| Pea aphid, Acyrthosiphon pisum(Harris)(Hemiptera: Aphidae), which includes Red morph and Green morph, both of them are one of the dominant insect pests on leguminous crops and grass such as alfalfa, pea, broad bean and so on. Of which, the green morph was the main species in northwest of china, but the red morph is becoming more and more popular in recent years. And the ozone aphere was destroyed, because of human activities, which lead to ultraviolet radiation become more serious, and finally have an effect on the biosphere.This dissertation was mainly dealt with the change of both Red morph and Green morph treated for continuously 8 generations by using low intensity UV-B radiation in different time, including population parameter, the content of activity of protective enzyme system and carbohydrate were measured as well in order to clarify the effect of population succession and body-color morphs differentiation by UV-B radiation, moreover provide theoretical support to comprehensive treatment of Acyrthosiphon pisum. The main results are as follows: 1. The effect of biological characteristics of Acyrthosiphon pisum by UV-B stressThe more longer of the continuous UV-B radiation time for two color morphs, with the increasing of generation, the more strong of inhibiting effect of UV-B stress on development and population growth of Acyrthosiphon pisum. Of which, with the time extension of radiation, Green morph generations increased, the weight or body length increased firstly and then decreased. The shortest body length was 1.63 mm, which reduced 49.22% by compared with control.the least weight was 1.18 mg which reduced 62.06% by compared with control. Net reproductive rate increased and then decreased, the least rate was 7.62% by compared with control, intrinsic rate finally decreased, the lowest was 33.96% by compared with control,the finite rate increased and then shortened, the shortest was 81.16% compared with control, mean generation time extended at last, the longest was 1.12 times compared with control. With UV-B radiation time prolonged, red pea aphids` average body length cut back, average weight lightened, net reproductive rate, intrinsic rate of increasing reduced, and the mean generation time prolonged in the same generation. With the same UV-B radiation, following generations, body length, average weight, net reproductive rate and intrinsic rate of increasing were all increased and then decreased, mean generation time showed a completely consequence,it declined at first, then increased. Up to F8, with different UV-B radiation time average body length was 42.58%~81.94% comparaed with CK, average weight was 33.77%~73.12% with CK, net reproductive rate was 6.94%~46.55% by CK, finite rate of increase was 77.00%~87.94%% for CK, the mean generation time was 1.20~1.38 times for CK. And intrinsic rate decreased, however, under the treatments of 50 min and 60 min was less than 1/2 of CK, it means that population quantity was negative increase. 2. The effect of Acyrthosiphon pisum protective enzymes and Soluble protein by UV-B stressIn UV-B stress earlier stage, the CAT enzymatic activity of Red morph or Green morph rose, in same generation, the longer of time, the higher of CAT enzymatic activity. But it was limited after lots of generations. The lowest CAT enzymatic activity of Red morph was 3.69 ug/mg·min, decreased 4.42% by comparaed with control, that of Green morph also declined, the lowest was 4.89 ug/mg·min but it was 1.14 times of control. The POD enzymatic activity declined by UV-B stress in same generation, Red morph became lower and then higher at last lower, lowest POD enzymatic activity was 4.27 ug/mg·min, decreased 33.8% than control,that of Green morph decreased by generations, the lowest was 3.95 ug/mg·min, decreased 54.07% than control. SOD enzymatic activity of two kinds morph all increased, the longer UV-B stress time, the more generations, the higher SOD enzymatic activity. The highest SOD enzymatic activity was 5.43 times for control of Red morph, the highest of Green was 4.28 times for control. The Soluble protein content of two kinds morph by UV-B stress all showed”lower-higher-lower”, in same generation, the longer UV-B stress time, the lower Soluble protein content. Compared with control, Red morgh Soluble protein content decreased 39.07%, Green morgh Soluble protein content decreased 28.96%. Acyrthosiphonpisumpurged harmful free radical by adjusting POD、SOD、CAT in UV-B stress, the most useful one was SOD. 3. The effect of Acyrthosiphonpisum carbohydrate by UV-B stress carbohydrate of two kinds morph increased by UV-B stress. The longer time UV-B stress, the higher value of soluble sugar or glycogen, and followed generations, sugar content became higher. F8 generation of red morph?s soluble sugar content in UV-B 60 min was highest 6.639ug/mg, 4.09 times for control, glycogen content was 4.960ug/mg, 3.58 times for control. Green morph F4 generation?s soluble sugar content and glycogen content in UV-B 60 min was highest, they were 5.381 ug/mg or 5.064 ug/mg, 3.18 or 3.67 times for control. The trehalose content of two kinds morph by UV-B stress decreased and then increased with generations, UV-B stress time longer trehalose content higher. trehalose content of F8 generation of red morph?s in UV-B 60 min was highest 2.684 ug/mg, 3.02 times than control. trehalose content of F4 generation of green morph was highest 2.072 ug/mg, 2.29 times for control. Long-term UV-B stress made soluble sugar content, glycogen content and trehalose content of Acyrthosiphon pisum increased, which showed that UV-B radiation was negative environment factor for Acyrthosiphonpisum,and because it was one of the adaptive mechanism of insects to stress that the increasing of sugar content. |
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