木霉对辣椒疫霉菌抑制作用的超微结构与细胞化学

哈茨木霉菌株NF9和TC3对辣椒疫霉病菌具有强烈的抑制作用。超微结构与细胞化学研究表明,木霉菌丝能够缠绕并寄生疫霉菌菌丝,且重寄生作用主要发生在培养基内的菌丝上。但在绝大多数情况下,木霉菌可直接水解和破坏疫霉菌菌丝,说明木霉抑菌作用的主要机制是直接向外分泌水解酶分解疫霉的细胞壁及细胞质,而不是重寄生作用。不同培养基对木霉的重寄生作用有重要影响,减少培养基中葡萄糖含量可以增强木霉的重寄生作用和抑菌效果。此外,在菌落生长后期,疫霉的新生菌丝均可侵染自身的老菌丝。

ULTRASTRUCTURAL AND CYTOCHEMICAL EXAMINATION ON ANTAGONISM OF TRICHODERMA HARZIANUM TO PHYTOPHTHORA CAPSICI

The isolates of Trichoderma harzianum, NF9 and TC3, exhibit strong inhibition on the growth of Phytophthora capsici in PDA culture medium. The ultrastructural and cytochemical analysis showed that NF9 and TC3 could enwind and infect the Phytophthora hyphae especially in the hypha within the medium. On the other hand, Trichoderma harzianum could directly degrade Phytophthora hyphae when they contacted. This is much more common than the mycoparasitism. These indicated that the antagonism mechanism depend mainly on the direct degradation; and the biocontrol effectiveness was determined by the coordination of various hydrolytic enzymes secreted by Trichoderma harzianum. There was significant effect on mycoparasitism by the different medium. Less sugar in the medium could result in higher frequency of mycoparasitism. It was also found that the younger hypha of Phytophthora capsici could infect its old ones during the senescence of the colonies.