Primary Studies On Inhibition And Mechanism Of Combined Medicinal Plant Extracts Against Botrytis Cinerea Pers.

According to screening of thirteen kinds of medicinal plants ethanol extracts for the fungitoxicity against Botrytis cinerea, three kinds of medicinal plants ethanol extracts showed significant inhibitory effect against mycelial growth and spores germination of Botrytis cinerea. On the base of this, three kinds of medicinal plant extracts were combined to screen fungicides with synergistic action. In vitro inhibition of the combined medicinal plant extracts on mycelial growh, spore germination, spore production and hyphae biomass growth of Botrytis cinerea, and morphological changes were analyzed in order to evaluate application probability of the combined medicinal plant extracts in controlling tomato gray mold; its control effects in vivo was measured as well. meanwhile, the mechanism of the combined medicinal plant extracts against Botrytis cinerea were studied primarily from two aspects that physiological toxicity the activities of three resistance-related enzymes in tamato seedlings. The results were listed as follows:Firstly, according to screening of thirteen medicinal plants ethanol extracts for the fungitoxicity against Botrytis cinerea by mycelium growth rate test and spore germination test, three medicinal plants which were K, J and M showed significant inhibitory effect against Botrytis cinerea.Secondly, according to the results of inhibition experiment by a cross-paper disc method, combinations of K/M showed synergistic action against Botrytis cinema, thus, the co-toxicity factor be used to optimize the combinations and the optimized rate was 2:1.Thirdly, in vitro experiment, the results showed that combinations of K/M (2:1) had significant inhibition on mycelial growth and spore germination of Botrytis cinerea. It could inhibit mycelial growh, spore germination and spore production of pathogen completely at a concentration of 4mg/ml. Furthermore, it could cause morphological change of pathogen, such as extending slowly and mycelial abnormality and so on. In vivo, combinations of K/M (2:1) had remarkably control effect on tamato gray mold at a concentration of 4mg/ml, the result of control efficacy was 64.67%. Fourthly, we studied the physiological toxicity of the combined medicinal plant extracts on Botrytis cinerea. Under the treatment of the combinations of K/M (2:1) for a period, the conductivity showed a decreasing trend, which showed the combinations of K/M (2:1) could not result in leakage of inclusion of mycelium. We also tested the content of soluble protein of mycelium treated by the combinations of K/M (2:1), the results showed that the content of soluble protein of mycelium declined compared to untreated mycelium after six hours. Moreover, the influence of the combined medicinal plant extracts on the activities of three resistance-related enzymes in tamato seedlings were studied, the results showed that the combinations of K/M (2:1) increased the activities of superoxide dismutase (SOD) and peroxidase (POD) in tamoto seedlings, but had no correlation with the change of activities of polyphenoloxidase (PPO).