中国农业科学 ›› 2004, Vol. 37 ›› Issue (10): 1521-1526 .

• 园艺 • 上一篇    下一篇

黄瓜不同生育期根际微生物区系变化研究

胡元森,吴坤   

  1. 南京农业大学生命科学院微生物学系
  • 收稿日期:2003-12-01 修回日期:2004-02-16 出版日期:2004-10-20 发布日期:2004-10-20
  • 通讯作者: 胡元森

Studies on Microbial Population Dynamics in the Cucumber Rhizospheres at Different Developmental Stages

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  1. 南京农业大学生命科学院微生物学系
  • Received:2003-12-01 Revised:2004-02-16 Online:2004-10-20 Published:2004-10-20

摘要: 对黄瓜根际主要微生物类群在不同生育期的变化进行了研究,着重用PCR-DGGE技术对根际土壤未培养优势菌群的变化进行了分析。结果表明,黄瓜根际微生物主要类群的数量与其生长发育呈正相关。根际微生物的数量一般是由栽种时开始升高,到花期或盛果期时达到最高峰,生长后期有下降趋势,根际微生物数量比同时期的对照要高。土壤微生物总基因组16SrDNA V3区的PCR-DGGE图谱显示农田土壤微生物区系组成稳定,但黄瓜生长对某些种群数量分布有一定影响,特别是黄瓜生长前期,根际细菌数量变化显著,在花期表现尤其明显,揭示黄瓜花期生长对根际微生物的影响可能较大,也说明这些类群微生物可能是对黄瓜花期生长起特殊作用的未培养微生物。另外,有许多在整个过程中亮度基本不发生变化的条带,这是一些对农田微生态环境的构成及稳定起重要作用的土居微生物群体,它们在土壤微生物中占有很大比重。

关键词: 土壤, 黄瓜, 根际微生物, PCR-DGGE

Abstract: The microbial population dynamics in the rhizospheres of cucumber was studied by cultivation and culti- vation-independent analysis based on directly extracted DNA. Rhizosphere samples were taken at 2nd, 4th, 7th and 10th week after the seeds were planted, which was positively related to the corresponding date of cucumber growth stages. Results showed that the total number of bacteria, fungi and actinomyces began to rise at planting and quickly reached its peak at seedling or flowering period, but decreased slightly later. Bacterial population in rhizosphere was higher than that of corresponding control except certain periods, while both showed the similar change trend at all stages. Nitrogen fixing bacteria, nitrogen-fixing bacteris and ammonifiers showed the same change tendency in population as bacteria and actinomyces did while cellulose decomposing microbes had the contrary rhizosphere effects as cucumber developed. There was a positive correlation between the rhizosphere microbe population and cucumber development. PCR was employed to amplify V3 region of 16SrDNA, then the products were subjected to denaturing gradient gel electrophoresis (DGGE). DGGE profile indicated that a few of microbe species lived stably in the farmland, but some were affected in population due to cucumber growth. Significant difference was observed in rhizosphere and control soils especially for the seedling and flowering samples. Few prominent bands in DGGE patterns which displayed stronger or less illumination means the bacteria represented had great population change in that period. This phenomenon indicated that flowering cucumber heavily affected rhizosphere bacteria, or the bacteria, most probably uncultured bacteria, functioned specially for cucumber flowering. Most detected bands with no illumination change in DGGE were likely to represent the indigenous microbles that were essential for constructing and stabilizing farmland microecological environment.

Key words: Soil, Cucumber, Rhizosphere microbe, PCR-DGGE