不同类型生物土壤结皮固氮活性及对环境因子的响应研究  

The Nitrogenase Activity of Biological Soil Crusts and Their Responses to Environmental Factors

作　　者：苏延桂[1,2] 李新荣[2] 赵昕[2] 李爱霞[2] 陈应武[3] 

机构地区：[1]中国科学院干旱区生物地理与生物资源重点实验室,中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011 [2]中国科学院寒区旱区环境与工程研究所沙坡头沙漠研究试验站,甘肃兰州730000 [3]河南科技大学林学院,河南洛阳471003

出　　处：《地球科学进展》2011年第3期332-338,共7页Advances in Earth Science

基　　金：国家自然科学基金项目“温带荒漠区生物土壤结皮对土壤碳通量的影响”(编号:41001067)和“蚁类对固沙植被生态系统的影响”(编号:40971156);国家自然科学杰出青年基金项目“干旱沙区土壤-植被系统修复的生态水文学机理”(编号:40825001)资助

摘　　要：利用乙炔还原法对腾格里沙漠东南缘沙坡头地区3种生物土壤结皮(藻结皮、地衣结皮和苔藓结皮)的固氮活性及生物结皮固氮活性对模拟不同降雨量(1、3和5 mm)、温度(13、24和28℃)和光强(0、400和1 000μmol/(m2.s))的响应进行研究。结果表明:不同类型生物结皮的固氮活性差异显著,依次为:藻结皮(16.6 mmol/(m2.h))>地衣结皮(6.9 mmol/(m2.h))>苔藓结皮(2.6 mmol/(m2.h));水分和温度对生物结皮的固氮活性具有显著影响,光强无显著影响。生物结皮的固氮活性在3和5 mm降雨显著高于1 mm降雨;在24℃下显著高于13℃;并且,3种生物结皮的固氮活性对环境因子变化的敏感性不同。生物结皮具有固氮能力,特别是结皮演替早期的藻结皮,它们对荒漠生态系统土壤氮素输入具有重要贡献,而降雨量和温度是控制生物结皮固氮活性的2个关键因素。Acetylene reduction was employed to study the nitrogenase activity（NA） of three types of biological soil crusts（algal,moss and lichen crusts） and the responses of NA to precipitation（1,3 and 5 mm）,light intensity（0,400 and 1 000 μmol/（m2·s）） and air temperature（13,24 and 28 ℃） were also investigated under the laboratory condition.Results showed that NA differed significantly among crusts,with highest value occurring for algal crusts（16.6 mmol/（m2·h））,followed by lichen（6.9 mmol/（m2·h）） and moss crusts（2.6 mmol/（m2·h））.Precipitation and temperature significantly affected the NA,while light intensity had no effect on NA.The 3 and 5 mm precipitations significantly activated NA compared with 1 mm precipitation.NA was profoundly enhanced under the air temperature of 24 ℃ compared with 13 ℃.Therefore,firstly,this study indicated that biological soil crusts have the capability of nitrogen fixation,especially the algal crusts,which contributed profoundly to the soil nitrogen input in the desert ecosystems;secondly,the precipitation and temperature are the regulating factors for NA.

关 键 词：生物土壤结皮 C2H4产量 结皮类型 固氮活性 乙炔还原法 

分 类 号：S154.4[农业科学—土壤学]