The Effects Of P. Aeruginosa ATCC 9027 And NTA On Phytoextraction Of Cd By Ramie(Boehmeria Nivea(L.) Gaud)

Cadmium(Cd) as a kind of heavy metal toxicity due to its biological toxicity and migration capability, which can not be readily biodegradable in the human through food chain. animals and plants. The heavy metal caused great harm to the health of animals and plants as well as the human body. Therefore, The control of pollution and remediation of soil heavy metals Cd is an important problems to be solved. Compared with the conventional chemical and physical techniques, Phytoremediation, a technology of applying vegetations to remediate contaminated soils, is generally considered as a low-cost, eco-friendly approach which has gained considerable interests worldwide. Exogenous substance-induced phytoremediation as phytoremediation derived its efficiency has been widely applied.Boehmeria nivea(L.) Gaud(ramie) was applied as the study plant which is a Cd-tolerant species with large biomass and fast growth rate. In pot experiments, the effects of Pseudomonas aeruginosa ATCC 9027 and nitrilotriacetic acid(NTA) on Cd phytoextraction from contaminated soil by Boehmeria nivea(L.) Gaud(ramie) was investigated. Ramie was grown in a sandy soil in the presence of 30 mg /kg Cd and 50 mg /kg Cd, respectively. Experimental pots were amended with P. aeruginosa ATCC 9027 or NTA at different levels(5, 10 and 20 mmol/kg) weekly. The purpose of the article is to analyze under Cd contamination the ramie of growth, the uptake of Cd, translocation, as well as to explain the photosynthesis and antioxidant systems. The main objective of the research was to investigate the potential ability of ramie in enhancing phytoremediation of Cd by application of NTA and P. aeruginosa ATCC 9027. The main conclusions of the study were as follows:(1). Ramie as a heavy metal Cd plants which has enrichment capability to resistt to heavy metals Cd The distribution of Cd content showed root> stem> leaf in ramie, And the majority of heavy metal enriched in plant roots. However, when Cd under the concentration of 30 mg/kg, 50mg/kg the capable of growth and metabolism of ramie plant caused varying degrees of damage. The growth was reduced; MDA content increased, chlorophyll and soluble protein content decreased, the performance showed that ramie can adapt to in environment under Cd stress.(2). Under heavy metals Cd stress applied to low concentrations of NTA(5 mmol/kg) can appropriate mitigation toxic effects in plant. While under heavy metals Cd stress,the inhibition of ramie caused in high concentrations NTA(10 mmol/kg, 20 mmol/kg) and showed a synergistic effect, such as increasing ramie's poisoning, heavy metal uptake inhibition. Especially in the 50mg/kg Cd stress, high concentrations of NTA(10 mmol/kg, 20 mmol/kg) showed that biomass was significantly decreased, and chlorophyll content decreased. especially increased MDA content. But when applying NTA, plant can significantly improve the transfer factor TF by 17.4% to 36.2% and 74.5% to 81.8%. under the concentration of 30mg/kg, 50mg/kg heavy metal Cd.(3). The inoculation of P. aeruginosa ATCC 9027 under Cd stress alleviated the Cd-induced damages, resulting in promotion of ramie growth, improvement of chlorophyll content. And the strain can significantly improve uptake of heavy metal, especially to improve heavy metal from the absorption of roots. By contrasting 30 and 50 mg/kg Cd treatments, the inoculation of P. aeruginosa ATCC 9027 increased accumulation in root ranging from 54% to 96% and 13% to 104% in 30 and 50 mg kg-1 Cd soils, respectively. The average accumulation of Cd with P. aeruginosa ATCC 9027 was about 1.95-fold(30 mg/kg Cd) and 1.54-fold(50 mg/kg Cd) compared to the corresponding NTA treatments.(4). When added with NTA, the accumulation of Cd in shoot of ramie was higher than the controls, but the inhibition of plant growth and related enzyme activities were observed. The experimental results demonstrated that P. aeruginosa ATCC 9027 can greatly enhance phytoremediation efficiency. The plants protected the integrity of the cell and decreased MDA content as well as ROS levels, thus alleviating peroxidation damage in Cd-induced stress.(5). The results also indicated that P. aeruginosa ATCC 9027 was more effective than NTA to improve the efficiency of ramie under cadmium stress in practical applications. At 30 mg/kg Cd stress, the suitable concentration of bacteria was the addition of twice, which has the largest biomass and the strain will not cause second pollution. This suggested that P. aeruginosa ATCC 9027 has a high effectiveness to repair heavy metal Cd. And it also has high research value and application prospects.