A Preliminary Study On Induced Systemic Resistance To Insect By Exogenous Signaling In Poplar

Plant resistance to herbivore attack is primarily concerned the two aspects: constitutive resistance and induced resistance. The latter plays a main role in the defense mechanisms of plant.The induced- resistance include two types due to exogenous factors.One is rapid local response,Hmiting the pathogen hi infected location.The other that induces a series of defense response leading to the systemic defense of plant is induced systolic resistance(ISR).The study on mechanisms of the induced resistance can not only get a deeper under-standing on interactions between herbivore and plant in theory,but also improve integrated pest management in practice,for example the cultivation of cultivar with high induced resi-stance to insect and development of revulsant et al.hi this study,methyl jasmonic acid(MeJA) and methyl salicylic acid(MeSA) which were two volatiles iduced by insects in plant were used to fumigate polar.Then the biological method was employed to analyze the growth and development of insects which fed on the two different fumigated leaves.The analysis of resistance component was to measure and analyze the hormone and phenolics in two different fumigated leaves by use of ELASE and HPLC respectively.The results showed that both the leaves which were fumigated by MeJA and MeSA limited the growth and development of Clostera anachoreta( Fabricius) and Lymantria dispar( (Linnaeus) to some extent including losing weight,decrease of digestibility coefficient ,reduction of conversion rate and utilization coeffcient, delay of the generation period,ghtening bodyweight and rise of the mortality.On the other hand,the contents of hormone and phenolics showed the change to a certain extent.Through the quantitative analysis of the growth and development of insects we found that as plant volatiles induced by insects.MeSA and MeJA which acted as signalling molecules can activate the defense system in poplar,leading to induced resistance to pests.We also found that MeJA and MeSA can induce the similar response to insect attack in plant through measuring the contents of hormone and oxybenzene in the leaves which were fumigated by MeJA and MeSA.lt can be concluded that both MeJA and MeSA were ?important alarm signalling molecules between plants-in response to insect pest.That's be side,two volatiles acted as chemnical communication at the same time.