Water Relations Are Fundamental to Sustaining Plant Life

作者：James R. Ehleringer, Russell K. Monson · 年份：2025 · DOI：10.1201/9781315118017-12 · 研究领域：Plant Physiology and Cultivation Studies

This chapter explores the unique characteristics of water as a crucial plant resource. The polar nature of water molecules endows them with distinctive physical properties essential for plant function. The chapter describes the movement of water vapor out of leaves through stomata and the transport of liquid water from the soil, through roots and stem xylem tissues, into leaves and then out to the atmosphere. Pressure gradients along the xylem conducting system drive this movement, though the xylem water column exists in a metastable state and can cavitate under stress. Additionally, soil texture and water potential are discussed as key factors influencing the availability of water to plant roots. The integration of seasonal soil water supply and diurnal atmospheric vapor pressure demand further elucidates plant–water relations, providing a comprehensive understanding of how plants manage water resources across the soil–plant–atmosphere continuum and across diurnal to weekly timescales.