Abstract: A superior cadmium (Cd)tolerance plant Celosia argentea was screened from a mining area in Dabao Mountain, Guangdong Province. The Cd absorption capacity of the plant was studied by cultivating its seedlings in soil with different concentrations of Cd. The results showed that the C. argentea was able to tolerate Cd at the concentrations higher than 40 mg·kg^-1 in soil. Moreover, the content of Cd in the C. argentea was positively correlated with the Cd concentration in a certain range in soil. With different concentrations of Cd (CdCl₂·2.5H₂O) added into the mediums, a strain of endophytic bacteria DE5 capable of tolerating Cd at a high concentration of 200 mg·kg^-1 was sifted from the leaves of Solanum nigrum, a kind of Cd hyperaccumulator, which was identified as Variovorax paradox (Genebank accession number: KF051781) by physiological and biochemical experiments and 16S rDNA sequence analysis. The C. argentea rootirrigated by DE5 fermentation broth was cultivated in the soil with a higher concentration (100 mg·kg^-1) of Cd in a pot experiment, and the plant height, biomass and Cd absorption capability were analyzed. The results showed that the dry weight of C. argentea treated with DE5 increased by 125.0% compared with the control, and noticeably, the total Cd absorbed by the aerial part and whole plant increased by 81.7% and 81.1%, respectively. Our study indicated that the C. argentea was a superior botanic resource conducive to the remediation of Cdpolluted soil. It is feasible and potentially applicable to inoculate DE5 into the rhizosphere of C. argentea, whose effect showed advantages over that of pouring the chelating agent EDTA.

Key words: natural Betula platyphylla forest, regional effect, meteorological factor, individual tree diameter increment