Analysis of depth effects on maintenance of water-uptake ability of rice root system in relation to drought resistance under rewatering conditions

在本研究中，研究了复水条件下水稻根系吸水能力的深度效应与根系发育和导水率的关系。土壤深层根系发育迅速是品种在复水期获得较高水分恢复能力的重要特征之一。抗旱性与根系吸水能力有关，胁迫条件下，根系细胞壁中木质素和纤维素含量较高，通过增加根系的硬度来支持吸水能力。在水分胁迫条件下，土壤深层根系的水势高于表层。在复水条件下，通过较高的水分胁迫恢复率获得足够的底物，抗旱品种的根系发育和导水率受到的限制比敏感品种小。

In this study, the depth effects on water-uptake ability of rice root system were investigated in relation to root system development and hydraulic conductance under rewatering condition.1. The rapid root system development in the deeper part of soil is one of the most important traits of cultivars in order to have higher recovery from water stress during rewatering period.2. The drought resistance is related to water-uptake ability, and high contents of lignin and cellulose in the root cell wall that support the water-uptake ability by increasing the rigidity of roots under stressed conditions.3. Root systems in the deeper part of soil experience higher water potential than in the surface layer under water stressed condition. Given adequate substrate by higher recovery from water stress under following rewatering condition, their root system development and hydraulic conductance of drought resistance varieties are less restricted than sensitive varieties.