高温对水稻开花期剑叶抗氧化酶活性及基因表达的影响

以杂交水稻‘Ⅱ优838’为研究材料,检测了高温胁迫下‘Ⅱ优838’开花期剑叶中叶绿素含量、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性及SOD、CAT、POD基因的表达水平。结果显示,高温胁迫使‘Ⅱ优838’剑叶中叶绿素含量及叶绿素a和叶绿素b含量的比值(Chl a/Chl b)降低且下降幅度显著低于‘冈优725’(对照);SOD和POD活性增高且增幅显著大于‘冈优725’,但CAT活性降低且降幅显著小于‘冈优725’;热胁迫使‘Ⅱ优838’剑叶中SOD、CAT和POD基因的表达量显著增加。说明‘Ⅱ优838’在开花期遭遇高温胁迫后能保持较高的光合效率,并通过提高抗氧化保护酶的基因表达水平以维持较高的活性来应答高温胁迫,这为深入剖析水稻高温胁迫下的生理反应和适应机理提供了参考。

Effects of High Temperature on the Activity and Expression of Antioxidative Enzymes in Rice Flag Leaves during the Flowering Stage

We determined the chlorophyll content, activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), as well as the gene expression of SOD, CAT and POD in rice flag leaves during the flowering stage under high temperature stress. We used real-time RT-PCR to disclose the mechanism of the physiological responses and adaptation of ‘Ⅱ YOU 838’ to heat stress. Upon heat treatment, the decline in chlorophyll content and the Chl a/Chl b ratio in ‘Ⅱ YOU 838’ was to a lesser degree than that of ‘Gang YOU 725’, and the activity of SOD and POD increased by a higher degree and the activity of CAT declined by a lower degree during the flowering stage. The expressions of the three antioxidative enzyme genes in ‘Ⅱ YOU 838’ were significantly higher than those in ‘Gang YOU 725’. These results implied that ‘Ⅱ YOU 838’ may have higher tolerance to heat stress by maintaining higher photosynthetic metabolism and improving protective antioxidant activity and expression.