The Characters Of Root Tolerance And Bioactivity Of Moso Bamboo (Phyllostachys Pubescens) Under The Heavy Metals Stress

The aim of this study as follows: Effect of heavy metals on the moso bamboo root morphology and the root tip cell ultrastructure analysis;the organic acids compound of moso bamboo root exudates and its bioactivity;effect of organic acid on the adsorption of heavy metals in soil.(1)The hydroponic experiment revealed there are differences of the tolerance characteristics of moso bamboo root under different the heavy metals stress.Root tips and root volume showed more sensitive than root length and root surface area under heavy metals stress.Root ultrastructural studies revealed that the cell structure and organelles changed significantly under heavy metals stress as compared to those of the control.Some particle could be observed in the xylem of the root through scanning electron microscope.It could be observed that the root growth of moso bamboo inhibited more seriously with the treatments of copper(Cu)and cadmium(Cd)than the treatments of zinc(Zn)and lead(Pb).(2)The root exudate of moso bamboo could affect the chemical form of heavy metals in soil.The malic acid,oxalic acid and lactic acid were the compound of root exudate under the heavy metals stress.The oxalic acid occupied more than 50% in the root exudate in all treatments.In sand culture experiment,moso bamboo could activate the insoluble heavy metal and enhance its accumulation ability.The mixed organic acids promote the adsorption of Pb and Cd in soil and inhibited the adsorption of Zn and Cu.The maximum adsorption amount order under organic acids treatment was Pb> Cd > Cu > Zn.(3)The chelates promoted the absorption ability of heavy metals of moso bamboo from soil.There are not any significant changes of soil pH after adding EDTA in the column experiment,while the mixed organic acids could increase the soil p H significantly.Both EDTA and organic acids inhibited the moso bamboo photosynthesis.EDTA induced moso bamboo uptake of Zn,Cu and Cd from the soil,while no significant different changes for organic acids treatments as compared with control.The concentration of insoluble heavy metals increased significantly with EDTA treatments,while there is no effect for the organic acids.