| Plants have many natural properties that make them ideally suited to clean up polluted soil in the process called phytoremediation. Most native hyperaccumulators can not be used broadly for their slow growth and little biomass. We tried to use transgenic approach for transferring the metal-accumulate related gene (AtPCS1) to the plant with advantages of high biomass and easy grown—alfalfa, to obtain transgenic plant which can accumulate heavy metals.Firstly, six alfalfa genotypes (A'ergangjin, Sandeli, Longdong, Gannong No.1 , Dahua and Tianlan) were evaluated for their callus induction capacity and plant regeneration ability. Leaf cylinders were used as explants using B5 based medium supplemented with 1 mg /L 2,-4 dichlorophenoxyacetic acid and 0.1 mg /L kinetin. Plant regeneration was accomplished on hormone free modified B5 medium. The genotypes tested showed high callus induction percentage (all are above 90%), and there is no obvious difference between genotypes (P>0.05). These genotypes showed no high regeneration capacities, with regeneration percentages ranged between 0 to 42.9%. Significant differences were observed between genotypes for regeneration ability (p<0.05) indicating that this criteria is genotype dependent and the Gannong No.1 has the highest regeneration ability. Furthermore, we compared callus induction and plant regeneration ability of different explants as leaf, hypocotyl and cotyledon, and there was no difference observed among these explants, but the calluses coming from leaf differentiated much earlier and had more regeneration buds than any others. The in vitro regenerated plants were successfully rooted in 1/2 MS medium and well acclimatized in growth cabinet conditions. It takes about 80-100 days to transfer the seedlings to soil. Those results above suggested that the leaf of Gannong No.1 is ideal explant for transgene research.Phytochelatin synthase (PCS) catalyzes the final step in the biosynthesis of...
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