Tolerance mechanism of Hedychium coronarium to copper stress.

Uptake and accumulation of copper in Hedychium coronarium(HC),the subcellular distribution of copper in leaf and chemical form of copper in plants under copper stress were investigated in a pot culture of simulated wetland.The results showed that the accumulation of copper in HC increased with the increase of the concentration of copper.When the concentration of copper was less than 150 mg·kg-1,the accumulation of copper in the plant was found in the order of rootleavestem.While it was in the order of leaverootstem when the concentration of copper was no less than 200 mg·kg-1.In all treatments,the copper in leaf was mainly on cell wall and in soluble fraction,while relatively lower in cell organelle.The copper in the root was predominated with Ethanol-and water-extractable forms,while NaCl-extractable form was dominant in the stem.Whereas NaCl-,HAC-and HCl-extractable forms in the leaf,which were less active,were dominant.In addition,HC had certain concentrating capability,yet the ability was not strong.When the concentration of copper was no less than 400 mg·kg-1,the plants suffered from physiological hurt and death quickly,which showed that HC was not satisfied with the standard of copper hyper-accumulation plant.It came to the conclusions that HC had certain tolerance,distributing selectivity and concentrating capability under copper stress,use of which to remedy copper -polluted wetland would relieve the pressure from copper pollution.