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  • Forest decline  (2)
  • Fine roots  (1)
  • Growth  (1)
  • Xylem development  (1)
  • Springer  (3)
  • 2000-2004
  • 1985-1989  (3)
Sammlung
Schlagwörter
Verlag/Herausgeber
  • Springer  (3)
Erscheinungszeitraum
  • 2000-2004
  • 1985-1989  (3)
Jahr
  • 1
    ISSN: 1432-1939
    Schlagwort(e): Forest decline ; Carbohydrates ; Picea abies ; Growth ; Leaf area index
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary This is the first in a series of papers on the growth, photosynthetic rate, water and nutrient relations, root distribution and mycorrhizal frequency of two Norway spruce forests at different stages of decline. One of the stands was composed of green trees only while the other included trees ranging in appearance from full green crowns to thin crowns with yellow needles. In this paper we compare the growth and carbohydrate relations of the two stands and examine relationships among growth variables in ten plots. The declining stand produced 65 percent of the wood per ground area compared with the stand in which all trees were green because its foliage produced less wood at any level of leaf area index. The difference in foliage efficiency between the sites could not be explained by differeneces in climate, competition or stand structure. The declining stand appeared to have lower carbon gain as indicated by a smaller increase in reserve carbohydrates before bud break, and weaker sinks for carbohydrates as indicated by less use of the stored carbohydrates than the healthy stand. Thus, growth reduction was probably related to factors which affect both photosynthesis and, even more, the sinks for carbohydrate.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1432-1939
    Schlagwort(e): Forest decline ; Ectomycorrhizas ; Fine roots ; Picea abies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The development of root tips and apparent ectomycorrhizas was compared in the Fichtelgebirge (FRG) over one growing season in two 30-year-old Picea abies stands, both on soils derived from phyllite but showing varying symptoms of decline. Visual symptoms of tree decline reflected a lower relative and absolute mycorrhizal frequency, a lower number of ectomycorrhizas per m2 leaf area and an uneven vertical distribution of root tips and ectomycorrhizas. The number of apparent ectomycorrhizas per ground area was correlated with the amount of magnesium, calcium, and ammonium, and the pH in the free-drainage soil solution, and with the molar calcium to aluminium ratio in mineral soil extracts. The foliage concentrations of magnesium and calcium were correlated with the numbers of apparent ectomycorrhizas per m2 leaf or ground area. These observations were used to formulate testable hypotheses concerning the role of the root system and the soil environment in forest decline.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 131 (1986), S. 142-152 
    ISSN: 1615-6102
    Schlagwort(e): Cellulose fibril formation ; Freeze-fracture ; Plasma membrane ; Rosette distribution ; Xylem development
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Germ roots of several higher plants—maize (Zea mays), mung bean (Vigna radiata) and cress (Lepidium sativum)—were freeze-fractured without cryoprotection in order to confirm and extend the informations on frequency and distribution of plasma membrane particle complexes with respect to cellulose formation. In all three objects the PF of developing xylem elements showed rosette accumulations in the regions of wall thickenings. The rosette-distribution pattern ranges from random in a young stage, to more grouped in a probable intermediate stage to strictly localized in later stages. The frequency of rosettes increases from stage to stage. In all three objects the EF of developing xylem elements is relatively poor in particles. Observations of “terminal globules” were rare and undistinct. This leads to the assumption that rosettes on the PF and terminal globules on the EF are not part of the same complex. A comparison of the number and distribution of microtubules underlying the xylem wall thickenings with rosette frequency and distribution leads to the conclusion that there seem to be no direct connections between these two structures. Microtubules may be involved in grouping of rosettes, thus indirectly orienting microfibril deposition. Calculations based on the observed rosette frequencies and the amount of wall material formed indicate that in xylem development 1,000 nm elementary fibril per rosette per minute may be formed and that the active phase of one rosette may be about 10 minutes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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