Aquaporins and plant transpiration

Although transpiration and aquaporins have long been identified as two key components influencing plant water status, it is only recently that their relations have been investigated in detail. The present review first examines the various facets of aquaporin function in stomatal guard cells and shows that it involves transport of water but also of other molecules such as carbon dioxide and hydrogen peroxide. At the whole plant level, changes in tissue hydraulics mediated by root and shoot aquaporins can indirectly impact plant transpiration. Recent studies also point to a feedback effect of transpiration on aquaporin function. These mechanisms may contribute to the difference between isohydric and anisohydric stomatal regulation of leaf water status. The contribution of aquaporins to transpiration control goes far beyond the issue of water transport during stomatal movements and involves emerging cellular and long-distance signalling mechanisms which ultimately act on plant growth. This review examines the relation between aquaporins and transpiration, two key components influencing plant water status. Aquaporins transport water and other molecules such as carbon dioxide and hydrogen peroxide during stomatal movements. The function of aquaporins in roots and shoots is also intimately linked to transpiration. Thus, aquaporins contribute to emerging cellular and long-distance signalling mechanisms which ultimately act on plant growth.