高温胁迫对丽蚜小蜂死亡率和保护酶系的影响

Effect of high temperature stress on mortality and protective enzymes of Encarsia formosa

摘要:

【目的】探究不同温度和时间处理对丽蚜小蜂（Encarsia formosa）的致死作用，明确丽蚜小蜂对温度胁迫的生理应答机制。【方法】测定不同温度（35、37 和 39 ℃）对丽蚜小蜂成虫 24 h 内存活率的影响和丽蚜小蜂成虫在 35、37 和 39 ℃下胁迫 4、8 h 后体内的超氧化物歧化酶（SOD）、过氧化氢酶（CAT） 和过氧化物酶（POD）活性。【结果】丽蚜小蜂成虫的死亡率随着胁迫温度上升和时间的延长而加剧，在 35 ℃以上 1 h 就出现死亡，与对照 25 ℃存在显著差异。丽蚜小蜂成虫的 SOD 和 POD 活性随着温度的升高，呈现先升高后下降的趋势，在 4 h 时，SOD 活性在 37 ℃达到峰值，显著高于对照（25 ℃）的活性； POD 活性在温度 35 ℃、8 h 时达到峰值且与其他温度和时间存在显著差异；CAT 活性在 37 ℃、4 h 时达到最大值，并与其他温度和时间存在显著差异。SOD、POD 和 CAT 3 种保护酶在 35 ℃、8 h 之内和 37 ℃、4 h 之内对丽蚜小蜂可起到保护的作用。【结论】温度高于 35 ℃的环境对丽蚜小蜂的种群数量具有显著影响。

Abstract:

【Objective】 In order to explore the lethal effects of different temperatures and time duration on Encar- sia formosa，and to understand the physiological response mechanism of E. formosa to temperature stress.【Method】 We recorded the survival rates of E. Formosa adults within 24 h at 35，37 and 39 ℃，as well as the changes of superox- ide dismutase （SOD），catalase （CAT） and peroxidase （POD） activities in vivo after 4h and 8h at 35，37 and 39 ℃. 【Result】 The mortality rate of the adults was aggravated with the increase of temperature and the prolongation of time. The death of E. Formosa adults was occurred in 1 hour above 35 ℃，which was significantly differed from that of the control at 25 ℃. With the increase of temperature，the SOD and POD activities in adults of E. formosa showed a trend of first increasing then decreasing. At 4 h，SOD activity peaked at 37 ℃，which was significantly higher thanthat of the control （25 ℃）. POD activity peaked at 35 ℃ at 8h and was significantly different from other treatments. CAT activity reached the maximum value at 37 ℃ at 4 h，and was significantly different from other treatments. SOD， POD and CAT can protect the E. formosa within 8h at 35 ℃ and 4 h at 37 ℃.【Conclusion】 The temperature higher than 35 ℃ had a significant effect on the population of E. formosa.