Characteristics Of Chromium Bioaccumulation Of Hemarthria Compressa

A pot experiment was carried out to evaluate the accumulation characteristics of Hemarthria compressa at different treatments of chromium(Cr). For all treatments spiked with different rates of Cr, the bioconcentration factors were higher than1.0and the transfer factors were less than1.0with the exception of the control. When the Cr treatment concentration was increased to80mg/L, the Cr contents in the roots, stems and leaves reached1565.83mg/kg,57.38mg/kg and763.68mg/kg respectively. The Cr contents in the subcellular distribution of the roots and leaves are followed by cell wall> plastid>the other parts and the other parts> chloroplast> cell wall sepaeately.The greatest amount of Cr in roots and leaves was in the extraction solution of residual state, followed by in0.6mol/L HCI. Plant height and root length of the treatments spiked with Cr was initially increasing with increasing concentrations of Cr and exceeded those of the control, and then decreased gradually.The chlorophyll and carotenoid contents in leaves increased firstly and decreased finally. The proline and malondialdehyde contents continued to rise, they were2.09and2.28times of the control separately when the stress concentration reached80mg/L. Phosphoenolpyruvate carboxylase(PEPC) activity in the roots and leaves increased significantly initially and decreased significantly in the end. Compared with the control, malate dehydrogenase(MDH) activity in the roots and leaves had less difference, it increased initially and decreased gradually.Organic acids contents in the roots and leaves increased significantly comparing with the control, the contents of them were7.08and1.81times of the control content separately. Similar changes were found for the contents of Phytochelatins (PCs), glutathione (GSH), non-protein thiols(NPT), total thiols (TT), and metallothioneins-like (MTL) in the roots and leaves of the test plants. The synthesis of PCs and GSH induced by Cr stress seemed to be low, while the synthesis of NPT and MTL were relatively high. The maximum contents of MTL in the roots and leaves were detected at the Cr treatment concentrations of10and20mg/L, respectively. In short, Hemarthria compressa showed a relatively strong capacity of Cr accumulation and had the potential for phytoremediation of Cr-contaminated soils. The contents MTL in plant organs is sensitive to Cr stress, and could be used to evaluate the situation of soil contamination by Cr.