Effects Of High Temperatures On The Biological Parameters And Resistance Associated Enzyme Activities Of Lipaphis Erysimi Kaltenbach

This paper, through the method of establishment of life table, studied the effects of five temperatures on the biological parameters of sensitive experimental population. These five temperatures were 25℃,27℃,28.5 ℃,30℃ and 31.5℃ respectively. The results showed that the survival rates of susceptible Lipaphis erysimi Kaltenbach at 25℃,27℃,28.5℃,30 ℃and 31.5 ℃, were significantly different. When the constant temperatures were 30 ℃ and 31.5℃, the survival curves were closed to Deevey Ⅲ model, which showed that these two temperatures were not suitable for the survival of susceptible Lipaphis erysimi Kaltenbach. However when the temperatures were 25℃,27 ℃ and 28.5 ℃, the survival curves were in close proximity to Deevey I type. As the temperature increased, the net reproductive rate and the finite rate of increase gradually reduced.30℃ is the highest temperature for the reproduction of population in their whole development process. As the temperature went up, the time required to complete a generation for a population showed a trend of decline after rising firstly. The population had the shortest average generation period at 28℃. The intrinsic growth rate (rm) and population trend index (Ⅰ) decreased with the rising of temperatures. At 30℃the growth of population was negative, that demonstrated that the individual number of experimental population contracted. The time of double population size (t) increased with the rising of temperatures. Results showed that 25℃was the optimal temperature for the survive of Lipaphis erysimi Kaltenbach. The influents of temperatures on survival rates of resistant Lipaphis erysimi Kaltenbach experimental population were relatively small. We found no significant differences in survival rates and life expectancy among 27℃,25℃ and 30℃, the same results could be found between 31.5℃ and 28.5℃. These two indexes between any two other processing temperatures were significantly different. The number of individuals at 31.5 "C remained essentially unchanged,27℃ was optimal for biological indicators. Among the five temperatures adopted by this experiment,27℃was suit to the survival and reproduction for resistant experimental population.Aiming at defining the changes of the activities of acetylcholine esterase (AchE), carboxylesterase (CarE) and glutathione transferases (GSTs) at high temperatures, and providing theoretical support for the prevention and control for Lipaphis erysimi Kaltenbach in the field, this adopted the leaf dipping method to test the toxicity of 48% chlorpyrifos EC, 5% beta-cyfluthrin ME, imidacloprid 75% WDG and 5.7% Emamectin Benzoate EW to resistant and susceptible populations of Lipaphis erysimi Kaltenbach, the results showed that the resistant population used in experiments could be known as a resistant group. By determining the effects of high temperatures on activities of acetylcholine esterase, carboxylesterase and glutathione transferase at different processing times and processing temperatures, it was aimed at illuminating the adaptive mechanism of resistant and sensitive Lipaphis erysimi Kaltenbach. When processing time was constant, with the increasing of temperatures, the AchE activities of Lipaphis erysimi Kaltenbach experimental population gradually declined. At a certain temperature, however, along with the growth of processing times, the activities of enzyme firstly decreased, then increased, decreased again. At 27℃ treated 12h, AchE activities of Lipaphis erysimi Kaltenbach experimental population were the highest, when the processing time was constant, with the rising of temperatures the activities of CarE firstly decreased,then increased, decreased again. At a certain temperature, along with the growth of processing times, the activities of enzyme changed at the same trend with above. At 28.5℃ treated 24 h, the CarE of Lipaphis erysimi Kaltenbach experimental population showed the highest activity. At a certain temperature, along with the growth of the processing times, activities of GSTs firstly rose, then fell. When the processing time was 4h 24h,48h or 72h, with the going up of processing temperatures GSTs activities of Lipaphis erysimi Kaltenbach experimental population gradually declined. When treated 12h or 8h, along with the increasing of temperatures, GSTs activities of declined after rising. At 27℃ treated 12h, GSTs activities of Lipaphis erysimi Kaltenbach experimental population were the highest. Resistant Lipaphis erysimi Kaltenbach experimental population was more sensitive to the changes of temperatures and the inhibitive effects were more obvious at high temperatures.