood, and hence quantifies the thermoosmotic effect. Results of the comparison verify the existence of a constant vapor entropy for wood in the stationary state.
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    Wood science and technology 26 (1992), S. 403-404 
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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
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    URL: http://dx.doi.org/10.1007/BF00226081
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    Seasonal influences on early wound reactions in Betula and Tilia (1992)
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    Wood science and technology 26 (1992), S. 405-412 
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    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 Seasonal influences on early wound reactions in the xylem of Betula pendula Roth and of Tilia americana L. were investigated by transmission electron microscopy. Wounding induced the synthesis of fibrillar material in the parenchyma with subsequent secretion through the pit membranes into adjacent vessels and fibers. The amount of secreted material after 3–4 weeks served as an indicator for the reaction intensity. Field tests with Betula revealed secretion throughout the year with high intensity between May and November and lowest level in February. Tilia developed intense wound reactions between May and September. In November the intensity appeared moderate, but wounding in February and March did not induce any secretion. Laboratory tests in the summer at 4°C revealed a different temperature sensitivity of Betula and Tilia. Betula retained its capability for secretion, whereas in Tilia secretion ceased completely. Temperature and the physiological stage influence the various steps of early wound reactions and the effectivity of compartmentalization.
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    Creep in chipboard (1992)
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    Wood science and technology 26 (1992), S. 429-448 
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    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 Matched samples to those used in a previously reported investigation (under constant environments employing eight board materials and solid wood) were subjected to five different levels of stress under four different cyclic environments for periods of six months. Relative creep increased slightly and linearly with respect to stress within the range of stress levels adopted, as well as increasing with severity of the environment. All materials showed greater sensitivity to alternating humidity than to alternating temperature. The effects of the three prinicipal variables (stress level, environment, material), and the strong interactions among them, were quantified using analysis of variance and found to be similar to those under constant environments: the effect of environmental condition was found to be far greater on relative creep than that of either stress level or material. Averaging over all conditions and stress levels, relative creep increased progressively among timber, plywood, waferboard, chipboard and fibreboard, though this ranking order varied at different stress levels and environments due to the presence of strong interactions. At a stress level of 30% and a time of 43,200 minutes, the relative creep under alternating humidity of 30↔90% was on average fourteen times greater than that under a constant humidity of 65% (averaging across the nine materials); however, there was considerable divergence among the materials in this ratio. At the same level of stressing, the mean relative creep for all materials under an alternating temperature of 10↔30 °C was 1.6 times higher than at a constant temperature of 20°C. The ranking order of materials in their sensitivity to alternating temperature was different to that under alternating humidity.
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    Suppression of the whistling noise in circular saws using “Silentalloy” (1992)
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    Wood science and technology 26 (1992), S. 449-459 
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    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 To suppress the so-called whistling noise in idling circular saws, a circular saw with slots in the peripheral area of the blade has been widely used. However, the effect of the slots is uncertain because the natural frequencies of saws vary, even among saws even if they were designed to suppress the whistling noise. Therefore, we made two types of tungsten carbidetipped circular saws; one with the sawblade made of a high-damping alloy named Silentalloy (SIA) and one with the blade made of the common alloy tool steel (SKS5). The noise levels and the power spectra of these saws during idling and cutting were measured at rotational speeds from 1,000 rpm to 6,000 rpm. The minimum damping capacity required to suppress the whistling noise in an idling circular saw was measured using the characteristic of SIA that the damping capacity can be changed depending on the temperature of the heat-treatment. The circular saws made of SIA generated neither the whistling noise nor the low discrete noise caused by the sawblade resonance. Slots are not necessary in a SIA saw because the coefficient of thermal expansion of SIA is relatively small. In fact, the slots raised the noise level of the SIA saw slightly. The degree of scatter in the noise levels of SIA saws was low unlike that of the SKS 5 saws. The noise level of the SIA saw during cutting was reduced a few decibels at the operator's position. It was demonstrated that the minimum damping capacity required to suppress the whistling noise is in the vicinity of 0.07 in logarithmic decrement. In conclusion, the whistling noise can be suppressed completely if a sawblade is made of a high-damping metal such as Silentalloy.
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    Determination of localized dynamic behavior of wood strip over foam rubber underlayment, composite flooring by random vibration (1992)
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    Wood science and technology 27 (1992), S. 11-21 
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    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 The localized dynamic behavior of composites consisting of wood flooring strips and foam rubber underlayment was investigated. Random dynamic loads were applied to the center of the strips by a small electromagnetic shaker, and applied force and response of the composite were measured in order to analyze the vibrational characteristics of the composites at the driving point on the basis of transfer functions.
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    Book review (1992)
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    Wood science and technology 27 (1992), S. 60-60 
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    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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203410
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    Long term bending creep of wood in cyclic relative humidity (1992)
    Springer
    Wood science and technology 27 (1992), S. 49-59 
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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 Long term creep and recovery test results of wood under a bending load of 10 MPa stress and subjected to relative humidity cycling are presented. In spite of the vast number of humidity cycles during these tests, the results do not give evidence of an existence of a mechano-sorptive creep limit. The results also indicate that the recovery is not complete on unloading when the humidity is cycled. A mechano-sorptive model that fits the test results is proposed. According to the model, the elastic bending deflection in a cyclic load of 10—3 MPa and subjected to natural outdoor relative humidity can be about doubled to account for the creep under ten years loading.
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    URL: http://dx.doi.org/10.1007/BF00203409
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    FTIR spectroscopic studies of the reactions of wood and of lignin model compounds with inorganic agents (1992)
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    Wood science and technology 27 (1992), S. 69-80 
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    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 Certain inorganic agents, particularly chromium trioxide, are known to be able to protect wood against weathering. In this paper, the reactions of chromium trioxide, and of some chromic and ferric salts, with wood and with the lignin model compound, guaiacol and derivative, calcium lignosulphonate, have been examined by FTIR reflectance and transmission spectroscopy. Reactions, to different degrees, were obtained with chromium trioxide, and the ferric salts but no reactions with the chromic salts. Intensity changes of bands in the spectra, particularly those near 1,505 and 1,595 cm-1, indicate that reaction of the agents with wood involves the aromatic rings of lignin.
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    URL: http://dx.doi.org/10.1007/BF00203412
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    On the activation energy of diffusion of water in wood (1992)
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    Wood science and technology 26 (1992), S. 73-82 
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    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 The diffusion equation for water in wood is expanded in terms of temperature and moisture gradient on the assumption that the driving force for the diffusion of water in wood is the partial pressure of water vapour. An analytic expression is then developed for the activation energy of diffusion in terms of enthalpy and entropy changes associated with the sorption process. The expression is compared with another published curve and some similarity was observed.
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    URL: http://dx.doi.org/10.1007/BF00194464
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    Stress-strain state of wood at kiln drying (1992)
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    Wood science and technology 26 (1992), S. 209-217 
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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 A model has been suggested which allows the calculation of stresses arising in kiln drying and humidification of wood, as well as the total residual strain, i.e. “set strain” ɛs, consisting of purely residual strain ɛr and the so-called “frozen strain” ɛf. Frozen strains arise under the operating influence of loading when the stiffness is increased because of a decrease in moisture content (or temperature) of the wood. The process of formation of set strains ɛs has been shown to depend on the history of loading, variations of the moisture content of the wood, as well as cooling of the section before the measurement of ɛs. The possibility of using set strain as a parameter of the state of stress of wood in kiln drying has been noted.
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    URL: http://dx.doi.org/10.1007/BF00224293
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    Determination of formaldehyde in particle boards using headspace gas chromatography (1992)
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    Wood science and technology 26 (1992), S. 219-226 
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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 Formaldehyde in particle board was analyzed by gas chromatography (GC) using instruments equipped with headspace injector and flame-ionization detector. The application of the method to the determination of formaldehyde desorbing from urea-formaldehyde and melamine-urea-formaldehyde resins used in manufacturing particle board is discussed. In the 47 samples analyzed, the concentration ranged between 10.34–56.29 mg of formaldehyde/100 g of particle board.
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    The thermochemical degradation of cork (1992)
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    Wood science and technology 26 (1992), S. 259-269 
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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 The thermochemical degradation of cork from Quercus suber L. was studied in the temperature range 150°C–450°C in relation to mass loss, chemical composition and the influence on the cellular structure. The degradation of cork is strongly dependent on temperature and mass losses become significant at 200°C (15% of initial dry weight) and increase rapidly for higher temperatures (27% at 250 °C, 49% at 300 °C, 62% at 350 °C) until ashing at 450 °C. The polysaccharides are the most heat sensitive components: at 200 °C, hemicelluloses disappear and cellulose is degraded to a considerable extent. Suberin is more resistant and degradation starts at approx. 250 °C; 300 °C-treated samples only contain 7% suberin. The cellular structure of cork is also significantly influenced by temperature. Upon heating, cells expand and the cell walls stretch, attaining at 250 °C a maximum cell volume increase corresponding to a factor of approximately 2. Above 300 °C, the structure of cell walls is considerably changed and show profound physical damage; in the later stages of pyrolysis, a cellular structure is no longer observed.
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    URL: http://dx.doi.org/10.1007/BF00200161
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    Modeling internal temperature changes of timber poles during ACA treatment (1992)
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    Wood science and technology 26 (1992), S. 227-240 
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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 The temperature-time-location relationships during steam conditioning and pressure treatment of timber poles using ammoniacal copper arsenate (ACA) have been studied and a new mathematical model that incorporates both the thermal properties of the poles and the parameters of the treatment process is discussed. Prediction equations and charts are presented that show the minimum required steaming time to satisfy the 1982 Rural Electrification Authority (REA) purchase specification, i.e. a center temperature above 150 °F (65.5 °C) for 2 hours. A six hour steaming time, commonly used for ACA treatment, has been found to be too short to bring poles with diameters larger than about 40 cm to the required sterilization conditions. Therefore longer steaming times, predicted using the methods given here, are recommended. The temperature of the preservative used does not appear to be a major factor in determining the maximum temperature achieved at the center of a pole, but it can influence the length of time the pole is above 65.5 °C.
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    URL: http://dx.doi.org/10.1007/BF00224295
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    Acoustic emission monitoring during partial compression to detect early stages of decay (1992)
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    Wood science and technology 26 (1992), S. 279-287 
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    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 The acoustic emissions (AEs) under partially compression were monitored with two softwood and one hardwood specimens in very eary stages of decay by a brown- and a white-rot fungus. Even slightly decayed specimens emitted AEs immediately after beginning of loading, typically when partial compression stress was applied to brown-rotted wood with the flat-headed attachment. With sound specimens of three wood species, only a few AEs were generated until the load reached at the proportional limit. These results suggest that AE monitoring will be one of the feasible means to detect the incipient stages of decay in a field test.
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    URL: http://dx.doi.org/10.1007/BF00200163
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    On the mechanical behaviour of water soaked wood at various states of stress (1992)
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    Wood science and technology 26 (1992), S. 295-306 
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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 The paper is concerned with an experimental investigation of the swelling strains and mechanical strains of water soaked wood under one- and two-dimensional stress states at changing moisture content. The aim of this paper is to develop an experimental basis for setting up the physical relations between strains, stresses and moisture content in wood.
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    URL: http://dx.doi.org/10.1007/BF00200165
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    Book reviews (1992)
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    Wood science and technology 26 (1992), S. 323-324 
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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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00200167
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    Enthalpy-entropy compensation and thermodynamic considerations in sorption phenomena (1992)
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    Wood science and technology 26 (1992), S. 329-333 
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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 Isosters for Western white pine were experimentally determined at temperatures of 30, 45, 60 and 70°C and relative humidities between 10 and 90%, approximately. The enthalpyentropy and free energy changes for water, were calculated and analyzed. The enthalpy-entropy compensation was proven to exist and the isokinetic temperature was calculated.
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    URL: http://dx.doi.org/10.1007/BF00226074
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    A theory of cross-sectional shrinkage distortion and its experimental verification (1992)
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    Wood science and technology 26 (1992), S. 353-368 
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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 A theory has been developed for calculating the cup and edge distortion that will occur when green boards are dried, or the moisture content of dry boards changes in service. The parameters on which the calculations are based are the annual ring orientation coordinates R and θ of the boards, and the transverse shrinkage factors. For boards of square-cross-section the theory agrees very closely with the shrinkage predicted by the older theory of Greenhill, MacLean and Keylwerth. For Beilschmiedia tawa specimens 50×50 mm in cross-section the experimental and calculated width and thickness shrinkage were in excellent agreement. For radiata pine boards 200×50 mm in cross-section the experimental cup, edge distortion and shrinkage in width and thickness agreed very closely with the values predicted by the theory.
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    Modeling lumber strength spatial variation using trend removal and kriging analyses (1992)
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    Wood science and technology 26 (1992), S. 369-381 
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    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 The techniques of kriging and trend removal analysis for modeling the strength properties of lumber have been discussed. Using these techniques, the within member compressive strengths of 38 mm × 89 mm 2100f-1.8E and the within member tensile strengths of 38 mm × 89 mm No. 2 spruce-pine-fir lumber have been modeled. The suitability of these techniques to model the strength properties of lumber has been evaluated by comparing the kriged compressive and tensile strength data to baseline experimentally collected compressive strength data and simulated tensile strength data, respectively. Comparisons of the results of statistical analyses of the baseline data and the kriged data show good agreement. The use of kriging and trend removal techniques to generate strength values in simulation studies for finite element analyses of wood structures is judged to be effective.
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    Process of absorption and desorption of water in a wood board, with 3-dimensional transport beyond the FSP (1992)
    Springer
    Wood science and technology 26 (1992), S. 307-321 
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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 The process of absorption of water in a piece of solid wood, as well as the following stage of desorption is studied, when the water content is beyond the fiber saturation point. A model based on a numerical method with finite differences is built and successfully tested. This model takes into account a 3-dimensional transport of water controlled by diffusion, with three principal axes of diffusion and three various principal diffusivities. The model is able to predict the kinetics of absorption or desorption when the three principal diffusivities are known, as well as the operational conditions.
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    URL: http://dx.doi.org/10.1007/BF00200166
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    Nonisothermal diffusion model based on irreversible thermodynamics (1992)
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    Wood science and technology 26 (1992), S. 325-328 
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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 A comparison is made between a nonisothermal diffusion model derived from irreversible thermodynamics and three other equations that have been applied to several series of nonisothermal experiments.
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    Wood in the stationary state: Zero entropy gradients for water vapor and bound water (1992)
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    Wood science and technology 26 (1992), S. 335-342 
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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 According to nonequilibrium thermodynamics, the local rate of entropy production is minimized for moist wood in the stationary state. Furthermore, the rate of entropy production due to moisture flow must be zero in this state. Conservation of energy applied to the steady flow of water vapor through an arbitrarily selected volume element of wood shows that the vapor entropy gradient is zero. Because the entropy production due to moisture flow must be balanced by a corresponding entropy flow away from the element, entropy gradients for bound water and water vapor are equal and the bound water entropy gradient also is zero.
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    Shrinkage and collapse in thin sections and blocks of Tasmanian mountain ash regrowth (1992)
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    Wood science and technology 26 (1992), S. 343-351 
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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 Total collapse values from the green condition to various equilibrium moisture contents (EMC) were obtained by comparing shrinkage before reconditioning in matched blocks and sections of the wood of Eucalyptus regnans. It was shown that while collapse to 17% EMC comprised the largest portion of total collapse, a significant component, apparently caused by drying stress, developed below 17% EMC. Between 5% EMC and 0% moisture content a collapse recovery of some 1% occurred, seemingly because of changes in drying temperature. After reconditioning, collapse recovery was only partial and a high level of residual collapse remained. It was shown that collapse recovery was highest near the sapwood-heartwood boundary, while residual collapse was highest near the heartwood centre. While residual collapse was weakly negatively correlated with specific gravity, this relationship was not significant after adjustment was made for change in shrinkage after reconditioning in sections. All types of collapse were positively correlated with R-ratios calculated for blocks. However, relationships were not as well defined when R-ratios for sections were employed, the exception being for collapse below 17% EMC which was highly negatively correlated with R. The difference between shrinkage before reconditioning and shrinkage after reconditioning in sections, while totalling near zero, was positively correlated with specific gravity. It was demonstrated that this quantity could not constitute collapse in the traditional sense of collapse of the cell lumens. A possible association with moisture content of the material was discussed.
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    On regioselectivity of the reaction of p-quinone methides with p-hydroxybenzyl alcohols (1992)
    Springer
    Wood science and technology 26 (1992), S. 383-392 
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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 1H NMR analysis of the reaction of lignin model p-quinone methides with aliphatic alcohols, phenols and p-hydroxybenzyl alcohols in chloroform solution has demonstrated a pronounced predominance of non-cyclic benzyl alkyl ethers over benzyl aryl ethers in the mixture of products, as a result of faster addition of alcohols than phenols. In the case of the simplest p-quinone methides, the only competing reaction seems to be a stereoselective isomerization into E-p-hydroxystyrenes.
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    Influence of the degree of substitution and pretreatments on the surface structure of cellulose nitrate fibres (1992)
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    Wood science and technology 26 (1992), S. 393-401 
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    Notes: Summary Cellulose nitrate fibres of three different degrees of substitution (DS) were prepared by heterogeneous reaction. The fibre surfaces were observed in the scanning electron microscope. Apart from the DS the influence of pretreatments such as prenitration and boiling of the fibres prior to nitration was studied. The results reveal an interaction between the cell wall layers and the esterification and swelling capacity of the nitration medium. In all cases the DS was determined by the composition of the nitration medium. A pretreatment influenced the fibre surfaces after nitration. The peculiar role of the primary wall during esterification is emphasized.
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    Thermo-mechano-chemical pretreatment of wood in a process development unit (1992)
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    Wood science and technology 26 (1992), S. 413-428 
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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 Continuous thermo-mechano-chemical pretreatment of wood (particle size: 0.25–0.50 mm) was conducted by steam injection for rapid heating-up of slurry (170–215°C), flow through homogenization valves (mechanical effects), and autohydrolysis in a plug flow reactor (90–95 s) (thermochemical reactions). The process was carried out in aqueous phase without addition of any chemicals. Residues resulting from the pretreatment were characterized by thermal and elemental analyses. The extent and selectivity (hemicellulose removal and delignification) of the wood solubilization were analyzed as a function of pretreatment temperature and the thermal severity factor, the goal being the optimization of hemicellulose dissolution. Experimental results were compared with those previously obtained in a batch cascade reactor system.
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    Combustion gas toxicity, hygroscopicity, and adhesive strength of plywood treated with flame retardants (1992)
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    Wood science and technology 26 (1992), S. 461-473 
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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 The results of tests of combustion toxicity, hygroscopicity, and adhesive strength for fire retardant-treated plywood are described. The plywood was prepared from veneers treated with diammonium phosphate and ammonium bromide, and from glue mixed with poly (ammonium phosphate). Furthermore, the plywood boards were coated with boric acid. High ammonium phosphate and low or 0 ammonium bromide contents with the boric acid-coatings gave the greatest improvement in the combustion toxicity. Influence of almost all the treatments on the hygroscopicity was not significant. In all treatments the dry adhesive strength and the cyclic boil adhesive strength were slightly and considerably reduced, respectively.
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    Formation and structure of reaction wood in Buxus microphylla var. insularis Nakai (1992)
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    Wood science and technology 27 (1992), S. 1-10 
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    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Anatomical differences in xylem between the upper and lower sides formed in the inclined stems of Buxus microphylla with different angular displacement from the vertical were examined microscopically. B. microphylla exhibited a pronounced growth promotion on the lower side of the inclined stems. Formation of tension wood (gelatinous fibers) was not observed. Xylem formed on the lower side showed some interesting features resembling the compression wood formed in gymnosperms. The reaction wood tracheids and vessels showed an excessive lignification in their secondary walls but lacked both helical cavities and an S3 layer, features that were almost the same as those of primitive gymnosperms. These results indicate that B. microphylla has an ability to form compression wood, suggesting that in the genus Buxus a different mechanism in the conducting elements was developed in the phylogenetic evolution.
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    Pyrolysis and combustion toxicity of wood treated with CCA (1992)
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    Wood science and technology 27 (1992), S. 35-47 
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    Notes: Summary The study was carried out in order to determine the effects of CCA on the pyrolysis and the combustion toxicity of wood. The results from CCA treated wood are summarized as follows: 1. CCA accelerated the beginning of pyrolysis of wood, increased the activation energies for the weight loss by pyrolysis, and increased the char yields in both air and helium. 2. Almost all the original amounts of cromium and copper were retained in the ash while some of the arsenic evolved into the gas phase, which increased with increasing temperature and air supply. 3. The combustion toxicity of wood samples was affected more by the sample density and CO concentration than CCA. It is concluded that for minimizing gaseous toxicants from arsenic, CCA treated wood must be burned at low temperatures with a reduced air supply.
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    Preparation and properties of oligoesterified wood blocks based on anhydride and epoxide (1992)
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    Wood science and technology 27 (1992), S. 23-34 
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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 Preparation and properties of oligoesterified woods in the form of block are reviewed. The oligoesterified wood blocks are prepared by stepwise addition reactions of dicarboxylic acid anhydride and epichlorohydrin (EpCl), or one-step chemical treatment with reactant solution of the anhydride and EpCl. Among the preparation methods investigated, the heating-suction method is industrially advantageous. In this method, wood blocks impregnated with the reactant solution are heated and then subjected to suction under reduced pressure and heating, to remove unreacted reactant solution. The oligoesterified wood blocks thus obtained contain oligoester chains formed by the alternate additions of the anhydride and EpCl to OH groups of wood. They also contain small amounts of free oligomers not linked with the wood matrix. Their dimensional stabilities against moisture and water become greater with increase in the apparent total weight increase due to the oligoester chains and the free oligomers. The oligoesterified wood blocks based on phthalic anhydride-EpCl are industrially promising, and exhibit higher compressive and flexural strenghts, greater chemical resistance, electric insulation, and much lower water absorption than untreated wood block. Furthermore, excellent resistances are observed against weathering and biodeterioration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203407
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    Organosolv fractionation of Ulex europæus with dilute hydrochloric acid and phenol. Two simple kinetic models for pre-hydrolysis and delignification (1992)
    Springer
    Wood science and technology 27 (1992), S. 61-68 
    Details
    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 The wood part of Ulex europæus, a common plant in Galicia (N. W. Spain), has been subjected to an organosolv treatment with dilute hydrochloric acid and phenol. The reaction was carried out at atmospheric pressure and 100 °C. Two simple kinetic models have been used to explain the pre-hydrolysis and delignification processes, studying the influence of the concentration of acid on both processes at three levels: 0.45, 0.90 and 1.80% by weight.
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    URL: http://dx.doi.org/10.1007/BF00203411
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  • 88
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    Development of the male scent organ ofCreatonotos transiens (Lepidoptera, Arctiidae) during metamorphosis (1992)
    Springer
    Zoomorphology 111 (1992), S. 125-139 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary (1) The male abdominal scent organ (corema) of the arctiid mothCreatonotos transiens consists of a basal bladder and four tubes. It can be everted from the sternal intersegmental membrane 7/8. Its scent hairs (scales) produce and release the pheromone hydroxydanaidal, which attracts both sexes. Pyrrolizidine alkaloids (PA) ingested by the larva with its food are not only precursors of the pheromone but also a morphogen, which quantitatively controls the growth of the pupal corema and, thus, its final size and number of hairs. (2) The coremata arise from epidermalanlagen at the anterior border of the 8th abdominal sternite. If male larvae are fed 1 mg PA these organs begin to develop from small vesicles, and four tubes then arise during the first 3 pupal days. The corresponding mitoses reach their peak at 36 h. During the next 2 days the tubes shorten, while the walls become thin and doubly folded. The total surface of the corema increases about 20 times because of the shape transformation of the epidermal cells from prismatic to very flat. (3) The scent hairs originate from trichogen cells, which arise together with their associated tormogen cells during the 1st pupal day by way of differential mitoses. As the trichogen cells grow, their nuclei enlarge by way of endomitoses, elongate distally, and thus produce the hairs that extend into the lumen of the corema. Tormogen cells degenerate by the 8th day at latest. The hairs in each tube form a thick, caudally oriented bundle. The hair cells are finally bottle-shaped and at day 6 they extend freely into the hemolymph space. They are probably also the pheromoneproducing cells in later pupal and early imaginal life. Mitoses that produce trichogen cells stop after the 1st day, those producing epithelial cells 2 days later. This delay shifts the ratio of the two cell types from about 1∶11 (18 h) to 1∶40. (4) The processes hitherto described refer to “normogenesis” with ample PA supply. “Control” coremata in PA-free or PA-deficient specimens develop in principle in the same way, but at a slower rate, with minimal hair cell numbers barely 1/10th of normal, or at any rates between, depending upon the earlier PA supply. The size of control coremata varies from very small to small; even the hair cells and the hairs are smaller. (5) PA regulates corema development quantitatively through the number of mitoses of its cells and of endomitotic steps of the hair cells. In PA-treated specimens the coremaanlage is already advanced prior to pupation, at about the time when its sensitivity to PA influence terminates, in the early prepupa. Since PA only affects the anlagen of the corema and not that of any other body part (not even the basal coremal bladder), we postulate a selective interaction of PA with the presumptive corema cells. We found earlier that ecdysone is also involved, since the respective cell numbers can only be realized if this hormone is present.
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    URL: http://dx.doi.org/10.1007/BF01632903
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    Spermiogenesis and sperm structure in the crabUca tangeri (Crustacea, Brachyura), with special reference to the acrosome differentiation (1992)
    Springer
    Zoomorphology 111 (1992), S. 161-165 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Early spermatids of the crabUca tangeri consists of the nucleus of granular chromatin and the cytoplasm, which contains a proacrosomal vesicle in close association with membrane lamellae. In the mid spermatids an invagination of the acrosomal vesicle membrane gives rise to the formation of the perforatorium, a spindle-shaped tubule which encloses tubular membranous structures. The pair of centrioles located at the base of the acrosome is not directly involved in perforatorial differentiation. The acrosomal vesicle shows a heterogeneous content composed of the operculum, the thickened ring, and three layers of different materials concentrically arranged around the perforatorium. During the late spermatid stage the nuclear profile differentiates numerous slender arms and the chromatin arranges into fibers. Membranous tubules from the cytoplasm become incorporated into the tubular structures of the perforatorium. The mature spermatozoon has the typical structure of the branchyuran sperm, with a complex acrosome, cupped by the nucleus, and a thin cytoplasmic band intervening between the former main elements. The centrioles are degenerate. The nuclear arms are unusually numerous (more than 20) and lack microtubules or microtubular derivatives.
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    URL: http://dx.doi.org/10.1007/BF01632905
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    Flexibility of the drinking mechanism in adult chickens (Gallus gallus) (Aves) (1992)
    Springer
    Zoomorphology 111 (1992), S. 141-159 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Drinking was studied in adult chickens by cinematography and radiography. Three subsequent behavioral phases occur. (1) Water is transported from the water box into the oropharynx when the beak is immersed. Then delicately tuned cyclic motion patterns of beaks, tongue, and larynx transport water by capillarity, squeezing, and suction. (2) During the elevation of the head the tongue is elevated and the larynx is depressed to keep the water in the pharynx against the gravitational and centrifugal forces that result from the upward swing of the head. (3) During the tip up phase gravity transports the water to the esophagus, while the adhering water is pushed and squeezed caudad by tongue and larynx movements. Flexibility in the adult drinking mechanism was analyzed by comparing the drinking of normal and beak-trimmed chickens under normal drinking conditions, as well as while drinking small drops. Three modes of behavioral flexibility were discussed: conservative, regressive, and progressive flexibility. Most behavioral elements of the modal action pattern in drinking are so flexible that a chicken can reorganize the movement patterns of jaws, tongue, larynx, and head to adapt the mechanism to external (drop drinking) or internal (beak-trimming) changes. However, in drop drinking, the normal chicken relies upon a regressive takeover by an ontogenetically earlier developed pattern in the craniocervical motion system. Presence of the observed progressive flexibility in lingual and cervical motion patterns is shown to be a precondition for the avian drinking mechanism to keep up with dominant evolutionary changes in feeding mechanisms.
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    URL: http://dx.doi.org/10.1007/BF01632904
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    Light and electron microscopic studies of the skin of the Palembang puffer,Tetraodon steindachneri (Teleostei, Tetraodontidae) (1992)
    Springer
    Zoomorphology 111 (1992), S. 193-205 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The skin ofTetraodon steindachneri is morphologically and cytologically adapted to the habits and locomotion of the fish, as well as to its ability to expand its body into a nearly spherical shape. Negative buoyancy, which facilitates precise maneuvers near the bottom, is achieved primarily by a very thick dermis. Various special features of the skin enable it to withstand the mechanical stresses of extreme expansion and deep folding: (1) the absence of a covering such as a cuticle on the outer surface of the epidermis, (2) the lack of scales, (3) the pronounced interdigitation of the epidermal cells, (4) the cytoskeleton of the filament-containing cells, and (5) the stratum compactum of the dermis. The spines, which inT. steindachneri can be extended and retracted, are derived, like the spines of diodontidae, from the scales of other teleosts. Each spine comprises cellular and acellular components, which together produce a complicated bilaterally symmetrical structure. Movement of the spines is mainly a passive mechanical concomitant of distension of the body, though active processes cannot be ruled out. The biological significance of the spine apparatus ofT. steindachneri is discussed.
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    URL: http://dx.doi.org/10.1007/BF01633008
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    Functional morphology of the locomotory podia ofHolothuria forskali (Echinodermata, Holothuroida) (1992)
    Springer
    Zoomorphology 111 (1992), S. 167-178 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ventral surface ofHolothuria forskali (Holothuroida, Aspidochirotida) is almost completely covered by small-sized podia that are locomotory. Each podium consists of a stem that allows the podium to lengthen, to flex, and to retract, and this is topped by a disc that allows the podium to adhere to the substratum during locomotion. Podia ofH. forskali do not end in a sucker and their adhesion to the substratum thus relies entirely on the disc epidermal secretions. The disc epidermis is made of five cell types: non-ciliated secretory cells of two different types that contain granules whose content is either mucopolysaccharidic (NCS1 cells) or mucopolysaccharidic and proteinic in nature (NCS2 cells), ciliated secretory cells containing small granules of unknown nature (CS cells), cilitated nonsecretory cells (CNS cells), and support cells. The cilia ofCS cells are subcuticular whereas those ofCNS cells, although also short and rigid, traverse the cuticle and protrude in the outer medium. During locomotion, epidermal cells of the podial disc are presumably involved in an adhesive/de-adhesive process functioning as a duogland adhesive system. Adhesive secretions would be produced byNCS1 andNCS2 cells and de-adhesive secretion byCS cells. All these secretions would be controlled by stimulations of the two types of ciliated cells (receptor cells) which presumably interact with the secretory cells by way of the nerve plexus. The lack of suckers and the coexistence of two adhesive cell types in the disc epidermis give the locomotory podia ofH. forskali a “compromise” structure which would perhaps explain their ability to move as efficiently along soft and hard substrata.
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    URL: http://dx.doi.org/10.1007/BF01632906
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    Functional anatomy of the valves in the ambulacral system of sea urchins (Echinodermata, Echinoida) (1992)
    Springer
    Zoomorphology 111 (1992), S. 179-192 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The water vascular system of sea urchins is examined with special reference to the valves positioned between the radial vessel and the ampullae of the tube feet. The lips of the valve protrude into the ampulla. Thus the valve functions mainly like a check valve that allows the unidirectional flow of fluid towards the ampulla. Each ampulla-tube foot compartment acts as a semi-autonomous hydraulic system. The lumina of the ampulla and the tube foot are lined with myoepithelia except for the interconnecting channels that pierce the ambulacral plate. The contraction of the ampulla results in an increasing hydraulic pressure that protrudes the tube foot, provided that the valve is closed. The retraction of the tube foot results in a backflow of fluid independent of the condition of the valve. The lips of the valve are folds of the hydrocoel epithelium. The pore slit lies in the midline. The perradial faces of the lips are covered with the squamous epithelium of the lateral water vessel. The ampullar faces are specialized parts of the ampulla myoepithelium. Turgescent cells which form incompressible cushions take the place of the support cells. The valve myocytes run parallel to the pore slit and form processes that run along the base of the ampulla and the perradial channel up to the podial retractor muscle. The findings lead to the hypothesis of multiple control of the ampulla-tube foot system: (1) The mutual activity of the ampulla and the tube foot is indirectly controlled by the lateral and podial nerves which release transmitter substances that diffuse through the connective tissue up to the muscle layers. (2) A muscle-to-muscle conduction causes the simultaneous contraction of the ampulla or the podial retractor muscles. (3) The valve muscles are directly controlled by the processes of the valve myocytes which make contact with the podial retractor. In extreme conditions a backflow of hydrocoel fluid towards the radial water vessel occurs.
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    Development of drinking mechanisms in the chicken (Gallus gallus) (Aves) (1992)
    Springer
    Zoomorphology 111 (1992), S. 217-228 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Development of the drinking mechanism from the day of hatching to the 4 week old chick was studied in relation to the growth of the oropharynx and drinking performance. Results indicate that due to scaling effects in the growing oropharynx, physical factors require the development of extra mechanisms. The swallowing mechanism to transport water from the pharynx into the esophagus during the tip up phase is already present in hatchlings, and does not change during ontogeny. The mechanism for water intake during the immersion phase changes considerably. Hatchlings display pecking behavior towards water. Week old chicks protrude the tongue far out, and the total volume ingested is sucked up by capillary action between the tongue, the floor, and the roof of the oropharynx. In 2 and 3 week old chicks the relative distance over which water is sucked up by capillarity decreases, whereas the volume of water pushed caudad by the tongue and bills increases. Laryngeal suction also develops in this period. At the age of 4 weeks chickens use the adult mechanism to drink. Most oropharyngeal elements increase two to three times in length and width during post hatching ontogeny. Due to these increases, water transport by capillarity alone does not suffice in the older age groups; therefore additional mechanisms such as pressure development by closing the bills and laryngeal suction must develop. Relative to the oropharyngeal length most elements grow isometrically. The width of the lingual alae and the larynx width, however, increase with positive allometry, which improves both capillary action as well as the transport of water during the tip up phase when the chicks grow older. The need to develop extra water transport mechanisms during growth due to scaling effects is shown to condition the radiation capacity of avian drinking mechanisms. Nidicolous birds are, however, not constrained by the need to have a properly operating drinking mechanism during the early ontogeny and may therefore have a better chance of developing alternativ drinking mechanisms then nidifugous birds.
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    The influence of an eucaryotic intranuclear cell parasite on the production of gemmules inEphydatia fluviatilis (Porifera, Spongillidae) (1992)
    Springer
    Zoomorphology 111 (1992), S. 207-216 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A prerequisite for the production of gemmules is the presence of intact archaeocytes and trophocytes, which give rise to the thesocytes with which the gemmule is eventually filled. The coat enclosing the gemmule requires spongioblasts for its formation and incorporates amphidisk spicules, which develop in amphidiskoblasts. The cell parasite, the development of which is described here, infects mainly archaeocytes but also spongioblasts and amphidiskoblasts. Even a moderate infection results in significant malformation of the gemmule covering. In the thesocyte nucleus, the parasite can survive the resting phase of the gemmule. After the gemmule has hatched, the parasite, again in the virulent form, is present in the young, developing sponge. The parasite may be a microsporidian of the primitive type, close to the genusMetchnikovella, which typically occurs in gregarines.
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    Adhesive glands in the Pterastericolidae (Plathelminthes, Rhabdocoela) (1992)
    Springer
    Zoomorphology 111 (1992), S. 229-238 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of anteroventral gland cells with processes penetrating the epidermis inPterastericola bergensis, P. fedotovi, P. pellucida and the undescribedP. (sp. Rottnest) was studied with transmission and scanning electron microscopy. Specimens ofP. pellucida were shock frozen in situ in the epithelium of their asteroid host to study the function of the glands. Secretory products released from the gland cell processes fan out towards the host epithelium. The glands are concluded to have an adhesive function. They are compared with similar structures in Neodermata and other rhabdocoel taxa. The phylogenetic significance of the glands is discussed.
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    The sphaeridia of sea urchins: ultrastructure and supposed function (Echinodermata, Echinoida) (1992)
    Springer
    Zoomorphology 112 (1992), S. 1-10 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sphaeridia are minute skeletal appendages of the echinoid test which are considered to be sense organs, organs of equilibrium, according to their shape. The sphaeridium forms a functional unit with the tubercle to which it adheres. The tubercle is encircled by a basiepithelial nerve ring of the epidermis. A circle of regularly arranged myocytes stretches from the tubercle to the sphaeridium. The muscles are distant from each other. The myofibrillar processes enter the pore space of the sphaeridial skeleton to which they are anchored by tendons; tendons are absent in the tubercle region. The cell bodies of the myocytes lie opposite to the nerve ring outside the skeleton. In this region the muscle cells and the nerve ring are in contact with each other, their basal laminae fuse. Tensions of the various myocytes are dependent on the position of the top-heavy sphaeridium. The nerve ring contains neurones which are provided with a cilium which lies close to the contact region with the myocytes. This arrangement leads to the assumption that the nerve cells in question have a proprioceptor function. Unique filter cells are present in the pore spaces of the sphaeridium and the tubercle. They possibly detoxicate the extracellular fluid that surrounds the myocytes. Phagocytes loaded with spacious phagosomes are crowded in the adjacent pore spaces. They are possibly extruded via the epidermis. Filter cells and phagocytes have obviously to do with the metabolism within the sphaeridium-tubercle-system.
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    The seminal vesicles of the male grass goby,Zosterisessor ophiocephalus (Teleostei, Gobiidae) (1992)
    Springer
    Zoomorphology 111 (1992), S. 239-248 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The fine structure of the seminal vesicles ofZosterisessor ophiocephalus, the annual changes during the reproductive cycle, and the composition of the secretion are investigated by electron microscopy and by enzyme, polysaccharide, and protein histochemistry. The seminal vesicles are accessory glands of the male reproductive system which produce sialoglycoproteins during the spawning period. They show a significant annual cycle. During the postspawning period they have a regressive phase, followed by a regeneration phase during interspawning and a proliferation phase during prespawning. Possible functions of the seminal vesicle secretion are discussed.
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    URL: http://dx.doi.org/10.1007/BF01633012
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  • 99
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    Photoreceptors with mitochondrial lenses inPogaina suecica (Plathelminthes, Rhabdocoela) (1992)
    Springer
    Zoomorphology 112 (1992), S. 11-15 
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    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The photoreceptors ofPogaina suecica correspond to the type of pigment cup ocelli. Each eye consists of one cup cell and three sensory cells. The most conspicuous differentiations of these eyes are lens elements formed by giant mitochondria densely filled with homogeneous electron-dense material. From electron microscopical findings available to date it is hypothesized that mitochondrial lensing might be an autapomorphy of a taxon comprising the Provorticidae Kirgisellinae, Dalyelliidae and Graffillidae groups which are ascribed to the paraphyletic “Dalyellioida”.
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    URL: http://dx.doi.org/10.1007/BF01632990
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    On the spinning apparatus and the structure of the capture threads ofDeinopis subrufus (Araneae, Deinopidae) (1992)
    Springer
    Zoomorphology 112 (1992), S. 27-37 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The spinnerets and spigots of two adult femaleDeinopis subrufus and one adult male were studied with the scanning electron microscope. The organization of the spinning apparatus corresponds very closely to that of Uloboridae. The capture threads produced by the male while subadult were studied with the light microscope and with the SEM. This study includes the questions of the glandular origin and the functions of the components of these threads. A hypothesis for howD. subrufus constructs capture threads is proposed.
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    URL: http://dx.doi.org/10.1007/BF01632992
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