THE EFFECT OF THE EXOGENOUS GIBBERELLIC ACID ON TWO SALT STRESSED BARLEY CULTIVARS

An alternative strategy to ameliorate salt stress could be to use exogenous application of plant growth regulators. The present investigation was carried out to study the effect of exogenous application of GA3 on germination, some growth parameters, protein banding pattern, nucleic acids content and some minerals of salt stressed two cultivars of barley. The grains of both cultivars Giza 126 and 123 were individually pre emergence treated with different concentrations of NaCl or mixture of NaCl and GA3 for 7 days. The results of germination percentage revealed that cv. Giza 123 had higher response to the interaction between salinity and GA3 than cv. Giza 126. The morphological characters revealed inhibition in all plant growth parameters by salinity stress and this inhibition was significantly alleviated after treatment with GA3. The protein electrophoresis of seedlings of cv. Giza 123 induced formation of unique newly protein bands including certain units may acting as protein receptors for gibberellins (M.W. 71.41 kDa). In addition, the DNA and RNA content of cv. Giza 123 showed its priority to the interaction between salinity and GA3. Regarding to minerals the data showed that cv. Giza 123 had the ability to discard salts and prevent the accumulation of them in its tissues especially Na+, k+ and Ca+2 elements. cv. Giza 123 seedlings could overcome the inimical effects of salt stress whereas cv. Giza 126 seedlings appeared to have an attenuated potential to do so resulting in an efficient tolerance of cv. Giza 123 seedlings