Abstract: Lipid phospholipid and fatty acid compositions, fluidity, phase transition temperatures and membrane-bound Ca2+ ,Mn2+ ,Mg2+-ATPase activities of plasmolemmas extracted from four reed Phragmites communis Trin. ecotypes in Hexi Corridor of Gansu province were investigated. The results showed that all plasmolemmas of the four reed ecotypes consisted of the same six phospholipid and seven fatty acid components, but their proportions in the plasmolemma lipids of various reed ecotypes were markedly different. Index of unsaturated fatty acid (IUFA)and fluidity of plasmolemmas increased in the sequence of swamp-,dune-, meadow-dune transitional zone, salt meadow reeds. The plasmolemmas of all reed ecotypes showed phase transition in the two ranges of low-, high temperatures (4–6℃, 20–28 ℃ ), their phase transition temperatures in the latter were markedly different, Plasmolemma-bound Ca2+ ,Mn2+ ,Mg2+-ATPase activity positively related to IUFA and fluidity. Combining the membrane properties with environments,in comparison with swamp reeds, the increases of phosphatidylcholine, cardiolipin and the significant rising of IUFA in plasmolemma lipids are closely responsible for reed saR-tolerance, whereas the increase of phosphatidylglycerol and the suitable rising of IUFA make a contribution to reed drought-tolerance.

Key words: Reed, Ecotypes, Environmental stress, Plasmolemma