MINERAL-CONTENT OF LEAF TISSUE FROM MANGR OVE SPECIES OF THE SONTECOMAPAN LAGOON (VERACRUZ, MEXICO) AND ITS RELATIONSHIP TO SALINITY

Analyses of leaf osmolality and total nutrient content (N, P, K, Ca, M g) of the coastal vegetation of the Sontecomapan lagoon (Veracruz, Mex ico) reveals the influence of penetration of sea water, and the differ ences in mineral uptake by typical halophytic species (Rhizophora mang le and Laguncularia racemosa), facultative halophytes (Acrostichum aur eum) and non-halophytes (Pachira aquatica). In these species leaf sap osmotic pressure and the leaf area/weight ratio increase, while the le af area decreases with the salinity of interstitial water. Total N and P contents are correlated in all species, and in the mangrove species their contents decrease in the sampling sites with higher influence o f marine water. The K/Na ratio is considerably higher in the non-halop hyte species (P, aquatica 15.9; A. aureum 18.1 to 14.1) compared to th e halophytic mangrove species (R. mangle 1.4 to 0.6; L, racemosa 3.3 t o 1.9).