Impact of culture vessel ventilation on the anatomy and morphology of micropropagated carnation

Dianthus caryophyllus cv. Nelken was cultured in vitro under different vent ilation rates (0.11, 0.21, 0.68 and 0.86 changes h(-1)). Ventilation modifi ed the anatomical characteristics of shoots and leaves described for plants grown in non-ventilated vessels: the cuticle became thicker, there was a d ecreased cell size and intracellular space size. Also, there were more phot osynthetic and supportive tissues, including thicker cell walls. Increased ventilation promoted in vitro hardening of micropropagated carnation shoots , and pushed the culture-induced phenotype closer to that of ex vitro accli matized plants. Anatomical variability of in vitro-grown plants was demonst rated to be a consequence of ventilation.