| Mine exploiting and metal smelting cause serious soil heavy metal pollution in its surrounding areas, and directly threaten to the quality and safety of agricultural products, ecological security and human health in the region. Therefore, the research of technologies that repair the soil polluted by heavy metal in mine areas is very important. Phytoremediation of hyperaccumuahors of heavy metals has been a hot topic in recent years, which possess low cost, social acceptability etc. advantages. In addition, chemical immobilization of heavy metals in soil is also one effective way to remediate the soil contaminated by heavy metal. Combining phytoremediation and chemical immobilization techniques in the remediation of soil contaminated by heavy metal is one of the hot researches. On the one hand, additives can fix the heavy metal ions in the soil, thus the plants increasing resistance to the heavy metal. On the other hand, some additives can promote the release of some heavy metal ions in soil and the efficiency of extraction to heavy metals of the plants may improve. Therefore, it is of great importance to carry out phytoremediation simultaneously chemical immobilization techniques on heavy metals contamination.A pot experiment was carried out to study the effect of chemical additives (meerschaum, zeolite, N, P and K fertilizer) on phytoremediation effectiveness of manganese and other metals in P. pubescens Bl. growing in the soil contaminated by Mn, and the results showed are as follow:1. Effects of different levels of meerschaum treatments on co-planted and single planted P. pubescens Bl.(1) By the2.0,4.0and8.0g/kg of meerschaum treatments, the contents of chlorophyll a, b,-SH and PCs, and the activity of POD and CAT were improved, while the cumulative of O2·-and H2O2were not affected in the leaves of single planting P. pubescens Bl.. The contents of-SH, GSH and PCs, and the activity of CAT were improved, while the cumulative of O2·-and MDA were reduced in the leaves of single planting brassica chinensis. Under the same level of meerschaum treatment, the plant weight, plant height and activity of CAT in leaves of co-planted P. pubescens Bl were higher than single planted P. pubescens Bl., while the contents of chlorophyll a and b,-SH, GSH and PCs, and the accumulation of H2O2in leaves of co-planted P. pubescens Bl were lower than single planted P. pubescens Bl, and the contents of-SH and PCs, and the activity of APX in the leaves of co-plantde brassica chinensis higher than single planted brassica chinensis, while the contents of GSH, the activity of POD,and the the cumulative of O2·-and H2O2of co-plantde brassica chinensis were lower than single planted brassica chinensis.(2) Under the blank treatment, the contents of Mn were up to14955.7mg·kg-1in leaves, and which were up to6748.8mg·kg-1in stems of single planted P. pubescens Bl.. Besides, both the TF ieaf/root and the TF stem/root were greater than1.These indicated strong enrichment and metastatic ability of manganese of P. pubescens Bl..Therefore, P. pubescens Bl. owns good prospects in remediation the contaminated soil. Under different levels of meerschaum treatments, the cumulative of Mn, Cr, Pb and Cu in leaves, the cumulative of Zn in roots, stems and leaves, and the absorption of Ca in roots of single planted P. pubescens Bl. were inhibited, and the cumulative of Cr in roots and leaves, the cumulative of Pb in roots, stems and leaves, the cumulative of Zn in leaves, and the cumulative of Cu in roots and leaves of single planted brassica chinensis were inhibited, while the cumulative of Mn in roots and leaves, the cumulative of Cr, Zn and Cu in stems, the absorption of Ca in roots, the absorption of Mg in roots stems and leaves of single planted brassica chinensis were promoted. Under the same level of meerschaum treatment, the contents of Mn, Cr, Pb, Zn and Cu in the roots, stems and leaves, the contents of Ca in roots and stems, and the contents of Mg in stems and leaves of co-planted P. pubescens Bl. were lower than single planted P. pubescens Bl, the contents of Mn in leaves,the contents of Cr, Pb and Ca in roots and stems, the contents of Zn and Cu in stems, and the contents Mg in roots, stems and leaves of co-planted brassica chinensis were lower than single planted brassica chinensis.(3) The repair efficiency of P. pubescens Bl. in Mn contaminated soil were improved by H8.0treatment, and compared with co-planted P. pubescens Bl., the single planted pattern is more conductive to P. pubescens Bl repair Mn contaminated soil.2. Effects of different levels of zeolite treatments on co-planted and single planted P. pubescens Bl.(1) By4.0,8.0and16.0g/kg of zeolite treatments, the contents of chlorophyll a,-SH and PCs, and the activity of POD, CAT and APX were improved, while the plant weight, plant height and activity of SOD and the cumulative of O2·-were reduced in the leaves of single planting P. pubescens Bl., and the contents of-SH, GSH and PCs were improved, while the activity of APX and the cumulative of O2·-, H2O2and MDA were reduced in the leaves of single planted brassica chinensis.Under the same zeolite level of treatment, the plant weight, plant height and the contents of chlorophyll b and GSH, and the activity of SOD in leaves of co-planted P. pubescens Bl. were higher than single planted P. pubescens Bl., while the contents of chlorophyll a,-SH and PCs, the activity of POD CAT and APX and the accumulation of02·-and MDA in leaves of co-planted P. pubescens Bl were lower than single planted P. pubescens Bl., and the contents of-SH and PCs and the accumulation of H2O2of co-planted brassica chinensis were higher than single planted brassica chinensis, while the accumulation of O2·-of co-planted brassica chinensis was lower than single planted brassica chinensis.(2) Under4.0,8.0and16.0g/kg of zeolite treatments, the cumulative of Mn and Cr in leaves, the cumulative of Zn in roots, and the cumulative of Cu in stems and leaves of single planted P. pubescens Bl. were inhibited, while the cumulative of Cr and Ca in stems, the cumulative of Cu in roots, and the cumulative of Mg in stems and leaves of single planted P. pubescens Bl. were promoted, and the cumulative of Mn in roots and leaves of single planted brassica chinensis were promoted. Under the same zeolite level of treatment, the contents of Mn in the roots, stems and leaves, the contents of Cr and Pb in stems, the contents of Zn in roots and stems, the contents of Cu in roots, the contents of Ca in roots and leaves, and the contents of Mg in stems and leaves of co-planted P. pubescens Bl. were lower than single planted P. pubescens Bl., and the contents of Mn in leaves of co-planted brassica chinensis was lower than single planted brassica chinensis, while the contents of Cr in stems, and the contents of Cu co-planted brassica chinensis were higher than single planted brassica chinensis. (3) The repair efficiency of co-planted P. pubescens Bl. in Mn contaminated soil was significantly improved by the treatment of16.0g/kg of zeolite.3. Effects of N fertilizer treatment on P. pubescens Bl.(1) By the60.0,120.0and180.0mg/kg of NH4Cl or urea treatments, the contents of chlorophyll a and b and GSH, and the activity of SOD, POD and CAT were improved, while the contents of-SH and PCs, and the cumulative of O2·-and H2O2were reduced in the leaves of P. pubescens Bl.. Under the same level of NH4Cl and urea treatment, when under NH4Cl treatment, the plant weight and the contents of chlorophyll a and chlorophyll b of P. pubescens Bl. were lower than urea treatment.(2) Under NH4CI or urea treatments, the cumulative of Mn in stems and leaves, the cumulative of Cr, Zn and Cu in roots, stems and leaves, the cumulative of Pb in stems, and the absorption of Ca and Mg in roots, stems and leaves of P. pubescens Bl. were inhibited, while the cumulative of Pb in roots and leaves were promoted. Under the same level of NH4CI and urea treatment, when NH4Cl treatment, the contents of Pb in leaves were above urea treatment.(3) By the NH4Cl or urea treatments, the growth of P. pubescens Bl. were promoted, but the enrichment of Mn of P. pubescens Bl. were inhibited.Therefore, the repair efficiency of Hyperaccumulator P. pubescens Bl. in Mn contaminated soil can not be promoted by these six treatments.4. Effects of P fertilizer treatment on P. pubescens Bl.(1) By the50.0,100.0, and200.0mg/kg of Na2HPO4or SSP treatments, the plant weight, plant height and the contents of chlorophyll a and GSH, and the activity of SOD, POD and CAT were improved, while the cumulative of O2·-, H2O2and MDA in were reduced the leaves of P. pubescens Bl. Under the same level, when under Na2HPO4treatment, the plant weight and the contents of chlorophyll a of P. pubescens Bl. were lower than SSP treatment, but the content of chlorophyll b of P. pubescens Bl was higher than SSP treatment.(2) Under50.0,100.0and200.0mg/kg of Na2HPO4or SSP treatments, the cumulative of Mn in stems and leaves, the cumulative of Cr, Pb, Zn and Cu in roots, stems and leaves, the absorption of Ca in roots, and the absorption of Mg in roots, stems and leaves of P. pubescens Bl. were inhibited, while the absorption of Ca in leaves of P. pubescens Bl. was promoted. Under50.0and100.0mg/kg of Na2HPO4or SSP treatments, the cumulative of Mn was promoted. (3) Under the Na2HPO4or SSP treatments, the growth of P. pubescens Bl. was promoted, but the enrichment of Mn of P. pubescens Bl. was inhibited. Therefore, these six treatments the repair efficiency of Hyperaccumulator P. pubescens Bl. in Mn contaminated soil can not be improved by these six treatments.5. Effects of K fertilizer treatment on P. pubescens Bl.(1) Under the100.0,200.0and300.0mg/kg of KCl or K2SO4treatments, the plant weight, plant height and the contents of chlorophyll a and b, and the activity of SOD, POD and CAT were improved, while the cumulative of O2·-and H2O2were reduced in the leaves of P. pubescens Bl.(2) Under the KCl or K2SO4treatments, the cumulative of Mn, Cr, Zn and Cu in roots, stems and leaves, the cumulative of Pb in stems and the absorption of Ca and Mg were inhibited, and the inhibition of the absorption of Ca was significant, while the cumulative of Pb in roots and leaves were promoted.(3) By the KCl and K2SO4treatments, the growth of P. pubescens Bl. was promoted, but the Mn enrichment of P. pubescens Bl. was inhibited.Therefore, so the repair efficiency of Hyperaccumulator P. pubescens Bl. in Mn contaminated soil can not be improved by these six treatments. |
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