Pb^(2+)/Cd^(2+)处理对冬小麦幼苗根际微生物种群数量的影响  

Effects of Pb^(2+)/Cd^(2+) on the Number of Microorganisms in the Rhizosphere of 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：《沈阳农业大学学报》2011年第4期443-448,共6页Journal of Shenyang Agricultural University

基　　金：国家自然科学基金项目(31000222);中央高校基金项目(CHD2009JC144)

摘　　要：采用盆栽试验培育冬小麦幼苗,待幼苗生长3周、7周和12周时,收集根系土,进行根际土壤细菌、真菌、放线菌、亚硝化菌和自生固氮菌数量的测定。结果表明:冬小麦幼苗生长3周时,Pb2+/Cd2+对根际细菌、自生固氮菌和亚硝化菌表现为显著(p<0.05)抑制作用,平均抑制率分别为20.41%~49.79%、26.62%~76.99%和87.15%~95.88%,而真菌、放线菌数量主要表现为增加,平均增加率分别为0.31%~38.88%和19.58%~113.64%,但微生物总数减少,而多样性指数增加,真菌/细菌比值升高;幼苗生长7周时,放线菌、自生固氮菌和亚硝化菌数量主要表现为增加现象,平均增加率分别为18.16%~19.72%、13.71%~24.59%、2.09%~519.29%,真菌数量降低,平均降低率为9.59%~39.46%,细菌数量在低浓度时增加,高浓度时减少,微生物总数增加,多样性指数主要表现为降低,真菌/细菌比值降低;幼苗生长12周时,Pb2+/Cd2+处理下细菌数量极显著(p<0.01)增加,真菌、放线菌、固氮菌和亚硝化细菌数量降低,平均降低率分别为12.05%~44.66%、1.94%~15.51%、12.44%~55.72%和97.88%~99.00%,微生物总数主要表现为增加,多样性指数降低,真菌/细菌比值极显著降低(p<0.01)。Pb2+/Cd2+处理对冬小麦幼苗根际各类微生物数量、微生物总数和多样性指数及真菌/细菌比值影响显著(p<0.05),且微生物多样性指数的变化主要取决于放线菌数量的变化;Pb2+/Cd2+对冬小麦根际固氮菌和亚硝化菌数量的影响规律不稳定,预示着Pb2+/Cd2+污染将影响其根际土壤N的固定和转化能力,且N源的可利用率不稳定。Pot experiments were conducted to culture winter wheat seedlings.The rhizosphere soil was collected to determine the number of bacteria,fungi,actinoplanes,nitrogen-fixing bacterial,and nitrosobacterial when seedlings had grown for three weeks,seven weeks,and twelve weeks,respectively.The number of bacteria,nitrogen-fixing bacteria,and nitrosobacteria in Pb2＋/Cd2＋ significantly（p0.05） decreased by 20.41%-49.79%,26.62%-76.99%,and 87.15%-95.88%,respectively,and the number of fungi and actinoplanes increased by 0.31%-38.88% and 19.58%-113.64%,respectively at the third week.Moreover,the total number of microorganisms decreased and the diversity and the ratio of fungi / bacteria increased in Pb2＋/Cd2＋ at the third week.When winter wheat seedlings grew for seven weeks,the number of actinoplanes,nitrogen-fixing bacteria,and nitrosobacterial mainly increased by 18.16%-19.72%,13.71%-24.59%,and 2.09%-519.29%,respectively and that of fungi decreased by 9.59%~39.46%.Moreover,the number bacterial increased in low doses of Pb2＋/Cd2＋ and decreased in high doses of Pb2＋/Cd2＋.At the same time,the total number of microorganisms increased and the diversity and the ratio of fungi/bacteria decreased in the stress of Pb2＋/Cd2＋.When winter wheat seedlings grew for twelve weeks in Pb2＋/Cd2＋,the number of bacteria significantly（p0.01） increased,and the number of fungi,actinoplanes,nitrosobacterial,and nitrogen-fixing bacterial decreased by 12.05%-44.66%,1.94%-15.51%,12.44%-55.72%,and 97.88%-99.00%,respectively.At the same time,the total of microorganism mainly increased,the diversity reduced,and the ratio of fungi / bacterial significantly（p0.01） decreased.The effect of Pb2＋/Cd2＋ on the number of rhizosphere microorganisms,diversities,and the ratio of fungi/bacteria was significant（p0.05） and the shift of the diversity was mainly due to the change of the number of actinoplanes.The irregular change of nitrosobacterial and nitrogen-fixing bacteria indicated that the nitrogen fixed capacity of soil

关 键 词：Pb2+/Cd2+ 冬小麦 根际微生物 多样性指数 真菌/细菌比值 

分 类 号：S154.3[农业科学—土壤学]