Submergence is a serious environmental condition that causes large loss in rice production in rain fed lowland and flood affected area. This study evaluated morphological and physiological responses of rice roots to submergence using two tolerant rice genotypes FR13A and Swarna-Sub 1 and two sensitive ones Swarna and IR42. The tolerant genotypes had higher survival rate and less shoot elongation but greater root elongation during submergence than the sensitive ones. After submergence, the tolerant genotypes also had higher root dry weight and more active roots than the sensitive ones. Tolerant genotypes exhibited less root injury, with less malondialdehyde production and slower electrolyte leakage after submergence. Tolerant genotypes also maintained higher concentrations of soluble sugar and starch in roots and shoots and higher chlorophyll retention after submergence than the sensitive ones. Our data showed that root traits such as root activity and root growth are associated with survival rate after submergence. This is probably accomplished through higher energy supply, and membrane integrity is necessary to preserve root function and reduce injury during submergence. These root traits are important for submergence tolerance in rice.

淹没是一种严重的环境条件，在雨水充沛的低地和受洪灾影响的地区，水稻生产将遭受重大损失。本研究使用两种耐性水稻基因型FR13A和Swarna-Sub 1以及两种敏感水稻基因Swarna和IR42评估了水稻根系对淹没的形态和生理响应。与敏感基因型相比，耐性基因型在淹水期间具有较高的存活率和较少的枝条伸长率，但根系伸长率更高。淹没后，耐性基因型的根干重也比敏感基因型高。耐性基因型表现出较少的根部损伤，具有较少的丙二醛生成，且浸没后电解质泄漏较慢。与敏感基因型相比，耐性基因型在根和茎中还保持较高的可溶性糖和淀粉浓度，并在浸没后保持较高的叶绿素保留率。我们的数据表明，根系特性（例如根系活动和根系生长）与淹没后的存活率相关。这可能是通过增加能量供应来实现的，并且膜的完整性对于保持根部功能和减少浸入期间的伤害是必要的。这些根系性状对于水稻的耐淹性很重要。膜的完整性对于保持根部功能和减少浸水时的伤害是必不可少的。这些根系性状对于水稻的耐淹性很重要。膜的完整性对于保持根部功能和减少浸水时的伤害是必不可少的。这些根系性状对于水稻的耐淹性很重要。