Effects of auxin and cytokinins on morphogenesis of three varieties of Episcia

The objective of this study was to determine the optimal auxin to cytokinin ratios for plant initiation from leaf blade and/or stolon explants of Episcia cupreata var. Chocolate Soldier, E. cupreata var. Silver Sheen, and E. dianthiflora. Knowledge of hormonal requirements necessary for morphogenesis would enable workers with these plants to propagate them more rapidly than is possible by conventional propagation techniques.

Blade and stem explants were cultured on modified Linsmaier and Skoog media with various combinations of auxin (IAA) and cytokinin (kinetin or 2iP). Plant-growth regulators were added to the medium at 0.0, 1.0, 2.5, 5.0, 10.0, or 15.0 mg/1. Shoots initiated from the explants were transferred to modified Knop's medium with sucrose where plantlets increased in size and produced roots. When plantlets were 2 to 3 cm tall, they were transplanted to soil.

Only low percentages of plant initiation were observed for E. dianthiflora on medium with IAA 5.0 mg/1 and kinetin 2.5 mg/1 and for E. cupreata var. Chocolate Soldier on media with IAA 1.0 mg/1 or with IAA 5.0 mg/1 and kinetin 1.0 mg/1. A high percentage of blade explants of E. cupreata var. Silver Sheen initiated shoots by 16 weeks on medium with IAA and 2iP at 1.0 mg/l. The different Episcia taxa have somewhat different media requirements for shoot initiation, and shoot initiation was usually preceded by intensive callus formation. However, not all callus produced shoots. Very few variant cultured plants were observed for any of the Episcia taxa.

The results of this study indicate that Episcia a can be propagated successfully in tissue culture; however, the requirements for shoot morphogenesis from explants varies with the taxon and the plant organ used for the explant.