Optimization of leaf morphology in relation to leaf water status: A theory

Abstract

The leaf economic traits such as leaf area, maximum carbon assimilation rate, and venation are all correlated and related to water availability. Furthermore, leaves are often broad and large in humid areas and narrower in arid/semiarid and hot and cold areas. We use optimization theory to explain these patterns. We have created a constrained optimization leaf model linking leaf shape to vein structure that is integrated into coupled transpiration and carbon assimilation processes. The model maximizes net leaf carbon gain (NPPleaf) over the loss of xylem water potential. Modeled relations between leaf traits are consistent with empirically observed patterns. As the results of the leaf shape–venation relation, our model further predicts that a broadleaf has overall higher NPPleaf compared to a narrowleaf. In addition, a broadleaf has a lower stomatal resistance compared to a narrowleaf under the same level of constraint. With the same leaf area, a broadleaf will have, on average, larger conduits and lower total leaf xylem resistance and thus be more efficient in water transportation but less resistant to cavitation. By linking venation structure to leaf shape and using water potential as the constraint, our model provides a physical explanation for the general pattern of the covariance of leaf traits through the safety–efficiency trade‐off of leaf hydraulic design.

Changes in elastic modulus, leaf tensity and leaf density during dehydration of detached leaves in two plant species of Moraceae

“…However, M. alba maintained the intracellular water availability just by changing the leaf internal structure (Figure 5). Similar results were reported by Ding et al (2020). The offset effects for intracellular water loss by shrinking mesophyll cells differed between B. papyrifera and M. alba, because the elastic-plastic behavior of their leaves and cells were different.…”

Climate and functional traits jointly mediate tree water‐use strategies

“…These results are consistent with the proposed coordination between plant hydraulics and gas exchange (Meinzer, 2002; Sperry et al, 2002; Mencuccini, 2003; Maherali et al, 2006; Henry et al, 2019) and with the notion that species operate close to their maximum transport capacity sustained by their hydraulic system (Manzoni et al, 2013). Large individual leaf areas were also related to higher G REF , probably as a result of higher leaf hydraulic conductance mediated by wider conduits (Schreiber et al, 2016; Ding et al, 2020), although this relationship may also be driven by the contrasting leaf areas between angiosperms and gymnosperms. The positive association of elevated G REF with deeper roots highlights the requirement of deep rooting to supply water to retain high transpiration rates, and probably arises via the coordination among R depth , Ψ P50 and K s (Mursinna et al, 2018).…”

Identification of Sorghum (Sorghum bicolor (L.) Moench) Genotypes with Potential for Hydric and Heat Stress Tolerance in Northeastern Mexico

“…Photosynthesis is the most affected physiological process caused by hydric stress due to cell turgor pressure loss, which, in turn, reduces the maximum carboxylation rate, causes damage to ATP production, and increases mesophyll resistance to CO 2 diffusion, resulting in stomatal closure and reduced mesophyll conductance [34,35]. Reddy et al [36] provided an ample analysis on biochemical and molecular plant responses to drought.…”