Inhibiting Mechanisms Of The Extration From Xanthium Sibiricum On Pests

In this paper,the inhibiting effect of the extration from Xanthium sibiricum on Botrytis cinerea,and the action mechanisms by microscope observation,physiological toxicity and pathogenesis-related protein were investigated,moreover,the preliminary studies on insecticidal activity of the extration from Xanthium sibiricum on armyworm were done.The results were as follows. (1)The extration from Xanthium sibiricum had high antifungal activity to Botrytis cinerea by inhibiting the formation and germination of spores.When the concentration was 20mg/ml,the inhibiting rate was over 70%,EC50 was 12mg/ml. By treatment with the extration from Xanthium sibiricum of 30mg/ml, conidiophores of Botrytis cinerea were 33500. Comparing with CK of 225000,the inhibiting rate was 85.1%. The extration from Xanthium sibiricum had strong inhibiting effect on producing conidiophores of Botrytis cinerea. Under the same concentration, the extracts of Xanthium sibiricum had better inhibiting effect on germination of conidiophores and the inhibiting rate reached 77.4%.Moreover, the extracts of Xanthium sibiricum caused conidia tubes of Botrytis cinerea became shorter and weaker and hyphae weren't generally uniform in shape,had more embranchments and longer space between burls;conidiophores were round,oval and malformed;inclusion of mycelium exuded and became much less,which led to hyphae couldn't keep normal physiological course. (2)Under the treatment of the extracts of Xanthium sibiricum for a period,the conductivity showed a increasing trend,Which showed the extracts of Xanthium sibiricum could result in leakage of inclusion of mycelium and change of penetrability of cell membrane to make conductivity increase.We also tested the content change of protein from Botrytis cinerea by treatment with the extracts of Xanthium sibiricum.We found the content of protein from Botrytis cinerea declined,the longer the treatment time was,the slower the change extent was.By the treatment with the extracts of Xanthium sibiricum,the CAT activity of Botrytis cinerea showed no regularity and prominence comparing with CK. (3)The activity of β-1,3-glucosidase,phenylalanine ammonia lyase(PAL),poly-phenoloxidase(PPO)and catalase(CAT)were increased by inoculating Botrytis cinerea and under different concentration treatment with the extracts of Xanthium sibiricum.These recovery enzymes played important roles in the course that tomato resisted diseases.The extracts of Xanthium sibiricum could induce improving of host resistance to Botrytis cinerea.Moreover, by treatment with the extracts of Xanthium sibiricum,chlorophyll of tomato was higher than CK. (4) The extracts of Xanthium sibiricum had insecticidal effect on armyworm.LC50 of contact poison was 771mg/ml.The extracts of Xanthium sibiricum showed antifeeding action to the larves of Mythimna separata.When the concentration was 700mg/ml, antifeeding rate was 41.14% and proofreading death rate reached 72.41%.With the increase of concentration,feeding quantity decreased regularly and antifeeding rate and death rate showed declining trend. In a word,the prospect of extracts of Xanthium sibiricum in future production and practice is brilliant.