| 1. The concentrations of Cd2+ treatment in germination experiment were 0, 5, 10, 20, 30, 40, 60, 80 and100 mg·L-1.With the concentration of Cd2+ increasing, the seed germination rate, germination vigor, germination index and vigor index decreased significantly, the toxic rate increased significantly, when the Cd2+ concentration beyond 30mg·L-1, the toxic rate reached 100%. The growth of seminal root and shoot were inhibited significantly, the effect on root was more serious than shoot.2. Plants were grown in sand culture which was poured Cd2+ treatment solution.The concentrations of Cd2+ treatment solution were 0, 5, 10, 30, 60, 100 and 200 mg·L-1, the treatment maintained 7 days.The above-ground part dry weight of Zoysia japonica had significant difference, the above-ground part biomass increased in the low Cd2+ concentration treatment and decreased on the high concentration. There were no significant difference in under-ground biomass, the ratio of under-ground and above-ground biomass. The difference of Chla and Chlb content was significant, Chla content increased at first and then decreased, maximized at 5mg·L-1. When the Cd2+ concentration beyond 10mg·L-1, Chlb content was significantly higher than the control. The MDA content of leaves increased at first and then decreased, maximized at 5mg·L-1. The activity of SOD decreased and then increased, when the Cd2+ concentration beyond 30 mg·L-1, the activity was significantly lower than the control, besides the activity higher than the control when the Cd2+ concentration beyond 200mg·L-1. The activity of POD increased at first and then decreased, maximized at 5mg·L-1.3. The concentrations of Cd2+ treatment in water culture experiment were 0, 5, 10, 30, 60 and 100mg·L-1.The treatment maintained 14 days. With the increasing of Cd2+concentration, the plant morphology of Zoysia japonica was seriously damaged, numbers of dead leaf increased, scores of leaf color decreased. The biomass of both under-ground and above-ground increased at first and then decreased,the ratio of under-ground and above-ground biomass decreased at first and then increased. The root length was higher than control, maximized at 5mg·L-1, the root volume increased and then decreased. The MDA content presented increasing trend, 21.31% higher than control at 100mg·L-1. The SOD activity increased dramatically, was significantly higher than control at 100mg·L-1. The POD activity presented increasing trend, 36.18% higher than control at 100 mg·L-1.4. The concentration of Cd2+ treatment in water culture experiment was 10mg·L-1, CK was the whlole Hoagland solution, the treatment maintained 30days.The content of O2·- and the relative conductivity were both significantly higher than control on the 30th day. The SOD and POD activity of leaves decreased and then increased compared with the control, inversely, the activity of CAT increased and then decreased. The Proline and Soluble sugar content were both higher than control, and the increasing range maximized on the 30th day. Besides, the content of Soluble protein increased and then decreased. Under the stress of Cd2+, although the content of Chlorophyll and Carotenoid did not have significant variety, they still decreased compared with the control. Pn ,Tr and Gs decreased significantly except of Ci. F0 , Fm, Fm′, F0′, Fs, Fv/Fm, Fv′/Fm′,ΦPSⅡ, rETR and qp all decreased significantly compared with control, whereas NPQ increased significantly on the 20th day. In the aspect of excitation energy distribution, both A and B decreased significantly, though the variety of C was not significant difference. With the treatment time increased, the Cd concentrations in under-ground part increased, which were higher than the concentrations of above-ground part during the 30 days. On the 20th day, the translation coefficient was the biggest. On the10th day, the distribution proportion of Cd in above-ground part was lower than that in the under-ground part, contrary on the 20th and 30th day. The concentration of Cd with the different chemical form had significant difference. The concentration of Acetate extractable Cd in the under-ground part was significantly higher than that in the above-ground part, the NaCl, HCl, Water and Ethanol extractable Cd were very significant higher than that in the above-ground part respectively. The Water, NaCl and Acetate extractable Cd were the main distribution forms in both above-ground part and under-ground part, and the proportion of Water extractable Cd was the highest.
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