淹水时间对洞庭湖典型湿地植物生长及水质净化能力的影响OA

This study investigated the morphological,physiological,and functional(nutrient removal)responses of five typical wet-land plants in Lake Dongting-Acorus calamus,Zizania latifolia,Phragmites australis,Carex brevicuspis,and Typha orientalis-to different flooding durations(30,60,90,and 120 days).Results indicated that flooding duration significantly affected all meas-ured aspects.Morphologically,biomass and plant height of A.calamus decreased significantly over time,whereas P.australis,Z.latifolia,and T.orientalis showed continued increases in plant height.C.brevicuspis maintained relatively stable biomass and root length,with only a slight decrease in plant height.Physiologically,responses were species-specific.In Z.latifolia,malondialde-hyde(MDA)and soluble sugar contents decreased significantly,while antioxidant enzyme activity and chlorophyll content in-creased.In P.australis,superoxide dismutase(SOD)activity and proline content decreased,while soluble sugar content in-creased.In C.brevicuspis,the contents of MDA,SOD,and chlorophyll decreased,while soluble sugar and proline contents in-creased.In T.orientalis,MDA,SOD,and proline levels showed dynamic changes,decreasing initially,peaking at 90 days,and then declining,whereas its chlorophyll content decreased continuously.Regarding purification function,nitrogen and phosphorus removal rates of P.australis and T.orientalis improved continuously with prolonged flooding.In contrast,A.calamus,Z.latifo-lia,and C.brevicuspis reached peak removal efficiency at 60-90 days before declining.In summary,responses were highly spe-cies-specific and time-dependent.P.australis and T.orientalis maintained high purification efficiency under prolonged flooding,indicating their greater suitability as dominant species for long-term flooded wetland ecosystems.