Effects of Bacillus and its exopolysaccharide on water spinach and crown daisy Cd uptake and soil aggregates
The study investigated the effect of exopolysaccharide-producing Bacillus strains on reducing Cd accumulation in stem vegetables and soil structure.A pot experiment was used with water spinach and crown daisy as test vegetables to investigate the effects and potential mechanisms of action of the test functional strains Priestia megaterium YG35 and Bacillus halodurans G20 in reducing Cd uptake by vegetables.Compared with the CK,the Priestia megaterium YG35,Bacillus halodurans G20,YG35 EPS,and G20 EPS treatment groups significantly increased the dry weight of edible tissues(37.8%-115.1%),significantly reduced the Cd content of edible tissues(21.9%-44.2%),brought the Cd content of crown daisy(0.057-0.061 mg·kg-1)to safe edible standards,significantly reduced the available Cd content of vegetable rhizosphere soil(3.7%-11.7%),significantly increased the polysaccharide content(35.9%-49.5%)and sucrase activity(15.3%-28.4%)of vegetable rhizosphere soil(P<0.05),and promoted the conversion of soil aggregates to larger grain sizes.Exopolysaccharide-producing bacterial strains YG35 and G20 and their EPS reduce the Cd accumulation of vegetables,promote vegetable growth,improve soil structure,and remediate Cd-contaminated soil for safe vegetable production.