Plant regeneration from cell suspension-derived protoplasts of Saintpaulia ionantha Wendl

Summary

Friable calli were induced on leaf segments of Saintpaulia ionantha Wendl. on B5 medium containing 1 mg l⁻¹ 2,4-D and 2 g l⁻¹ casein hydrolysate. Cell suspension cultures were readily established from these friable calli and protoplasts could be isolated from the cells with yields of 1–3×10⁷/g f. wt.. By culturing in 0.1 % gellan gum-solidified B5 medium supplemented with 1 mg l⁻¹ 2,4-D and 0.1 M each of sucrose and mannitol at a density of 1×10⁵/ml, the protoplasts divided within 6 days and formed macro-colonies after 2 months of culture. Shoot regeneration from protoplast-derived calli was obtained by sequential treatment of the calli with plant growth regulators: initially with 1 mg l⁻¹ each of NAA and BA for 2 months followed by 0.01 mg l⁻¹ NAA and 5 mg l⁻¹ BA for 4 months. Regenerated plants were established after rooting of the shoots on half-strength MS medium, and successfully transferred to the greenhouse. The regenerated plants grew into flowering stage and showed the same phenotype as the parent plant.