The Mechanism Of Accumulation Of Chromium In Mentha Haplocalyx Briq

A experiment of pot culture was carried out to investigate the effects of chromium on antioxidant enzymes activities,subcellular distribution,chromium accumulation,root system vigor,chlorophyll content,antioxidant enzymes and MDA of Mentha haplocalyx Briq..It was observed that with the increasing of chromium concentrations and time,antioxidant enzymes activities increased then decreased,reached a peak at 40mg/L of chromium;Among the chromium content of cell wall,plastid(chloroplast), nucleus,mitochondrion and soluble fraction,cell wall>plastid>nucleus>mitochondrion> soluble fraction in root cells;soluble fraction>cell wall>chloroplast>nucleus> mitochondrion in leaf cells.chromium accumulation of different organs increased continuously.And the chromic content of roots can reach 80%～93%.With the increasing of chromium concentrations and time, root system vigor decreased continuously; on the contrary,MDA content of different organs increased ; Chlorophyll content increased then decreased with chromium concentrations. Compared with the control, the values of net photosynthetic rate(Pn), intercellular CO2 concentration(Ci), transpiration rate(Tr) and stomatal conductance(Gs)decreased under the 10-60mg/L chromium stress treatment. These results implied that the high chromium concentration stress has stronger inhibitory capability of the photosynthesis for the Mentha haplocalyx Briq. than the low chromium stress. The results suggest that the antioxidant enzymes,the cell wall of root and the vacuole of leaf played important roles in the major mechanism for Mentha haplocalyx Briq. accumulate chromium and resistant to chromium toxicity.