• 关键词：东南景天  镉  内生细菌  油菜  促生作用  巨大芽孢杆菌

• 基金项目：国家高技术研究发展计划（No.2012AA101401）；留学人员科技活动择优项目；中央高校基本科研业务费专项资金（No.2013FZA6005）；浙江省大学生科技创新活动计划（新苗人才计划）（No.2012R401267）

• 潘风山
• 浙江大学环境与资源学院 污染环境修复与生态健康教育部重点实验室, 杭州 310058

• 陈宝
• 浙江大学环境与资源学院 污染环境修复与生态健康教育部重点实验室, 杭州 310058

• 马晓晓
• 浙江大学环境与资源学院 污染环境修复与生态健康教育部重点实验室, 杭州 310058

• 杨肖娥
• 浙江大学环境与资源学院 污染环境修复与生态健康教育部重点实验室, 杭州 310058

• 冯英
• 浙江大学环境与资源学院 污染环境修复与生态健康教育部重点实验室, 杭州 310058

• 摘要：以我国原生的镉超积累植物东南景天为材料，从其根部筛选到4株对镉具有耐性的内生菌株，它们均可产生生长素（IAA）、铁载体等促生物质.砂培试验发现，接种上述菌株能促进油菜植株的生长，提高植物对镉的积累量，其中，以菌株SaN1的作用效果最显著，可使油菜苗期地上部的生物量和镉积累量分别提高18.6%和45%.生理生化鉴定与16S rDNA分析证明，SaN1为巨大芽孢杆菌（Bacillus megaterum）；该菌株接种到LB液体培养基后，12 h进入对数生长期，42 h达到稳定生长期，54 h进入衰亡期；其最佳培养温度为30 ℃，最适pH为中性.

• Abstract：A native cadmium (Cd) hyperaccumulator Sedum alfredii Hance was studied to understand the microbiological mechanisms of metal accumulation in plant and four Cd-tolerant endophytic bacterial strains were isolated from the roots. The four strains had the potential of producing plant growth-promoting substances such as indole-3-acetic acid (IAA) and siderophore. Sand culture experiments showed that inoculating these strains into oilseed rape plants enhanced plant growth, and improved Cd accumulation in the plants. One of strains named SaN1 showed the highest efficacy. It increased plant biomass and Cd accumulation in shoots by 18.6% and 45%, respectively. Based on its physiological and biochemical characteristics as well as 16S rDNA sequence information, SaN1 is identified as Bacillus megaterum. The growth of the strain in LB liquid medium reached a logarithmic phase in 12 h, a stationary phase in 42 h, and a decline phase in 54 h. Its optimal growth conditions were 30 ℃ and a neutral pH.

• Key words：Sedum alfredii Hance  Cd  endophytic bacteria  oilseed rape  growth promoting effect  Bacillus megaterum

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