On the minimum leaf conductance: its role in models of plant water use, and ecological and environmental controls.

Contents Summary 693 I. Introduction 693 II. Comparison of various definitions and measurement techniques of minimum conductance 694 III.

Climate drives vein anatomy in Proteaceae.

Premise Of Study: The mechanisms by which plants tolerate water deficit are only just becoming clear. One key factor in drought tolerance is the ability to maintain the capacity to conduct water through the leaves in conditions of water stress. Recent work has shown that a simple feature of the leaf xylem cells, the cube of the thickness of cell walls divided by the lumen width (t/b)(3), is strongly correlated with this ability.

Leaf hydraulic vulnerability is related to conduit dimensions and drought resistance across a diverse range of woody angiosperms.

Hydraulic dysfunction in leaves determines key aspects of whole-plant responses to water stress; however, our understanding of the physiology of hydraulic dysfunction and its relationships to leaf structure and ecological strategy remains incomplete. Here, we studied a morphologically and ecologically diverse sample of angiosperms to test whether the water potential inducing a 50% loss in leaf hydraulic conductance (P50(leaf)) is predicted by properties of leaf xylem relating to water tension-induced conduit collapse. We also assessed the relationships between P50(leaf) and other traits considered to reflect drought resistance and ecological strategy.

Leaf hydraulics and drought stress: response, recovery and survivorship in four woody temperate plant species.

Efficient conduction of water inside leaves is essential for leaf function, yet the hydraulic-mediated impact of drought on gas exchange remains poorly understood. Here we examine the decline and subsequent recovery of leaf water potential (Psi(leaf)), leaf hydraulic conductance (K(leaf)), and midday transpiration (E) in four temperate woody species exposed to controlled drought conditions ranging from mild to lethal. During drought the vulnerability of K(leaf) to declining Psi(leaf) varied greatly among the species sampled.