Inhibiting Mechanism of Two Fungicides on Rhizoctonia solani
YIN Da-chuan;QI Jin-yu;DENG Yu-xia;GAO Guo-ping;DU Hui;CHEN Fang-zheng;DENG Xun;College of Forestry, Shenyang Agricultural University;Experimental Forest Farm, Liaoning Forestry Vocational and Technical College;Forestry Protection Institute, Heilongjiang Academy of Forestry;
In order to study on inhibition o f Rhizoctonia solani by mancozeb and carbendazim, the methods of mycology and biochemistry were used to test the toxicity function on R. solani and analyze the antibacterial rates and bacteriostatic concentration(EC_(50)). The response of R. solani through growth and physiology to fungicide stress was determined. The effect of mancozeb was better than that of carbendazim. The highest antibacterial rate reached to 90%. The mancozeb's EC_(50) was 10.23 mg·L~(-1), and carbendazim's EC_(50) as 2213.77 mg·L~(-1)by regression equation. In terms of growth, the growth of R. solani could all be inhibited by mancozeb and carbendazim. In the aspect of physiological metabolism, the use of carbon and phosphorus were inhibited. PCA showed that fungicide was mainly through inhibiting the strain nutrition used to achieve sterilization. In addition, with the use of ethephon bacteriostatic concentration method, under the stress of potions, the antioxidant enzyme activity and cell osmotic regulation substances content changes were studied. In the treatment with fungicide, the osmotic regulation substances in strain cell(soluble protein and MDA) and the activity of antioxidant enzyme(CAT, POD and SOD) increased, indicating that the R.solani was damaged, with a better effect of mancozeb than that of carbendazim. The above may be the sterilization mechanism of mancozeb and carbendazim on R. solani, and the results can be used as scientific prevention and control of seedling blight.