UV-B辐射下青藏高原高寒草甸土壤微生物生态学研究

项目名称： UV-B辐射下青藏高原高寒草甸土壤微生物生态学研究

项目编号： No.30870438

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 冯虎元

作者单位： 兰州大学

项目金额： 33万元

中文摘要： 增强的uv-b辐射对高寒草甸生态系统中土壤细菌丰度、群落结构以及微生物活性以及植物叶片内生菌多样性及其特征进行了研究。在UV-B辐射下，0-10cm之间和10-20cm之间的可培养微生物数量分别为2.46×6 CFU/g 和1.44×6 CFU/g, 而对照为(2.94×6 CFU/g 和1.65×6 CFU/g。UV-B辐射显著降低了微生物的多样性，表层从20到13，底层从16降到13。运用微热量法测定的土壤微生物活性也发生了明显变化，UV-B辐射导致土壤微生物活性下降。同时，对来自13种植物的内生细菌的形态和生理特性以及遗传多样性研究结果发现UV-B处理条件下的内生细菌菌群密度，明显高于正常条件。已鉴定出的22种内生细菌在13种植物中分布存在差异。恢复培养的内生细菌中，大部分都能够产生黄色、橘红或粉红色的色素。已鉴定的细菌中G+占的比例较高。这与其它冷环境如冻土和冰川微生物的特性相一致，而与温和环境中植物内生细菌的特性差异较大。说明环境条件对内生细菌的种群结构具有很强的选择作用，即相似的环境选择相似的细菌类群。也反映出内生细菌对于环境的适应机制和生存策略。

中文关键词： 青藏高原；UV-B 辐射；土壤微生物；臭氧层衰减；微量热法

英文摘要： The effects of enhanced UV-B radiation on soil bacteria abundance, community composition and the total microbial activity in alpine meadow ecosystem of Qinghai-Tibet Plateau were investigated. Traditional counting and 16S rRNA sequencing were used to investigate the culturable bacteria amount and composition in soil, meanwhile the total microbial activity was measured by microcalorimetry technique. The amount of soil culturable bacteria was slightly reduced with the enhanced UV-B radiation in both two depths (2.46×6 CFU/g in upper layer (0-10cm), 1.44×6 CFU/g in under layer (10-20cm)), compared with control (2.94×6 CFU/g in upper layer, 1.65×6 CFU/g in under layer), although the difference was not statistically significant (p>0.05). However, the bacteria diversity decreased obviously due to enhanced UV-B, the number of species for upper layer was decreased from 20 to13, and from 16 to 13 for under layer. The distribution of species was also quite different between the two treatments. Another obviously decreased data induced by enhanced UV-B radiation was the total soil microbial activities, which was represented by the microbial growth rate constant (k) in our experiment. The results indicated that the culturable bacteria community composition and the total activity of soil microbes have been considerably changed by the enhanced UV-B radiation. At the same time, It was founded that different plant species had different culturable endophytic bacteria and there was changed under the different treatment conditions.

英文关键词： Qinghai-Tibet Plateau; UV-B radiation; soil microbes; Ozone depletion; Microcalorimetry