Influence of exogenously supplied potassium and sodium salts on the abscisic acid-induced proline accumulation in barley leaf segments |
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Authors: | P. Pesci N. Beffagna |
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Affiliation: | Centro di Studio del C.N.R. per la Biologia Cellulare e Molecolare delle Piante, Dipartimento di Biologia dell unclearniversitd de-gli Studi di Milano, via G. Celoria, 26, 1-20133 MUano, Italy. |
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Abstract: | A stimulation of the abscisic acid (ABA)-induced increase in proline was observed in leaf segments of barley ( Hordeum vulgare L. cv. Georgie) if K+ or Na+ were supplied in the external medium as salts of monovalent anions such as NO3, Br, Cr and I, but not when sulphate or phosphate were used. To a lesser extent, the effect was evident also with RbCl, but it did not occur when chlorides of Li+. Cs+, NH4+, Mg:+ and Ca2+ were used. Both KC1 and NaCl in the concentration range 2–100 m M influence the ABA-dependent proline accumulation to the same extent; the increase induced was about 100% at 10 m M , and reached a maximum between 60 and 100 m M. The effect is not due to the osmotic activity of the salts and does not seem to depend on changes in K+ and Na+ levels within the leaf tissue, but it is somehow linked to their external concentration. The existence of a specific interaction between ABA and K+ or Na+, possibly at the cell membrane level, is proposed. |
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