Phosphorus (P) is a scarce, nonrenewable resource; its acquisition by plants decreases when soil moisture declines, as anticipated under future climate-change scenarios. It is, therefore, important to understand plant responses and adaptations to dual moisture and P limitations, in order to maintain crop productivity and predict plant performance in natural ecosystems. We review current knowledge of the effect of simultaneous water and P shortage on plant function, and identify key knowledge gaps. Plants have developed a range of adaptations to ensure P uptake is adequate to maintain vital functions within a broad range, at least until a certain level of P and/or drought stress is exceeded. Differences in plant growth and amount of P taken up under dual moisture and P limitations greatly depend on the rate of soil drying and wetting, the severity and duration of drought cycles, plant uptake capacity, root system plasticity, presence and magnitude of hydraulic redistribution, P-resorption ability, and soil properties such as waterholding capacity, P diffusion rate, P mineralization and fixation rates, and the activity of arbuscular mycorrhizal (AM) symbioses. During the process of soil drying, both P fertilization and association with AM fungi may increase performance under drought, until a certain level of water stress is exceeded. A small number of previously reported contradictory results probably reflect differences/limitations in experimental approaches. When breeding crop varieties to increase the efficiency of P and water acquisition, and when examining performance of species in natural ecosystems, multiple and interacting processes, from the scale of cellular to whole plant, must be considered. © 2014 Elsevier Inc.
|Journal||Advances in Agronomy|
|Publication status||Published - 2014|