Linking leaf hydraulic properties, photosynthetic rates, and leaf lifespan in xerophytic species: a test of global hypotheses.

Leaf venation and its hierarchal traits are crucial to the hydraulic and mechanical properties of leaves, reflecting plant life-history strategies. However, there is an extremely limited understanding of how variation in leaf hydraulics affects the leaf economic spectrum (LES) or whether venation correlates more strongly with hydraulic conductance or biomechanical support among hierarchal orders. We examined correlations of leaf hydraulics, indicated by vein density, conduit diameter, and stomatal density with light-saturated photosynthetic rates, leaf lifespan (LLS), and leaf morpho-anatomical traits of 39 xerophytic species grown in a common garden. We found positive relationships between light-saturated, area-based photosynthetic rates, and vein densities, regardless of vein orders. Densities of leaf veins had positive correlations with stomatal density. We also found positive relationships between LLS and vein densities. Leaf area was negatively correlated with the density of major veins but not with minor veins. Most anatomical traits were not related to vein densities. We developed a network diagram of the correlations among leaf hydraulics and leaf economics, which suggests functional trade-offs between hydraulic costs and lifetime carbon gain. Leaf hydraulics efficiency and carbon assimilation were coupled across species. Vein construction costs directly coordinated with the LLS. Our findings indicate that hierarchal orders of leaf veins did not differ in the strength of their correlations between hydraulic conductance and biomechanical support. These findings clarify how leaf hydraulics contributes to the LES and provide new insight into life-history strategies of these xerophytic species.

Li F ，McCulloh KA ，Sun S ，Bao W ... -  《-》

How do leaf veins influence the worldwide leaf economic spectrum? Review and synthesis.

Sack L ，Scoffoni C ，John GP ，Poorter H ，Mason CM ，Mendez-Alonzo R ，Donovan LA ... -  《-》

Relating Stomatal Conductance to Leaf Functional Traits.

Kröber W ，Plath I ，Heklau H ，Bruelheide H ... -  《Jove-Journal of Visualized Experiments》

Safety-efficiency tradeoffs? Correlations of photosynthesis, leaf hydraulics, and dehydration tolerance across species.

The tradeoffs between carbon assimilation and hydraulic efficiencies and drought-tolerance traits on different scales are considered a central tenet in plant ecophysiology; however, no clear tradeoff between these traits has emerged in previous studies using woody angiosperms or grasses by investigating several hydraulic tolerance and gas exchange efficiency and/or water transport efficiency traits. In this study, we measured numerous efficiency, resistance, and leaf anatomical traits, including light-saturated gas exchange, leaf hydraulic vulnerability curves, pressure-volume curves, and leaf anatomical traits, in seven species with diverse drought tolerance. A substantial variation in photosynthetic rate, stomatal conductance, mesophyll conductance, maximum leaf hydraulic conductance (Kmax), mesophyll anatomical traits, and leaf vein density across species was observed. Both mesophyll conductance and Kmax were related to leaf anatomical traits, but other gas exchange traits were decoupled from Kmax. Although the efficiency and tolerance traits varied widely across estimated species, no clear trade-off between safety traits and efficiency traits was observed. These findings suggested that postulated leaf-level drought tolerance-carbon assimilation and hydraulic efficiency tradeoff does not exist among distant species and that the fact that different leaf anatomical traits determine efficiency and tolerance capacity might contribute to the lack of such tradeoffs.

Xiong D ，Flexas J 《-》

Leaf maximum photosynthetic rate and venation are linked by hydraulics.

Brodribb TJ ，Feild TS ，Jordan GJ 《-》