| The verticillium wilt of cotton is difficult to control because microsclerotia formed by Verticillium dahlia kleb. can resist the adverse environment and allow a long-term survival in the soil. The application of cotton biochar can overcome the disadvantages of straw returning and prevent the entrance of Verticillium dahlia kled. into the soil. The objective of this study is to explore the influence mechanism of cotton biochar on Verticillium dahlia kleb. by examinig the effects of cotton biochar on the mycelial growth, microsclerotium germination and toxin secretion of Verticillium dahlia kleb. Shake cultivation and plate culture were used to test the resulting influences of cotton biochar on the mycelial growth of V. dahlia and the germination of microsclerotium. The dish dipping method was used to observe the germination of cotton seed and melon seed to investigate the effects of biochar on reducing toxicity of Verticillium dahlia. Results showed that cotton biochar had no significant effects on the mycelial growth of V. dahlia under liquid culturing condition, while it had promotional effects under solid culture condition. In addition, cotton biochar inhibited the germination rate of the microsclerotium. As treatment time went on, the inhibition effect became disappeared. Moreover, the addition of cotton biochar seriously reduced the toxicity of V. dahlia under liquid culture conditions. At the mid-stage of liquid culturation, cotton seed germination rates were 53.3% and 33.3% after 12 days in the treatments of 2.0 g·L-1 biochar and CK, respectively (P<0.05). At the prophase, middle and late stages, the seedling length with the treatment of 0.5 g·L-1 biochar were 3.9, 1.1 and 2.2 times more than that with the CK treatment, respectively. Compared to CK, biochar enhanced the melon seed germination, radicle length, plumule length and seedling length. In conclusion, biochar could slightly inhibit the mycelial growth and microsclerotium germination of V. dahlia, while it could significantly reduce the toxicity of V. dahlia. |