Effects of Sea Salts on Induction of Cell Proliferation in Liquid Cultures of Mangrove Plants, Sonneratia caseolaris and S. alba

摘要

The effects of five salt ingredients of sea water, KCl, NaCl, CaCl2, MgCl2 and MgSO4, on induction of cell prolif-eration in Sonneratia caseolaris were investigated. Proliferation was examined in tissue explants derived from such as leaves, cotyledons, and hypocotyls using a small-scale liquid culture method. Addition of 12.5-25 mM of MgCl2 was unique in stimulating cell proliferation in all tissues of S. caseolaris. Otherwise, different effects of salts were observed among the three tissues. In hypocotyl culture, 25-50 mM of NaCl and CaCl2 stimulated cell divisions. Tolerance to 100 mM of MgSO4 was observed in leaves. Three osmotically active compounds commonly used in tissue culture, sorbitol, mannitol and glycinebetaine, were also tested to assess the importance of osmotic effects on cell proliferation. No significant stimulation by these was observed over a wide range of concentrations. Data were compared with those of cotyledon cultures of another mangrove, S. alba, which exhibits no stimulation by MgCl2, stimulation by KCl and tolerance to NaCl. Mechanisms for adaptation of mangrove plants to various and high salts were discussed by comparing the differences in reaction to salts in cultures of two Sonneratia mangrove species of the same genera growing different salt environment.