重金属Cd^(2+)对冬小麦幼苗根际微生物种群数量的影响  

Effects of Cd^(2+) on the Number of Rhizospheric Soil Microbial from Winter Wheat Seedlings

作　　者：贾夏[1] 周春娟[1] 董岁明[1] 

机构地区：[1]长安大学环境科学与工程学院,西安710054

出　　处：《中国农学通报》2011年第21期246-252,共7页Chinese Agricultural Science Bulletin

基　　金：中央高校基金"重金属镉对幼苗期小麦根际微生态系统的影响机制"(CHD2009JC144);国家自然科学基金"我国干旱河谷景观特征研究"(NO.31000222)

摘　　要：利用盆栽试验进行了Cd2(+对照、5.0、10.0、20.0、50.0、70.0mg/kg干土)对冬小麦幼苗根际土壤微生物数量影响的研究。研究结果表明,在冬小麦出苗3周时,与对照相比,Cd2+对根际土壤细菌、真菌、自生固氮菌和亚硝化菌数量主要表现出显著抑制作用(P<0.05),而对放线菌数量表现为极显著促进作用(P<0.01),细菌数量在群落中所占比重降低,放线菌和真菌的比重增加,微生物总数减少,而多样性指数增加,真菌/细菌比值显著升高(P<0.05);出苗7周时,Cd2+对细菌和亚硝化菌数量表现出极显著促进作用(P<0.01),对真菌、放线菌和自生固氮菌数量主要表现为抑制作用,细菌在群落中所占比重增加,放线菌和真菌的比重降低,微生物总数增加,而多样性指数降低,真菌/细菌比值极显著降低(P<0.01);当12周时Cd2+处理下细菌和真菌数量极显著增加(P<0.01),而放线菌、自生固氮菌和亚硝化菌数量主要表现为降低现象,细菌和真菌在群落中所占比重增加,放线菌所占的比重降低,微生物总数主要表现为增加,而多样性指数主要表现为降低,真菌/细菌比值总体表现出较对照增加的现象。总体来讲,在整个幼苗初期,与对照相比,Cd2+处理下冬小麦根际微生物总数减少,多样性指数增加,而在幼苗生长后期微生物总数增加,多样性指数却减少。The number of microorganisms from winter wheat rhizospheric soil under Cd^2＋ pollution（0.0,5.0,10.0,20.0,50.0,70.0 mg/kgdry soil） was studied using pot experiment.The results indicated that the number of bacterial,fungi,nitrogen-fixing bacterial,and nitrosobacterial mainly decreased significantly（P0.05）,however the number of actinoplanes increased significantly（P0.01） at three weeks after winter wheat seedlings emerged under Cd^2＋.At the same time,the ratio of bacterial in microorganism communities decreased and that of fungi and actinoplanes increased,however the total number of microorganism reduced,the Shannon-Wiener diversity index increased,and the ratio of fungi/bacterial rise under Cd2＋.After seven weeks when winter wheat seedlings emerged,the number of bacterial and nitrosobacterial increased significantly（P 0.01） and the number of fungi,actinoplanes,and nitrogen-fixing bacterial decreased.At the same time,the ratio of bacterial in microorganism communities increased and that of fungi and actinoplanes decreased.The total number of microorganism went up,but the Shannon-Wiener diversity index reduced and the ratio of fungi/bacterial reduced insignificantly（P0.01） under Cd^2＋.After twelve weeks when winter wheat seedlings emerged,the number of bacterial and fungi increased significantly（P0.01） and that of actinoplanes,nitrosobacterial,and nitrogen-fixing bacterial mainly decreased.At the same time,the ratio of bacterial and fungi in microorganism communities increased and that of actinoplanes decreased.The total of microorganism mainly increased,the Shannon-Wiener diversity index mainly reduced and the ratio of fungi/bacterial decreased mainly under Cd^2＋.On the whole,the amount of microorganism decreased and the Shannon-Wiener diversity index increased under Cd^2＋ during early winter wheat seedling growth,but the amount of microorganism increased and the Shannon-Wiener diversity index decreased under Cd^2＋ during later seedling growth compared to 0.0 mg/kgdry soil.

关 键 词：Cd2+ 冬小麦 根际微生物 数量 多样性指数 真菌/细菌比值 

分 类 号：S147.5[农业科学—肥料学]