2,4-表油菜素内酯缓解水稻花期高温胁迫的生理机制

Physiological Mechanism of Brassinolide on Alleviating High Temperature Stress of Rice at Flowering Stage

为探究喷施2,4-表油菜素内酯(EBR)在水稻开花期缓解高温胁迫的作用,研究分析了在高温胁迫下喷施EBR对水稻产量构成因素、花粉活力、抗氧化酶活性以及内源激素的影响。结果表明,水稻花期受高温胁迫后,结实率、花药开裂率以及穗子花粉活力明显降低,而喷施EBR后水稻的结实率、花药开裂分别提高24.09%、55.4%,且穗中部和下部花粉活力提高了8.64%和24.2%。在高温胁迫下,SOD、POD、CAT活性显著降低,脯氨酸和可溶性糖含量减少,喷施EBR后SOD酶活性提高51.76%,脯氨酸和可溶性糖含量分别增加8.23%和11.02%,但对POD和CAT酶活性无显著影响。此外,高温胁迫下,内源激素ABA含量上升,GA含量降低,而喷施EBR后ABA含量提高4.78%,GA含量降低18.81%。表明喷施EBR可以通过调节水稻内源激素的变化缓解高温伤害。

In order to investigate the effects of EBR in alleviating high temperature stress of rice at flowering stage, the yield components of rice, pollen activity, percentage of anther dehiscence, physiological indicators and endogenous hormones were analyzed. In this study, the seed seeding rate, pollen activity and percentage of anther dehiscence significantly reduced under high temperature stress, while the seed setting rate, anther cracking percentage increased by 24.09% and 55.4%, and pollen activity of rice middle and lower parts of panicles increased by 8.64% and 24.2% by spraying EBR. The activity of SOD, POD, CAT was significantly reduced under high temperature stress, but EBR treatment significantly increased the activity of SOD by 51.76%. EBR treatment also greatly increased the accumulation of proline and soluble sugar under high temperature stress, which was helpful to alleviate high temperature stress. Under high temperature stress, the endogenous hormone ABA content increased, GA content decreased, while spraying EBR further increased ABA content by 4.78% and decreased GA content by 8.71%, indicating that EBR treatment can alleviate the damage of high temperature to rice by regulating the changes of endogenous hormones. In short, spraying EBR is an effective measure to reduce high temperature damage on rice.