高低温对水稻Ⅱ优6078开花结实的影响研究

EFFECTS OF HIGH AND LOW TEMPERATURE ON FLOWERING STAGE OF RICE SUBSPECIES HYBRID Ⅱ YOU 6078

在人工气候箱内观察了高低温度对籼粳稻亚种间重穗型组合Ⅱ优６０７８和对照汕优６３开花结实的影响。结果表明，在高低温度下，两组合结实率均与温度呈二次曲线分布。Ⅱ优６０７８开花结实期抗高温能力弱于汕优６３，抗低温能力强于汕优６３。高温对两组合结实率的影响依次为开花期＞减数分裂期＞花粉充实期。结实率不低于８５％的临界高温（１ｄ内持续６ｈ），Ⅱ优６０７８为３１．８℃，汕优６３为３３．０℃；结实率不低于７０％的临界低温（日均温持续３ｄ），Ⅱ优６０７８为１８．１℃，汕优６３为１８．９℃。ＳＯＤ酶活性测定表明，两组合抗高、低温能力趋势与上述结果一致。

The effects of high and low temperature on flowering stage of rice subspecies hybrid Ⅱ You 6078 and Shan You 63 as check were observed in growth chamber. Results showed that the resistance of Ⅱ You 6078 to high temperature was weaker than that of the check, while its low temperature resistance was higher. The period of flowering was the most vulnerable to high temperature, then comes the period of meiosis, lastly the period of inflation. High temperature in the period of meiosis led to a high rate of blighted grains rather than a high rate of empty grains in the period of flowering given the same high temperature. The critical high temperature that guaranteed the setting percentage no less than 85% were sequentially 31.8℃ for Ⅱ You 6078, and 33℃ for the check in the flowering stage, while the critical low temperature no less than 70% were 18.1℃ fo Ⅱ You 6078 and 18.9℃ for the check in 3 days. The data of superoside dismatase (SOD) supported the points presented above.