Effects of salt and alkali stress on seed germination of Limonium gmelinii and Limonium otolepis

Abstract: Limonium gmelinii and L. otolepis are perennial herbaceous plants and belong to Limonium, Plumbaginaceae. They are the main edificatos of haloeremion areas in Xinjiang. Continual observation dedicated that seedling recruitment was very slow in the population of the two species. As it may be related to the germination of seeds; the experiment was hypothesized to study the two Limonium seed germination under different concentrations of NaCl, NaHCO3 and mixed solution of NaCl and NaHCO3. The results indicated that all of the salt solutions at different concentrations influenced seed germination significantly. With increasing concentration of the solution; the germination rate, germination power and germination index of Limonium seeds decreased gradually. The mixed solutions had stronger influence than others in restraining the seed germination. The salt tolerance of L. gmelinii seed was stronger than that of L. otolepis under different treatments. The experiment also showed that when seeds were transferred from salt solutions to distilled water they could have a high germination rate. The salinity inhibition of the seed germination of Limonium was through osmotic stress. In natural conditions, the soil salinity stress was one of the most important factors affecting seedling recruitment in the Limonium population.