Research On The Physiology Of Rice Under High Temperature Stress

The differences of seed-setting rate,1000-grain weight and rice quality traits were analyzed in artificial greenhouse, observed under high temperature stress and suitable temperature treatment during flowering and filling stage.18 indica rice cultivars,Ⅱ-you-7954, Liangyoupeijiu,Ⅱ-you-838, Jinyou-207, Qianyou-1, Qianyou-0506, and their parentsⅡ-32B, Qianjiang-1B, Jin-23B, Pei'ai-64, Zhehui-7954,9311, Fuhui-838, Zhehui-0506, Xinhui-207, as well as IR64, Katy, Lement, were pot-grown and subjected to high temperature stress (40℃,8:30-17:30, other natural temperature) during flowering and filling stage, and the suitable temperature (28℃,8:30-17:30, other natural temperature) was taken as the control, in artificial greenhouse. The differences of pollen vitality of indica rice Qianjiang-1B and Jin-23B were also analyzed observed under 28℃,38℃,41℃temperature treatments, in artificial climate chamber. The results show that:①ollen vitality, stainable pollen grains rate and anther dehiscence significantly decreased during high temperature stress period. The pollen of Qianjiang-1B could keep normol vitality in 5 days under 38℃stress period, while losed the vitality in the third day under 41℃stress period. The heat tolerance of Qianjiang-1B was better than Jin-23B.②here were negative influence to the rice growth under high temperature stress during flowering and filling stage, seed set rate and harvest index significantly decreased under high temperature stress, while the negative influence was worse during flowering stage than filling stage.③here was no consistency of the heat tolerance among different types of hybrid with their parents. The heat injury index of hybrids which female parent was Qianjiang-1A was lower than their parents, while the same as Liangyoupeijiu. The heat injury index of hybrids which female parent wasⅡ-32A was stronger than female parent but lower than male parent. The heat injury index of hybrids which female parent was Jin-23A was stronger than its parents.④1 000-grain weight relatively decreased under high temperature stress to some varieties, but some were significantly higher. The results appear similar to amylose content,gel consistency and alkali spreading value, high temperature effects on the gel consistency was more complex. For most of the varieties, amylose content and alkali spreading value relatively decreased under high temperature stress.⑤Brown rice rate and head rice rate relatively decreased under high temperature stress during filling stage, but chalkiness rate, chalkiness degree and protein content relatively increased.⑥In the 55 pairs of the rice quality correlation, there were 13 pairs appeared in the opposite correlation coefficient, but 4 pairs appeared consistent with significant correlation, between high temperature stress and suitable temperature during filling stage. Significantly positive correlations were found between chalky grain rate and chalkiness, but significantly negative correlations between chalky grain rate and gel consistency, between gel consistency and amylose content, and between chalkiness and gel consistency too, both under high temperature stress and suitable temperature during filling stage. During the filling stage under high temperature stress, there was insignificant correlations between seed set rate and protein content, and between 1 000-grain weight and alkali spreading value, but significantly positive correlations between chalky grain rate and protein content, and between chalkiness and protein content. But during the filling stage under suitable temperature, significantly negative correlations were found between seed set rate and protein content, but significantly positive correlations between 1 000-grain weight and alkali spreading value, between chalky grain rate and amylose content, and between chalkiness and amylose content.