CO2 (40, 200, 400 loM) was added to the root systém of 10-d-old pea plants (Pisum sativum L. cv. Ran). The Co2'''-excess caused a reduction in the plant fresh and diy masses and water and chlorophyll contents. The rates of photosynthesis and transpiration decreased, while proline content and stomata resistance increased. The dramatic effect of Co2+-toxicity was expressed both in an inhibition of ribulose 1,5- bisphosphate (RuBP) carboxylase activity and a stimulation of RuBP-oxygenase and phosphoenolpyruvate carboxylase activities on the 4‘h day of cnltivation of plants in a solution of 400 pM C6^*.
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.