Seed germination and growth of various resistant cucumber seedlings under Fusarium oxysporum crude toxin stress

The effect of Fusarium oxysporum crude toxin stress on seed germination and growth of various resistant cucumber seedlings were researched.The results show that radicle growth and lateral root amount of various resistant cucumber seedlings are suppressed by F.oxysporum crude toxin.The more concentrated the toxin is,the more germination and growth are suppressed.However,the degree of suppression of susceptible varieties is higher than that of resistant varieties.Under F.oxysporum crude toxin stress,cell membrane permeability,MDA and soluble sugar contents increase.Cell membrane permeability and MDA content of susceptible varieties are higher than those of resistant varieties,but the soluble sugar content is lower.Under F.oxysporum crude toxin stress for 36 h,PAL,PPO and POD activity initially increases but subsequently drops.PAL and PPO peak value occurs after 12 h of continuous stress,but POD peaks after 24 h.Peak values of PAL,PPO and POD of resistant varieties are higher than those of susceptible varieties.The capability of resistance to F.oxysporum crude toxin of resistant varieties precede that for susceptible varieties.