| Aphis craccivora Koch is one of the main pests in mung bean fields,and its occurrence and damage degree in Heilongjiang Province are gradually increasing.Long-term chemical control has led to the emergence of the "3R" problem.Therefore,green prevention and control of Aphis craccivora Koch is a top priority at present.The use of insect-resistant varieties and insect-resistance varieties induced by exogenous inducers are important ways in green control.In this study,the aphid-susceptible mung bean variety Xiaominglu selected by the laboratory,was chosen as the test variety.In this laboratory,potted inoculation method is used to study the changes of aphid resistance index,such as nutrient content,defense enzyme activities and secondary metabolites of the aphid-susceptible mung bean plants treated with methyl jasmonate and salicylic acid;and to study the effects on the growth indicator,such as population size,population life table parameters and feeding amount of Aphis craccivora.By doing so,this lab examines the anti-aphid mechanism of mung bean plants induced by inducers.The main findings are as follows:1.The resistance identification of Xiaominglu sprayed with different concentrations of exogenous methyl jasmonate and salicylic acid is carried out by establishing the indoor Aphis craccivora Koch population life table method.The results showed that compared with CK,the development period and population doubling time of the Aphis craccivora Koch on mung bean treated with five different concentrations of methyl jasmonate and salicylic acid were longer;the average generation period was shortened;the survival rate,fecundity,net reproductive rate,intrinsic growth rate and adult lifespan all decreased.2.We measure the amount of feeding and secretion of potted insects and Aphis craccivora Koch obtained from Xiaominglu sprayed with five different concentrations of exogenous methyl jasmonate and salicylic acid.The results showed that: within 24 hours,the secretion of honeydew after Aphis craccivora Koch feeding on the treated mung bean was significantly lower than that after feeding on CK;The Aphis craccivora Koch populations on Xiaominglu were significantly lower than those on the control treatment.3.Under Aphis craccivora Koch stress,the contents of chlorophyll and soluble protein in mung bean plants decreased slowly with time after the inducer treatment,and the soluble sugar showed a trend of increasing first and then decreasing.Five concentrations of methyl jasmonate treatment had very significant effects on chlorophyll content in mung bean plants,but had no significant effect on soluble protein and soluble sugar content.Under different treatment times,the effects on chlorophyll,soluble protein and soluble sugar content in mung bean plants were extremely significant;five A concentration of salicylic acid treatment has no significant effect on the chlorophyll content of mung bean plants,but has a very significant effect on the soluble protein and soluble sugar content.4.Under the stress of Aphis craccivora Koch,the POD and SOD activities of mung bean plants treated with the inducer increased,while the PAL increased first and then A declining inverted "V" trend.Five concentrations of methyl jasmonate treatment had extremely significant effects on SOD and POD enzyme activities,but had no significant effect on PAL content.Different treatment times had extremely significant effects on SOD,POD and PAL enzyme activities in mung bean plants;five concentrations of salicylic acid treatment,had no significant effect on PAL enzyme activity,but had a very significant effect on SOD and POD enzyme activities;different action times had no significant effect on SOD enzyme activity in mung bean plants,but had a very significant effect on POD and PAL enzyme activities.5.Under the stress of Aphis craccivora Koch,the contents of total phenols,flavonoids and tannins in mung bean plants increased first and then decreased.The dual interaction effects of methyl jasmonate at different concentrations and durations on the contents of total phenols,flavonoids and tannins in mung bean plants were extremely significant;The dual interaction effects of Ning content were extremely significant.The experimental study showed that after spraying the inducer,a number of anti-aphid indicators in mung bean plants had been induced when the insects were not inoculated,and there were significant differences compared with the control.At the same time,under Aphis craccivora Koch stress,the application of two inducers,methyl jasmonate and salicylic acid,could reduce the content of chlorophyll and soluble protein,the aphid-resistant indicators of aphid-susceptible mung bean varieties,and the content of soluble sugar,total phenols,tannins and flavonoids.When the content increased,the activities of SOD,POD and PAL increased,the population of Aphis craccivora Koch decreased,and the feeding amount of bean aphid decreased,indicating that the induction of the inducer improved the aphid resistance of the susceptible mung bean varieties.The five concentrations of methyl jasmonate treatment changed with time.At the concentration of 0.05 mmol/L,the induction effect on the aphid resistance index of mung bean was the most significant on the 6th and 9th days;the five concentrations of salicylic acid treatment Then,with the change of time,on the 3rd and 6th days,the induction effect on the aphid resistance index of mung bean was the most significant when the concentration of 5mmol/L was treated.Both inducers of methyl jasmonate and salicylic acid could induce aphid resistance of aphid-susceptible mung bean varieties.When the exogenous methyl jasmonate was0.05 mmol/L and the concentration of salicylic acid was 5 mmol/L,in the first treatment The growth inhibition effect on Aphis craccivora Koch and the induction effect on the aphid resistance index of Xiaoming green plants were the most significant from 3 to 9 days. |
