Seasonal Variation of Microbial Communities in the Rhizosphere of Impatiens hainanensis（Balsaminaceae） at Different Altitudes

Key words: 
• Impatiens hainanensis /
• mycorrhizal fungi /
• bacterium /
• vegetation community /
• limestone habitat

Abstract: The rhizosphere soils of Impatiens hainanensis in different seasons were collected at different altitudes,high（1 000 m）,medium（400 m） and low（190 m）,and the fungi and bacteria of the collected samples were isolated by using the morphological method and molecular detection technology and cultured for analysis of the microbial community composition and dynamic changes to reveal the dynamic changes of fungi and bacterial communities in the rhizosphere of I.hainanensis at the different altitudes.The results show the operational taxonomic unit（OUT） number,diversity index and richness index of the fungi in the rhizophere in the habitats of the different altitudes were higher in the dry season than in the wet season,while the OTU number,diversity index and abundance index of the bacteria was higher in the wet season than the dry season.Dominant species of Trichoderma,Talaromyces,Penicillium,and Aspergillus in the rhizosphere fungal community were observed most frequently in the high altitude in the dry season and the dominant bacterial species of Bacillus and Burkholderia in the rhizosphere bacterial community were most found at the low altitude in the wet season.The redundancy analysis of fungi and bacterial communities in the rhizosphere indicated the dry and wet season were the main driving force of the rhizosphere microbial community,followed by altitudes.In the limestone area where I.hainanensis grows,rhizosphere fungi and bacteria showed an opposite trend in response to the seasons and altitudinal gradients.