Effect of elevated CO2 concentration on acclimation of tobacco plantlets to ex vitro conditions

• Published in: Journal of experimental botany 1999-01, Vol.50 (330), p.119-126
• Main Authors: Pospís̆ilová, Jana, Synková, Helena, Haisel, D., Čatský, J., Wilhelmová, Nad'a, Šrámek, F.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Carotenoids; chlorophyll content and fluorescence; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Metabolism; Net assimilation, photosynthesis, carbon metabolism. Photorespiration, respiration, fermentation (anoxia, hypoxia); Nicotiana tabacum; Nutrition. Photosynthesis. Respiration. Metabolism; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; stomatal conductance
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/50.330.119

Nicotiana tabacum L. plants grown in vitro were transferred to ex vitro conditions and grown for 28 d in a greenhouse under normal CO2 concentration (C, 330 µmol mol−1) or elevated CO2 concentration (E, 1000 µmol mol−1). Stomatal conductances of abaxial and adaxial epidermes measured under optimal conditions were not significantly affected by growth under E, but the stomatal regulation of gas exchange was better. Leaf photosynthetic rate (A) of elevated CO2 plants was similar to that of control plants when both were measured under normal CO2, but higher when both were measured under elevated CO2. The A of elevated CO2 plants was much higher than the A of control plants when measured under their respective growth CO2 concentration, which resulted in their higher growth rate. Chlorophyll a and b contents, and activities of whole electron transport chain and of photosystem (PS) II were not markedly affected by growth under E, and the maximum efficiency of PSII measured as the ratio of variable to maximum fluorescence was even slightly increased. Hence no down-regulation of photosynthesis occurred in transplanted plants grown for 4 weeks under E. The contents of β-carotene and of xanthophyll cycle pigments (violaxanthin+antheraxanthin+zeaxanthin) were lower in E plants. The degree of de-epoxidation of xanthophyll cycle pigments was not changed or was even lower after transfer to ex vitro conditions, which indicated that no photoinhibition occurred. Therefore, CO2 enrichment can improve acclimation of in vitro-grown plantlets to ex vitro conditions.