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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Trees 6 (1992), S. 147-155 
    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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  • 2
    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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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Trees 1 (1987), S. 135-138 
    ISSN: 1432-2285
    Keywords: Flowering ; Malus x domestica Borkh ; Water stress ; Defoliation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A series of experiments involving defoliation or water stress at different dates indicated that either of these treatments can make potted apple trees flower a second time in any one year, as long as the treatment is given near the end of July. The results suggest that the reflowering after a period of water stress was primarily a result of the loss of leaves that occurred when the plants were subsequently rewatered. Reflowering normally occurred only if flower primordia had already differentiated at the time of the treatment. There was an indication that in early July water stress was more effective than defoliation at stimulating reflowering.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2285
    Keywords: Carbon balance ; Cones ; Photosynthetic CO2 refixation ; Picea abies ; Respiration ; Seasonal course
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Dark respiration and photosynthetic carbon dioxide refixation in purple and green Picea abies cones were investigated from budbreak to cone maturity. The rate of dark respiration per unit dry weight and CO2 refixation capacity decreased during cone maturation. At the beginning of the growing season, photosynthetic CO2 refixation could reduce the amount of CO2 released by respiration in green and purple cones by 50% and 40%, respectively. The seasonal performance of the components of the cone carbon balance was calculated using information on the seasonal course of respiration, refixation capacity and the light response curves of cone photosynthesis, as well as the actual light and temperature regime in the field. The daily gain of CO2 refixation reached 28%–34% of respiration in green and 22%–26% in purple cones during the first month of their growth, but decreased later in the season. Over the entire growth period refixation reduced carbon costs of cone production in both cone colour polymorphs by 16%–17%.
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  • 5
    ISSN: 1432-2285
    Keywords: Fatty acids ; Heartwood ; Pinus sylvestris ; Sapwood ; Seasonal variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The lipid levels and fatty acid composition of three fractions (free fatty acids, triacylglycerols and sterol/triterpenoid esters) extracted from the sapwood and heartwood of three stems of Pinus sylvestris were determined to investigate both seasonal changes in sapwood and possible metabolic changes related to heartwood formation. Seasonal changes were observed only in the amount of the free fatty acids in the sapwood: the level of free fatty acids was greatest at the beginning and end of the growing season. In the January and March samples the amount of the free fatty acid fraction in the sapwood was very small. The amount of the other fractions remained at the same level throughout the study. Marked seasonal changes in the fatty acid composition occurred only in the free fatty acid fraction of the sapwood: the saturation grade increased during the winter.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Trees 1 (1987), S. 145-150 
    ISSN: 1432-2285
    Keywords: Ozone ; Picea abies ; Stomata ; Wax
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Potted cuttings of a 12-year-old Picea abies tree were fumigated with ozone, 100 or 300 μg O3· m−3 (50 or 150 ppb O3) being added to charcoal-filtered air during the 1985 growing season for a total of 1215 h. The wax structure of ozone-fumigated needles was no different from that of controls. Because flattened wax structures and fused wax fibrils also occurred in controls, these phenomena could not serve as bioindications for the ozone concentrations applied. A smooth layer was found beneath the soluble wax layer and covered needle surface and stomatal openings of ozone-fumigated needles to a greater extent than in controls. Wax quantity was considerably reduced by fumigation with 300 μg O3 · m−3. Leaf pigments (as extracted with the wax) were less abundant in needles treated with 300 μgO3; the smooth layer probably contributed to the impeded extraction of pigments.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Trees 1 (1987), S. 189-190 
    ISSN: 1432-2285
    Keywords: Aphids ; Choline ; Choline oxidase ; Phloem exudate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Choline, a necessary compound in an artificial diet for phloem-feeding aphids, was determined quantitatively in the phloem exudates of 16 tree species. The method used was a combination of choline oxidase action and oxygen determination with an oxygen electrode. Choline was found in all species, the concentration ranging between 36 and 5340 μM.
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  • 8
    ISSN: 1432-2285
    Keywords: Cambial activity ; Frost hardiness ; Phenology ; Salix ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The ultrastructure of cells in the cambial region of Salix dasyclados Wim. (clone 78056) was studied during the development of winter hardiness and the onset of cambial activity in spring. Plants were grown at relative growth rates (RG) of 8% and 12% respectively, resulting in different nitrogen content in the stems. Frost hardiness of the plants was estimated by standardized freezing tests. Plants with a higher nitrogen status ceased growth later and started re-growth earlier in spring than plants with lower nitrogen content. Differences in ability to withstand low temperatures during autumn and spring were found between plants grown in the two nutrient treatments. During the development of frost hardiness in the autumn, the number of meristematic cells in the cambial region decreased. The cessation of meristematic activity was accompanied by cell wall thickening and ultrastructural changes in the cells. Frost hardiness increased from the ability to survive -6° C in October to survival of -80° C at the beginning of December. From November to February the cambial region comprised a layer of 2–3 thick-walled cells with conspicuous ultrastructural features. Starch accumulated in plastids in September, decreased during November to March and then increased again in accordance with changes of frost hardiness. Onset of cambial activity began between the end of March and the beginning of April, as shown by increased vacuolization of meristematic cells and mitotic activity. By April, the starch content had increased and lipolysis was observed. Frost hardiness had decreased, and plants with low and high nitrogen content were able to survive -15° C and -10° C, respectively. After budburst, all axillary shoot parts were damaged at temperatures below-3° C.
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  • 9
    ISSN: 1432-2285
    Keywords: Stomatal conductance ; Water potential ; Urban ; Nutrient deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Growth and water relations of 10-year-old sweet gum (Liquidambar styraciflua L.) street trees were studied in sites with low and high potential evapotranspiration to determine how these differences are integrated by growth and water relations over time. The trees were located in the parking strip between the curb and sidewalk at a partially vegetated urban park and an urban plaza in Seattle, Washington. Crown size, and seasonal and diurnal stomatal conductance and water potential, as well as diurnal air temperature and humidity, were measured over 2 growing seasons. Yearly trunk growth since transplanting was measured from increment cores. Vapor pressure deficits and air temperatures averaged 18% greater at the plaza, but whole-tree water loss appeared to be much lower than the park trees due to more restricted stomatal conductance and crown size. In addition, yearly diameter increment declined progressively once the plaza trees were established in the existing soil several years after transplanting. Lower water potential in the plaza trees indicated greater internal moisture deficits than the park trees, and tissue analysis revealed lower nutritional status, particularly nitrogen. A manipulative study of water and fertilizer to several additional plaza trees showed an interaction between water and nutrient deficiencies in the coarse and shallow soil that apparently limited growth. Furthermore, soil limitations probably interacted with paved surface conditions over time by reducing nutrient recycling from leaf litter, and generating higher vapor pressure deficits that would contribute to prolonged stomatal closure. Restricted growth and water relations status of the plaza trees represented an equilibrium between chronic high-resource demand above ground and limited below ground.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Trees 7 (1993), S. 214-219 
    ISSN: 1432-2285
    Keywords: Pinus sylvestris ; Precipitation ; Temperature ; Wood formation (cambium, radial cell expansion, secondary wall thickening)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary To find the optimal conditions for growth and development of tracheid walls in Scots pine stems the effects of temperature and precipitation on xylem cell production by the cambium, radial cell expansion and secondary wall thickening have been studied. The observations were carried out on 10 specially chosen 50 to 60-year-old trees, growing in central Siberia, over 2 seasons. The data on the number of cells in differentiation zones and mature xylem along radial rows of tracheids, radial and tangential sizes of tracheids and their lumens were used for calculating cambial activity, the rates and durations of cell development in the zones, and both the thickness and cross sectional areas of tracheid walls. The mean day, mean maximal diurnal and mean minimal nocturnal temperatures have been shown by correlation and regression analyses to affect differentially separate stages of cytogenesis. The temperature influenced the initial division the side of xylem and radial cell expansion mainly in May–June, while the influence of precipitation increased in July–August. Throughout all seasons it was the temperature that had the main influence on the biomass accumulation in cell walls. Optimal values of temperature and precipitation for cell production by cambium, radial cell expansion and secondary wall thickening have been calculated. The data are discussed in connection with productivity and quality of wood.
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