Gas Exchange and Malate Accumulation in Haberlea Rhodopensis Grown Under Different Irradiances

Treatment of excised marrow (Cucurbita pepo L., zucchini) cotyledons with methyl ester of jasmonic acid (MeJA) had no effect on their growth in darkness. On the other hand, MeJA induced the synthesis of three polypeptides (69, 60 and 43 kDa) and stimulated the accumulation of other polypeptides (97.4 and 53 kDa). These changes in the polypeptide profile were accompanied by a suppression of total protein and RNA synthesis as well as the activity of nuclear RNA polymerases. In contrast to MeJA, N6-benzylaminopurine (BAP) significantly enhanced cotyledon growth and stimulated protein and RNA synthesis. Furthermore, BAP, when applied together with MeJA, was able to counteract some effects of MeJA including the appearance of specific MeJA-induced polypeptide bands.