Efficient culture protocol for plant regeneration from petiole explants of physiologically mature trees of Jatropha curcas L.

Abstract

An efficient and reproducible protocol for induction of adventitious shoot buds and plant regeneration from petiole explant cultures of Jatropha curcas, an important biofuel crop, is described. Physiologically mature trees of three J. curcas genotypes were selected and explants were prepared from young petioles. Treating the explants with high concentrations (5 to 120 mg/L) of thidiazuron (TDZ) solution for short time periods (5 to 80 min) helped increase the regeneration frequency and improved the quality of the regenerated buds significantly. The age of the petioles and inoculation methods were found to influence the culture results. The best shoot buds induction (65.78%) and number of buds (6.77) per explant was seen in the second petiole explants of genotype M-1 treated with 20 mg/L TDZ solution for 20 min, followed by 35-day culture on hormone-free Murashige and Skoog medium. The regenerated buds could elongate to become shoots in a medium containing gibberellic acid. The elongated shoots initiated roots to become intact plantlets in rooting medium containing indole-3-butyric acid and L-glutamine (Gln), and supplementing 16 mg/L Gln into the rooting medium effectively stimulated the initiation and growth of roots, with the best rooting rate (51.72%). After acclimatization, these plantlets were transplanted to soil wherein normal growth was observed. Therefore, an intact plantlet could usually be obtained at 60 days of culture by using the culture protocol described in this study. This protocol can be used for mass production of true-to-type plants and the production of transgenic plants through Agrobacterium/biolistic-mediated transformation.