桑尺蠖越冬幼虫的耐寒性研究

研究了桑尺蠖越冬幼虫的耐寒能力 ,测定了虫体内抗寒物质的组成成分 ,并对其耐寒机理作了初步探讨。结果表明 :越冬幼虫从越冬初期至越冬滞育期 ,4龄幼虫的平均过冷却点从初期的-1 7 2℃下降至滞育期的 -2 4 4℃ ;5龄幼虫的平均过冷却点从 -1 3 4℃下降至 -2 4 8℃。越冬幼虫体内水分、糖元、脂肪含量下降 ,其中以糖元含量下降明显 ;越冬幼虫以“小分子糖—氨基酸—糖蛋白”物质系统形成抗寒基质 ,增强耐寒性。

Study on Cold Hardiness of Overwintering Larvae, Phthonandria atrilineata Butler

The capacity of cold tolerance of overwintering mulberry looper larvae was studied by testing the ingredients of hardy substances.The mechanism of cold hardiness is discussed in this paper.The main results are as follows:From overwintering primary stage to diapause stage,mean supercooled points of the fourth larvae decreased from -17 2℃ to -24 4℃,and that of the fifth instar larvae reduced from -13 4℃ to -24 8℃.The contents of water and crude fat,especially the glycogen decreased,while the contents of crude protein,trehalose,dextrose,threonine,alanine,serine,methionine and arginase increased significantly.So there is a substance system including “low molecular weight sugars-amino acid-glycoprotein" which enhances cold hardiness for overwintering larvae.