保持系稻株对孕穗期干旱胁迫伤害与补水修复的育性响应

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孕穗期耐旱性,并以干旱胁迫指数人为划分钝感、耐旱、不耐旱与敏感4个等级,其中K22-B、金23-B为孕穗期干旱胁迫钝感材料,珍汕97-B、中9-B为孕穗期干旱胁迫敏感材料,比较研究它们对干旱胁迫伤害的育性响应与补水修复的特征。结果表明,钝感或敏感保持系稻株主穗耐旱性均强于分蘖穗,粒位间强势粒耐旱性均高于弱势粒。这一生物学现象似"植物顶端优势"的逆境生理学表现。比较孕穗期中花粉母细胞减数分裂期、花粉粒形成期与花粉粒充实期的耐旱性,花粉粒充实期耐旱性最弱,花粉母细胞减数分裂期耐旱性较强。孕穗期干旱后补水对结实伤害的恢复效果明显,尤其对耐旱性强的保持系稻株修复更明显,主要途径是降低秕谷率而不降低空壳率,表明干旱胁迫育性损伤是不可逆的。

Fertility Responses to Drought Injury at Booting Stage of Rice Maintainers and Remedy Effects of Water Complement

Drought tolerance traits of 14 widely used Chinese rice maintainers were evaluated at booting stage by using both soil moisture meter and drying soil methods. According to drought stress index, the maintainers were classified as four classes, i.e. 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, Zhong9-B were selected to suffer drought treatments. The results indicated that secondary panicles were more sensitive than primary panicles, and inferior grains were more sensitive than superior grains to drought stress in both drought-insensitive and drought-sensitive maintainers. These drought-tolerant varieties showed an apical dominance in rice panicles. Drought tolerances at three growth stages corresponding to pollen-mother-cell-meiosis, pollen-forming and pollen-filling stages were also compared, showing that pollen-filling stage was most sensitive to drought stress while pollen-mother-cell-meiosis stage was most insensitive to drought stress. Drought-injury at booting stage was ameliorated obviously with water supplement remedy, especially in the inferior grains of drought-insensitive maintainers. Percentage of partially filled grains other than that of abortive grains decreased obviously. It indicates that drought-caused abortion to rice grains is irreversible.