花期干旱胁迫钝感与敏感水稻保持系的生理特性

以负压式土壤湿度计和取土烘干法双重监控盆栽试验的土壤水势变化,观测我国14个常用水稻保持系的花期耐旱性,并以干旱胁迫指数人为分为钝感、耐旱、不耐旱与敏感4个耐旱等级,其中K22-B、金23-B为花期干旱胁迫钝感材料,珍汕97-B、中9-B为花期干旱胁迫敏感材料,选此4个典型保持系,研究它们对花期干旱胁迫的生理效应。结果表明:(1)花期干旱胁迫钝感保持系稻株比之敏感保持系稻株剑叶与小穗(颖花、籽粒)具有较高水势,缺水引发水稻器官水势下降,剑叶蒸腾速率也因干旱而下降,但下降程度小于敏感材料。(2)钝感与敏感保持系稻株的光合速率并无明显差异,但因干旱胁迫而下降的程度有明显不同,钝感保持系光合速率下降程度小于敏感材料。(3)花期干旱胁迫钝感与敏感保持系花粉数/花药相似,也不因花期干旱胁迫而明显下降(P0.05),花粉粒充实度与柱头着粒花粉的发芽率也不因花期干旱胁迫而明显变化(P0.05),干旱胁迫敏感保持系稻株的花药开裂度与柱头上花粉着粒数均低于钝感保持系稻株。总之,对花期干旱胁迫钝感的保持系稻株比之敏感保持系稻株经干旱胁迫,保持较高的器官水势与蒸腾速率,有利于花药开裂与柱头着粉受精,维持相对较高的光合效率与物质转移效率,有益受精籽粒灌浆成熟。

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 (P>0.05), 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.