【摘要】 【目的】探讨高温胁迫对水稻胚乳灌浆影响的酶学生理特征。【方法】选用水稻耐热型品种082、农大228和热敏感品种协青早B、茉莉占,采用高温胁迫与常温对比试验方法,研究灌浆前期高温对胚乳淀粉合成酶类活性及淀粉积累的影响。【结果】胚乳淀粉合成酶活性高峰出现在花后9～12d。高峰期间及之前,胚乳SS、AGPase、SSS和Q酶受高温影响活性上升,高峰之后,除Q酶外,均较对照下降,耐热品种胚乳淀粉合成酶类活性的下降幅度明显小于热敏感品种。高温影响淀粉积累速率与AGPase、SSS、SS和R酶活性相关显著。【结论】不同水稻品种胚乳淀粉合成酶对高温的感应存在差异,AGPase、SSS、SS和R酶是高温影响淀粉积累速率的关键酶。高温影响直链淀粉含量下降与Q酶活性不存在必然的联系。更多还原

【Abstract】 【Objective】Physiological mechanisms of the impact of high temperature stress on rice endosperm filling were discussed. 【Method】 On the basis of the field controlled canopy, four early indica rice cultivars with different heat sensitivities, namely Nongda228 and 082 (heat-resistant) and Molizhan and XeiqingzaoB (heat–sensitive), were applied to compare their difference in response of some enzymes involved in starch synthesis to high temperature stress at early filling stage.【Result】The results indicated that the active peak of amylosynthease in endosperm appeared in 9-12 day after anthesis. Affected by high temperature, before and during the period of the peak, the activities of SS, AGPase, SSS and Q enzymes increased. After that, these activities decreased except for Q enzyme. The decreasing extent in heat resistance cultivars was obviously lower than that in heat sensitive cultivars. There was a significant correlation between the rate of starch accumulation and the AGPase, SSS, SS, and R enzymes activities.【Conclusoin】For different rice varieties, the amylosyntheases have different responses to the high temperature. The AGPase, SSS, SS and R enzymes are key enzymes affecting the rate of starch accumulation at high temperature. The decrease of amylase percent affected by high temperature was not necessarily related with Q enzyme activities.更多还原