Abstract: A pot experiment was conducted in sewageirrigated garden soil (2.28 mg·kg^-1 Cd) pretreated with different concentrations of NaCl. The differences between two amaranth cultivars (BRLA and ARW) in accumulations of Cd and main osmotic adjustment substances under salt stress were investigated. Under salt stress, the contents of Cd and Na⁺ in roots and leaves of cultivars BRLA and ARW significantly increased compared with the control (P<0.05), and the Cd content was obviously higher in ARW than in BRLA. BRLA had stronger Na⁺ retention capacity in roots than ARW, decreasing the transportation of Na⁺ from root to leaf. In 0.4% NaCl treatment, the K⁺/Na⁺ ratio decreased by 39.2% in leaves of BRLA, and by 56.9% in leaves of ARW. Mg²⁺ content increased in roots and leaves of BRLA and decreased in roots of ARW. More proline accumulated in roots and leaves of both cultivars under salt stress compared with the control (P<0.05) and BRLA exhibited greater proline synthetic ability than ARW. Contents of soluble protein and free amino acids in roots and leaves of both cultivars decreased with the increase of soil salinity, while soluble sugar in roots of both cultivars increased with the increase of soil salinity. These results suggested that BRLA had lower Cd uptake, higher salt tolerance and stronger osmotic adjustment ability than ARW. Our study provided some useful information for screening and breeding of salt tolerant cultivars with low Cd accumulation.

Key words: Astragalus membranaceus var mongholicus, resource survey, suitability of origin