Leaf Water Transport: A Core System in the Evolution and Physiology of Photosynthesis
In most terrestrial ecosystems, water availability is the principal governor of primary productivity. Vascular plants can only sustain high rates of photosynthetic activity by transporting enormous quantities of water from reserves in the soil to the sites of gas exchange in leaves to prevent desiccation of photosynthetic tissues. This demand for water requires plants to invest in a vascular system that begins as a simple pipe system in roots and branches and terminates in a sophisticated network of veins in the leaf. This chapter will examine the tight linkage between photosynthesis and the efficiency of water transport in leaves, explaining how plants use a non-living network of xylem to deliver water under high tension to evaporating cells. We explore how plants achieve high efficiency in water delivery by developing an intricately branched system of leaf veins as a means of piping water close to the stomatal layer, and how evolution has shaped the venation of higher plant species as densely reticulated networks.
difference in water potential
flux rate of water
hydraulic conductance of the leaf
Authors gratefully acknowledge the support of the Australian Research Council who supported TJB with a Future Fellowship during the period of writing this chapter.
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