Mechanisms Of Tolerance Induced By Temperature In Pardosa Astrigera L.Koch

Spiders need thermal energy mainly from solar radiation for life activities as exothermic animal. The most important factors on spiders is temperature which will greatly influence on all aspects of the spiders. Pardosa astrigera is a predatory natural enemy widely distributed in forest, orchard and farmland. This paper studied the effect of Pardosa astrigera by different temperature inducing on survival rate, enzyme activity, the supercooling point and heat shock proteins. The results are as follows:1、Changes in survival rate in different seasons of Pardosa astrigera under extreme temperature and by inducing were measured. After extreme temperature stress of different seasons, the survival rate of Pardosa astrigera decreased with the high temperature rise and low temperature decrease. When Pardosa astrigera was at 43.5 ℃ the survival rate decreased significantly. The temperature was the sensitive temperature of it. High temperature stress to female spiders have higher survival rate than the male. Low temperature stress to male spiders have higher survival rate than the female. After high temperature induction,the highest survival rates were induced by 38℃ in spring and summer and induced by 36℃ in autumn. In three seasons the survival rates of Pardosa astrigera were all raised by induced at 38℃.After low temperature induction, the highest survival rate was all induced by 4℃ in three seasons.2、The supercooling point and the freezing point of Pardosa astrigera was determined in the different seasons. And the changing trend of high and low temperature induced on Pardosa astrigera by imitating external temperature. The results showed that:There exists a significant seasonal variability in the supercooling point and freezing point of Pardosa astrigera. The rules of the supercooling point was in order of post March<October<July. The supercooling point and freezing point of Pardosa astrigera were induced by high temperature were both higher than control. When five low temperatures induced on spiders, the supercooling point-9.03 ℃ was lower than the control-8.40 ℃ but the freezing point-6.1℃ was no significant difference with control-6.59 ℃.The bigger the difference of Pardosa astrigera between the supercooling point and freezing point was, the stronger the super-cooling ability could be. Therefore, The super-cooling ability and cold hardiness of Pardosa astrigera in March was the strongest in the other month. It was the weakest in July in the other month. The super-cooling ability and cold hardiness of Pardosa astrigera was weak induced by high temperature. But the super-cooling ability and cold hardiness of Pardosa astrigera can be stronger induced by suitable low temperature. This result was the same as measuring in fields. Study the effects of environmental temperature on the cold hardiness of Pardosa astrigera through the simulation environment, which lay a foundation for better using of Pardosa astrigera to control pests and predicting the suitable establishment areas, providing a theoretical basis.3、Five kinds of enzyme activity of high-low induced Pardosa astrigera were measured. With increasing temperature the protective enzymes (SOD, POD and CAT) activities all increased at first and the decreased. The protective enzymes activities were highest after inducing by 38℃ and 4℃.The LDH activities were the same trend of protective enzyme after high temperature induction and gradually decreased after low temperature induction.The Na+-K+-ATPase activities gradually increased with temperature increasing after high temperature induction. The activities gradually decreased after low temperature induction. Therefore, Pardosa astrigera was induced by suitable temperature can make the protective enzyme and energy metabolism enzyme activities increased Pardosa astrigera can enhance the enzyme activities to strengthen the resistance by temperature induction, when it encountered bad environment.4、The relative expression of Hsp70 and 90 of Pardosa astrigera induced by different temperature was determined. Results show that, the expressions of Hsp70 and Hsp90 were very low and close to control from 16℃ to 26℃.From the beginning of the 26℃ the expression of Hsp70 and Hsp90 first increased and then decreased with temperature increasing. The highest expression of Hsp70 and Hsp90 were 716.46 and 10.44 times than the control after inducing by 38℃. From the beginning of the 16℃ the expression of Hsp70 and Hsp90 gradually increased with temperature decreasing. The highest expression of Hsp70 and Hsp90 were 334.53 and 9.38 times after inducing by-2℃.Hsp70 and Hsp90 of Pardosa astrigera all can be expressed after temperature induction. But the expression hsp70 of Pardosa astrigera was higher than Hsp90 when it in the same temperature induced. Therefore, the expression of hsp70 can quickly response to stress but the expression of hsp90 was relative lag, when spiders were induced 2 hour at-2-16℃ and 26-38 ℃.