温度胁迫对二化螟滞育幼虫生理指标的影响

为从生理生化水平上探讨二化螟滞育幼虫应对温度胁迫的生理机制,分别对系列温度胁迫(STS)和梯度温度胁迫(GTS)处理后的幼虫水、脂质、总糖、小分子碳水化合物含量及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性进行了测定.结果表明:随着温度的降低,两种处理二化螟滞育幼虫虫体含水量趋于减少,且0℃以下时GTS处理下降幅度较STS处理显著;两种处理脂质含量均逐步下降且二者间无显著差异;两种处理总糖含量分别先减后增和持续下降,均检测出4种小分子碳水化合物,其中STS处理葡萄糖、甘油和果糖含量先增后减,海藻糖含量变化与此相反,而GTS处理海藻糖含量先减后增,葡萄糖和甘油含量呈相反变化,果糖含量无变化;14～-14℃范围内STS处理SOD和POD活性较GTS处理低,CAT活性相反.二化螟滞育幼虫生理指标的变化反映了其应对不同温度胁迫的生理响应.

Effects of temperature stress on physiological indices of Chilo suppressalis Walker (Lepidoptera: Pyralidae) diapause larvae

To understand the physiological mechanisms of temperature stress on the diapause larvae of rice stem borer Chilo suppressalis Walker at physiological and biochemical levels, determinations were made on the contents of water, lipid, total sugar and low molecular mass carbohydrates and the activities of SOD, POD, CAT in the larvae after series temperature stress (STS) and gradient temperature stress (GTS). With the decrease of temperature, the water content in the larvae decreased, and the decrement below 0 degrees C was significantly larger in treatment GTS than in treatment STS. The lipid content in the larvae decreased gradually, but no significant difference was observed between treatments STS and GTS. The total sugar content in the larvae in treatment STS increased after an initial decrease, but that in treatment GTS continued to decline. Four species of low molecular carbohydrates, i. e. , trehalose, glucose, glycerol and fructose were detected in the larvae. In treatment STS, the contents of glycose, glycerol and fructose in the larvae decreased after an initial increase, while the trehalose content was in adverse. In treatment GTS, the trehalose content decreased first and increased then, the glucose and glycerol were in adverse, but the fructose content had little change. In the range from 14 to -14 degrees C, the SOD and POD activities in the larvae in treatment STS were significantly lower than those in treatment GTS, but the CAT activity was in adverse. The changes of these indices reflected the physiological responses of C. suppressalis diapause larvae to different temperature stress.