Abstract
We profiled leaf cations and osmolytes in Bruguiera gymnorrhiza, Rhizophora stylosa, Sonneratia alba, and Avicennia marina growing on Iriomote Island in order to compare those concentrations (1) among four mangrove species growing in the estuary of the Shiira River, (2) between day and night in four species, and (3) among locations along the Shiira and Maira Rivers in B. gymnorrhiza and R. stylosa. No significant correlation was detected between concentrations of osmolytes and leaf Na+:K+ at the estuary of the Shiira River. Comparisons between day and night indicated that total sugar concentration in the daytime was higher than at night in R. stylosa and A. marina. Significant correlations were found between leaf osmolytes and salinity, pH, and deissolved oxygen in river water in B. gymnorrhiza. These results indicate that osmotic adjustment does not change within the distributional range of each species.
