关键词: 棉花, 拟轮枝镰孢霉, 毒素, 致病力, 酶活性

Abstract: In order to study the relationship between pathogenicity and toxin activity of Fusarium verticillioides, as well the effect of toxin on root protective enzymes of cotton seedlings, the cotton seeds and seedlings of variety ‘Xinluzao 82’ were treated with crude toxin solution of F. verticillioides hydroponically. Seed germination rate, radicle inhibition rate, seedling wilting degree, root conductivity, activities of superoxide dismutase (SOD), phenylalanine ammonia-lyase (PAL), peroxidase (POD), polyphenol oxidase (PPO) in root were measured. The results showed that the activities of F. verticillioides mycotoxin was positively correlated with the pathogenicity of cotton seedlings and the activities of root protective enzymes. Toxins extracted from different pathogenic strains and their different concentrations had significant effects on germination rate and radicle inhibition rate of cotton seeds. After being treated with pathogenic bacteria toxin solution, the activities of SOD, PAL, POD and PPO in cotton seedling roots all increased first and then decreased, with the highest activity occurring within 12~24 h after treated. This study provided reference for understanding the interaction between host and pathogenic bacteria, and for the application of toxins in disease resistance breeding and new methods of disease control.

Key words: cotton, Fusarium verticillioides, toxin, pathogenicity, enzyme activity