Investigation On The Wild Salix In Chifeng And The Growth And Physiology Response Of Two Species Of Salix To Cadmium Stress

Collection and investigation of wild Salix plants had been done in some areas of Chifeng,Inner Mongolia.Including Saihanwula National Natural Reserve,Heilihe Natural Reserve,Xilamulun Basin and Wulanba Natural Reserve.The characteristic, habitats and application potential of14species Salix plants were described and appraised.Salix maizhokung garensis and Salix psammophila cutting experiments show that:river sand is the best substrate in term of length of the longest root, number of the induced bud,length of the longest branch and number of the leaf of Salix maizhokung garensis. River sand is the best substrate in term of number of the root, length of the longest root,length of the longest branch and number of the leaf of Salix psammophila. Growth regulator has obvious improving effect on number of the root of Salix maizhokung garensis. Growth regulator has no effects on Salix psammophila.The systematic studies had been done with respect to the effect of Cd toxicity by sand culture based on the investigation of Cd on plant growth, physiological metabolisms in Salix maizhokung garensis and Salix psammophila. The main results are as follows:Cd toxicity symptoms,like slow growth, chlorisis leaves, brown roots were observed. Stronger toxicity symptoms appeare on older leaves. Plant height,leaf number,leaf dry weight,stem dry weight,root dry weight,chlorophyll contents reduce significantly with the increment of heavy metal stress, thereby Cd are more toxic to Salix maizhokung garensis and Salix psammophila. The Physiological and biochemical changes of Salix maizhokung garensis and Salix psammophila to the stress of Cd at different concentrations had been measured.The results of Salix maizhokung garensis show that POD activity,SOD activity,Pro content first rises then falls as Cd concentration increase. MDA content,cell membrane relative permeablity increase as Cd concentration increase. Chlorophyll contents reduce as Cd concentration increase. It can be concluded that Salix maizhokung garensis is resistant to Cd stress at50mg·kg-1, while is reduce to Cd stress at high concentration. The results of Salix psammophila show that SOD activity,Pro content first rises then falls as Cd concentration increase. MDA content,cell membrane relative permeablity increase as Cd concentration increase. POD activity.Chlorophyll contents reduce as Cd concentration increase. It can be concluded that Salix psammophila is resistant to Cd stress at1mg·kg-1, while is reduce to Cd stress at high concentration.