根源信号参与调控气孔行为的机制及其农业节水意义

在土壤干旱情况下，根源信号一方面向植物地上部分的长距离传输，为地上部分提供了土壤水分获取能力的测度，另一方面调控气孔开度，抑制蒸腾作用并提高植物的水分利用效率．文中综述了根源信号参与调控植物水分利用的生理机制和理论模型，指出该模型与根系吸水模型、气孔导度模型耦合，能够更好地反映植物叶片对土壤干旱以及大气干旱的响应、评述了在根源信号参与调控植物水分关系的基础上发展的调亏灌溉(RDI)、部分根系干旱(PRD)和控制性交替灌溉(CAI)等有效灌溉手段，有助于合理配置根系层供水量，通过根土相互作用和信号物质的传输，降低蒸腾和提高水分利用效率、另外，根源信号在调控根系生长发育、延缓地上部分生长以调节根冠比例，优化资源分配以利于生殖生长等方面均有所为，为全面提高农田水分利用效率提供节水生理基础。

Mechanism of stomatal regulation by root sourced signaling and its agricultural significance

Under soil drought condition,root sourced signal abscisic acid (ABA) plays an important role in the long distance signaling process,and can be a measurement of soil water availability.ABA is also an effective stomatal closing agent,and acts to reduce transpiration and canopy water loss.This paper briefly introduced the physiological mechanism and theoretical model about the stomatal regulation by root sourced signaling,and indicated that the combination of this model with root water absorption model and stomatal conductance model could be more effective in depicting the response of plant to soil drying and atmospheric drought.In addition,some effective irrigation approaches,such as regulated deficit irrigation (RDI),partial root zone drying (PRD) and controlled alternative irrigation (CAI) were profited from the mechanism of plant water use regulation by the root sourced signaling.These irrigation measures favored to reasonably distribute available soil water in root zone.Root signaling system also played important role in regulating root growth and its development,retarding shoot growth to adjusting root shoot ratio,and optimizing assimilation allocation to favor to improve reproductive development.These processes hold substantial promise for enhancing crop water use efficiency.