Die Gefäßleitung

Hüber, Bruno

doi:10.1007/978-3-642-94678-3_30

Cited by 20 publications

(13 citation statements)

References 65 publications

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“…2d, e). Also, when relating foliage area (A F ) to sapwood area (A S ) in each tree individual (A F /A S , adapted from the reciprocal ' 'Huber value'', Huber 1928, 1956Tyree and Ewers 1991;Tyree and Zimmermann 2002;Fig. 3) and averaging, irrespective of species, across the tree individuals per study site, stand-level ratios were similar in the spruce monoculture and mixed beech/spruce stand of the mountainous site to those of the mixed stand at low elevation.…”

Section: Mountainous and Colline Elevationmentioning

confidence: 93%

Transpiration of forest trees and stands at different altitude: consistencies rather than contrasts?

et al. 2009

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Compared to lowland trees and forests, evidence on water relations at mountainous and sub-alpine sites with their climatic and topographic peculiarities is scarce. On such limited grounds, the outcome of three pilot studies is reviewed, intended to launch working hypotheses for initiating integrative research across the altitudinal gradient of the European Alps. Highlighted are tree transpiration and structural differentiation as well as stand water balance of mono-specific and/or mixed forests with Picea abies, Pinus cembra, Larix decidua and Fagus sylvatica at sub-alpine (timberline ecotone), mountainous and colline elevation. Given the preliminary evidence, treeallometric structures of relevancy for water transport appeared to be independent of elevation and forest type, although timberline trees under open-canopy conditions did not buffer transpiration by internal water storage and had enhanced foliage/sapwood area ratios. Transpiration appeared to depend on site conditions rather than sitedependent adaptation. Canopy transpiration approached 20% of the high seasonal precipitation at the mountainous site, with about 60% being ascribed to run-off, whereas the water budget of the colline site was balanced during summer. The water balance of the subalpine site resembled, at lower precipitation, that of the mountainous site. The derived hypotheses focus on mixed-stand transpiration under altitude-specific topography and moisture regimes, hydraulic adaptation and water demand versus uptake capacity, as this latter ratio is crucial at high altitude in view of expected warming. The clarification of consistencies relative to contrasts indicated by the pilot studies will be challenging across altitudes in view of tree species, forest types and topography.

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Section: Mountainous and Colline Elevationmentioning

confidence: 93%

Transpiration of forest trees and stands at different altitude: consistencies rather than contrasts?

et al. 2009

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“…The fundamentals of water movement in plants have been understood for some time (Dixon & Joly, 1896;Dixon, 1914;Huber, 1928Huber, , 1956Van den Honert, 1948;Scholander, 1972) and has been reviewed by and Boyer (1985). Huber (1928) and Van den Honert (1948) made important contributions to our understanding oflong distance water flow with the application of the Ohm's lawanalogy, and Richter (1973) provided a valuable discussion of some misunderstanding and nnisuse of this principle.…”

Section: Ohm's Lam Analogymentioning

confidence: 99%

“…In small plants the lowest conductance (main resistance) to water flow is in the living tissues of the roots and leaves (Huber, 1956;Kramer & Kozlowski, 1979;Boyer, 1985). In large woody plants, there are many instances documented in which stems are responsible for the lowest conductance to water flow from the roots to leaves (HelJkvist, Richards & Jarvis, 1974;Tyree, Caldwell & Dainty, 1975;Zimmermann, 1978;Tyree et al 1983 ;Ewers & Zimmermann 1984o, 6;Ewers et al 1989).…”

Section: General Featuresmentioning

confidence: 99%

The hydraulic architecture of trees and other woody plants

1991

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summary In this paper, we have reviewed how the hydraulic design of trees influences the movement of water from roots to leaves. The hydraulic architecture of trees can limit their water relations, gas exchange throughout the crown of trees, the distribution of trees over different habitats and, perhaps, even the maximum height that a particular species can achieve. Parameters of particular importance include: (1) the vulnerability of stems to drought‐induced cavitation events because cavitation reduces the hydraulic conductance of stems, (2) the leaf specific conductivity‐of stems because it determines the pressure gradients and most negative water potentials needed to sustain evaporation from leaves, (3) the water storage capacity of tissues because this might determine the ability of trees to survive long drought periods. All of these parameters are determined by the structure and function of anatomical components of trees. Some of the ecological and physiological trade‐offs of specific structures are discussed.

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“…(k h theo , m 4 s 71 MPa 71 ) was calculated with the Hagen-Poiseuille equation (Huber 1956), and related to three different conduit diameter classes (d ¼ 5-15 mm, 15-25 mm and 425 mm). For these calculations, the viscosity coefficient Z H 2 O /208C was set to 1.002 10 73 Pa s (Zwieniecki et al 2001).…”

Section: Anatomical Analysismentioning

confidence: 99%

Influence of salinity on root hydraulic properties of three olive varieties

Rewald

Leuschner

Wiesman

2011

Plant Biosystems - An International Journal Dealing with all As

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Three varieties of olive, Barnea, Arbequina and Proline, varying in salt tolerance, were examined to check the sensitivity of their root system hydraulic properties to salinity. Up to three levels of saline water (EC ¼ 1.2, 4.2 and 7.5 dS m 71 ) were used for long-term irrigation of mature trees. Specific conductivities and embolism rates of roots and branches were estimated by low-pressure conductivity measurement; variability and plasticity of root and branch axial conductivities were calculated. Cross-sections of roots were analysed with respect to xylem anatomy. Barnea, and to a minor degree Arbequina, were found to be more salt-resistant than Proline. Axial root hydraulics under salt stress reacted in a more plastic fashion than branch conductivities. Increased specific conductivities of roots, different plasticities of root hydraulics and modifications in mean conduit diameters can be dismissed as foremost reasons of the observed differences in salt resistance. Instead, a high withinpopulation variability in root conductivity, as found in the salt-tolerant Barnea and Arbequina varieties, coming to full effect in high conductivity roots of Barnea trees, and an increased bimodal distribution of conduit sizes may represent favourable traits to enhance water uptake in soils with heterogeneous salinity.

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Die Gefäßleitung

Cited by 20 publications

References 65 publications

Transpiration of forest trees and stands at different altitude: consistencies rather than contrasts?

Transpiration of forest trees and stands at different altitude: consistencies rather than contrasts?

The hydraulic architecture of trees and other woody plants

Influence of salinity on root hydraulic properties of three olive varieties

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