THE CYTOKININ PREFERENCE FOR IN-VITRO GERMINATION AND PROTOCORM GROWTH OF CYPRIPEDIUM-CANDIDUM

Cytokinin preference and optimum levels were investigated for in vitro germination and protocorm growth of Cypripedium candidum Muhl. ex Wil ld. (Lady's Slipper Orchid) using seed collected 8 weeks after pollina tion. Benzyl adenine (BA) and 6-(alpha,alpha-dimethyiallylamino)-purin e (2iP) in concentrations of up to 0.8 mg l(-1) enhanced germination s ignificantly in comparison to controls without cytokinin. Kinetin did not enhance germination. The pattern of germination over time in cultu re varied with cytokinin type. After 4 and 8 weeks, a higher germinati on percentage occurred on media with BA and 2iP. Nine morphological ty pes of protocorms were identified and a model to explain protocorm dev elopment is proposed. Protocorms developed faster and the production o f multiple protocorms increased with all three cytokinins in compariso n to the control. However, the type of protocorms observed on the kine tin and control treatments was different from that observed on BA and 2iP and may have resulted via a different pathway. BA at the highest c oncentrations delayed root development.