Effect of seawater on the growth, ion content and water potential of Rhizophora mucronata Lam.

Growth and physiological responses at seedling (six months old) and sapling (12 months old) stages were studied under various seawater concentrations. The optimum growth of plants was obtained at 50% seawater and declined with further increases in salinity. Leaf water and osmotic potentials and xylem tension increased with an increase in media salinity both in seedlings and saplings, whereas stomatal conductance was decreased. Concentrations of sodium and chloride ions increased, while those of potassium and calcium decreased with an increase in salinity.