Research On The Response Of Aralia Elata Var.inermis And Toona Sinensis To Pb Or Cd

Because of the shortage of water severely,Tianjin's farmland have been cultivated by sewage irrigation,otherwise,the abuse of agricultural products and the natural sedimentation of air pollutants also caused farmland polluted by heavy metals,in which Pb-contaminated soil and Cd-contaminated soil are the most serious.In order to study the possibility of cultivating Aralia elata var.inermis and Toona Sinensis in the farmland of Tianjin,this paper applied the Aralia elata and Toona Sinensis as the research objective to compare the potential of remediating the soil contaminated by Pb or Cd.The results showed that:From the aspect of remediation effect,when the content of Pb in the soil reached to 100 mg/kg or more,the remediation effect of Toona Sinensis is higher than Aralia elata in the Pb-contaminated soils.When the content of Cd in the soil reache to 1 mg/kg or more,compared to Aralia elata,the remediation effect of Toona Sinensis is better.From the aspect of accumulation and migration of heavy metals in plant,the bioconcentration coefficient(BCF)of underground part of Toona Sinensis was higher than the aerial part under the Pb-soil or Cd-soil,and the translation factor was lower than 1.At the same time,the Pb content of leaves of Toona Sinensis was lower than the pollutant limit standard of national food security,it can be considered edible.When the concentration of Pb was less than 500 mg/kg,aerial part's BCF of Aralia elata was higher than the underground part;when the concentration was higher than 500 mg/kg,it was in contrast.However,uder the stress of Cd,the aerial part's BCF was higer than the underground part.Otherwise,the leaves of Aralia elatacan not be edible,because the content in leaves is higher the standard limit.From the effects of heavy metals on plant physiological characteristics,chloroplast pigment content in leaves of Aralia elata and Toonan Sinensis generally showed a lower concentration to prmote and higher concentration to inhibit.Othwise,the MDA content was highest at the pb-concentration was 500 mg/kg;the MDA content showed firstly increased then decreased with the increase of Cd concentration.From the aspect of nutrition quality,soluble sugar,vitamin C and organic acid of Toona Sinensisfistly promted then inhibited with the increase of Pb concentration,but the soluble protein was in contrast.The nutrition quality under the Cd stress is advese.The soluble protein,sugar and organic acid of Aralia elata firstly promoted then inhibited in Pb-stress,but the Vc content decreased.The soluble protein and Vc decreased under the Cd stress,but the sugar and organic acid content firstly increased then decreased.