A Preliminary Study On The Enrichment And Degradation Of Heavy Metals And Organic Pollutants In Soil By Malus Robusta

Malus robusta is rosaceae family plant,which is originated in China.Malus robusta is small deciduous trees which characterized by its bright color flower and bright red fruit,it can be used as apple rootstock.Due to well developed root systeam,Malus robusta showed a very strong viability in the environment.There have been many studies showed that Malus robusta have strong resistance to salt,and also have very good ability to survive in other harsh soil environments.As Malus robusta have resistance to many environmental stress,we speculated that Malus robusta also had a certain degree of tolerance on heavy metal and organic pollutants.To clarify the role of Malus robusta on metabolic of pollutants and ecological restoration of soil,we study absorption,metabolism and enrichment of pollutants by analysis residues in Malus robusta,Cobaltous Chloride,2,4,6-Trinitrotoluene(TNT),Acrylamide were choosed and anlysised in this study.The main results are as follows:1.Malus robusta have certain tolerance ability for cobalt chloride,TNT,acrylamide.When the concentration of cobalt chloride,TNT and acrylamide were 0.46mmol/L,0.84mmol/L,12.32mmol/L,the growth of Malus robusta was inhibited,the leaves especially young leaves begin to turn yellow and dry.2.Analysis of heavy metals and organic pollutants in different parts of Malus robusta,clarify the role of Malus Robusta on the accumulation of heavy metals and organic pollutants.The results show that:Malus robusta could absorb cobalt chloride,TNT and Acrylamide.Malus robusta absorbed Cobalt chloride mainly distributed by root part,but TNT absorbtion was mainly distributed by aerial part.The contents of cobalt chloride,TNT in aerial and root part were all increased with the increase of the concentration of cobalt chloride,TNT.When the concentration of cobalt chloride was 50μmol/L and 500μmol/L,Malus robusta absorbed 23.44%,34.89%cobalt chloride,respectively,and then the absorption rate decreased gradually.After 7 days,Malus robusta absorbed 54.42%and 52.95%cobalt chloride,respectively,and the root system contained 86.57%and 81.70%respectively.When Malus rbusta was treated with 0.1mmol/L,0.2mmol/L,0.5mmol/L and lmmol/L TNT for 6 days,respectively,Malus robusta absorbed 70%-80%TNT.When Malus robusta was treated with acrylamide,and the concentration was 0.01mmol/L,0.05mmol/L and 0.5mmol/L,Malus robusta woulde absorbe all acrylamide at the first,fourth and seventh day,respectively.However,when acrylamide was increased to 5 mmol/L,Malus robusta absorbed 31.25%in 7 days.3.To determine role of Malus robusta on degradation heavy metals and organic pollutants,the dynamic processes of heavy metals and organic pollutants were monitored.The results show that:Malus robusta can degrade TNT,but can’t degrade cobalt chloride.We detected the metabolic degradation of heavy metals and organic pollutants in Malus robusta by detecting the dynamic process of heavy metals and organic pollutants.The results showed that the root,leave,stem of Malus robusta can degrade TNT,but can’t degrade cobalt chloride.When Malus robusta was treated with 0.lmmol/L,lmmol/L TNT for 7 days,Malus robusta absorbed 100%,76.348%,respectively,and the root system contained 23.012%and 18.532%,stem,leaf contained 49.593%and 39.053%,and degradated 27.396%,18.763%.4.Analysis of different concentrations of heavy metals and organic pollutants stress on the antionxidant enzymes of Malus robusta.The results show that:With the increasing concentration of cobalt chloride,TNT and acrylamide,the extension of stress time,the chlorophyll content of Malus robusta showed a decreasing trend but the root activity was significantly decreased.With the increasing of cobalt chloride concentration,the content of proline and MDA was decreased first and then increased,SOD activity was induced significantly,and the activity of POD and CAT increased first and then decreased subsequently.With the increasing concentration of TNT and acrylamide,the content of proline and MD A increased,and the activities of three enzymes increased significantly.