Soil Microorganisms In The Cotinus Coggygria Plantation And The Relationship With Verticillium Wilt

Cotinus coggyria(L.)Soop, which is the main specie of red leaf landscape in Xiangshan Park, plays an important role in ecological development of Beijing. However, lack of effective control measure, the Verticillium wilt which happened in recent years not only destroyed the red leaf landscape but also lead to the death of C. coggyria on the large scale, and it had become the serious biological disaster that influenced the landscape construction in Beijing. Therefore, in order to better understand of the disease mechanism and provide the basic theory support for ecological control and non-harmful management, this paper was studied the soil properties, the population and structure of soil and rhizosphere microorganism in the C. coggygria plantation in Xiangshan Park, Badachu, Badaling in Beijing. Through the analysis on soil and rhizosphere microorganism in seven stands of C. coggyria plantation in Beijing, the conclusion was made as follow:1 The number of soil microorganisms in different stand changed largely, and the maximum and minimum of the soil microorganism had achieved 2 orders of magnitude. The number of microorganisms decreased with the increase of the soil depth. The number had significant difference in health stand and wilt disease infected stand.2 The root of C. coggygria had Rhizosphere Effects after studied the rhizosphere microorganism of the health and infected plant. The effect in health one was much stronger than the infected plant, and the effect between the health and infected plant had significant difference.3 The soil microorganisms in health forest stand and forest stand infected by the C. coggygria wilt were analyzed, the results indicated that the dominant fungi population is different in health and infected stand because the population of Fusarium is dominant in infected stand in contrast to health stand. The dominant population of soil actinomyces in two kind of stand was also different.4 The dominant populations of actinomyces isolated from the surface of soil in the health stand were white colony, yellow colony, dust-color colony, golden colony and grey colony, and the amount of these colonies occupied 88.88% of the total soil actinomyces. The populations in the middle layer and the bottom layer also contained these five colonies, and the proportion of these colonies increased a little bit. However, the amount of yellow and dust-color colony increased in contrast to decrease of other colonies that isolated from the surface of the stand infected by C.coggygria wilt. During the study, the dominant population of rhizosphere fungi also exist changes in the health forest and forest infected by Verticillium wilt.5 Endophytic fungus from 20 gena were isolated from health plant of C.coggygria. Among these gena, 15 gena such as Ascochyta, Cercospora, Aspergillus and so on were isolated from stem, and 8 gena isolated from leaf mainly included Phomopsis,Mycosphaerella,Penicillium,Aspergillus and Cylindrocarpon were isolated from root. More endophytic fungus were isolated from stem, and the gena of Penicillium and Aspergillus can be isolated from all parts of the plant.6 The plate antagonistic experiment on the pathogen of C. coggygria wilt was taken by using the 4 strains of Trichoderma isolated from the soil in Xiangshan Park. All four strains include 2 strains of T. harzianum, 1 strain of T. atroviride and 1 strain of T. inhamatum had antagonistic function to the pathogen. Among these strains, the antagonistic function from the strain of T. inhamatum was significant.