| Heavy metals contamination is the main type of soil contamination. Nowadays, more research work have been conducted on the phytoremediation of copper contaminated soil in China. Solution culture and pot experiment, field experiment have been done to investigate the physiological and biochemical response to copper toxicity, and its phytoremediation potential of copper from the contaminated soil by E. splendens. Elsholtzia argyi, another Cu-tolerant and accumulating plant species, also show the potential for the phytoremediation of heavy metal polluted soil. In this study, solution culture, pot culture and field experiment were used to do some investigations about both E. splendens and E. argyi: the response of both Elsholtzia plants to copper toxicity, Cu tolerance and accumulation in plant by transmission electron microscope (TEM) technique, cell wall nature and its complexation with copper by FTIR technique, sorption and desorption properties of copper to cell wall of both Elsholtzia plants, the phytoavailability of Cu, Pb, Zn and Cd in the multi-metal contaminated soil and rhizospheric soil of E. splendens as affected by soil amendments, and Cu, Pb, Zn and Cd removel by E. splendens, the changes of volatile oil components in shoot of both Elsholtzia plants under different Cu supplies both in solution culture and under naturally growing conditons by GC/MS technique, and their activities to resist Bacillus, Coccus, and so on. The main results are listed as follows:1. The response of both Elsholtzia plants to copper toxicity indicated that E. splendens and E. argyi naturally growing in Zhuji-mined soil, Sanmeng-mined soil, Fuyang contaminated soil, Huajiachi non-contaminated soil, and Jiuxi non- contaminated soil can grow well, with the concentrations of macro- and micro-nutrients in plant kept at the normal level, except for the plantt of E. argyi in the Fuyang contaminated soil, that the significantly constrained growth of plant and the increased levels of K, Mg and Ca were observed. Zhuji-E. splendens, Sanmen-E argyi (PFE1) ant its variation (WFE), Jiuxi-E. argyi (PFE2) were studied in response to copper toxicity. The results indicated that E. splendens can tolerate more copper than PFE1 and WFE, while PFE2 is more like Cu-sensitive plant species. 50 μmol L-1 Cu resulted in the tolerance index (TI) of Zhuji-E. splendens of >100%, while for PFE1, WFE and PFE2, it was 65%, 62%, 58%,respectively. At 100 μmol L-1 Cu, TI of Zhuji-E splendens, PFE1, WFE and PFE2 were decreased to 95%, 62%, 59% and 42%, respectively. Copper caused more toxicty to E. argyi than to E. splendens. At 100 μmol L-1 Cu, no significant difference were noted for macronutrient and micronutrient in Zhuji-E. splendens, while for PFE1, WFE and PFE2, the considerably reduced K was observed at 50 μmol L-1 Cu. As for biomass, when suppiled at the same Cu supplies level (<100 μmol L-1 Cu), PFE2 has the greater shoot biomass than Zhuji E. splendens and PFE1. The total accumulating factor for copper followed PFE2>WFE> PFE1>E. splendens, and the bioaccumulation factor for root and shoot were also exhbited: PFE2>WFE>PFE1>E. splendens. As compared to E. argyi, Zhuji-E.splendens can mobilize more copper to its root than PFE1.2. The ultrastructure results indicated that the marked tocixity was observed at the root, stem, and leaf of Sanmen E. argyi when plant exposed to 50 μmol L-1 Cu, following the order of root > stem > leaf. While for E. splendens, it didn't markedly affated by 50 μmol L-1 Cu. The thickened cell wall was observed under copper toxicity of ≥ 50μmol L-1 for E. argyi and ≥ 250μmol L-1 E. splendens.3. EDS analyses indicate that, at 100μmol L-1 Cu, Much more electron density bodieswer found at the surface of cell wall and within cell wall of root, stem and leaf of E. splendens, with the highest level Cu and higheat Cu/C ratio and Cu/O ration. The cell wall of E. splendens, especially root cell wall, play more important role in accumulating and detoxifying high copper toxicity. At 50μmol L-1 Cu, the...
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