In vitro precultivation of tobacco affects the response of antioxidative enzymes to ex vitro acclimation

Both growth under elevated CO2 (CE) conditions and/or treatment with abscisic acid (ABA) during acclimation to ex vitro conditions and precultivation in vitro in tightly closed glass vessels (G-plants) or ventilated Magenta boxes (M-plants) affected activities of antioxidative enzymes of tobacco 28 days after the transfer. Single treatment with 5 μmol/L ABA immediately after transplantation caused an increase in net photosynthetic rate and in the content of chlorophyll a, and decreases in the activities of glutathione reductase, Mn-SOD, peroxidases, malic enzyme (ME), and glucose-6-phosphate dehydrogenase (G-6P-DH) in both types of plantlets. Contrary to this, CE effects were dependent on the plant origin and promoted activities of peroxidase, ME, and G6PDH were observed more in M-plants than in G-plants. Effects of a single ABA treatment lasted throughout the whole acclimation and alleviated transplantation shock more efficiently than CE, irrespective of plant precultivation. However, under combined treatment (CE+ABA) CE effects prevailed over ABA.