添加铜尾矿矿砂的栽培基质对黄花苜蓿幼苗生长及部分生理指标的影响

采用盆栽法对种植于添加铜尾矿矿砂(体积分数0%、25%、50%、75%和100%)栽培基质中的黄花苜蓿(Medicago falcata Linn.)幼苗的生长及部分生理指标的变化进行了分析。结果表明:随栽培基质中铜尾矿矿砂体积分数的提高,黄花苜蓿的株高、根长、地上和地下部分干质量以及耐性指数均呈逐渐下降的趋势且总体上低于对照,但仅在铜尾矿矿砂体积分数较高(75%和100%)的条件下株高和地上部分干质量与对照差异显著(P<0.05);地上和地下部分的CAT活性和叶片光合色素(包括叶绿素a、叶绿素b和类胡萝卜素)含量均逐渐下降且总体上低于对照,而地上和地下部分的POD活性、GSH含量和O-·2含量则总体上呈逐渐增加的趋势且高于对照。在铜尾矿矿砂体积分数25%~75%的条件下,地上和地下部分的SOD活性逐渐增加且显著高于对照;而在铜尾矿矿砂体积分数100%的条件下,地上部分的SOD活性显著低于对照,而地下部分的SOD活性则略降低但显著高于对照。各处理组幼苗地上和地下部分的MDA含量均不低于对照;而各处理组AsA含量变化则呈波动趋势。综合分析结果表明:黄花苜蓿对铜尾矿矿砂具有一定的适应性,可用于铜尾矿矿砂的绿化固着以及铜污染环境的植物修复。

Effect of culture substrate added with copper tailing sand on growth and some physiological indexes of Medicago falcata seedlings

Changes of growth and some physiological indexes of Medicago falcata Linn. seedlings planted in culture substrate added with copper tailing sand of volume ratio of 0%, 25%, 50%, 75% and 100%were analyzed by pot culture method. The results show that with rising of volume ratio of copper tailing sand in culture substrate, seedling height, root length, dry weights of above- and under-ground parts, and tolerance index of M. falcata all appear the trend of decreasing gradually and are generally lower than those of the control. But only under condition of copper tailing sand with higher volume ratio （75% and 100%） , there are significant differences in seedling height and dry weight of above-ground part （ P〈0. 05） with those of the control. CAT activity in above- and under-ground parts and photosynthetic pigment （including Chla,Chlb and carotenoid） content in leaf all decrease gradually and are generally lower than those of the control, while POD activity, GSH content and O-＆#183;2 content in above- and under-ground parts generally appear the increasing trend and are higher than those of the control. Under condition of copper tailing sand with volume ratio of 25%-75%, SOD activity in above- and under-ground parts increases gradually and is significantly higher than that of the control, but under condition of copper tailing sand with volume ratio of 100%, SOD activity in above-ground part is significantly lower than that of the control while that in under-ground part decreases slightly but is significantly higher than that of the control. MDA content in above-and under-ground parts of every treatment group is not lower than that of the control, while AsA content of every treatment group appears the fluctuation trend. The comprehensive analysis result indicates that M. falcata has a certain adaptability to copper tailing sand, so it can be used for green fixing of copper tailing sand and for phytoremediation in Cu polluted environment.