高温胁迫对不同早稻品种胚乳淀粉合成酶类活性的影响

Effects of High Temperature Stress on Activity of Amylosynthease in Endosperm of Early Indica Rice Varieties

【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。

[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.