五指山野菜对镉的积累及其机理研究

试验通过对五指山野菜对镉的积累及其机理研究，从而为利用五指山野菜对土壤进行植物修复这一技术提供理论基础。试验在盆栽的基础上进行了植物的地上部生物量和镉含量，可溶性蛋白、叶绿素，叶片质膜透性等生化指标的测定，以及分析上述指标与土壤中镉浓度的关系。通过试验，得出以下结果：随处理浓度的增加，根、茎和叶Cd含量逐渐上升，且根部变化趋势最突出；在土壤中处理浓度为50 mg/kg时，植物根、茎和叶含量就已超过超积累植物临界值，且当处理浓度为400 mg/kg时，三者含量分别高达6566.00、948.46、520.39 mg/kg；但为800 mg/kg时，植株出现死亡；在处理浓度为0~50 mg/kg下，转移系数和累积系数均大于1，但在100~400 mg/kg之间，转移系数逐渐变小；在0~50 mg/kg下可溶性蛋白逐渐上升，质膜透性、生物量和叶绿素变化差异不显著（5%），但当处理浓度再增加时（100~400 mg/kg），植物叶绿素、生物量、可溶性蛋白等呈现下降趋势，而质膜透性上升。以上结果说明五指山野菜是Cd超积累植物，且50 mg/kg时是五指山野菜正常生长的临界值，高于此浓度，将对其产生毒害，当浓度为800 mg/kg时，植株出现死亡；随处理浓度的增加，转移系数逐渐变小，说明植物在高Cd胁迫下阻止Cd向地上部分转移而产生更严重的毒害。

The Research of Cadmium Accumulation and Mechanism in Sauropus androgynus (L.) Merr.

Biomass and contents of Cd in the abovegrounds of Sauropus androgynus (L.) Merr.. were determined in this experiment proceeded in the pots, as well as some biochemical indicators , including soluble protein, chlorophyll, membrane permeability in leaves, in which the anylsis of the relationship and Cd concentration in solution was also taken in the experiment that was due to provide a scientifically theoretical basis for the phytoremidiation in the soils contamminated by Cd with S. androgynus. The results presented that Cadmium contents in roots, stems and leaves increased gradually with treated concentrations rising in the experiment, and the change of Cadmium content in root was the most insignificant among them, in which the contents of Cd had all been more than the hyperaccumulators critical value, when the concentration 50 mg/kg was in solution. and when 400 mg/kg, contents of Cd in roots, stems and leaves were up to respectively 6566.00、948.46 mg/kg and 20.39 mg/kg, but 800 mg/kg had resulted in the death of S. androgynus. Under the concentrations of CK-T2, A/R and transfer coefficient were both more than 1, but when concentration reached T3-T6, there was a slight decrease in transfer coefficient. the difference among membrane permeability, biomass and chlorophl was no insignificant on the level of 5% , and contents of soluble protein increased from 0 to 50 mg/kg, the content of chlorophl, biomass and soluble protein, while, fell down when concentration in solution was from 100~400mg/kg, but membrane permeability was on the contrary, the results indicated that S. androgynus was a kind of hyperaccumulator in Cd, with critical value of 50 mg/kg, above which would cause poison in S. androgynus, and even dead when it was up to 800mg/kg; transfer coefficient would decrease with the increase in treated concentrations, which show that plant would protest Cd against transferring to above-grounds and causing poison.