镉胁迫对荻生长、镉富集和土壤酶活性的影响

采用盆栽土培法,从播种开始培育132d后,研究0,3,6,9mg/kg镉胁迫对荻的生长、镉富集与分布和土壤酶活性的影响。结果表明:荻耐性指数随处理浓度的增加先上升后下降,镉浓度≤6mg/kg时,促进荻生长,镉浓度为9mg/kg时,抑制荻生长。叶绿素、丙二醛和可溶性糖含量均随处理浓度的增加先升高后降低,在镉浓度为6mg/kg时达到最大值;类胡萝卜素含量为先降低后升高,在6mg/kg时达最小值。荻根部铜、锌和铁含量均随处理浓度的增加而升高,地上部铜和铁含量先降低后升高,而锌含量持续降低。根部和地上部镉含量随镉处理浓度增加呈线性增加趋势,且根部镉含量均高于地上部;不同浓度镉处理荻根部富集系数均大于1,但地上部富集系数和转运系数均小于1;根部镉积累量随处理浓度的增加先升高后降低,在镉浓度为6mg/kg时达到最大值,地上部镉积累量持续升高,荻体内镉主要分布在根部。镉处理组的土壤脲酶和过氧化氢酶活性与对照相比总体无显著差异(P0.05),镉浓度为6mg/kg和9mg/kg对土壤脲酶活性有一定促进作用,但会抑制过氧化氢酶活性,根际土壤酶活性总体高于非根际土壤酶。研究表明,荻对镉有较强的耐性,且根部对镉有较强的富集能力,因此,荻在土壤镉污染稳定化修复方面具有一定的应用潜力。

Effects of Cd Stress on the Growth, Cd Accumulation and Soil Enzyme Activities of Miscanthus sacchariflorus

The effects of Cd stress (0,3,6 and 9 mg/kg) on the growth,Cd accumulation and soil enzyme activities of Miscanthus sacchariflorus were studied by pot experiments from seed germination and cultivation for 132 d.The results showed that:The tolerance index of Miscanthus sacchariflorus increased at first and then decreased with the increase of the concentration of Cd.It was beneficial for plant growth when the concentration of Cd was no more than 6 mg/kg,whereas the growth was suppressed when the concentration of Cd was greater than 9 mg/kg.With the increase of Cd concentration,the content of chlorophyll,MDA and soluble sugar in leaves increased firstly and then decreased,and the peak appeared in 6 mg/kg Cd concentration;while the carotenoid content of leaves showed a contrary tendency with the increase of Cd concentration.Three micronutrients (Cu,Zn and Fe) in root increased gradually with the increase of Cd concentration.Specifically,with increasing Cd concentration,Cu and Fe concentrations in aboveground part decreased at first and then increased,while Zn concentration showed a continued slowdown.Cd concentration of root and aboveground part rose gradually with increasing Cd concentration and the distribution of Cd was higher in root than in aboveground part.The root bioconcentration factors (BCF) of Miscanthus sacchariflorus exceeded 1 in various Cd concentrations,but the aboveground part BCF and translocation factors (TF) were less than 1.Cd accumulation of root increased at first and then decreased with the increase of Cd concentration;while Cd accumulation of aboveground part increased all the time.Furthermore,root was the main part of Cd accumulation.Soil enzyme activities had no significant differences among different Cd concentrations (P＞0.05).Soil urease activity was promoted by Cd concentrations of 6 and 9 mg/kg,while,soil catalase activity was inhibited.Overall,the enzyme activities of urease and catalase in rhizosphere were high than those in non-rhizosphere.The findings indicate that Miscanthus sacchariflorus has high tolerance to Cd and the root presents strong capacity to accumulate Cd,therefore the plant had a certain potential in the stabilizing remediation of Cd contaminated soils.