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不同草原类型针茅根部可培养内生细菌群落结构及其功能

胥婷1,2,杨丽强1,2,宋宇3,李新宇1,张惠文1**   

  1. (1中国科学院沈阳应用生态研究所森林与土壤生态国家重点实验室, 沈阳 110164; 2中国科学院大学, 北京 100049; 3辽东学院, 辽宁丹东 118003)
  • 出版日期:2015-11-10 发布日期:2015-11-10

Endophytic bacterial community structure and function of Stipa roots from different types of steppes in northern China.

XU Ting1,2, YANG Li-qiang1,2, SONG Yu3, LI Xin-yu1, ZHANG Hui-wen1**   

  1. (1State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China; 2University of Chinese Academy of Sciences, Beijing 100049, China; 3Eastern Liaoning University, Dandong 118003, Liaoning, China)
  • Online:2015-11-10 Published:2015-11-10

摘要: 为了研究我国北方草原针茅根部内生细菌的群落结构多样性与功能,从新疆、甘肃、内蒙3省区6个草原样地(亚高山草甸、高山草甸、戈壁、荒漠草原、典型草原和草甸草原)采集针茅根样品。通过严格的表面消毒和平板分离,共获得针茅根部内生细菌200株,分布在4门7纲28属。其中,芽孢杆菌属细菌为针茅根部绝对优势属,约占总菌株数的1/2。在戈壁采集的样品中以假单胞菌属为优势属,其余5个样地样品中均以芽孢杆菌属为优势属。亚高山草甸的Shannon多样性指数最高,典型草原和草甸草原覆盖的属最多,丰富度指数和均匀度指数均较高,而高山草甸覆盖的属最少,Shannon多样性指数、丰富度指数及均匀度指数均最低。各样地间内生细菌种群相似性系数在0.25~0.61,其中高山草甸与其他草原类型的相似性系数均很低,为0.25~0.33,其次是戈壁和荒漠草原的相似系数。另外,在200株内生细菌中,73株具有产生IAA的能力,35株有溶磷活性,23株有拮抗病原真菌的能力,20株有固氮活性,6株具有解钾活性。从样地分布来看,各样地产IAA的菌株也最多,尤其是高山草甸、亚高山草甸和荒漠草原。溶磷菌株在高山草甸所占比例较大,拮抗菌株在亚高山草甸所占比例较大,而固氮菌在荒漠草原所占比例较大,解钾菌株在各样地所占比例均较小。各功能菌株分布在25个属中,多样性较高,其中芽孢杆菌属和假单胞菌属具有多种功能菌株,在各样地所占比例也较高,可能是针茅根部重要的内生细菌。本研究还获得了14株生物学功能较强的菌株,具有潜在的应用价值。

关键词: 有效积温, 抽薹, 叶用莴苣, 花芽分化, 春化

Abstract: In order to study the diversity and function of endophytic bacteria, the roots of Stipa sp. were collected from six types of steppes (subalpine meadow, alpine meadow, Gobi desert, desert steppe, typical steppe, and meadow steppe in northern China) across Xinjiang, Gansu and Inner Mongolia. By strict surface disinfection and streak plate method, 200 endophytic bacteria that belonged to 28 genera, 7 classes, 4 phyla were isolated from the roots of Stipa sp. Half of the isolates were identified as Bacillus, which was the most dominant genus in the roots of Stipa sp. Pseudomonas and Bacillus were the most dominant genera in the samples of Gobi desert and the other five steppes, respectively. Subalpine meadow had the highest Shannon index, and typical steppe and meadow steppe had relatively higher Margalef index and evenness index. Alpine meadow which contained the lowest genus number showed the lowest Shannon index, Margalef index and evenness index. The similarity coefficients varied from 0.25-0.61 between the six steppes. Alpine meadow had relatively lower similarity coefficients (0.25-0.33) with the other steppes, followed by the similarity coefficients between Gobi desert and desert steppe. Furthermore, out of 200 isolates, 73 strains showed IAA-producing activity, 35 isolates turned out to have phosphatesolubilizing activity, 23 isolates were confirmed to have antifungal activity, 20 strains were proved to be diazotrophic bacteria, and 6 strains showed potassiumsolubilizing activity. Isolates producing IAA all ranked the first in abundance in each of the six steppes, especially in alpine meadow, subalpine meadows and desert steppe. Isolates with phosphatesolubilizing activity had a relatively larger proportion in alpine meadow, and the same to the isolates with antagonistic activity strains in subalpine meadow and nitrogenfixing bacteria in the desert steppe. However, the isolates with potassiumsolubilizing activity were in relatively lower abundance in all six steppes. The functional endophytic bacteria belonged to 25 genera, so their diversity was high. In addition, the isolates from Bacillus and Pseudomonas had more detected functions and high abundance, suggesting that endophytic bacteria belonging to Bacillus and Pseudomonas were important in the roots of Stipa. The study also collected 14 bacteria with high activity for detected function, which had great applied potential.

Key words: leaf lettuce, vernalization, bolting, effective accumulated temperature, flower bud differentiation