Effect of Metalaxyl on Membrane Permeability of Phytophthora nicotianae var. nicotianae

In order to clarify the physiological mechanism of the resistance to metalaxyl of Phytophthora nicotianae var.nicotianae,the changes of the relative leakage of sensitive,lower-resistant and higher-resistant strains treated with metalaxyl at different concentrations within 540 minutes were studied.The results showed that metalaxyl might damage the membrane of P.nicotianae var.nicotianae,whose permeability increased after metalaxyl treatment; the speed and degree of metalaxyl effect on the membrane permeability of the sensitive strain,ZC002 were similar to those of the lower-resistant strain,10M-006, which increased when metalxyl concentration (0.1~100.0 μg/mL) increased; those of the higher-resistant strain,10M-004 were lowest,which increased when metalxyl concentration (50.0~100.0 μg/mL) increased.10M-004 had stronger ability to adapt to metalaxyl than ZC002 and 10M-006 had,which decreased when metalaxyl concentration increased.