title: Acclimation of Hydrilla verticillata to sediment anoxia in vegetation restoration in eutrophic waters.
abstract: Sediment anoxia generally results from intense organic enrichment and is a limiting factor in the restoration of vegetation in eutrophic waters. To investigate the effect of sediment anoxia on a typical pollution-tolerant submerged macrophyte species, Hydrilla verticillata, and acclimation mechanisms in the plant, a gradient of sediment anoxia was simulated with additions of sucrose to the sediment, which can stimulate increased concentrations of total nitrogen, NH4(+) and Fe in pore water. H. verticillata growth was significantly affected by highly anoxic conditions, as indicated by reduced total biomass in the 0.5 and 1% sucrose treatments. However, slight anoxia (0.1% sucrose addition) promoted growth, and the shoot biomass was 22.64% higher than in the control. In addition to morphologic alterations, H. verticillata showed physiological acclimations to anoxia, including increased anaerobic respiration and changes in carbon and nitrogen metabolism in roots. The soluble protein and soluble carbohydrate contents in roots of the 1% treatment were both significantly higher compared with those in the control. The increase in alcohol dehydrogenase activity and pyruvate content in the roots suggested that H. verticillata has a well-developed capacity for anaerobic fermentation. This study suggests that highly anoxic sediments inhibit the growth of H. verticillata and the species has a degree of tolerance to anoxic conditions. Further in situ investigations should be conducted on the interactions between sediment conditions and macrophytes to comprehensively evaluate the roles of sediment in the restoration of vegetation in eutrophic waters.
authors.affiliation: College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wu
authors.affiliation: College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
authors.forename: Yanran
authors.initials: Y
authors.lastname: Dai
authors.affiliation: College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
authors.forename: Shengyang
authors.initials: S
authors.lastname: Rui
authors.affiliation: College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
authors.forename: Naxin
authors.initials: N
authors.lastname: Cui
authors.affiliation: Marine Fisheries Research Institute of Jiangsu Province, Nantong, 226007, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Zhong
authors.affiliation: College of Environmental Science and Engineering, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai, 200092, China. shpcheng@tongji.edu.cn.
authors.forename: Shuiping
authors.initials: S
authors.lastname: Cheng
mesh_terms: D000064:Acclimatization; D000693:Anaerobiosis; D002681:China; D003247:Conservation of Natural Resources; D005068:Eutrophication; D005618:Fresh Water / Q000032:analysis*; D019015:Geologic Sediments / Q000737:chemistry*; D031321:Hydrocharitaceae / Q000254:growth & development / Q000502:physiology*; D010100:Oxygen / Q000032:analysis*
chemical_list: D010100:Oxygen
keywords: Hydrilla verticillata; Sediment anoxia; Submersed macrophyte; Vegetation restoration