低温对'寒富'苹果花芽呼吸和抗氧化酶活性的影响

以‘寒富’苹果花芽为试材,设置梯度低温(-25-、30-、35和-40℃)处理,研究顶花芽和腋花芽的呼吸速率和抗氧化酶活性对低温的响应特点。结果表明:顶花芽呼吸速率随着温度的下降表现出先升高后显著下降再升高的趋势,在-30℃顶花芽呼吸速率降到最低点,且明显低于腋花芽,此后顶花芽的呼吸速率虽呈上升的趋势,但一直处于较低水平。腋花芽呼吸速率在低温处理的前期呈逐渐降低的趋势,在-30℃降到最低点,此后急速升高,在-35℃达到最高点后快速下降。2种类型花芽的SOD酶活性在-10~-25℃均是快速升高,此后顶花芽的SOD酶活性急剧下降并一直处于较低水平,腋花芽的SOD酶活性下降幅度较小且维持在较高的水平。顶花芽的POD酶活性变化呈升高-下降交替出现的特点,在-25℃和-35℃出现峰值;腋花芽则表现为降低-升高-降低的趋势,在-35℃达到峰值且高于顶花芽。顶花芽的CAT酶活性在低温下呈先升高后降低的变化趋势,在-25℃出现峰值;腋花芽CAT酶活性则呈升高-降低交替出现的特点,在-25℃和-35℃出现峰值。此外,腋花芽的POD和CAT酶活性升高幅度明显高于顶花芽。由此认为,腋花芽的呼吸途径活性受低温抑制的程度低于顶花芽,以及其抗氧化酶清除活性氧的能力高于顶花芽,都有利于减少低温胁迫引起的活性氧伤害。

Research on the Effect of Low Temperature on Respiratory Rate and Antioxidant Enzymes Activities in 'Hanfu' Apple Flower Buds

In order to research the response characteristics of respiratory rate and antioxidant enzymes activities in apical flower buds and lateral flower buds under low temperature treatment(-25,-30,-35 and-40℃),’Hanfu’ apple flower buds were used as materials.The results showed that the respiratory rate of apical flower buds increased firstly and decreased sharply to the lowest point at-30℃ which was lower than that of lateral flower buds,and then kept at a relative low level although it increased slightly.In contrast,respiratory rate of lateral flower buds decreased firstly to the lowest point at-30℃ and increased sharply to peak at-35℃,and then decreased again.In both apical flower buds and lateral flower buds,SOD activity displayed fast increasing trend when temperature went down from-10℃ to-25℃,and then SOD activity in apical flower buds decreased sharply and kept at a relatively low level,while SOD activity in lateral flower buds only decreased slightly and kept at a relatively high level.POD activity in apical flower buds changed in zigzag mode,appeared peaks at-25℃ and-35℃;however,POD activity in lateral flower buds decreased firstly and increasing subsequently to the peak at-35℃ which was higher than that of apical flower buds,and then decreased again.CAT activity in apical flower buds increased firstly to the peak at-25℃ and decreased subsequently,in contrast,CAT activity in lateral flower buds was changing zigzag with peaks at-25℃ and-35℃.The increasing ranges of POD and CAT activity in lateral flower buds were obvious higher than that of apical flower buds additionally.It was hypothesized that higher respiratory rate and ability of eliminating ROS in lateral flower buds were contributed to alleviating oxidative stress induced by cold temperature.