scholarly journals Whole tree hydraulic conductance and water loss regulation in Quercus during drought: evidence for stomatal control of embolism?

1996 ◽  
Vol 53 (2-3) ◽  
pp. 197-206 ◽  
Author(s):  
H Cochard ◽  
N Bréda ◽  
A Granier
Keyword(s):  
Water Loss ◽  
Hydraulic Conductance ◽  
Stomatal Control ◽  
Whole Tree

Loss of whole-tree hydraulic conductance during severe drought and multi-year forest die-off

Oecologia ◽  
2014 ◽  
Vol 175 (1) ◽  
pp. 11-23 ◽  
Author(s):  
William R. L. Anderegg ◽  
Leander D. L. Anderegg ◽  
Joseph A. Berry ◽  
Christopher B. Field
Keyword(s):  
Hydraulic Conductance ◽  
Severe Drought ◽  
Whole Tree

Variability in hydraulic architecture and gas exchange of common bean (Phaseolus vulgaris) cultivars under well-watered conditions: interactions with leaf size

1999 ◽  
Vol 26 (2) ◽  
pp. 115 ◽  
Author(s):  
Maurizio Mencuccini ◽  
Jonathan Comstock
Keyword(s):  
Gas Exchange ◽  
Exchange Rates ◽  
Common Bean ◽  
Water Loss ◽  
Leaf Size ◽  
Hydraulic Conductance ◽  
Hydraulic Architecture ◽  
Greenhouse Study ◽  
Whole Plant ◽  
Leaf Level

In a greenhouse study, 12 common bean cultivars from a wide geographical range were compared for their morphological, gas exchange and hydraulic architecture characters. Cultivars bred for cultivation in hot and dry regions had significantly smaller leaves and crowns, but higher stomatal conductances and transpiration rates per unit of leaf area. Short-term variability in gas exchange rates was confirmed using leaf carbon isotope discrimination. A literature survey showed that, although previously unnoticed, the strong inverse coupling between leaf size and gas exchange rates was present in three other studies using the same set of cultivars. Several measures of ‘leaf-specific hydraulic conductance’ (i.e. for the whole plant and for different parts of the xylem pathway) were also linearly related to rates of water loss, suggesting that the coupling between leaf size and gas exchange was mediated by a hydraulic mechanism. It is possible that breeding for high production in hot regions has exerted a selection pressure to increase leaf-level gas exchange rates and leaf cooling. The associated reductions in leaf size may be explained by the need to maintain equilibrium between whole-plant water loss and liquid-phase hydraulic conductance.

Whole-tree water relations of co-occurring mature Pinus palustris and Pinus elliottii var. elliottii

2011 ◽  
Vol 41 (3) ◽  
pp. 509-523 ◽  
Author(s):  
Carlos A. Gonzalez-Benecke ◽  
Timothy A. Martin ◽  
Wendell P. Cropper,
Keyword(s):  
Leaf Area ◽  
Water Use ◽  
Water Relations ◽  
Longleaf Pine ◽  
Pinus Palustris ◽  
Pinus Elliottii ◽  
Hydraulic Conductance ◽  
Slash Pine ◽  
Southeastern Us ◽  
Whole Tree

The natural range of longleaf pine ( Pinus palustris P. Mill.) and slash pine ( Pinus elliottii var. elliottii Engelm.) includes most of the southeastern US Coastal Plain, and there is now considerable interest in using these species for ecological forestry, restoration, and carbon sequestration. It is therefore surprising that little information is currently available concerning differences in their ecological water relations in natural stands. In this study, we compared water use, stomatal conductance at the crown scale (Gcrown), and whole-tree hydraulic conductance of mature pine trees growing in a naturally regenerated mixed stand on a flatwoods site in north-central Florida. We found remarkable similarities between longleaf and slash pine in stored water use, nocturnal transpiration, and whole-tree hydraulic conductance. Mean daily transpiration rate was higher for slash than for longleaf pine, averaging 39 and 26 L·tree–1, respectively. This difference was determined by variations in tree leaf area. Slash pine had 60% more leaf area per unit basal sapwood area than longleaf pine, but the larger plasticity of longleaf pine stomatal regulation partially compensated for leaf area differences: longleaf pine had higher Gcrown on days with high volumetric water content (θv) but this was reduced to similar or even lower values than for slash pine on days with low θv. There was no species difference in the sensitivity of Gcrown to increasing vapor pressure deficit.

scholarly journals Effects of size and microclimate on whole-tree water use and hydraulic regulation inSchima superbatrees

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5164
Author(s):  
Xiao-wei Zhao ◽  
Lei Ouyang ◽  
Ping Zhao ◽  
Chun-fang Zhang
Keyword(s):  
Water Use ◽  
Water Consumption ◽  
Large Scale ◽  
Hydraulic Conductance ◽  
Canopy Conductance ◽  
Wet Season ◽  
Sap Flux Density ◽  
Tree Water Use ◽  
Tree Transpiration ◽  
Whole Tree

BackgroundPlant-water relations have been of significant concern in forestry and ecology studies in recent years, yet studies investigating the annual differences in the characteristics of inter-class water consumption in trees are scarce.MethodsWe classified 15 trees from aSchima superbaplantation in subtropical South China into four ranks using diameter at breast height (DBH). The inter-class and whole-tree water use were compared based on three parameters: sap flux density, whole-tree transpiration and canopy transpiration over two years. Inter-class hydraulic parameters, such as leaf water potential, stomatal conductance, hydraulic conductance, and canopy conductance were also compared.Results(1) Mean water consumption of the plantation was 287.6 mm over a year, 165.9 mm in the wet season, and 121.7 mm in the dry season. Annual mean daily water use was 0.79 mm d−1, with a maximum of 1.39 mm d−1. (2) Isohydrodynamic behavior were found inS. superba. (3) Transpiration was regulated via both hydraulic conductance and stoma; however, there was an annual difference in which predominantly regulated transpiration.DiscussionThis study quantified annual and seasonal water use of aS. superbaplantation and revealed the coordinated effect of stoma and hydraulic conductance on transpiration. These results provide information for large-scale afforestation and future water management.

scholarly journals Mutations in the tomato gibberellin receptors suppresses xylem proliferation and reduces water loss under water-deficit conditions

2020 ◽  
Author(s):  
Natanella Illouz-Eliaz ◽  
Idan Nissan ◽  
Ido Nir ◽  
Uria Ramon ◽  
Hagai Shohat ◽  
...  
Keyword(s):  
Water Deficit ◽  
Water Loss ◽  
Water Status ◽  
Stomatal Closure ◽  
Normal Growth ◽  
Hydraulic Conductance ◽  
Leaf Water Content ◽  
Whole Plant ◽  
Drought Conditions ◽  
Gibberellin Activity

AbstractLow gibberellin (GA) activity in tomato (Solanum lycopersicum) inhibits leaf expansion and reduces stomatal conductance. These lead to lower transpiration and improve water status under transient drought conditions. Tomato has three GIBBERELLIN-INSENSITIVE DWARF1 (GID1) GA receptors with overlapping activities and high redundancy. We have tested whether mutation in a single GID1 reduces transpiration without affecting growth and productivity. CRISPR-Cas9 gid1 mutants were able to maintain higher leaf water content under water-deficit conditions. Moreover, while gid1a exhibited normal growth, it showed reduced whole plant transpiration and better recovery from dehydration. Mutation in GID1a inhibited xylem vessels proliferation that led to lower hydraulic conductance. In stronger GA mutants, we also found reduced xylem vessel expansion. These results suggest that low GA activity affects transpiration by multiple mechanisms; it reduces leaf area, promotes stomatal closure and reduces xylem proliferation and expansion and as a result, xylem hydraulic conductance. We further examined if gid1a perform better than the control M82 in the field. Under these conditions, the high redundancy of GID1s was lost and gid1a plants were semi-dwarf, but their productivity was not affected. Although gid1a did not perform better under drought conditions in the field, it exhibited higher harvest index.HighlightThe loss of the tomato gibberellin receptors GID1s reduced xylem proliferation and xylem hydraulic conductance. These contribute to the effect of low gibberellin activity on water loss under water-deficit condition.

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