| Alligator weed(Alternanthera philoxeroides) is a vicious weed in the world currently. Due to that its clonal reproductive capacity, adaptability and resistance to environment are robust., it have been jeopardizing diversity of species, agricultural production, aquaculture and the ship industry seriously. Nimbya alternantherae SF-193that our laboratory isolated from Alternanthera philoxeroides is a strongly phytopathogenic fungus of Alternanthera philoxeroides and inhibit the growth of the weed in the field rapidly. In this paper, we study the weeding effect of different fungi agent of SF-193and Chemical herbicides when they were use on alligator weed. Response surface methodology (RSM) was applied to optimize composition ratio of solid-medium fermented Nimbya alternantherae SF-193. Finally, we also study the influence of different incubation temperature and time on the activity of CWDE. All of this experiment supplied adequate theoretical basis for in-depth study of pathogenic factors and large scale production of SF-193.(1) we compared the efficacy of different fungal agents and herbicides against alligator grass.When the application rate of the dust of SF-193were10、20、30g/m2, the disease index of7days after spray were69.29、80.21、84.57,and the index of15days after spray were61.36、73.7.77.73. When we used the dust10、20、30g/m2respectively together with fluroxypyr, the disease index of7days after spray were73.17、78.83、86.78, and the disease index of15days after spray were84.76.90.23.97.54. It suggest that, the powder has a higher efficacy against field weed than liquid, it has a same efficacy with fluroxypyr and the efficacy is more early. When they used together the efficacy is better and longer.(2) Response surface methodology (RSM) was applied to optimize composition ratio of solid-medium fermented Nimbya alternantherae SF-193and evaluate the combined effects of the three main independent parameters, rice flour, soymeal and carrot meal on mycelium growth. The results showed that the interaction between soymeal and carrot meal was significantly positive effect on the growth of mycelium. And the combined effects of rice flour with other components were also significant. The optimum concentration of rice flour, soymeal and carrot meal in solid-medium were found to be61. g/L,9.0g/L and1.1g/L, respectively.(3) Though colorimetric assays of DNS, we detected CWDE activities of healthful leaves and leaves which had been vaccinate with SF-193. activities of cellulase、Xylanase and PG in inoculated leaves were higher than heathful leaves’. Incubation time had strongly influence on Cx, β-glucosidas Xylanase, and had some influence on PG activity,1days after inoculation, PG activity went its highest value which is33.05U/mg, then its activity decreased.2days after inoculation, Xylanase went to their highest activity, the value was54.71U/mg, then its activity decreased. Cx and β-glucosidas had their highest activity which value were105.85,88.62U/mg respectively.In the3th day. All of them decreased to their lowest activity. In the5th day their activity increased slightly. But PMG activity is no significant change in these days after inoculation. Different temperature influence activities of Cx, β-glucosidas, Xylanase and PG severely. The first three’ activities went to their highest value when the temperature was30℃, their higest value respectively were96.10U/mg.78.05U/mg、48.00U/mg. PG had the highest activity when temperature was35℃, the value was36.87U/mg. But temperature had no effect on PMG activity. |
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