Four different ecotypes of reeds——fresh water swamp reed,salty water swamp reed,lower salt meadow reed and higher salt meadow reed were investigated in the Yellow River Delta.The growth status,composition and dominance of reed community were observed,and the organic and inorganic osmotica,osmotic potential and osmotic adjustment ability were determined.Results are as follows:The abundance,coverage,plant height,leaf water content and osmotic potential all decrease with the increasing salinity levels of habit...