1994 Volume 63 Issue 3 Pages 505-514
Callus derived from cotyledons of 'Fuji' apple were cultured on 1/3 MS medium supplemented with various concentrations of BA and NAA. The effects of BA, TDZ, and CPPU at 1.0 to 8.0 mg•liter-1 on shoot regeneration from calli and NAA on subcultured calli were investigated.
1. Cotyledons produced callus profusely when cultured on a medium supplemented with 0 to 4.0 mg•liter-1 BA and 0.5 to 10.0 mg•liter-1 NAA. Callus formation occurred only at the proximal part of the cotyledon exposed to 0 or 0.1 mg•liter-1 NAA. However, calli formed from the distal and middle regions at 0.5 mg•liter-1NAA or higher.
2. Callus morphology was dependent on concentrations of NAA and BA. With NAA alone, soft calli were produced, whereas at 0.5 to 4.0 mg•liter-1 BA and at combinations of 0 to 0.1 mg•liter-1 NAA and 0.5 to 8.0 mg•liter-1 BA hairy calli were induced. Combinations of 10.0 mg•liter-1 NAA and 2.0 to 10.0 mg•liter -1 BA gave rise to globular calli.
3. When globular calli were cultured on the medium with 4.0 mg•liter-1 CPPU and 0 NAA and then subcultured onto a fresh medium at 2-week interval for 6 weeks, 60% of the callus explants regenerated shoots; about 12 shoots per callus were obtained 12 weeks after beginning the experiment. TDZ also produced a positive effect on shoot regeneraiton from callus, but the percentage of explants forming shoots and the number of shoots formed were less than those treated with CPPU. The effect of BA on shoot formation from callus was comparatively weak. The addition of 0.1 mg•liter-1 NAA to CPPU greatly reduced the number of shoots regenerated.