The evaluation of resistance to Co²⁺ of lawn plant at seedling stage and its concentration property at adult stage

In order to evaluate the resistance of lawn plant to Co²⁺ at germination stage and discuss its concentration property at adult stage, four kinds of lawn plant which have some growth advantages in Co²⁺ polluted environment were selected as experimental materials in this research. They are tall fescue, timothy grass, inflorescences, and annual ryegrass. The results show that the evaluation of resistance to Co²⁺ of tall fescue's seed is the highest; the evaluation of resistance to Co²⁺ of annual ryegrass seed is the lowest. The low consistence Co²⁺ could improve the seed germination. With Co²⁺ concentration increase, the accumulation coefficient of four plants increased at first and decreased later; the accumulation coefficient of underground portion is higher than the accumulation coefficient of aboveground; with Co²⁺ concentration increase, the transfer coefficient of four plants have a remarkable decline. In these plants, the accumulation coefficient of tall fescue and annual ryegrass is bigger than other two plants. As the concentration of Co²⁺ treatment increased to 100 mg/kg, the aboveground enrichment of Co²⁺ in F. elata reached 75 mg/kg, followed by L. multiflorum (68.9 mg/kg), P. pratense (48.8 mg/kg), and D. glomerata (27.2 mg/kg).The highest underground enrichment of Co²⁺ in F. elata reached 836.46 mg/kg, in contrast to the lowest underground enrichment in D. glomerata, 264.67 mg/kg. It shows that fescue and annual ryegrass have a better enrichment property to Co²⁺ and have a better prospect for the treatment of cobalt-contaminated soil. This research could provide some scientific basis and main technical approach for the soil contaminated by Co²⁺.