Study On Heavy Metal Absorption Of Amaranth In Soil

Heavy metal pollution in soil is one of the common environmental pollution,which will affect the normal growth of plants to some extent.When the heavy metal is absorbed and accumulated by plants to a certain threshold,the normal cell division and ion homeostasis in plants will be seriously disturbed,resulting in the abnormal growth and development of plants.When the crops are polluted by heavy metals,the growth,yield and quality of them decline.At present,the treatment of soil heavy metal pollution is an important part of environmental and ecological research as well as plant protection research.The research group conducted experiments on heavy metal pollutants adsorbed by amaranth soil with field cultivation and indoor pot cultivation for three consecutive years from 2016 to 2018,in order to provide scientific basis and practical basis for heavy metal pollution control in paddy fields and cultivated land.The research results are as follows:(1)the absorption effect of amaranth on different heavy metals amaranth was planted in soil of contaminated cultivation for 60 d,and the content of heavy metals was determined by icp-aes.The results showed that the contents of Mn,Cd,As,Pb,Hg,Cr and other heavy metals in soil decreased from 888.63mg/kg,1.107mg/kg,19.718mg/kg,51.035mg/kg,0.213mg/kg and 85.880mg/kg in amaranth before planting to 260.397mg/kg,0.612mg/kg,15.27mg/kg,46.257mg/kg,0.206mg/kg and 0.612mg/kg in amaranth after planting Mn70.69% > Cd23.4%> As22.5% > Pb9.6% > Hg3.2% > Cr2.89% > Ni-2.3%.The results showed that amaranth had a certain absorption effect on various heavy metals in the cultivated soil,so that the content of heavy metals in the soil decreased.(2)the absorption of Cd and Mn by different amaranth varieties On the pollution to soil tillage planting red round leaf amaranth,dazzle beautiful full red willow amaranth,strictly choose eight different varieties of amaranth 60 d,the sampling results,to carry on the heavy metal content determination,the results showed eight different amaranth varieties of Cd enrichment coefficients is greater than 1,red round leaf amaranth enrichment coefficient up to 6.3,wild amaranth minimum 2.62;Cd content in soil decreased and that in amaranth increased.Eight amaranth varieties showed this law(P<0.05),indicating that Cd in soil was transferred to amaranth,that is,amaranth absorbed Cd in soil.The enrichment coefficient ofMn was greater than 1,the enrichment coefficient was 1.06,and the lowest value of wild amaranth was 0.31.The red round leaf amaranth was selected as the best amaranth with the best ability to absorb heavy metals for further study.(3)soil heavy metal absorption of amaranth planted for two consecutive years the soil Cd and Mn contents were measured by planting amaranth with red round leaves in the soil of polluted cultivation land for successive 2a.The results showed that the soil heavy metal Cd and Mn in situ cumulative index(Igeo index)after planting amaranth with red round leaves for successive 2a decreased from 2.5 to 0.82 and 0.4 to-1.63,respectively.Soil Cd pollution levels ? reduced to ?,make Mn pollution levels from?is 0.The results showed that amaranth had the ability of purifying the heavy metal Cd and Mn in soil and had the function of repairing soil.(4)distribution of heavy metals in amaranth plant tissues Respectively in potting soil to add height and 2 kinds of different concentrations of heavy metals combination,the concentration of 1(concentration)in Cd 1.0mg/kg,300mg/kg Cr,Pb concentration of 300 mg/kg and 2(high concentration): Cd 2.0mg/kg,600mg/kg Cr,Pb 600mg/kg,red round leaf amaranth 40d(edible stage),sampling harvest,respectively,the heavy metal content determination of amaranth root,stem and leaf,the results show that three kinds of heavy metal Cd,Pb,Cr content in plant size are: stem leaves roots.The contents of heavy metals in leaves and roots of amaranth sativus l.were 0.56mg/kg,0.68mg/kg,0.78mg/kg and 1.19mg/kg,1.79mg/kg and 1.15mg/kg,respectively.The contents of heavy metals in leaves were close to the edible range of 0.2mg/kg,0.5mg/kg and 0.3mg/kg.The higher concentrations in the roots were 1.80mg/kg,3.12mg/kg and 2.47mg/kg,all exceeding the risk value of agricultural products by more than 10 times.It was speculated that heavy metals were transported from the roots to the stems and leaves.(5)after the amaranth absorbed heavy metals in soil,the content of heavy metals returned to soil was determined Add in potting soil with the same processing(4),in does not add(1)transplanting soil,adding moderate concentration of heavy metals(2)transplanting soil and higher concentration(3)transplanting soil in potting soil red round leaf amaranth 60 d after transplanting to potting soil 15 d,continue to grow in concentration in the soil to absorb the heavy metal content of amaranth transplanting in three kinds of transplanting soil,soil Cd,Cr,Pb content fell 20.23%,42.57% and 26.5% respectively;In high concentration,itdecreased by-57.9%,-145% and-113.7% respectively,indicating that amaranth could absorb Cd in the soil with light to moderate heavy metal pollution,and it could fix Cd by itself.In a certain planting time,Cd would not be returned to the soil,so it had better repair characteristics for Cd.(6)determination of Cd,Cr and Pb in amaranth and rice after rotation Two heavy metals with the same concentration in(4)were added to the soil,and the heavy metals in the rice plant were determined by sampling the soil after 30 d of rice planting and 30 d of amaranth after 30 d of amaranth planting.The data showed that the heavy metal content of Cd,Cr and Pb in rice plants planted directly were all higher than that in rice plants planted after amaranth planting.The plant content of rice inoculated directly in the soil with medium concentration was 1.49mg/kg,25.96mg/kg,18.07mg/kg.The rice plant content of amaranth and rice rotation was 0.86mg/kg,20.97mg/kg,16.00mg/kg.The results showed that amaranth could significantly absorb heavy metals in soil and reduce the absorption of heavy metals in rice.The results showed that the cultivation of amaranth can significantly reduce the content of heavy metals in the cultivated land,reduce the degree of heavy metal pollution,and reduce the adsorption of heavy metals in the rice after the stubble,and play a role in repairing soil heavy metal pollution.The study provides a theoretical and practical basis for the treatment of soil heavy metal pollution by fallow cultivation of amaranth.