Cu2+ effect upon photosynthesis, chloroplast structure, RNA and protein synthesis of pea plants

Ten day old pea plants {Pisum sativum L., cv. Ran) were ušed to analýze the effects of Cu2+ ions on the dry mass, chlorophyll, carotenoid and proline contents, rates of photosynthesis (En) and transpiration {E), stomatal resistance {r^, carboxylation enzymes activities (RuBPC, PEPC), RNA and protein syntheses and changes in chloroplast structure. Cu^^ treated plants showed lower chlorophyll a and carotenoids contents, and higher than Controls. Pii, E and protein synthesis were significantly reduced. Four days after metal treatment P^ was 5-7 % at 500 and 1000 pM Cu2+ from the Controls, was reduced and E was increased by all ušed metal concentrations. The lower RuBPC activity after the 4 d treatment by 1000 pM Cu2+ could be due to the inhibition of de novo protein synthesis. The higher proline content was probably due to the same reason. Cu2+ ions did not change RNA synthesis in pea leaves. We foímd complete disintegration of chloroplast lamellar systém 4 d after 1000 pM Cu2+ treatment, which confirmed the observed ftmctional changes.