不同供磷水平对四种超富集植物生长及吸收重金属的影响

本论文通过水培试验研究了以KH2PO4作为磷(P)源在不同浓度(0~45.52 mg·L-1)和以Ca3(PO4)2作为磷(P)源在22.76 mg·L-1对Zn/Cd超富集植物东南景天Sedum alfredii、Zn/Cd/Ni超富集植物遏蓝菜Noccaea caerulescens(两个品种)和Ni超富集植物庭荠属Alyssum murale在20 mg·L-1(Zn)、18 mg·L-1(Ni)、10 mg·L-1(Pb)和0.5 mg·L-1(Cd)胁迫下的生长和吸收重金属的影响.试验结果表明严重缺磷的无磷和磷酸钙源处理显著抑制了这些超富集植物的生长,但4种超富集植物的地上部生物量在11.38、22.76、45.52 mg·L-13个磷水平处理之间均无显著差异.正常营养液的供磷水平(22.76 mg·L-1),S.alfredii对Zn/Cd和N.caerulescen 1号对Zn/Cd/Ni的吸收累积达到最大值,而高浓度的磷素供应(45.52 mg·L-1)显著抑制了这两种植物对相应元素的吸收;A.murale对Ni/Cd/Pb的吸收累积均在高浓度的磷素供应(45.52 mg·L-1)获得最大;增加磷的供应对N.caerulescen 1号吸收累积Zn/Ni/Cd/Pb产生了不同的效应.这些超富集植物提取重金属的最佳供P水平因植物种类而不同.

Effect of different P levels on the growth and heavy metal uptake for four Hyperaccumulators

This study aimed to investigate the effects of different P concentrations (0~45.52 mg · L^-1) with KH₂PO₄ supply and a fixed P concentration of 22.76 mg · L^-1 with Ca₃(PO₄)₂ supply on the growth and heavy metal uptake of Zn/Cd hyperaccumulator Sedum alfredii, Zn/Cd/Ni hyperaccumulator Noccaea caerulescens (two species) and Ni hyperaccumulator Alyssum murale under the concentrations of 20 mg · L^-1(Zn), 18 mg · L^-1(Ni), 10 mg · L^-1(Pb) and 0.5 mg · L^-1(Cd) by hydroponic experiment. The results showed that the growth of all four hyperaccumulators were inhibited with P deficiency treatments including the control and 22.76 mg · L^-1 treatment supplied with Ca₃(PO₄)₂. However, there were no significant difference for the shoot biomass of four hyperaccumulators among the 11.38, 22.76 and 45.52 mg · L^-1 treatments. Zn and Cd accumulation in S.alfredii and Zn, Cd and Ni accumulation in No 1 N.caerulescens reached the maximum with 22.76 mg · L^-1 treatment (P concentration in normal nutrient solution), and significantly decreased with high P concentration of 45.52 mg · L^-1. Ni, Cd and Pb accumulation in A.murale reached the maximum with 45.52 mg · L^-1 treatment, and the accumulation of Ni, Zn, Cd and Pb in No 1 N.caerulescens was different with different P concentrations. The optimal P level for the most metal accumulation in hyperaccumulators differed with plant categories.