Halophyte Seed Germination

Abstract

Halophyte seed germination, although displays a high degree of inter-and intra-specific variability, shows some patterns in response to various environmental factors. Seeds of stem succulent species germinated better in highly saline conditions. The salt tolerance decreased progressively from leaf succulent, secreting to non-secreting grass halophytes. Seed germination of cold desert halophytes progressively increased with an increase in temperature while seeds of warm desert halophytes showed better germination at cooler temperatures. Halophytes from moist temperate regions germinated better at cooler temperatures. The percentage of un-germinated seeds that recovered when they were transferred to distilled water varied significantly with variation in salinity and temperature regimes in different species. Seeds of some species failed to germinate when exposed to high salinity and temperature stress. While seeds of other halophytic species showed various levels of recovery ranging from 20% to complete recovery of germination. There are some species where recovery of germination is higher then untreated control. Higher temperature inhibited germination recovery for most of the species reported. Germination regulating chemicals like GA 3 , kinetin, ethylene, fusicoccin, proline, betaine, thiourea and nitrate released the innate dormancy in seeds of some subtropical species while GA 3 was most effective. Germination regulating chemicals had better effect in releasing innate dormancy of Great Basin halophytes and fusicoccin appeared to be more effective. Alleviation of salinity induced dormancy using different chemicals was more successful in Great Basin species in comparison to subtropical species. Fusicoccin and ethephon succeeded with subtropical species while all chemicals alleviated either partially or completely the salinity-induced dormancy in Great Basin halophytes except for proline, betaine and nitrate.