title: Changes in carbohydrate content and membrane stability of two ecotypes of Calamagrostis arundinacea growing at different elevations in the drawdown zone of the Three Gorges Reservoir.
abstract: BACKGROUND
  The Three Gorges project has caused many ecosystem problems. Ecological restoration using readily-available plants is an effective way of mitigating environmental impacts. Two perennial submergence-tolerant ecotypes of Calamagrostis arundinacea were planted in an experimental field in the drawdown zone. Responses of the two plant ecotypes to flooding stress in the drawdown zone were unknown.
  
  
  RESULTS
  Carbohydrate content and membrane stability, two key factors for survival of plants under flooding stress, of two ecotypes (designated "dwarf" and "green") of C. arundinacea growing at different elevations of the drawdown zone were investigated. Live stems (LS) and dead stems (DS) of the two plant ecotypes at eight elevations (175, 170, 162, 160, 158, 155, 152 m and 149 m) were sampled. Contents of soluble sugar, starch and malondialdehyde (MDA), as well as plasma membrane permeability of live stems were measured. The lowest elevations for survival of dwarf and green C. arundinacea were 160 m and 158 m, respectively. Soluble sugar content of live stems of both ecotypes decreased with elevation, with amounts from an elevation of 170 m being lower than from an elevation of 175 m. MDA content and plasma membrane permeability in live stems of green C. arundinacea did not increase with the decrease in elevation, while these measures in dwarf C. arundinacea from an elevation of 162 m were significantly higher than from an elevation of 175 m.
  
  
  CONCLUSIONS
  Carbohydrate content, especially soluble sugar content, in both ecotypes was more sensitive to flooding stress than membrane stability. Green C. arundinacea had a higher tolerance to submergence than dwarf C. arundinacea, and thus green C. arundinacea can be planted at lower elevations than dwarf C. arundinacea.
authors.affiliation: Managing Office for National Assets and Laboratory Equipments, Linyi University, Linyi, China; Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing, China.
authors.forename: Shutong
authors.initials: S
authors.lastname: Lei
authors.affiliation: Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zeng
authors.affiliation: Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing, China.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Su
mesh_terms: D050260:Carbohydrate Metabolism; D002462:Cell Membrane / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002681:China; D017753:Ecosystem; D008315:Malondialdehyde / Q000378:metabolism; D018547:Plant Stems / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D006109:Poaceae / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism*; D045483:Rivers; D012995:Solubility; D013213:Starch / Q000378:metabolism
chemical_list: D008315:Malondialdehyde; D013213:Starch