| From 20th century, with the rapid industrial development, the pollution becomes a more and more serious problem. Therefore, the world has to face up to the tough challenges that how to control the pollution. Nowadays, how to ameliorate heavy metal polluted soil is one of the hottest and most difficult fields all over the world. The heavy metal not only lowers the fertility of the soil, which will further decrease the crops'yield and quality, but also deteriorates the water, which will jeopardize human being's health, even life. Phytoremediation is a promising, green and inexpensive method to ameliorate the heavy metal polluted soil. The low bio-availability of heavy metal in the soil is still the bottleneck of the development of Phytoremediation technique. The micro-activity can influence the bio-availability of heavy metal, and enhance the effect of Phytoremediation. Microbe-Plant unite remediation is a key solution to ameliorate heavy metal polluted soil. However, it is so difficult to be applied in practice that no great breakthroughs have been made yet. This research uses pot experiments and microorganism selecting technical methods to solve pollution soil problems. Aiming at improving phytoremediation efficiency of Cd, Pb and Zn contaminated soils, the stimulation experiments were carried out. Studies on the ability of absorption accumulation for Cd, Pb and Zn in the soil with nine kinds of plant in different bulk materials; Series of pot experiments were performed to determine the effects of cadmium in soil on chlorophyll content,CAT, POD and SOD activities in shoots of Brassica juncea; Checking the beneficial influences on microorganism for the plant absorption ability. Using duality mobile phase of sodium phosphoric acid buffer solution and acetonitrile, we could determine the content of organic acid in fermentation liquor by reversed-phase high performance liquid chromatographic method. The main results are summarized as follows:(1) The simulated test of compound contamination with cadmium, zinc and lead was carried out with meadow cinnamon soil and Brassica juncea as tested soil and plant respectively. The results indicated that the amounts of Cd, Pb and Zn uptake in the aboveground parts of Brassica juncea are 2.77~38.56mg/kg, 12.38~37.84mg/kg, and 67.23~687.64mg/kg respectively. The bioaccumulation factors of Cd, Pb and Zn in the aboveground parts of Brassica juncea are 0.350~7.078, 0.023~0.405, and 0.410~1.280 respectively. It showed the extremely significant linear correlation between the contents of the plant absorbing Cd, Zn and Pb and the contents of these metals in the soil of compound treatment with these metals, i.e. YCd=0.548XCd,YPb=13.823+0.018XPb,YZn=0.613XZn.There are no compound effects among the 3 kinds of heavy metal in soil for their sorption by Brassica juncea. The simulated test of compound contamination with cadmium, zinc and lead was carried out with meadow cinnamon soil and Brassica juncea as tested soil and plant respectively. The results indicated that the average amounts of Cd, Pb, and Zn sorption in the aboveground parts of the seven species of Brassica juncea are respectively 2.73~51.23mg/kg, 16.87~75.03mg/kg, and 153.53~7346.59mg/kg. The average amounts of Cd, Pb, and Zn sorption in the underground parts are respectively 7.32~101.33mg/kg, 28.85~613.36 mg/kg, and 348.91~954.29mg/kg. The amount of Cd sorption inⅥis the highest and the amounts of Pb, Zn sorption inⅡare the highest. In short, the ability of translocation is Zn>Cd>Pb, the ability of bioaccumulation is Cd>Zn>Pb. There is no compound effect between the 3 kinds of heavy metal for their sorption by Brassica juncea. The simulated test of compound contamination with cadmium, zinc and lead was carried out with meadow cinnamon soil and Lolium multif lorum & Festucaarundinacea as tested soil and plant respectively. The results indicated that, under the compound pollution of Cd and Zn, the amount of Cd sorption of the ground part of Festucaarundinacea is 5.76mg/kg, the amount of Pb sorption is 19.77mg/kg, and the amount of Zn sorption is 418.18mg/kg; the amounts of Cd, Pb and Zn sorption of the underground part of Festucaarundinacea are 129.82mg/kg, 256.66mg/kg, and 354.66mg/kg respectively. The amount of Cd sorption of the ground part of Lolium multif lorum is 5.57 mg/kg, the amount of Pb sorption is 26.13mg·kg-1, and the amount of Zn sorption is 467.18mg/kg; the amounts of Cd, Pb and Zn sorption of the underground part of Festucaarundinacea are 114.53mg·kg-1, 155.98mg/kg, and 513.48mg/kg respectively. Through the ANOVA analysis, there is no significant difference between the amounts of heavy metals accumulation of the two kinds of plant. It showed the extremely significant linear correlation between the contents of Cd,Pb,Zn in the aboveground part of plant and the ionic impulsion in the soil. The bioaccumulation ability of the two plants is: Zn>Cd>Pb. The sorption of Zn is special, when the content of Zn>400mg/kg in the soil, the translocation factor>1, the ability of bioaccumulating Zn is very powerful. They can be used as phytoremediation plant to remedy Zn pollution soil. There are no compound effects amoung the three kinds of heavy metal for their sorption by the two plants.(2) Series of pot experiments were performed to determine the effects of cadmium in soil on chlorophyll content,CAT, POD and SOD activities in the aboveground parts of Brassica juncea. The results indicated that Brassica juncea has a strong tolerance to Cd pollution. It can grow all right in the soil with the content of Cd from 0mg/kg to 200mg/kg. With the content of Cd increasing, the biomass of Brassica juncea exhibited a parabolic change current. Nevertheless, Cd influences the growth of Brassica juncea by postponing its growth stages. The content of Cd in Brassica juncea increases with the content of Cd in soil adding. The contents of Cd are about 7.824~102.672mg/kg in the aboveground parts and 0.374~191.910mg/kg in the underground parts respectively. The bioaccumulation factors of heavy metal in the ground parts take downward trend, while the bioaccumulation factors of heavy metal in the underground parts take upward trend. Meanwhile, the translocation factor is 20.920~0.535. It takes on a gradually downward trend. The POD, CAT and SOD activities increase at lower contents of Cd, but decrease at higher contents of Cd. When the content of Cd added in the soil is 120mg/kg, the POD, CAT and SOD activities reach the highest. The number of microorganisms is Bacteria> actinomycetes>mould. The number of microbes is increasing during the Cd added in the soil. When the content of Cd added in the soil is more than 160mg/kg, the number of microbes is going down.(3) The bio-availability of heavy metal on the sorbtion for Brassica juncea was disscussed. Quartz sand and cinnamon soil were used as different bulk materials, comparing with the treatments of Bacillusme gaterium and Bacillus mucilaginosus compound. The reaserch shows that the sorbtion capability of heavy metal for Brassica juncea in the sand is stronger than in cinnamon, especially for Cd. The contents of Cd, Pb and Zn sorption in the aboveground parts of Brassica juncea growing in the sand are 110.99, 6.19, and 1.72 times higher than growing in cinnamon soil respectively, and the contents of Cd, Pb and Zn sorption in the underground parts of Brassica juncea growing in the sand are 33.95,28.04 and 10.61 times higher than growing in cinnamon soil respectively. The contents of heavy metal in the underground parts are about 1~3 times higher than in the aboveground parts. Adding microorganism can enhance the sorption capacity of heavy metals of Brassica juncea.(4)In order to understand the enhancement effect of Brassica juncea for phytoremediation of Cd contaminated soil with the addition of EDTA. The pot experiment was conducted to study the effects of application dose and stage of EDTA on mobilization of Cd, Pb and Zn in compound contaminated soil and its uptake by Brassica juncea. The results showed that the application of EDTA could decrease the biomass and increase Cd uptake in shoots of Brassica juncea remarkably, and the total Cd accumulation was 0.50~1.63 times higher than the treatment without applying EDTA. The contents of available Cd in soil were lower than the treatment without applying EDTA. With Cd contents increasing, the biomass and total Cd accumulation of Brassica juncea exhibited a parabolic shape, and the upper limiting content of Cd was 120mg/kg. When EDTA was applied to the soil in doses of 1mmol·kg-1 in one time or 3 times could achieve the optimized remediation effects. For the former application program, the Cd, Pb accumulations were 1.21 and 2.66 times respectively higher than the control treatment, while the Zn accumulation was lower than the control treatment. For the latter program, the Cd, Pb and Zn accumulations were 1.13, 3.78 and 1.29 times respectively higher than the control treatment. When the optimized program was applied to micro-field experiment, the heavy metals uptake in shoots of Brassica juncea increased remarkably, and the total Cd, Pb and Zn accumulations were 1.24, 2.06, and 2.07 times respectively higher than the control treatment.(5) Aiming at improving phytoremediation efficiency of Cd, Pb and Zn contaminated soils, the stimulation experiments were carried out with Brassica juncea as a hyperaccumulator to study effects of Bacillusme gaterium and Bacillus mucilaginosus compound, Aspergillus niger ferment 30177 and Aspergillus niger ferment 30582 on phytoremediation. The results indicated that Bacillusme gaterium and Bacillus mucilaginosus compopud can not only promote the growth of the hyperaccumulator, increase bio-availability of Cd, Pb and Zn in the soil but also increase the remediation efficiency largely. In the soil which added soluble Cd, Pb and Zn, the amounts of Cd, Pb and Zn extrated from soil are respectively 1.18, 1.54 and 0.85 times higher than the control. In the polluted sediment soil, the amounts of Cd, Pb and Zn extrated from sediment soil are respectively 4.00, 0.64 and 0.65 times higher than the control. Therefore, the enhancement effect of Bacillusme gaterium and Bacillus mucilaginosus compopud in polluted sediment soil is better than in the soil which added soluble Cd, Pb and Zn. Aspergillus niger ferment 30177 can significantly promote Brassica juncea to absorb Cd, Pb and Zn from the soils. In the soil which added soluble Cd, Pb and Zn, the amounts of Cd, Pb and Zn sorption in the aboveground parts of Brassica juncea are respectively increased by 88.82%, 129.04%, and 16.80% comparing with the control. In the polluted sediment soil, the amounts of Cd, Pb and Zn sorption in the aboveground parts of Brassica juncea are respectively increased by 78.95%, 113.63%, and 33.85% comparing with the control. Nevertheless, it can not take effect in improving the phytoremediation efficiency, and even decrease the biomass of Brassica juncea significantly. Aspergillus niger ferment 30582 takes on the affection of immobilizing Cd, Pb and Zn in the soil. It is of some value to the research on in situ microbial stabilization of Cd, Pb and Zn in the soils.Using duality mobile phase of sodium phosphoric acid buffer solution and acetonitrile (98∶2,V/V), we could determine the content of organic acid in fermentation liquor by reversed-phase high performance liquid chromatographic method. Flow rate of mobile phase was 1.0 mL/min with UV-detection at 210 nm.The results showed that there are trartaric acid (TA) and Vitamin C (VC) in Bacillusme gaterium and Bacillus mucilaginosus fermentation liquor.(6)28 bacterial strains were selected which can produce organic acids from natural pollution soil. Through the pot experiment, we find that the bacterial strains with the number of A-4-2,b-1-0,c-5-5,c-4-0 can promote the sorption ability of heavy metals of Brassica juncea, b-3-7 has the opposite affect. Through the physiological biochemistry analysis, the 16S rDNA extraction purification and sequencing analysis on the above strains, we can identify that c-4-0 is Listeria denitrificans, b-1-0 is Bacillus cirallans, c-5-5 is Listeria grayi, and b-3-7 is Neisseria sicca. Using duality mobile phase of sodium phosphoric acid buffer solution and acetonitrile (98∶2,V/V), we can determine the content of organic acid in fermentation liquor by reversed-phase high performance liquid chromatographic method. Flow rate of mobile phase was 1.0 mL·min-1 with UV-detection at 210 nm.The results showed that there are oxalic acid(OA), trartaric acid(TA), and malic acid(MA) in the fermentation liquor of above bacterial strains These organic acids can effect the bio-availability of heavy metals in soil, and then their sorption by plants.
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