本课题以高生物量植物为材料，研究了可生物降解螯合剂EDDS对植物生长和铜积累的影响，目的是要阐明EDDS诱导植物重金属积累的机理和创建新颖的效率高、环境风险低的污染土壤植物修复技术。利用阴离子交换色谱柱及紫外-可见光检测器建立了植物及土壤中金属-EDDS复合物离子色谱分析方法。利用水培实验，研究了高浓度EDDS对植物生长、铜积累、根系结构和根细胞质膜稳定性的影响。EDDS处理可以缓解过量铜对植物的毒害作用、降低铜在植物中的积累。不同伤根预处理可以提高植物地上部铜积累，根系的电解质渗漏率与其地上部含铜量之间有显著的正相关，表明Cu-EDDS复合物不易被植物吸收，根系生理伤害在增加重金属在地上部中的积累有重要作用。在土培实验中，螯合剂溶液经过加热后浇灌、或在螯合剂施用后对土壤进行加热处理，比常规螯合剂施用方法更显著地提高植物地上部重金属的积累，并利用田间实验中得到初步验证了这一新颖的植物修复技术。采用化学沉淀的方法研究了大豆和玉米初生根凯氏带对铜离子和柠檬酸铜复合物的通透性。结果显示，Cu2+可以通过二种植物初生根的凯氏带，大豆初生根则不能通过。

In this study, high-biomass plant species were used to investigate the effects of the biodegradable chelating agent S,S-ethylenediaminedisuccinic acid (EDDS) on the growth and copper uptake by plants. The aims of the present study are to gain insight into the mechanisms involved in EDDS-inducd metal accumulation in plants and to develop novel strategies for the phytoremediation of heavy metal contaminated soils with maximizing the total metal removal and minimizing the potential environmental risk. A method of analyzing the complexes of metals and EDDS in plants and soils was developed using ion chromatography and electrospray ionization mass spectrometry. The possible effects of EDDS on the growth of plants, Cu accumulation, structure of roots and stability of plasma membrane of root cells were investigated using hydroponic experiments. Results showed that in the presence of excess Cu, the addition of EDDS increased plant biomass, and decreased the relative electrolyte leakage of root cells and the concentration of Cu in shoots. When the roots were pretreated with 65 oC hot water or with 1 - 100 mM HCl before the exposure to 50 μM Cu + 100 μM EDDS, the concentration of Cu in shoots increased considerably compared with the plants without any pretreatment. A statistically significant correlation was found between the Cu concentrations in shoots and the relative electrolyte leakage of root cells. These results indicated that Cu-EDDS might be a less bioavailable form to plants, and that some physiological damages to the roots could enhance accumulation of Cu in plant shoots. In pot experiments, after the application of EDDS or EDTA, soils were treated with high temperature, which significantly increased the concentrations of heavy metals in shoots of corn and beans and the metal phytoextraction from contaminated soils. In a preliminary field experiment, increasing soil temperature 2 d after the chelant addition also increased the shoot Cu uptake about five-fold compared with the control. This new technique may represent a potential engineering-oriented approach for phytoremediation of metals polluted soils. Using a technique of insoluble salt precipitation, the permeability of endodermal Casparian bands (CBs) for Cu2+ and Cu-citrate was investigated in primary roots of soybean and corn. The results showed that Cu2+ could arrive at xylem through CBs directly. The permeability of endodermal CBs for Cu-citrate in primary roots of soybean was also true but was not in corn.

本课题以高生物量植物为材料，研究了可生物降解螯合剂EDDS对植物生长和铜积累的影响，目的是要阐明EDDS诱导植物重金属积累的机理和创建新颖的效率高、环境风险低的污染土壤植物修复技术。利用阴离子交换色谱柱及紫外-可见光检测器建立了植物及土壤中金属-EDDS复合物离子色谱分析方法。利用水培实验，研究了高浓度EDDS对植物生长、铜积累、根系结构和根细胞质膜稳定性的影响。EDDS处理可以缓解过量铜对植物的毒害作用、降低铜在植物中的积累。不同伤根预处理可以提高植物地上部铜积累，根系的电解质渗漏率与其地上部含铜量之间有显著的正相关，表明Cu-EDDS复合物不易被植物吸收，根系生理伤害在增加重金属在地上部中的积累有重要作用。在土培实验中，螯合剂溶液经过加热后浇灌、或在螯合剂施用后对土壤进行加热处理，比常规螯合剂施用方法更显著地提高植物地上部重金属的积累，并利用田间实验中得到初步验证了这一新颖的植物修复技术。采用化学沉淀的方法研究了大豆和玉米初生根凯氏带对铜离子和柠檬酸铜复合物的通透性。结果显示，Cu2+可以通过二种植物初生根的凯氏带，大豆初生根则不能通过。