Advances of root-soil interface effect of phosphorus and water interaction and mechanisms of their efficient use

Objectives Low use efficiencies of phosphorus and water are key limiting factors in intensive farming system. Only under the driving flow by soil water, phosphorus can be absorbed by plants mainly via the root-soil interface. Root-soil interface effects of phosphorus and water interactions are the key points in their efficient use mechanism by crop. This review summarizes recent advances on the mechanisms of interactions of phosphorus and water in root-soil interface and puts forward the rhizosphere management strategies of improving phosphorus and water use efficiency through enhancing their synergy in the plant-soil system. Advances The biological availability of phosphorus and water can be highly affected by root morphological and physiological plasticity, and in turn, root development and rhizosphere physiological processes are also dependent on phosphorus and water supply status. Under an appropriate intensity of water and phosphorus supply, root and rhizosphere process efficiency can be maximized to increase the resource use efficiency. Plant roots can highly respond to not only integral supply strength of phosphorus and water in root zone, but also heterogeneous spatio-temporal distribution of phosphorus and water with changing root morphological and physiological reactions. Phytohormones are closely related to the root plasticity under different phosphorus and water supply. ABA, ethylene, and NO are involved in the regulation processes of plant responses to phosphorus and water supply. Apoplast pH could play an important role in plant regulation processes to cope with water and nutrient deficiency.Prospects Better understanding of synergy effects and regulating mechanisms of phosphorus and water interactions in the root-soil interface is critical to increase use efficiency of phosphorus and water in intensive farming system. Hence, future research directions and emphases are proposed:exploring the mechanism of phosphorus and water interactions and the relationships with phytohormone in the plants, clarifying the interface effects of phosphorus and water interaction processes and their synergy mechanisms in the rhizosphere, and establishing effective rhizosphere management strategies and pathways for increasing phosphorus and water use efficiency in various cropping systems. These advances will provide scientific basis for improving use efficiency and coupling of water and nutrients in intensive crop production through engineering crop root and rhizosphere interaction processes.