【摘要】 选用4个耐热性不同的籼稻品种,分别于抽穗(始穗后0～10d)和灌浆早期(始穗后11～20d)进行高温(白天温度>33℃)处理,以同期自然温度(白天温度<30℃)为对照,研究高温对产量的影响及其生理机制。结果表明,与对照相比,高温处理显著降低热敏感品种的花粉可育率、受精率,而耐热品种与对照无显著差异。高温胁迫明显降低热敏感品种的结实率,导致产量显著下降,且抽穗期高温处理影响大于灌浆早期处理。高温胁迫显著增加耐热品种黄华占叶片的抗氧化酶活性,对热敏感品种影响不大。高温胁迫显著降低热敏感品种籽粒ATP酶活性,耐热品种结果则相反。高温处理增加两类品种叶片温度和丙二醛(MDA)含量,降低根系活力和叶片光合速率,耐热品种增降的幅度显著小于热敏感品种。在高温胁迫下较低的叶片温度,较强的根系活力和抗氧化保护系统能力及较高的籽粒ATP酶活性是耐热性品种保持较高产量的重要生理原因,也是耐热品种的重要生理特征。更多还原

【Abstract】 Heading/flowering and early grain filling are the most stress-sensitive periods in rice growth and development.However,little is known how heat-stress during these periods affects the yield formation.This study investigated pollen development,yield components,and some physiological parameters under high temperature treatments during heading and early grain filling.Four indica rice cultivars,Shuanggui 1 and T219(heat-sensitive),Huanghuazhan and T226(heat-tolerant),were pot-grown and subjected to high temperature treatments(the mean temperature during the day > 33℃) during heading/flowering(0-10 d after heading) and early grain filling(11-20 d after heading),and the natural temperature(the mean temperature during the day < 30℃) was taken as the control.The results showed that the high temperature treatment significantly reduced pollen and spikelet fertility rate in heat-sensitive cultivars,and not in heat-tolerant cultivars compared with the control.Seed-setting rate was significantly decreased under the high temperature for heat-sensitive cultivars,leading to a significant reduction in grain yield,with a more reduction under the treatment during heading than during early grain filling.It was less affected for heat-tolerant cultivars.The heat-stress treatment significantly increased activities of enzymes involved in antioxidant system in leaves for the heat-tolerant cultivars,while it much less affected for heat-sensitive cultivars.The high temperature significantly reduced ATPase activity in grains for the heat-sensitive cultivars,and the result was reversed for the heat-tolerant ones.The high temperature increased leaf-temperature and malondialdehyde content in leaves,and reduced root activity and the photosynthetic rate of the flag leaf for both kinds of cultivars,but the increase or reduction was less for heat-tolerant cultivars than for heat-sensitive cultivars.These results suggested that lower leaf-temperature,higher root activity,higher ATPase activity in grains,and higher photosynthetic rate and activities of antioxidant enzymes in leaves would be important physiological traits leading to a higher grain yield for a heat-tolerant rice cultivar.更多还原