Cadmium tolerance and accumulation in different Bermuda grass genotypes

As a common and dominant species in heavy metal contaminated soils in southern China, Bermuda grass can be potentially used for Cd phytoremediation. The growth response following exposure and tolerance to Cd, as well as accumulation of Cd of 10 Bermuda grass genotypes were studied under hydroponic culture conditions with 1.5 mmol·L-1 of Cd. The results indicated that under Cd stress conditions, all of the Bermuda grass genotypes appeared to show symptoms such as slow growth, drawl plant, yellow and wilting leaves, and poor root growth. Differences in the degree of damage in different genotypes were significant. Among them, three genotypes (WBD242, WBD245, and WBD193) exhibited less severe damage in turf quality, chlorophyll content, and transpiration rate under Cd stress. These three genotypes showed the strongest Cd accumulation ability (119.0, 177.0, 124.2 mg·kg-1 in aboveground parts, respectively), which surpassed the putative criteria for hyper-accumulation plants expected to be used for phytoremediation of severe Cd contaminated soil. However, we also found that two other accessions, WBD144 and WBD147, showed the highest translocation capacity for Cd, but with weaker Cd tolerance, which could be applied for phytoremediation of slightly polluted area. Our findings could be used as guidance for future studies on phytoremediation and reconstruction.