When smaller is better: leaf hydraulic conductance and drought vulnerability correlate to leaf size and venation density across four Coffea arabica genotypes

2014 ◽  
Vol 41 (9) ◽  
pp. 972 ◽  
Author(s):  
Andrea Nardini ◽  
Eele Õunapuu-Pikas ◽  
Tadeja Savi
Keyword(s):  
Gas Exchange ◽  
Exchange Rates ◽  
Coffea Arabica ◽  
Leaf Size ◽  
Hydraulic Conductance ◽  
Climate Change Scenarios ◽  
Drought Vulnerability ◽  
Leaf Hydraulic Conductance ◽  
Vein Density ◽  
Major Vein

Leaf hydraulic conductance (Kleaf) and drought vulnerability in terms of leaf water potential inducing 50% loss of Kleaf (P50), were assessed in four genotypes of Coffea arabica L. We tested three hypotheses: (1) leaf P50 is lower in small leaves with higher vein densities; (2) lower P50 translates into lower Kleaf, limiting gas exchange rates and higher leaf mass per unit area (LMA); (3) P50 values are coordinated with symplastic drought tolerance. We found partial support for Hypotheses 1 and 3, but not for Hypothesis 2. Significant correlations existed among leaf size, vein network and drought resistance. Smaller leaves displayed higher major vein density, higher Kleaf and more negative P50. Kleaf was correlated with leaf gas exchange rates. A negative relationship was observed between Kleaf and LMA, whereas P50 was found to be positively correlated with LMA. Across coffee genotypes, reduced leaf surface area and increased vein density shifts P50 towards more negative values while not translating into higher LMA or lower Kleaf. Breeding crop varieties for both increased safety of the leaf hydraulic system towards drought-induced dysfunction and high gas exchange rates per unit of leaf area is probably a feasible target for future adaptation of crops to climate change scenarios.

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.

scholarly journals Gas exchange recovery following natural drought is rapid unless limited by loss of leaf hydraulic conductance: evidence from an evergreen woodland

2017 ◽  
Vol 215 (4) ◽  
pp. 1399-1412 ◽  
Author(s):  
Robert P. Skelton ◽  
Timothy J. Brodribb ◽  
Scott A. M. McAdam ◽  
Patrick J. Mitchell
Keyword(s):  
Gas Exchange ◽  
Hydraulic Conductance ◽  
Leaf Hydraulic Conductance

Stomatal conductance scales with petiole xylem traits in Populus genotypes

2016 ◽  
Vol 43 (6) ◽  
pp. 553 ◽  
Author(s):  
Caroline A. Brocious ◽  
Uwe G. Hacke
Keyword(s):  
Stomatal Conductance ◽  
Current Knowledge ◽  
Hybrid Poplar ◽  
Leaf Size ◽  
Exchange Capacity ◽  
Vein Density ◽  
Wide Range ◽  
Major Vein ◽  
Size And Morphology

Progress has been made in linking water transport in leaves with anatomical traits. However, most of our current knowledge about these links is based on studies that sampled phylogenetically distant species and covered a wide range of leaf size and morphology. Here we studied covariation of leaf anatomical traits and hydraulic capacity in five closely related hybrid poplar genotypes. Variation in stomatal conductance and leaf hydraulic conductance was not linked to vein density or other anatomical lamina properties. A strong correlation was found between stomatal conductance and the transport capacity of the petiole, estimated from the diameter and number of xylem vessels. An inverse relationship existed between leaf size and major vein density. The role of bundle sheath extensions is discussed. Our data suggests that petiole xylem is an important predictor of gas exchange capacity in poplar leaves.

Water transport from stem to stomata: the coordination of hydraulic and gas exchange traits across 33 subtropical woody species

2019 ◽  
Vol 39 (10) ◽  
pp. 1665-1674 ◽  
Author(s):  
Xiaorong Liu ◽  
Hui Liu ◽  
Sean M Gleason ◽  
Guillermo Goldstein ◽  
Shidan Zhu ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Transport ◽  
Explanatory Power ◽  
Woody Species ◽  
Hydraulic Conductance ◽  
Co2 Assimilation ◽  
Leaf Hydraulic Conductance ◽  
Net Co2 Assimilation ◽  
Leaf Tissues

Abstract Coordination between sapwood-specific hydraulic conductivity (Ks) and stomatal conductance (gs) has been identified in previous studies; however, coordination between leaf hydraulic conductance (Kleaf) and gs, as well as between Kleaf and Ks is not always consistent. This suggests that there is a need to improve our understanding of the coordination among hydraulic and gas exchange traits. In this study, hydraulic traits (e.g., Ks and Kleaf) and gas exchange traits, including gs, transpiration (E) and net CO2 assimilation (Aarea), were measured across 33 co-occurring subtropical woody species. Kleaf was divided into two components: leaf hydraulic conductance inside the xylem (Kleaf-x) and outside the xylem (Kleaf-ox). We found that both Kleaf-x and Kleaf-ox were coordinated with gs and E, but the correlations between Kleaf-ox and gs (or E) were substantially weaker, and that Ks was coordinated with Kleaf-x, but not with Kleaf-ox. In addition, we found that Ks, Kleaf-x and Kleaf-ox together explained 63% of the variation in gs and 42% of the variation in Aarea across species, with Ks contributing the largest proportion of explanatory power, whereas Kleaf-ox contributed the least explanatory power. Our results demonstrate that the coordination between leaf water transport and gas exchange, as well as the hydraulic linkage between leaf and stem, were weakened by Kleaf-ox. This highlights the possibility that water transport efficiencies of stem and leaf xylem, rather than that of leaf tissues outside the xylem, are important determinants of stomatal conductance and photosynthetic capacity across species.

scholarly journals Water supply and demand remain coordinated during breakdown of the global scaling relationship between leaf size and major vein density

2016 ◽  
Vol 214 (1) ◽  
pp. 473-486 ◽  
Author(s):  
Julio V. Schneider ◽  
Jörg Habersetzer ◽  
Renate Rabenstein ◽  
Jens Wesenberg ◽  
Karsten Wesche ◽  
...  
Keyword(s):  
Water Supply ◽  
Supply And Demand ◽  
Leaf Size ◽  
Vein Density ◽  
Scaling Relationship ◽  
Major Vein ◽  
Global Scaling ◽  
Water Supply And Demand

scholarly journals Decline of Leaf Hydraulic Conductance with Dehydration: Relationship to Leaf Size and Venation Architecture

2011 ◽  
Vol 156 (2) ◽  
pp. 832-843 ◽  
Author(s):  
Christine Scoffoni ◽  
Michael Rawls ◽  
Athena McKown ◽  
Hervé Cochard ◽  
Lawren Sack
Keyword(s):  
Leaf Size ◽  
Hydraulic Conductance ◽  
Leaf Hydraulic Conductance

scholarly journals Leaf energy balance modelling as a tool to infer habitat preference in the early angiosperms

2015 ◽  
Vol 282 (1803) ◽  
pp. 20143052 ◽  
Author(s):  
Alexandra P. Lee ◽  
Garland Upchurch ◽  
Erik H. Murchie ◽  
Barry H. Lomax
Keyword(s):  
Gas Exchange ◽  
Exchange Rates ◽  
Habitat Preference ◽  
Thermal Tolerance ◽  
Leaf Size ◽  
Cooling Capacity ◽  
Basal Angiosperms ◽  
Weedy Species ◽  
Key Aspects ◽  
Slow Growing

Despite more than a century of research, some key aspects of habitat preference and ecology of the earliest angiosperms remain poorly constrained. Proposed growth ecology has varied from opportunistic weedy species growing in full sun to slow-growing species limited to the shaded understorey of gymnosperm forests. Evidence suggests that the earliest angiosperms possessed low transpiration rates: gas exchange rates for extant basal angiosperms are low, as are the reconstructed gas exchange rates for the oldest known angiosperm leaf fossils. Leaves with low transpirational capacity are vulnerable to overheating in full sun, favouring the hypothesis that early angiosperms were limited to the shaded understorey. Here, modelled leaf temperatures are used to examine the thermal tolerance of some of the earliest angiosperms. Our results indicate that small leaf size could have mitigated the low transpirational cooling capacity of many early angiosperms, enabling many species to survive in full sun. We propose that during the earliest phases of the angiosperm leaf record, angiosperms may not have been limited to the understorey, and that some species were able to compete with ferns and gymnosperms in both shaded and sunny habitats, especially in the absence of competition from more rapidly growing and transpiring advanced lineages of angiosperms.

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