Rare Earth And Water Retention Agent On Composting Matrix Of Lawn Plant Stress Physiology Ecological Impact

Municipal solid waste compost was used as turfgrass medium instead of soil and rare earths and water-retaining agent were added. The effects of rare earths and water-retaining agent on seed germination, biomass and chlorophyll of turfgrass were investigated. On that basis, the effects of rare earths and water-retaining agent on the growth of turfgrass under adversity stress (drought stress, salt stress, acid rain stress and low temperature stress) were investigated by measuring physiological and biochemical index. The results showed that:(1) Rare earths and water-retaining agent could promote seed germination and primary growth of turfgrass and increase its adversities. Lanthanum nitrate at low concentrations had similar impact on seed germination with cerium nitrate at high concentrations. Lanthanum nitrate at0.2g·kg-1achieved the best results, increasing germination rate, germination index and vigor index of F. arundinacea by27.9%,32.7%and34.5%, respectively, relative to control. The highest chlorophyll a and total chlorophyll contents were found at0.6g·kg-1cerium nitrate, which were15.4%and14.3%, respectively higher than control. Low concentration of two particle sizes of water-retaining agents had better effects on seed germination, aboveground biomass and root growth than high concentration.(2) Rare earths and water-retaining agent could promote the growth of F. arundinacea.under drought stress and relieve the inhibiting of drought stress. Rare earths has better effects than water-retainging agents on biomass, Lanthanum nitrate at0.2g-kg-1and cerium nitrate at0.4g·kg-1, increasing biomass by19.4%and20.4%respectively.(3) Lanthanum could induce resistance to salt on F. arundinacea and L. perenne. Lanthanum nitrate at0.4g-kg"1achieved better result when salt content are0.5%and0.8%for F. arundinacea, its aboveground biomass increased by9.7%and12.5%respectively relative to control. For L. perenne Lanthanum had similar impact.(4)Under acid rain stress, lanthanum could relieve the damage through increase the biomass, proline content, chlorophyll content and the activities of POD and CAT of F. arundinacea and L. perenne, decrease MDA content and relative electrical conductivity of F. arundinacea and L. perenne. Lanthanum nitrate at0.4g·kg-1achieved better result when pH is5.0and4.0for F arundinacea, its aboveground drybiomass increased by25.9%and13.1%respectively relative to control. For L. perenne its aboveground drybiomass increased by31.4%and18.2%respectively relative to control.(5) Lanthanum could induce resistance to low temperature on L. perenne and F. arundinacea, and reduce its damage. Lanthanum nitrate at0.2g·kg-1achieved the best results for L. perenne and at0.4g·kg-1achieved the best results for F. arundinacea.