Different rootstocks decrease the cadmium accumulation of the post-grafting generation of Brassica juncea var. megarrhiza

A pot experiment was designed to assess the effects of different rootstocks on cadmium (Cd) accumulation and the growth of the post-grafting generations of Brassica juncea var. megarrhiza. Four treatments, including ungrafted and B. juncea var. megarrhiza as the scion grafted on the rootstocks of Brassica napus, Brassica chinensis and Brassica campestris respectively, were analysed. The three grafting treatments decreased the content of Cd in the first post-grafting generations of B. juncea var. megarrhiza but increased the length of roots, tuberous roots and leaves, and tuberous root diameters, as well as the biomass of the various organs and edible parts. In addition, the grafted rootstocks could enhance the level of photosynthetic pigments and the activity of peroxidase but reduce the activities of superoxide dismutase and catalase and the soluble protein content of the first post-grafting generations of B. juncea var. megarrhiza. The different rootstocks grafts could also decrease the available concentration of Cd in the soil but increase the soil pH. Therefore, the grafting could decrease the accumulation of cadmium in the post-grafting generation of B. juncea var. megarrhiza, and the graft on B. campestris was the most effective.