Nutrients alleviate the deleterious effect of salinity on germination and early seedling growth of the psammophytic grass Elymus farctus

摘要: Elymus farctus L. is a perennial grass, dominating the Mediterranean coastal sands of Egypt. Germination of E. farctus seeds was monitored under the impact of NaCl levels up to 300 mmol·L−1, either in water or in nutrient solution containing nitrogen in the form of ammonium, nitrate, or ammonium nitrate. Seed germination was more salt tolerant than extension of embryonic axis, and radicle elongation was more salt tolerant than plumule elongation. NaCl applied in water sharply reduced germinability beyond a threshold of 55 mmol·L−1, but progressively inhibited embryonic axis elongation. Presence of nutrients alleviated the effect of salinity, particularly if nitrogen was in the form of nitrate. The effect of salinity on speed, uniformity, and synchrony of germination was in general modulated by the presence of nutrients. Salt-treated seeds readily recovered from stress when moved to distilled water, without a lag period, and with high speed, uniformity, and synchrony of germination but with a lower recovery percentage compared with the germination of fresh seeds in distilled water, which might point to a combination of osmotic and specific ion effects of salinity on seed germination.