雷公藤根际微生物特征研究

摘要

根际微生物的代谢作用,直接促进或抑制根的营养吸收和生长,也影响根际土壤中的物质转化,雷公藤根系发达且多与其他树种混交栽培,其根际微生物活性对雷公藤的生长和土壤肥力均有不可忽视的影响.以福建省泰宁县3种不同栽培模式雷公藤林(野生雷公藤林、杉木雷公藤混交林、厚朴雷公藤混交林)为研究对象,通过稀释平板法测定3种不同雷公藤林分根际土壤和非根际土壤中细菌、真菌、放线菌的数量.结果表明:根际土的微生物数量大于非根际土的微生物数量;3种林分,无论是在根际土壤中,还是在非根际土壤中,均表现为细菌数量＞放线菌数量＞真菌数量；根际微生物(R)比非根际微生物(S)更活跃,3种林分的3大类微生物的R/S数量比值均大干1；3种林分的微生物活性表现为厚朴雷公藤混交林＞杉木雷公藤混交林＞野生雷公藤林,表明混交方式可促进雷公藤根际微生物活性.%Rhizosphere is the zone of soil surrounding a plant root, which provide a conducive special environment for a wide range of microorganisms. Root secretions at different plant growth stages provide nutrition and energy for microorganisms, thereby notably influencing their number, composition and activity. Metabolism of microorganisms in the rhizosphere promotes or limits plant nutrient absorption and growth, and also influences the transformation of substances in rhizosphere soil. Tripterygium wilfordii Hook. F. Has well-developed root systems, and is frequently planted along with other trees. This makes the study of rhizosphere microorganism activity very important for soil fertility and growth of T, wilfordii. This paper used three different T. Wilfordii forest stands [mixed Cunninghamia ianceolata (Lamb.) Hook (Chinese fir) and T. Wilfordii forest, mixed Magnolia qfficinalis Rehd. Et Wils. And T. Wilfordii forest, and natural T, wilfordii forest) in Taining County, Fujian Province as experimental materials and the dilution-plate technique to determine the number of bacteria, fungi and actinomyces in rhizosphere and non-rhizosphere soils. The results showed that: the number of rhizosphere microorganisms was much larger than non-rhizosphere microorganisms. In the three forest stands, the number of microorganisms in either rhizosphere or non-rhizosphere soil was in the order of: bacteria > actinomyces > fungi. Rhizosphere microorganisms were more active than non-rhizosphere microorganisms. In three forest stands, rhizosphere to non-rhizosphere ratio of microorganisms number was higher than 1. The activity of microorganisms in the three forest stands was in the order of: mixed M. Qfficinalis and T. Wilfordii forest > mixed Chinese fir and T. Wilfordii forest > natural T. Wilfordii forest. This suggested that mixed forest modes enhanced the activity of microorganisms.