低温胁迫对稻茬小麦根系抗氧化酶活性及内源激素含量的影响

为探索低温对小麦根系的伤害机理,在分蘖期和拔节期模拟低温,研究低温胁迫对稻茬不同小麦品种(烟农19,抗寒性较强;郑麦9023,抗寒性较差)根系抗氧化酶活性及内源激素含量的影响。结果表明,低温胁迫对小麦根系中抗氧化酶活性和内源激素含量的影响均达到显著水平(P0.05)。2个小麦品种受到低温胁迫后,根系中超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性均显著增强,丙二醛含量(MDA)显著下降,且拔节期低温处理小麦的抗氧化酶活性增强幅度更大,MDA含量下降幅度更小。抗寒性较强的小麦品种(烟农19)根系中脱落酸(ABA)、赤霉素(GA3)和生长素(IAA)含量在低温胁迫后均表现为上升趋势。抗寒性较差的品种(郑麦9023)根系中GA3含量在低温胁迫后增加;ABA含量在低温胁迫后下降;IAA含量在分蘖期低温胁迫后表现为增加,拔节期表现为下降。以上结果表明,分蘖期和拔节期遭受低温后,不同品种稻茬小麦根系中抗氧化酶活性及激素含量受影响的程度不同,抗寒性差的品种根系受低温影响较大,且以拔节期影响更为严重。

Effect of Low Temperature on Antioxidative Enzymes Activity and Endogenous Hormone Content in Wheat Root of Rice-wheat Rotation

In order to explore the damage mechanism of low temperature on wheat root and provide a theoretical basis for breeding high-yielding varieties with stress resistance,the effects of low temperature stress on antioxidative enzymes activity and endogenous hormone content in root of two wheat cultivars(Triticum L.)(Cold resistant cv. Yannong 19 and weak cold tolerance cv. Zhengmai 9023) grown after rice(Oryza sativa L.) were investigated at the tillering and jointing stages. The results showed that low temperature stress had significant impacts on activity of endogenous protective enzymes and the content of hormones in wheat root(P<0.05). After exposure to low temperature,the activities of antioxidative enzymes,superoxide dismutase(SOD),peroxidase(POD) and catalase(CAT) were enhanced,while the content of malondialdehyde(MDA) was decreased in the root. The activities of antioxidative enzymes were markedly increased,while MDA showed a smaller decrease at jointing stage. The content of abscisic acid(ABA),gibberellin(GA₃) and auxin(IAA) showed rising trend after low temperature stress in root of Yannong 19.After exposure to low temperature,the GA₃ content was increased,and the ABA content decreased,and IAA content was increased at tillering stage,but decreased at jointing stage in Zhengmai 9023(weak cold tolerance) root. The results suggested that when exposure to low temperature at the tillering and jointing stages,antioxidant enzyme activity and hormone content were affected by different degrees in different genotypes wheat root. The variety with weak cold tolerance got severe degree,and more serious at jointing stage.