Preliminary Studies On Allelopathy And Mechanism Of Extracts From Garland Chrysanthemum On Watermelon Fusarium Wilt

Fusarium wilt as one of the main diseases harming watermelon industry, traditional methods such as the use of chemical fungicide had posed threat to the natural ecological environment, however, Botanical fungicides taken as a novel approach for the future treatment of plant disease provided a way of thinking for sustainable development of ecological environment. The growth rate method was used to study the allelopathy of thyl acetate extracts from garland chrysanthemum with consentration of 1g/mL, 0.5g/mL,0.25g/m L, 0.125g/mL, 0.0625g/mL, 0.03125g/mL, 0.015625g/m L respectively on watermelon fusarium wilt in vitro,relevant physical and chemical properties of the antifungal active ingredients explored, and the mechanism was preliminary analysised,aimed at providing theoretical basis for the development of botanical pesticides. The results are as follows:? The extracts from garland chrysanthemum have remarkble allelopathy effect on watermelon fusarium wilt, which had the highest inhibition rate, 100%, in the concentration of 1g/mL during 48-72 h, the lower the concentration and longer the acting time, the weaker the effect of allelopathy.? After treat with heat, ultraviolet radiation and reducing compounds, it turned out that the higher the temprature, the longer the acting time of ultraviolet radiation and the higher the consentration of reducing compounds, the lower the inhibition rates of the extracts from garland chrysanthemum on watermelon fusarium wilt in vitro. To keep physical and chemical properties of effective antimicrobial component of extracts from garland chrysanthemum the optimal environment condition was: temperature below 40?,uv irradiation time not more than 90 min, and consentration of reducing compounds Na2SO3 below 0.7 mg/mL.? After treat with different consentration of extracts from garland chrysanthemum,the relative enzyme activities indexes and soluble protein content of fungus decrease compared with the control, and MDA content was higher than the control. Meanwhile, the higher the consentration was, the lower the relative enzyme activities and the higher the MDA content.? After root-irrigation treat with different consentration of extracts from garlandchrysanthemum, the intracellular protective enzyme(SOD, POD, CAT), the difense-related enzymes(PAL, PPO, chitinase) and the content of H2O2, soluble protein of the watermelon seedlings were higher then the control, MDA lower than the control.