Effect of Methyl Ester of Jasmonic Acid, Abscisic Acid and Benzyladenine on Chlorophyll Synthesis in Excised Cotyledons of Cucurbita
نویسندگان
چکیده
Except for the first stages of illumination, exogenous methyl ester of jasmonic acid (MeJA) inhibited much stronger than abscisic acid (ABA) the accumulation of chlorophyll in excised cotyledons of C. pepo L. (zucchini) exposed to controlled light conditions. Benzyladenine (BA) applied in a combination with MeJA or ABA at equimolar concentrations completely neutralized their inhibitory effect. In contrast to ABA, preincubation of cotyledons with MeJA in the dark increased its inhibitory effect on chlorophyll synthesis while the effect of ABA remained almost unchanged. Determination of δ-aminolevulinic acid (δ-ALA) in greening cotyledons revealed a close correlation between the effect of phytohormones on chlorophyll content and δ-ALA accumulation. MeJA inhibited to a greater extent than ABA the synthesis of δ-ALA. Our results suggest different mechanisms of inhibition of chlorophyll synthesis by both inhibitors. MeJA preferentially inhibitied chlorophyll accumulation at the level of chlorophyll precursors in the dark while ABA exerted its effect on the light-dependent reactions of chlorophyll synthesis.
منابع مشابه
INTERACTION BETWEEN METHYL ESTER OF JASMONIC ACID AND BENZYLADENINE DURING THE GROWTH OF EXCISED GREENING COTYLEDONS OF Cucurbita pepo L. (zucchini)
Treatment of excised marrow cotyledons (Cucurbita pepo L. (zucchini) growing under photoperiod with methyl ester of jasmonic acid (MeJA) resulted in a decrease of their fresh weight. This effect did not depend on the exogenously applied MeJA concentrations. Furthermore, in vivo labelling experiments showed an inhibition of the total protein synthesis. On the other hand, specific quantitative ch...
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