Study On Tolerance Valuation Of Five Broad Leaved Greenism Tree Species In Cu Contaminated Soils

This work was focused on the characteristics of uptake and accumulation of Cu on five broad leaved greenism tree species including Fraxinus chinesis,Sophora japonica,Salix matsudana, Euonymus japonica and Forsythia suspensa,as well as the effect of Cu stress on growth,physiological and biochemical activities.In order to provide support and basis for vegetation restoration and construction in serious Cu contaminated soil tolerance plants and indicator species for soils contaminated with Cu were screened.Cu spreaded starting mainly from the roots,then to the stem,and the Cu content of leaves came lest.The level of Cu content differed among the five spieces,the Cu content in root,stem and leaf of Euonymus japonicus and Forsythia suspensa were significantly higher than that of Fraxinus chinesis, Sophora japonica and Salix matsudana;the Cu content of the Euonymus japonicus roots was 2063.32mg·kg^-1under a value of 2000mg·kg^-1for the concentration of Cu in soil;while under high concentration treatment of Cu(2000mg·kg^-1),the Cu accumulation of different species followed this sequences:Forsythia suspensa(35.98mg)＞Euonymus japonicus(27.03mg)＞Fraxinus chinesis (7.88mg)＞Sophora japonica(3.57mg)＞Salix matsudana(2.30mg).The Effect of Cu pollution on the growth of tree was significant:slowed down or even dead may result from a high concentration treatment.In Cu stress,the specific leaf weight and biomass reduced, chlorophyll content decreased,photosynthesis was inhibited,the content of malondialdehyde(MDA) increased,enzyme activity imbalanced,the membrane permeability increased,the content of praline was stimulated and the activities of root activity was inhibited.The growth and Physiological activities of Euonymus japonicus and Sophora japonica were seriously inhibited.Fraxinus chinesis and Forsythia suspense were less affected;Salix matsudana was at the middle.The index system of plants' tolerance to Cu contaminated soil by the principal component analysis to all the index studied was determined,which included total chlorophyll content,photosynthetic rate, fluorescence,POD,membrane permeability,proline,root activity,specific leaf weight,biomass,Cu content and Cu accumulation.Integrated cluster analysis showed:Forsythia suspense and Fraxinus chinesis showed strong tolerance to Cu contaminated soil,and can be used as plant material for phytoremediation;and at the same time Euonymus japonicus was selected as indicator materials for Cu contaminated soil.