Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Humidity responses in forest trees: Precautions in thermal scanning surveys (1985)
    Springer
    Meteorology and atmospheric physics 36 (1985), S. 83-98 
    Details
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Description / Table of Contents: Zusammenfassung Die Arbeit behandelt ein spezielles pflanzenphysiologisches Phänomen, das für eine Reihe meteorologischer Fragestellungen, insbesondere für die Interpretation von Falschfarben-Luftbildern und von Temperaturscanner-Daten relevant ist. Über die stomatäre Steuerung der Transpiration können Pflanzen direkt auf das Wasserdampfkonzentrationsgefälle zwischen Blatt und umgebender Luft reagieren. Auf Grund der Empfindlichkeit der Stomata auf die Luftfeuchte in der Blattumgebung kann es zu einer Einschränkung der Transpiration kommen, ohne daß dies mit blattinternem Wasser streß verknüpft sein muß. Beispiele für das Stomataverhalten von 8 verschiedenen Baumarten, von denen 7 wichtige Elemente von Wäldern der temperaten Zone sind (2 aus der Südhemisphäre), werden angeführt. Es wird gezeigt, daß verschiedene Arten ganz unterschiedlich auf Luftfeuchtegradienten reagieren können. Diese Ergebnisse werden an Hand der Baumtypen und der natürlichen Umweltbedingungen diskutiert. Es erscheint unberechtigt, auf Grund der Transpirationsrate von Baumkronen (etwa über Meßdaten von einem Temperaturscanner) Schlüsse bezüglich der Wasserversorgung der Blätter zu ziehen, ohne das spezifische physiologische Verhalten der Bäume zu kennen. Verminderte Transpirationsraten, die sich in erhöhter Blattemperatur niederschlagen können, sind nicht notwendigerweise ein Hinweis auf Wasserverknappung oder pathogen induzierten Wasserstreß.
    Notes: Summary This paper deals with a special plant physiological phenomenon that is relevant to many meteorological considerations and in particular to the interpretation of false colour aerial photographs and data of temperature scanners. It is well established that plants are able to respond to the vapour concentration gradient between leaf and ambient air by stomatal control of transpiration. Stomatal sensitivity to external humidity conditions can cause a decline in transpirational vapour flux without concommitant symptoms of plant water stress. Examples are provided for the stomatal behaviour of 8 different tree species, 7 of which are prominent components of forests in the temperate zone (2 from the Southern Hemisphere). It is shown that different species exhbibit marked differences in their response to the vapour concentration gradient. These responses are discussed in relation to tree type and the natural environment. It is concluded that it is unjustified to draw conclusions about tree water status from estimates of canopy transpiration (e.g. via data from a thermal scanner) without knowledge of the specific physiological behaviour of the very tree species. Comparatively reduced rates of transpiration are not necessarily an indication of water shortage or pathogen induced water stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269459
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    A global survey of carbon isotope discrimination in plants from high altitude (1988)
    Springer
    Oecologia 74 (1988), S. 623-632 
    Details
    ISSN: 1432-1939
    Keywords: Photosynthesis ; δ 13C ; Alpine ecology ; Atmospheric CO2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Carbon 13/12 isotope ratios have been determined from leaves of a hundred C3 plant species (or ecotypes) from all major mountain ranges of the globe, avoiding drought stressed areas. A general increase in 13C content was found with increasing altitude, i.e. overall discrimination against the heavy isotope is reduced at high elevation. The steepest decline of discrimination is observed in taxa typically ranging to highest elevations (e.g. the genus Ranunculus). Mean δ 13C for all samples collected between 2500 and 5600 m altitude is-26.15‰ compared to the lowland average of-28.80‰ (P〈0.001). Forbs from highest elevations reach-24‰. According to theory of 13C discrimination this indicates decreasing relative limitation of carbon uptake by carboxylation. In other words, we estimate that the ratio of internal to external partial pressure of CO2 (p i /p a )in leaves of high elevation plants is lower than in leaves of low altitude. These results confirm recent gas exchange analyses in high and low elevation plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380063
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Dry matter partitioning and root length/leaf area ratios in herbaceous perennial plants with diverse altitudinal distribution (1987)
    Springer
    Oecologia 74 (1987), S. 411-418 
    Details
    ISSN: 1432-1939
    Keywords: Alpine ecology ; Shoot/root ratio ; Fine roots ; Rooting density ; Climate stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Partitioning patterns in 22 exclusively low and 27 exclusively high altitude perennial herbaceous species were examined in order to test the hypothesis that plants of high altitudes allocate more dry matter to below-ground parts and in particular to storage organs, than typical low altitude plants. Our results raise some doubts about the general validity of this hypothesis. The mean fractions of total dry matter allocated to green leaves (22±2% s.e. at low and 24±2% at high altitude) and special storage organs (28±4% at both altitudes) do not differ significantly among sites. The mean relative portions of total dry matter allocated to above-ground plant parts amount to 57±3% at low and 42±3% at high elevation (P=0.002) and differ less than often assumed. The greater below-ground fraction at high altitude results from reduced stem and proportionally increased fine root compartments. At high altitude specific root length is increased by 50% and mean individual rooting density is tripled. Fine root length per unit leaf area is 4.5 times greater (P〈0.001). However, interspecific variation in all these quantities is considerable and species with quite contrasting partitioning patterns coexist at both elevations. This suggests that the success of perennial herbaceous plants at high elevations does not necessarily depend on a large below ground biomass fraction. The increased fine root length at high altitude may substitute for reduced mycorrhizal infection. Figure 1 provides a graphical summary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378938
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The dynamics of leaf extension in plants with diverse altitudinal ranges (1987)
    Springer
    Oecologia 72 (1987), S. 279-283 
    Details
    ISSN: 1432-1939
    Keywords: Poa ; Leaf extension ; Altitude ; Temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The dynamics of leaf extension in five species of Poa were studied with electronic auxanometers (LVDTs) along an elevational gradient from 600 to 3200 m in the Austrian Alps. Extension rates peak at midday at all elevations and rates at 20°C are almost twice as high at low elevation as compared with those from the highest sites. The low temperature threshold for leaf extension drops by 7 K over this range of elevation, with plants from the highest sites showing some extension around freezing point. Thus, there is a substantial adaptive adjustment in response of leaf extension to declining mean temperatures with increasing altitude, which is not paralleled by known altitudinal trends of photosynthetic responses in herbaceous plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379279
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The dynamics of leaf extension in plants with diverse altitudinal ranges (1986)
    Springer
    Oecologia 70 (1986), S. 222-226 
    Details
    ISSN: 1432-1939
    Keywords: Leaf extension ; Temperature-Altitude ; alpine habitats ; Achillea millefolium ; Agrostis stolonifera ; Poaalpina ; Rumex arifolius ; Asteraceae ; Poaceae ; Polygonaceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Rates of leaf extension have been studied with electronic auxanometers at mid-altitude in the Austrian Alps, where both low and high altitude species co-occur. The results demonstrate a clear differentiation in the temperature responses of extension between these two groups of species. For the low or mid-altitude species of Achillea millefolium, Agrostis stolonifera, Poa alpina and Rumex arifolius, the average rate of leaf extension increases from 0.1 to 0.4 mm h-1 between 10 and 20° C. For the high-alpine species of Achillea erba-rotta ssp moschata, Poa alpina ssp vivipara and Polygonum viviparum the average rate of leaf extension was considerably lower from 0.016 to 0.064 mm h-1, between 10 and 20° C. Leaf extension in the lowland species was not observed below an average temperature of about 5° C, whilst no limit was observed for the upland species, down to a temperature of about 0° C. In the cases of the dicotyledons that were studied, leaf plus petiole shrinkage was observed to occur, for as much as 2 to 4 h, during periods of high water vapour pressure deficits. This response was not observed for the monocotyledons. The observations of leaf extension show that daily totals of extension in species from high altitudies will be much less sensitive to day, to day variations in local climate than will the species from low altitudes. The lowland species will have higher rates of extension during clear and warm weather conditions but lower rates in cold, cloudy weather.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379243
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Stomatal responses and water relations of Eucalyptus pauciflora in summer along an elevational gradient (1985)
    Springer
    Oecologia 66 (1985), S. 443-455 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The spatial and temporal variation of lead conductance (g) in Eucalyptus pauciflora was analysed with respect to photon flux area density (I), temperature (T), water vapour concentration deficit (Δw), and leaf water potential (Ψ) at four different sites between 940 m and 2,040 m altitude in the Snowy Mountains of south-eastern Australia. Along this altitudinal gradient the precipitation/evaporation ratio increases from 1 to 4. The results show that gas diffusion in this tree species is primarily controlled by I and Δw at all sites, independently of the specific soil moisture regime. Even under dry midsummer conditions with predawn leaf water potentials of-1 MPa at the lowest altitude, Ψ had no striking effect on g. The humidity threshold for the onset of stomatal closure does not vary greatly between the study sites (12.2±1.3 Pa kPa-1). The highest and lowest values observed for Ψ, the osmotic potential at water saturation (from pressure/volume curves), the mean and maximum g and stomatal dentity, all increase with elevation. The highest (least negative) osmotic potentials were obtained at all sites in midsummer. It therefore appears that there is no osmotic adjustment to drought in the seasonal course. The maximum difference between osmotic potentials obtained at the lowest and highest sites is 0.46 MPa. In general osmotic potential varies less than has been reported for other plant species exposed to varying water regimes. This may be the consequence of the pronounced feed-forward response of the stomata to evaporative demand, which led to only moderate tissue desiccation, never exceeding the turgor loss point. E. pauciflora is a tree species with a very conservative utilisation of soil water, which adjusts to drought via stomatal control of water loss, rather than via osmotic properties. These results explain previous reports of the comparatively high susceptibility of E. pauciflora to severe drought and its positive influence on the hydrological balance of mountain ecosystems in the Australian Alps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378313
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The nutritional status of plants from high altitudes (1989)
    Springer
    Oecologia 81 (1989), S. 379-391 
    Details
    ISSN: 1432-1939
    Keywords: Nitrogen ; Specific leaf area ; Partitioning ; Life form ; Photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Are plants at high altitudes short in nutrients? In order to answer this question the mineral nutrient content of leaves from over 150 plant species from 9 different mountain areas of all major climatic zones were analyzed (Kjeldahl nitrogen in all, phosphate in half of the samples, K, Mg, Mn, Ca in the Alps only). The majority of data are from herbaceous perennials, but shrubs and trees were studied as well. N-partitioning was studied in 45 herbaceous species from contrasting altitudes in the Alps. The survey falls into three categories: (1) comparisons of whole communities of species from contrasting altitudes, (2) analysis of altitudinal gradients, and (3) additional collections from high altitude sites alone. Unlike the other mineral nutrients, nitrogen content follows consistent altitudinal and latitudinal trends. The higher altitude sample always had higher N content per unit leaf area, irrespective of life form, wherever comparable plants (the same or related species) were investigated at contrasting altitudes. N content per unit dry weight (%) increased with altitude in herbaceous plants (in some species 〉4%), but was remarkably stable in evergreen woody plants (around 1%). The mean fraction of total plant N allocated to leaves of herbaceous plants in the Alps was the same at low and high altitude (1/3 of total). Leaf N (%) from the regional upper limits of higher plant life reveals a latitudinal decrease from subarctic to equatorial mountains, which may be related to the duration of annual leaf activity. Since mean N content per leaf area hardly differs between the uppermost sites, life span expectation (sink-duration) seems to control carbon investments rather than N input per leaf area. The growth of leaves at high altitude seems to be controlled in a way that leads to comparatively high nutrient contents, which in turn support high metabolic activity. Inherent developmental growth constraints inhibit nutrient dilution in the plant body and thus defy the application of classical concepts of plant-nutrient versus soil-nutrient relations developed for lowlands and in particular for cultivated plants. The results re-emphasize the global significance of links between nitrogen content, leaf sclerophylly, leaf longevity and photosynthetic capacity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377088
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Altitudinal variation in stomatal conductance, nitrogen content and leaf anatomy in different plant life forms in New Zealand (1986)
    Springer
    Oecologia 69 (1986), S. 577-588 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This study is part of a series of investigations on the influence of altitude on structure and function of plant leaves. Unlike most other mountain areas, the Southern Alps of New Zealand provide localities where physiologically effective moisture stress occurs neither at high nor at low elevation, but the changes in temperature and radiation with elevation are similar or even steeper than in most other regions. In comparison with results from other mountains, where moisture may impair plant functioning at low elevation, this study allows an estimation of the relative role of water for the expression of various leaf features typically associated with alpine plants. Maximum leaf diffusive conductance (g), leaf nitrogen content (LN), stomatal density (n) and distribution, as well as area (A), thickness (d) and specific area (SLA) of leaves were studied. Three different plant life forms were investigated over their full altitudinal range (m): trees, represented by Nothofagus menziesii (1,200 m), ericaceous dwarf shrubs (1,700 m), and herbaceous plants of the genus Ranunculus (2,500 m). In all three life forms g, LN, and n increased, while SLA and A decreased with elevation. Recent investigations have found similar trends in other mountains from the temperate zone, but the changes are larger in New Zealand than elsewhere. Herbs show the greatest differences, followed by shrubs and then trees. It is concluded that g is dependent upon light climate rather than water supply, whereas SLA and related structural features appear to be controlled by the temperature regime, as they show similar altitudinal changes under different light and moisture gradients. The higher leaf nitrogen content found at high elevations in all three life forms, suggests that metabolic activity of mature leaves is not restricted by low nitrogen supply at high altitude. In general, the leaves of herbaceous plants show more pronounced structural and functional changes with altitude than the leaves of shrubs and trees.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410366
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...