磷对节节草铜富集性和转运能力的影响

Effects of Phosphorus on Cu Accumulation and Translocation in Hippochaete Ramosissimum

通过溶液培养试验,探讨了不同供磷水平下节节草(Hippochaete ramosissimum)对铜的富集特性和转运能力的变化。结果表明,低浓度的磷(≤0.5mmol·L^(-1))处理下,节节草地上部分、地下茎和根的生物量均有一定程度的增加,但在高浓度磷(≥2.0mmol·L^(-1))处理下,其生长均受到一定的抑制。在铜胁迫和非铜胁迫下适当的供磷可有效地提高节节草对铜的吸收和积累能力。尤其当磷低于0.5mmol·L^(-1)(T1、T4)时,节节草地上部分和根部的铜含量分别是其对照组的3.38、1.49倍和1.57、1.19倍,而此时其地下茎的铜含量明显下降,仅为其对照的50%左右,这表明供磷水平较低(≤0.5mmol·L^(-1))有利于节节草吸收铜离子以及将地下茎的铜离子向地上部转运,且其转运系数随磷浓度的提高而呈上升趋势。而当高浓度磷处理时(≥2.0mmol·L^(-1)),节节草对铜的吸收和转运能力受到了明显的抑制。试验结果表明,适当增施磷肥有利于提高节节草的生物量,促进铜向其地上部转运,有效提高节节草地上部分铜的积累量,这可能会增加其对铜污染土壤的修复能力。

In this paper,the effects of different levels of phosphorus supply on copper enrichment and transport capacity of Hippochaete ramosissimum are studied by solution culture experiment.The results show that the biomass of aboveground part,underground stem and root of H.ramosissimum increas to a certain extent under low phosphorus concentration(≤0.5mmol·L^-1),but their growths are inhibited under high phosphorus concentration(≥2.0mmol·L^-1).In addition,appropriate phosphorus addition can promote copper accumulation in various parts of H.ramosissimum under copper stress and non-copper stress.Especially when P≤0.5mmol·L^-1(T1,T4),the copper content in aboveground parts and roots of plants is 3.38,1.49 and 1.57,1.19 times higher than that of the control group,while the copper content in underground stems decreases significantly,which is only about 50%of the control group.The findings indicate that low phosphorus supply(≤0.5mmol·L^-1)is conducive to the uptake of copper and the transport of copper from rhizome to shoot of H.ramosissimum,and its transport coefficient increases with phosphorus concentration.However,when the phosphorus concentration is high(≥2.0mmol·L^-1),the absorption and transport capacity of copper is significantly inhibited.The results suggest that proper application of phosphorus fertilizer can improve the biomass of H.ramosissimum,promote the transport of copper to its aboveground parts,and effectively increase the accumulation of copper in its aboveground parts,thus leading to increase the possibility of this plant to remediate the copper-contaminated soil.