Changes in the biochemical parameters of albino, hyperhydric and normal green leaves of Caladium bicolor cv. "Bleeding hearts" in vitro long-term cultures.

Caladium bicolor is an excellent landscape and pot plant grown for its ornamental value due to the varied shapes and multi-colored foliage. However, the ornamental value of in vitro clonally propagated plants is affected by the occurrence of morpho-physiological anomalies in the long-term cultures. During the long-term culture of rhizome-derived shoot cultures of C. bicolor cv. "Bleeding hearts", some incidences of hyperhydricity and albinism were observed. Hyperhydricity occurred at high frequency in the shoot cultures and was more prevalent in the liquid over solid medium cultivated plantlets. The addition of silver nitrate at 7.5 μM reduced prevalence of the condition over other treatment concentrations but, changes in the gelling agent concentration and photoperiodic incubation were ineffective. Albinism also occurred at a higher frequency but, was more prevalent in the cultures incubated below or above 12 h light/dark photoperiods. Evaluation of the physiological, biochemical parameters showed differences between the leaves of albino, hyperhydric and normal green C. bicolor micro shoots. The experimental results obtained suggested an effective role of pigment molecules, cellular osmolytes, and enzymatic and non-enzymatic antioxidant systems in the development of albino and hyperhydric leaves in C. bicolor micro shoot cultures. Photoperiodic incubation and culture conditions showed some effect on the incidences of hyperhydricity and albinism in the shoot cultures.