| Abstract: | This paper briefly reviews the physiological mechanisms for improving crop water use and water use efficiency in dryland farming regions of Loess Plateau on the basis of its environmental conditions and progress in crop water relations and the biological basis of water-saving agriculture, especially in non-uniform stomatal closure, ABA effects, communication between root and shoot, and water use efficiency. Root chemical signals about water shortage are feedforward effect which contributes to balanced water relations within the plant compartment of the soil-plant-atmosphere continuum. ABA production is increased in tissues during these stresses, and this causes a variety of physiological effects, including stomata closure in leaves. It is concluded that the root chemical signal ABA is very important to improve the crop water use efficiency in semi-arid area of Loess Plateau. |
