Pluronic F-68 enhanced shoot regeneration in a potentially novel citrus rootstock

The effects have been studied in vitro of the non-ionic, co-polymer surfactant, Pluronic F-68, on shoot regeneration and bud induction in epicotyl and cotyledon explants of Citrus depressa, a potential alternative rootstock to C. jambhiri for commercial Citrus. Supplementation of Murashige and Skoog (1962)-based, agar-solidified shoot regeneration/bud induction (SRBI) medium with 1.0 mg l(-1) 6-benzylaminopurine and 0.5% (w/v) Pluronic F-68 significantly (P < 0.05) increased mean fresh weight by a maximum of 60%, the proportion of explants exhibiting shoot/bud regeneration by 25% and the mean number of shoots per epicotyl explant by 184%, compared to untreated controls. Similarly, 0.5% (w/v) Pluronic F-68 significantly (P < 0.05) enhanced the mean percentage bud induction (91%) and the number of buds regenerated (>4-fold) per cotyledon explant. Interestingly, the mean fresh weight gain for both explants was unaffected across the range of concentrations (0.001-0.1% w/v) of Pluronic F-68 evaluated. Regenerated plants from epicotyl explants were transferred and acclimatized to glasshouse conditions.