In this work the adverse effects of salinity (100 and 200 mM NaCl) on some physiological responses of barley (Hordeum vulgare L.cv. Giza 121) plant were studied. Salt stress induced the accumulation of the osmoprotectants (proline and soluble sugars), total-soluble-N, amino-N and increased the activity of phosphatases (acid and alkaline). Protein-N and total-N contents were significantly decreased in comparison with the control (tap water). The Na+ content was significantly increased under salinity stress, while P3+, K+, Ca2+ and Mg2+ contents decreased. Application of 50 µM ABA or 100 µM GA3 as a grain soaking or shoot spraying, counteracted the adverse effects of salinity. This was achieved by significant increases in the total-nitrogen and amino-N contents, and significant decreases in proline content and phosphatases activity. Also, this treatment with hormones decreased Na+ accumulation and significantly increased P3+, K+, Ca2+ and Mg2+ contents, compared with the control. Hormones and changes in the activity of phosphatases might play a role in regulating ion distribution in barley plants. Furthermore, results showed much better growth of plants whose grains were originally soaked in gibberellins than those of other treatments.
Key words: Abscisic acid, Acid phosphatase, Alkaline phosphatase, Gibberellic acid, Salinity.
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