| Cadmium and lead is the dangerous pollutants in the soil. Because these two sources of heavy metal pollution extensive and easy to accumulate in the soil, while cadmium, lead in the biosphere may be migration, conversion, enrichment and along the food chain "biological amplification." Therefore cadmium and lead compound for phytoremediation of contaminated soil has a high theoretical and practical value. In this study, the use of rape as a high biomass plant repair plants, cadmium, lead and soil phytoremediation; the same time, to take soil improvement measures to enhance the soil, cadmium, lead plant availability, to achieve the purpose of improving the efficiency of rapeseed repair The main conclusions are:1) According to Soil Environmental Quality Standard (GB15618-1995) three criteria, we have evaluated southern Yunnan mine soil, and the findings show that the soil content of cadmium (4.06～5.8 mg·kg-1) are all exceeding the standard of lead content in soil (653.99～1294.48 mg·kg-1)In addition to CA-3 has also exceeded the individual collection spots, indicating farmland soil by heavy metals cadmium, lead compound pollution;2) In the low concentration of cadmium (1 mg·kg-1) pollution, the rape aboveground biomass increased 9%, rape root biomass declined by 14%; in high concentrations of cadmium (4 mg·kg-1) pollution,, the rape aboveground biomass reduction of 4%, root biomass, reduced by 10%; in low concentrations of lead pollution, the rape aboveground biomass increased by 2%, rape root biomass increased by 14%; in high concentrations lead (850 mg·kg-1) pollution, the rape aboveground biomass reduced by 7%, rapeseed root biomass were reduced by 17%; in the combined pollution experiments, at low concentrations of complex experiments (Cadmium 1+Lead 500 mg·kg-1), the aboveground biomass of oilseed rape reduced by 4%, root biomass decreased by 14%; in high concentrations of complex experiments (Cadmium 4+Lead 850 mg·kg-1), the rape aboveground biomass was reduced by 22%, root biomass decreased by 32%; in cadmium, lead, under the single and combined pollution of heavy metals have resulted in injury to plants, leading to rape aboveground biomass, root biomass and total biomass decreased significantly, and the With the increasing concentration of heavy metal pollution showed a gradual decreasing trend;3) In the low concentration of cadmium (1 mg·kg-1) pollution, the rape of cadmium in shoot 1.843 mg·kg-1; high concentration of cadmium (1 mg·kg-1) pollution, the rape of cadmium in shoot 4.06 mg·kg-1; at low concentrations of lead (500 mg·kg-1) pollution, the rape of the lead content of shoot 28.43 mg·kg-1; high concentrations of lead (850 mg·kg-1) pollution, the rape shoot the lead content of 133.342 mg·kg-1; in the composite pollution experiments, low concentrations (Cadmium 1+Lead 500 mg·kg-1), the rape shoot cadmium and lead content were:10.09 mg·kg-1 and 17.36 mg·kg-1; high concentration (Cadmium 4+Lead 850 mg·kg-1) pollution, rape shoot cadmium and lead content were: 53.62 mg·kg-1, and 75.689 mg·kg-1; cadmium, lead single and combined pollution, the rape of cadmium and lead absorption rule is:Rape in vivo cadmium and lead content of soil with cadmium and lead content of growth and growth; in cadmium, lead compound pollution, the rape of cadmium and lead uptake mechanism is different from,in heavy metal pollution, the rape of the absorption of heavy metals on Rape is not a single heavy metal pollution heavy metal uptake by a simple superposition, but are subject to the interaction between the impact of heavy metals; rape on Cadmium uptake by the soil with lead Add the increase in the amount of increase, while the rape of lead absorption of cadmium in the soil, along with the added amount of the increase in decline;4) In the cadmium, lead single and combined pollution, the rape by starting their own protection mechanisms. This study showed that:when the body contains a lot of rape, when heavy metal ions, rape by enzyme decomposition of ascorbic acid ascorbic acid gets rid of the reactive oxygen species in order to eliminate active oxygen in plants the accumulation of heavy metals on plants to alleviate the harm;5) In order to improve the cadmium and lead contaminated soil phytoremediation efficiency, improvement of contaminated soil matrix, the traditional measures in agriculture-fertilizer, different nitrogen fertilizers on cadmium and lead combined pollution under the impact of rape biomass pot experiment was not significantly different. Compared with the control experiment, pairs of rape absorption of cadmium and lead can serve as a catalyst for the enrichment of heavy metals showed the same discipline to rape enrichment of cadmium and lead was followed by ammonium chloride treatment to promote "ammonium sulfate treatment" urea treatment.Effect of different potassium cadmium, lead and combined pollution under the impact of rape biomass pot experiment was not significantly different. Compared with the control experiment, pairs of rape absorption of cadmium and lead can serve as a catalyst, but the performance of heavy metal enrichment is inconsistent for the enrichment of lead in the promotion of oilseed rape, followed by potassium treatment "of potassium nitrate treatment" potassium chloride treatment; for Rape enrichment of cadmium promotion, potassium nitrate, potassium sulphate and potassium chloride treatment was significantly lower than handling.6) Because the key to successful promotion of phytoremediation are:in a certain period of time to reach the purpose of cleaning the soil. Therefore, phytoremediation can be carried out at the same time, in combination with other soil remediation measures, this study shows that soil replacement can effectively ease the heavy metals cadmium, lead and damage to plants, while in the diluted soils planted with high biomass repair plant, side edge of governance to achieve the effect of restoration can effectively shorten the time for phytoremediation. |
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