Cu污染土壤中溪荪和花菖蒲的生长状况及对Cu的积累及转运能力

摘要

采用土壤栽培方法,研究了在Cu添加量为0(CK)、200、400、600、800和1 000μg·g-1的土壤中溪荪(Iris sanguinea Donn es Horn.)和花菖蒲(I.ensata Thunb.var.hortensis Makino et Nemoto)叶和根的数量、长度及生物量(干质量)6个生长指标的变化趋势,并对叶和根中的Cu含量和积累量、全株的Cu积累量、Cu的富集系数及转运系数进行了比较分析.结果表明:随土壤中Cu添加量的提高,溪荪的根数逐渐降低且显著低于对照;而溪荪的其余5个生长指标和花菖蒲的6个生长指标均总体呈现出在Cu添加量较低的条件下逐渐增加并显著高于对照、在Cu添加量较高的条件下逐渐减小且显著小于对照的变化趋势;其中在Cu添加量1 000μg·g-1的土壤中2种植物的生长均受到显著抑制(P＜0.05);而添加400和600μg·g-1Cu则分别对2种植物的生长有一定的促进作用.随土壤中Cu添加量的增加,溪荪和花菖蒲叶及根中的Cu含量均逐渐提高;溪荪对Cu的富集系数和转运系数以及花菖蒲对Cu的富集系数均显著小于对照,而花菖蒲对Cu的转运系数则呈现在Cu添加量较低的条件下高于对照、Cu添加量较高的条件下低于对照并逐渐减小的趋势;在添加了Cu的土壤中,溪荪叶、根和全株对Cu的积累量均低于花菖蒲,但均显著高于对照,且2种植物根的Cu含量及积累量均大于叶片,表明溪荪和花菖蒲均具有一定的Cu积累能力,且主要积累在根中,花菖蒲对Cu的积累能力优于溪荪.综合分析结果显示:溪荪和花菖蒲不是Cu超积累植物,但对Cu胁迫均具有一定的耐性,且花菖蒲的耐性略强于溪荪;溪荪和花菖蒲分别适宜栽植于Cu含量400和600μg·g-1以下的土壤中,可用于轻度和中度Cu污染土壤的植物修复和环境美化.%The change trends of six growth indexes including number, length and biomass ( dry weight)of leaf and root of Iris sanguinea Donn ex Horn.and Ⅰ.ensata Thunb.var.hortensis Makino et Nemoto in soil with Cu additions of 0( CK), 200,400, 600, 800 and 1 000 μg · g-1 were studied by soil culture method, and Cu content and accumulation in leaf and root, Cu accumulation in whole plant, Cu enrichment and translocation coefficients of the two plants were analyzed comparatively.The results show that with rising of Cu addition in soil, root number of Ⅰ.sanguinea decreases gradually and significantly lower than that of the control, while other five growth indexes of Ⅰ.sanguinea and six growth indexes of Ⅰ.ensata var.hortensis all generally appear the change trend of increasing gradually and significantly higher than those of the control under low Cu addition conditions, decreasing gradually and significandy lower than those of the control under high Cu addition conditions.In which, growth of the two plants in soil added with 1 000 μg · g-1 Cu is inhibited significantly (P＜0.05 ), but adding 400 and 600 μg · g-1 Cu has a certain promotive effect on growth of the two plants, respectively.Cu content in leaf and mot of Ⅰ.sanguinea and Ⅰ.ensata var.hortensis all increases gradually with rising of Cu addition in soil.Cu enrichment and translocation coefficients of Ⅰ.sanguinea and Cu enrichment coefficient of Ⅰ.ensata var.hortensis all are significantly lower than those of the control, while Cu translocation coefficient of Ⅰ.ensata var.hortesis is higher or lower respectively than that of the control under low or high Cu addition conditions with a trend of decreasing gradually.In soil added with Cu, Cu accumulation in leaf, root and whole plant of Ⅰ.sanguinea is lower than that of Ⅰ.ensata var.hortensis, but all of them are significantly higher than that of the control, and Cu content and accumulation in root of the two plants are higher than that in leaf, showing that Ⅰ.sanguinea and Ⅰ.ensata var.hortensis both have a certain accumulation ability to Cu, and being mainly accumulating in root, Cu accumulation ability of Ⅰ.ensata var.hortensis is better than that of Ⅰ.sanguinea.The comprehensive analysis results show that Ⅰ.sanguinea and Ⅰ.ensata var.hortensis are not hyper-accumulators, but still have some resistance to Cu stress, and resistance of Ⅰ.ensata var.hortensis is slightly stronger than that of Ⅰ.sanguinea.The two plants are suitable to plant in soil with Cu content lower than 400 and 600 μg · g-1, respectively, and they can be used to phytoremediation and environmental beautification in light and moderate Cu polluted soils.