Effects Of Ultraviolet Radiation On Biological And Biochemical Characteristics Of Therioaphis Trifolii

Therioaphis trifolii is a common pest in the plant of alfalfa.When the population was huge,it will cause a significant reduction in alfalfa.The reduction of the level of ozone in the atosphere significantly increased the level of the Ultraviolet-B（280-320nm）radiation reaching the surface.Ultraviolet radiation can affect the physiology and ecology of insects.In the present study,T.trifolii nymph,produced with in 12 hours,was respectively treated with 40 W UV-B radiation for 20 min,30 min,40 min,50min and 60 min once a day and was continuously irradiated for 8 generations.By establishing the life table to calculate the population variables and the determination of the protective enzymes,protein content,sugar content and fat content,the changes in the population variables and the protective enzyme and substance content of T.trifoliii group in the environment of ultraviolet radiation were explored,and then the ultraviolet radiation pair was identified.In order to clarify the effects of growth,development and reproduction of T.trifoliiis has been explored in UV-B radition,it will provide a theoretical basis for the population evolution,ecological in heritance and comprehensive prevention and control of T.trifoliiis.The test results are as follows:1.Effect of ultraviolet radiation on the biological characteristics of T.trifoliiis.Ultraviolet radiation inhibited the growth and development of T.trifoliii,with the treatment of radiation algebra increased,the effect of inhibited ecreased first and then increased,it will get a maximum value in the treatment of 30 min,T.trifoliii nymph period of radiation was shorter than the control in each generation（P<0.05）,With the treatment of radiation algebra increased,the body length became shortened then extended,the minimum length was 1.14 mm,only 68.26%of the control;With the treatment of radiation algebra increased,the nymph period was prolonged then shorten,the value of generation of F₂^F₈ of treatment longer than the control,it will get a maximum value was 6.56 d;The life longevity of adult aphid became shortened then extended with the extension of radiation time,the minimum value was 10.67 d,only 83.16%of the control;The net reproductive rate became extended then shortened with the extension of radiation time,the minimum value only 45.91%of the control,the value significantly decreased than control in each F₃^F₈ generation（P<0.05）,the minimum value occurred in the treatment of 30 min in each F₄^F₈ generation;The mean generation time became extended then shortened with the extension of radiation time;With the increase of the radiation algebraic,the intrinsic rate of natural first decreased and then increased in each generation of F₃^F₈（P<0.05）,it will get a minimum value in each generation,which value only 77.78%of the control;With the increase of the radiation algebraic,the finite rate first and decreased then increased,all of the value shorter than the control,the significant decreased in the generation of F₃^F₇（P<0.05）,which value only 92.31%of the control.In the F₈generation,the parameters of the F₁ generation were not restored.2.Effect of ultraviolet radiation on the protective enzyme system and soluble protein content of T.trifoliii.When the UV-B radiation affected T.trifoliii the CAT active varied with the increased of radiation generation and radiation time,the value became decreased after increased,the active significantly higher than the control in the generation of F₁^F₇（P<0.05）,the maximum value occurred in the treatment of 40min in each generation,the maximum value was 7.58 times as the control;the POD active varied with the increased of radiation generation and radiation time,the value became increased after decreased,the maximum value was 2.09 times as the control;the SOD active significantly higher than the control（P<0.05）,with the increased of radiation generation and radiation time,the value became increased after decreased,except the generation of F₆,the active got a maximum value in the treatment of 40min in each generation,the maximum value was 8.05 time as the control;With the increased of radiation generation and radiation time,the value of the soluble protein became increased after decreased,all of the value was significantly higher than the control（P<0.05）,except the treatment of 30 min of the generation of F₇,the maximum value occurred in the treatment of 40 min in the whole generation,it will get a maximum value was 9.72 ug/mg.T.trifoliii increased the active of CAT,POD and SOD to cut down the damage of UV-B,the active of CAT and SOD play an important role in reduced the damage,more longer UV-B radiation T.trifoliii will get adaptive,the significant change will occurred in the treatment of 30 and 40 min.3.Effect of ultraviolet radiation on the content of sugar and fat in T.trifoliii.Contents of soluble sugar,trehalose,glycogen,and fat in T.trifoliii were also affected by UV-B radiation,the specific manifestations were that soluble sugar,trehalose,glycogen,and fat content were higher than those of the same generation in control.The value increased first and then decreased with increasing irradiation generation,the soluble sugar and glycogen content increased first and then decreased,the trehalose content decreased first and then increased,the value increased first and then decreased with increasing irradiation time,the contents of soluble sugar,trehalose,glycogen,and fat became increased first and then decreased,the contents of soluble sugar significantly higher than those of the same generation in control in the generation of F₂^F₇（P<0.05）,it will get a maximum value was 14.31 ug/mg,which value was 1.84 times as the control;the contents of trehalose was significant higher than the control in the treatment of 30⁵0 min（P<0.05）,except the generation of F₆,the contents get a maximum value in the treatment of 40 min in a whole generation,the minimum value increased by 48.15%of the control;the contents of glycogen was significant higher than the control（P<0.05）,it got a maximum value in the treatment of40 min and in the generation of F₆,the maximum value was 5.36 times as the control;the contents of fat was significant higher than the control（P<0.05）,the maximum value was 2.00 times as the control.The UV-B radiation will increased the contents of soluble sugar,trehalose,glycogen,and fat,the most obvious negative effects were obtained in the treatments of UV-radiation for 30 min and 40 min,it may be that the T.trifoliii had adaptability in the late radiation stage.