开花期低温胁迫对水稻花粉性状及剑叶理化特性的影响

以耐冷水稻品种996和冷敏感品种4628为材料，开花期在人工气候室进行7 d低温（06:00-8:00和19:00-23:00，19 ℃；08:00-10:00和16:00-19:00，21 ℃；10:00-16:00，23 ℃；23:00-06:00，17 ℃）和适温（06:00-8:00和19:00-23:00，24 ℃；08:00-10:00和16:00-19:00，26 ℃；10:00-16:00，30 ℃；23:00-06:00，22 ℃)处理，研究了低温胁迫对水稻花药开裂、花粉性状及剑叶叶绿素、可溶性糖和可溶性蛋白质含量、膜透性等理化特性的影响.结果表明：开花期低温胁迫导致水稻花药开裂系数、花粉萌发率显著下降，中部和下部颖花的不育花粉率增加.996的花药开裂系数和花粉萌发率显著高于4628，表明耐冷品种996在开花期低温胁迫下能保持较好的花粉散落特性和花粉萌发特性.低温胁迫下，996的剑叶可溶性蛋白质和游离脯氨酸含量及其增幅显著高于4628，而丙二醛含量和相对电导率及其增幅却显著低于4628，说明耐冷品种在低温胁迫下的保护性反应更迅速和强烈，其膜结构及功能更稳定.

Effects of low temperature stress during flowering period on pollen characters and flag leaf physiological and biochemical characteristics of rice

Taking cold-tolerant rice cultivar 996 and cold-sensitive rice cultivar 4628 as test materials, a growth chamber experiment was conducted to investigate their pollen characters and flag leaf physiological and biochemical characteristics under the effects of low temperature stress. The plants were respectively treated with low temperature ［19 ℃ (06:00-8:00;19:00-23:00)/21 ℃ (08:00-10:00;16:00-19:00)/23 ℃ (10:00-16:00)/17 ℃ (23:00-06:00)］and optimal temperature ［24 ℃ (06:00-8:00; 19:00-23:00)/26 ℃ (08:00-10:00;16:00-19:00）/30 ℃ (10:00-16:00)/22 ℃ (23:00-06:00)］ for seven days after heading. Low temperature stress decreased the anther dehiscence coefficient and pollen germination rate, as well as the sterile pollen rate of spikelets on middle and lower parts of panicles, with the anther dehiscence coefficient and pollen germination rate of cultivar 996 being significantly higher than those of cultivar 4628, indicating that cold tolerant cultivar 996 had the capability to keep better pollination and pollen germination. Under low temperature stress, the flag leaf soluble protein and free proline contents and their increments of cultivar 996 were significantly higher than those of cultivar 4628, while the MDA content and relative conductivity and their increment were in adverse, indicating that cold-tolerant cultivar 996 had more quick and strong protective responses, and was able to keep stable membrane structure and function.