摘要
对祁连山高寒草原碱性土壤可培养固氮菌数量、固氮基因(nifH)群落结构及其理化性质进行了研究.结果表明:固氮菌数量在土层0～40cm处于3.6×105～0.21×105 CFUs.g-1之间,除了海拔3 001m的土样AQ4外,其他3个土样固氮菌数量随着土壤深度的加深而减小.固氮菌数量与地下生物量呈显著正相关性,与有机碳、可溶有机氮、速效磷和速效钾呈正相关性,而与pH值和全盐呈负相关性.通过基因测序得到的37个固氮基因nifH克隆中,蓝藻门占41%,变形菌门占8%,厚壁菌门占14%,未知菌株占37%;蓝藻门在除了AQ4外的土样中普遍存在,并且是AQ1的优势固氮菌群.此外,还发现了4个新的nifH基因,分别是AQ1-12(KC412109)、AQ4-3(KC412133)、AQ4-4(KC412133)、AQ4-5(KC412133),其中后三者是土样AQ4的优势种群.
The physicochemical characteristics,the number of culturable nitrogen-fixing bacteria and the community structure of nitrogen-fixing(nifH) genes in the alkali soils of alpine steppe in the Qilian Mountains are investigated in the present study.It is found that the number of culturable nitrogen-fixing bacteria is between 3.6×105~0.21×105 CFUs·g-1 within the depth of 0-40 cm.The number of nitrogen-fixing bacteria decreases with soil depth in three soil samples,except one sample(AQ4) at the altitude of 3 001 m. The number of nitrogen-fixing bacteria has a significant positive correlation with the underground biomass,and positive correlations with organic carbon,soluble organic nitrogen,rapidly available phosphorus and rapidly available potassium.However,it has negative correlations with soil pH value and total salt.Gene sequencing shows that in a community structure of 37 nitrogen-fixing(nifH) genes there are Cyanobacteria genes(41%),Proteobacteria genes(8%),Firmicutes genes(14%) and unknown bacterium genes(37%).Cyanobacteria genes exist in all soil samples,except for the sample AQ4,and are dominate nitrogen-fixing(nifH) genes in the sample AQ1.It is also found four new nitrogen-fixing(nifH) genes.They are AQ1-12(KC412109),Q4-3(KC412133),AQ4-4(KC412133) and AQ4-5(KC412133),among which AQ4-3(KC412133),AQ4-4(KC412133) and AQ4-5(KC412133) are the dominate genes in sample AQ4.
出处
《冰川冻土》
CSCD
北大核心
2013年第1期208-216,共9页
Journal of Glaciology and Geocryology
基金
中国科学院重点部署项目(KZZD-EW-04-05)
国家自然科学基金项目(31070357
91025002
31100365)资助
关键词
祁连山高寒草原
碱性土壤
固氮微生物
固氮基因
群落结构
alpine steppe in the Qilian Mountains
alkali soils
nitrogen-fixing microorganism
nifH genes
community structure
作者简介
康文龙（1988-），男，甘肃天水人，2010年毕业于兰州交通大学，现为兰州交通大学在读硕士研究生，主要从事环境微生物研究．
通讯作者：李师翁，E-mail：lishweng@mail．1zjtu．cn
