低含量Pb对Cd处理下冬小麦根际土壤氧化还原酶活性、BIF及C/N的影响  

Effects of Low Doses of Pb on Rhizosphere Soil Oxidoreductase Activities, BIF, and C : N Ratio of Winter Wheat Seedlings Under Cd

作　　者：贾夏[1] 董岁明[1] 周春娟[1] 

机构地区：[1]长安大学环境科学与工程学院,西安710054

出　　处：《应用与环境生物学报》2012年第6期917-923,共7页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目(No.31000222);中央高校基金(No.CHD2009JC144)资助~~

摘　　要：为正确评价重金属污染下冬小麦根际土壤微生态系统的安全性和稳定性,采用盆栽试验法研究了铅(Pb)含量低于国家"土壤环境质量标准(GB 15618-1995)"规定的Ⅱ类土壤环境基准值(350.00 mg/kg,干土)时,与镉(Cd)复合处理对冬小麦幼苗根际土壤氧化还原酶活性、肥力指数(Biological index of fertility,BIF)及碳/氮(C/N)的影响.结果表明:(1)幼苗生长3周时,Cd处理下过氧化氢酶和多酚氧化酶活性显著(P<0.05)增加,脱氢酶活性显著(P<0.05)降低;7周时多酚氧化酶和过氧化氢酶活性显著(P<0.05)降低;12周时,多酚氧化酶和脱氢酶活性显著(P<0.05)降低.此外,根际土壤生物学肥力指标BIF值主要表现为降低,而根际土壤C/N值在幼苗生长3周和12周时显著(P<0.05)降低,7周时却极显著(P<0.01)升高.(2)低含量Pb与Cd对脱氢酶和过氧化氢酶活性、BIF值主要起协同抑制效应,对多酚氧化酶活性表现出拮抗效应.幼苗生长3周和12周时,低含量Pb可减轻Cd对C/N值的降低效应,7周时,低含量Pb和Cd协同促进C/N值升高.土壤Pb含量低于国家"土壤环境质量标准"规定的Ⅱ类土壤环境基准值时,仍会明显影响Cd污染下冬小麦幼苗根际土壤的生化功能特征.The aim of this research was to evaluate the stability and security of rhizosphere soil micro-ecosystem of winter wheat under the heavy metal polluted soil. The effects of low doses of Pb （350.00 mg/kg in dry soil） and Cd on soil oxidoreductase activiiies, biological index of fertility （BIF）, and the C ： N ratio in winter wheat seedling rhizosphere were investigated using the pot experiment. The results indicated that： （1） The activities of polyphenoloxidase and catalase increased significantly （P〈0.05） and that of dehydrogenase decreased significantly （P〈0.05） in Cd treatment when wheat seedlings had grown for three weeks. The activities of polyphenoloxidase and catalase decreased significantly （P〈0.05） in Cd treatment at the seventh week. In the meantime, the BIF value decreased significantly in Cd treatment at three growth stages, and the C ： N ratio increased significantly （P〈0.05） at the third and twelfth weeks and decreased significantly （P〈0.01） at the seventh week in Cd treatment. （2） The activities of catalase and dehydrogenase reduced significantly （P〈0.05） in the treatments of the low dose of Pb and Cd, and the low dose of Pb treatment alleviated the effect of Cd on polyphenoloxidase activity. Meanwhile, the low dose of Pb stimulated evidently the repression of Cd on the BIF value. And the low dose of Pb reduced the repression of Cd on the C ： N ratio at the third and twelfth weeks and the C ： N ratio increased in Pb/Cd treatment compared with Cd treatment alone at the seventh week. （3） The low dose of Pb still significantly （P〈0.05） affected the biochemical function of Cd polluted soil in winter wheat seedling rhizosphere.

关 键 词：PB Cd 冬小麦幼苗 根际土壤 土壤氧化还原酶 土壤肥力指数BIF 土壤C N 

分 类 号：S512.11[农业科学—作物学]