In recent years, regulated deficit irrigation and deficit irriga-tion, which are important measures of agricultural water-saving,have been widely adopted in crop, vegetable and fruit produc-tion . The theoretical basis for benefits of regu-lated deficit irrigation and deficit irrigation is that plants canundergo compensatory growth upon post-drought rewatering. Inother words, plants display reduced growth under drought stressbut increases their growth rate when water supply becomes avail-able. The reduced growth caused by drought stress is compensatedor exceeded by rapid growth under sufficient water supply. Plantroots are vitally important to growth because they play a key rolein organic substance storage, water and inorganic nutrient absorp-tion and abscisic acid (ABA) and cytokinin synthesis . Thus under-standing how roots affect compensatory growth upon post-droughtrewatering in plants and the factors involved may provide usefulinformation for improving agricultural water-saving.