Physiological Characteristics of Drought-Sensitive and Drought-Insensitive Rice Maintainers at Florescence under Drought Stress

Drought tolerance traits of 14 widely used Chinese rice maintainers were evaluated at flowering stages using both soil moisture meter and drying soil methods.Based on their drought-stress-caused fertility injury and water-supplying remedy,four ranks were classified as drought-insensitive,drought-resistant,drought-friability and drought-sensitive.Typical drought-insensitive maintainers K22-B,Jin 23-B and typical drought-sensitive maintainers Zhenshan 97-B,Zhong 9-B were selected to suffer drought treatments and to study their physiological responses to drought.The results indicated that the water potential of reproductive organs and flag-leaf transpiration rate were decreased by drought,but when compared with the drought-sensitive maintainers,the drought-insensitive maintainers showed a higher water potential which was decreased relatively slower with drought enhancing.There was no difference of photosynthetic rate between drought-insensitive and drought-sensitive maintainers under normal water condition,but the photosynthetic rate was decreased by drought treatment,and the decreases were bigger for drought-sensitive maintainers than for drought-insensitive maintainers.There was no significant difference between the two types of maintainers in pollen and anther number in drought condition(P0.05),and in pollen-fullness and germination rate on stigma.However,pollen number on stigma and opening degree of anther were decreased more in drought-sensitive maintainers than in drought-insensitive maintainers.Therefore,the drought-insensitive maintainers have a higher photosynthesis and higher photosynthate transportation efficiency than drought-sensitive maintainers.