关键词: 核桃; 腐烂病发病程度; 可培养微生物数量; Biolog技术; 微生物多样性

Abstract: 【Objective】 To study the relationship between quantities and functional diversity of soil microorganism and walnut rot disease and provide a theoretical basis for the further prevention and control of walnut rot disease by microbiological control techniques.【Method】Soils of 12 years walnut trees at health, mild disease, moderate degree and severe disease status were taken as the research object to determine microbial diversity in root soil using culturable microorganism count and biolog ecological plate and to analyze the correlation microbial diversity with the degree of disease.【Result】The results showed that there were significant differences in the number of three culturable microbes in the rhizosphere soil of walnut with different degrees of rot disease. Compared with the healthy soil, the numbers soil bacteria in different levels of soil increased first and then decreased, the soil of mild and moderate onset soil increased by 15.67% and 12.28% respectively, and the soil of severe onset decreased slightly by 33.46%.. The number of soil actinomycetes in moderate and severe soil decreased by 47.33%, 32.98% and 19.27% respectively, and the number of fungi decreased by 49.32, 22.68% and 42.68%, respectively. The utilization of Biolog carbon sources showed that soil microbial diversity of walnut rot was significantly different with different degrees of disease. From the AWCD value of 144 h, it could be seen that the microbial activity in the soil of mild disease was the highest. The healthy soil decreased by 12.03%,the soil of moderate and severe disease decreased by 14.56% and 18.42% compared with the soil of mild disease respectively. The Shannon richness index (H) of mild disease soil was higher than that of healthy, moderate and severe soil. The study on the utilization of different carbon sources showed that the soil microbes of healthy and mild disease had strong utilization to carbohydrate and amino acid. However, the use of carbohydrates, amino acids and phenolic acid carbon sources in the soil where the disease was more serious was decreasing. The principal component analysis showed that there were certain differences in soil microbial communities under different levels of rot disease. Among the 31 carbon sources, carbohydrates and amino acids determined the differences of the principal components.【Conclusion】The microbial activities in the soils of moderate degree and severe disease were lower than those in the soil of the lower degree disease and the healthy soil. Therefore, according to the different carbon sources used by soil microbes, designing reasonable trace element fertilizer will hopefully reduce the occurrence of walnut rot disease.

Key words: walnut; different levels of rot disease; culturable microbial quantities; biolog ecological plate; microbial diversity