Responses of three Zoysiagrass species to salt stress

The effects of salt(NaCl)on the antioxidant system and soluble protein content during growth of Zoysia macrostachys,Z.matrellaand Z.japonica was investigated.The biomass and the soluble protein contents of all three grasses reduced gradually with increasing salt concentration and duration of exposure,while leaf relative conductance and malondialdehyde(MDA)content increased.Under lower salt concentration(0.2%-0.4%),leaf relative conductance and MDA increased slightly,but both peaked at 0.8% salt.The proline content peaked 10 days after treatment application but subsequently declined.Under lower salt concentrations the activities of catalase and superoxide dismutase in all three grasses reduced gradually,while under0.6%-0.8% salt,they initially increased,declined and then increased again.Z.macrostachys had the lowest leaf relative conductance and the lowest MDA,but the highest protective enzyme activity and soluble protein content.Consequently Z.macrostachys demonstrated greater salt resistance than Z.matrellaand Z.japonica.