The Growth Characteristics and Accumulation Abilities of Heavy Metals of Brassica juncea and Kochia Scoparia Under Zn and Cd Stress

Using Brassica juncea and Kochia Scoparia as experimental plant, through the hydroponic experiments, the growth characteristics, biochemical index and accumulation abilities of heavy metals of B. juncea and K. Scoparia under Zn, Cd stress were studied. The results showed that Zn and Cd inhibited the germination, bud and root elongation of B. juncea and K. Scoparia; Under the stress of single zinc(Zn) and single cadmium(Cd), with the increase of treatment concentration, the free proline in B. juncea and K. Scoparia increased firstly then reduced, the peroxidase in K. Scoparia increased; In terms of the total amount, with the increase of treatment concentration, the accumulation of various parts of B. juncea and K. Scoparia were also increased correspondingly. Under Zn stress, the accumulation of Zn in the aerial parts of B. juncea was higher than that of roots. Under Cd stress, when the low concentration of Cd²⁺ was less than 5 mg/L, the roots of B. juncea and K. Scoparia were higher than the aerial parts. When the high concentration of Cd²⁺ was greater than 15 mg/L, the aerial parts were higher than the roots. The results of the present study suggested that B. juncea and K. Scoparia were able to accumulate and tolerate in a certain amount of Zn and Cd. In a conclusion, the B. juncea and K. Scoparia have a promising remedial potential for Zn and Cd contamination soil, because they have the well developed rhizome which have the absorbing and accumulation function for Zn and Cd from the contaminated soil.