红缘天牛越冬幼虫耐寒性研究

Cold-hardiness of Overwintering Asias halodendri Larvae

旨在探索红缘天牛越冬幼虫的耐寒性。采用热电偶法和昆虫生理生化的主要研究方法,测定越冬幼虫的过冷却点、冰点、含水率、脂肪含量、糖原含量和血淋巴中游离氨基酸种类及质量浓度,并分析上述指标变化与幼虫耐寒性的关系。结果表明:不同大小幼虫的过冷却点与冰点均无显著差异(P>0.05);幼虫经5℃1d处理后,过冷却点升高,冰点降低,均呈现显著差异(P<0.05);含水率由71.89%减至69.97%;血淋巴液中谷氨酸、缬氨酸、蛋氨酸、苯丙氨酸、赖氨酸、组氨酸、精氨酸和脯氨酸占总量的百分比均有所提高;脂肪和糖原含量变化差异不显著(P>0.05)。研究结果说明:红缘天牛越冬幼虫具有较强的过冷却能力,通过调节血淋巴液中氨基酸质量浓度的变化抵御短时间低温环境变化,提高其对寒冷的适应能力。

In order to explore the cold-hardiness of overwintering Asias halodendri larvae, this study had determined their supercooling point, freezing point, water ratio, lipid content, glucogen content, type and mass concentration of free amino acids in the haemolymph by using thermocouple method and major research methods of insect physiological and biochemical and analyzed the relationship between cold-hardiness of larvae and the change trends of these indexes. The results showed that the supercooling point and freezing point in different sizes of A. halodendri larvae had no significant difference at 0.05 levels（P〉0.05）. After 5 ℃ 1 d low temperature treatment,the supercooling point of A. halo dendri larvae increased and the freezing point decreased. Both of these two indicators had significant difference at 0.05 levels（P〈0.05）. Also the water content of larvae body had decreased from 71.89% to 69.97%, the content of glutamic acid, valine, phenylalanine, methionine, lysine, histidine, arginine and proline had increased after acclimatization. But the lipid and glucogen content have no significantly changes（P〉0.05）. The results indicated that overwintering A. halodendri larvae have strong supercooling capacity. They could resist cold environmental temperature across adjusting mass concentrations of free amino acids in haemolymph, and thus improve the ability of acclimatization to the cold winter.