生物肥与甲壳素和恶霉灵配施对香蕉枯萎病的防治效果

通过盆栽试验研究了生物肥与甲壳素和恶霉灵配施防治香蕉枯萎病效果,试验结果表明,生物肥与恶霉灵配施(H+F)处理香蕉枯萎病病情指数最高,生物肥与甲壳素配施(C+F)处理病情指数最低。单独生物肥处理防病效果为32.8%,生物肥与甲壳素配施处理为42.5%,而生物肥与恶霉灵配施加重了香蕉枯萎病病情。Biolog Eco微平板研究发现,AWCD(平均每孔颜色变化率)和Shannon等4个多样性指数变化趋势与防病效果相反:防病效果好的处理,土壤细菌功能多样性指数反而低,经检测发现病原真菌(Fusarium oxysporum f. sp. cubense)可利用Biolog Eco微平板上碳源底物并发生颜色变化,干扰测定结果。T-RFLP分析土壤细菌DNA多样性,对照(灭菌生物肥)土壤中TRFs末端限制性片段最少,生物肥与甲壳素配施处理最多。与网上数据库比较,生物肥与甲壳素配施增加了土壤中芽胞杆菌种类,与恶霉灵配施降低了芽胞杆菌种类。分析发现,T-RFLP和Biolog的主成份分析载荷图具有较高一致性。因此,生物肥与生物农药甲壳素配施,从生态角度控制土传病害,优势互补,提高了土壤细菌多样性,改善了土壤细菌群落结构,有利于提高防病效果。

Effects on controlling banana Fusarium wilt by bio-fertilizer, chitosan, hymexazol and their combinations

The control effect of banana Fusarium wilt(Fusarium oxysporum f. sp. cubense, Foc)by bio-fertilizer (F), chitosan degrading liquid (C), hymexazol (H) and their combinations was studied. The soil bacterial community diversity was investigated by Biolog Eco plate and T-RFLP techniques under pot experiment. The results showed that banana Fusarium wilt index in the treatment of the combination of bio-fertilizer and hymexazol (H+F) was the highest, and the lowest in the combination of bio-fertilizer and chitosan degrading liquid(C+F), compared with the sterilized bio-fertilizer treatment(CK). The control effect of C+F treatment was 42.0%, higher than that of single bio-fertilizer (32.8%). However, The treatment of H+F increased the severity of Fusarium wilt. The average well color development (AWCD) in Biolog plate indicated the ability of carbon utilization of microbial communities, while the indices of Shannon, Smipson and McIntosh were calculated to show the richness, dominance and evenness of the functional diversity. The changes of AWCD and diversity indices (including to Shannon H, Simpson D, Mcintosh U) were negatively correlated with the control effect in different treatments. The better effect of controlling disease showed the lower microbial diversity indices in soils, which further studied by the comparison of AWCD in three samples, including the soil (S), banana pathogenic fungi (Foc) and the mixture of soil and banana pathogenic fungi (S+Foc) by Biolog Eco plate and bacterial identification plate (patent publication number: CN101200755). The results suggested that the pathogenic fungal Foc utilized some carbon substrates well in two plates, which interfered the final color reaction. Therefore, the type and population of pathogens may be considered in the determination of the soil bacterial community functional diversity by Biolog plate. T-RFLP results demonstrated that the number of terminal restriction fragments (TRFs) was the lowest in CK treatment, and the highest in C+F, which meant the better effect of controlling disease with the higher soil bacterial genetic diversity. Compared T-RFLP information with database on the website, the soil bacterial communities traits in the treatments of C+F and F contained the more Bacillus species (the numbers were 17 and 15, respectively) than H+F and CK (3 and 4, respectively) in soil, which implied that the more Bacillus species could be used as effective functional microbes on controlling banana Fusarium wilt. The Biolog and T-RFLP shared the same distribution characteristics by the loadings of principal component analysis (PCA) in treatments, F and C+F were nearer in the space. The combination of bio-fertilizer with chitosan degrading liquid, a kind of bio-pesticides, could effectively control banana Fusarium wilt by enhancing the soil bacterial diversity and improving the community structure, especially the changes of population and diversity of Bacillus spp.