SALINITY INFLUENCE ON GERMINATION OF FOUR IMPORTANT MANGROVE SPECIES OF THE SUNDARBANS, BANGLADESH

Salinity is an important factor of mangrove establishment, growth and development. Present study was conducted to evaluate the influence of salinity on seed germination of Heritiera fomes Buch.-Ham., Xylocarpus mekongensis Pierre, Xylocarpus granatum K.D. Koenig and Amoora cucullata Roxb from the Sundarbans, Bangladesh. This experiment was conducted with different salinity levels (0 to 40 ppt at 5 ppt interval) with Completely Randomized Design for 10 weeks. Moreover, influence of seed dipping at different salinity levels (0 to 40 ppt at 5 ppt interval) on germination was also examined in a Randomized Block Design. Significantly (p 0.05) higher germination was observed at non saline to less saline (5 ppt) conditions for all the studied species. Seed germination of all the species was found to decrease at higher saline levels. About 57% and 21% of seeds of X. mekongensis and X. granatum were germinated respectively at 40 ppt salinity. While, germination of H. fomes and A. cucullata was ceased at salinity level of 35 ppt and 20 ppt respectively. The seeds of X. mekongensis found to viable even dipping for longer time with higher salinity level compared to other species. In the extreme situation, seed germination of H. fomes, X. mekongensis and X. granatum was ceased at 10 ppt salinity and no germination was observed for A. cucullatta after dipping of 4 weeks. In conclusion, seed germination and seed viability found to vary with the species, salinity and dipping duration.