Effect of different factors on plant regeneration from leaf explants of Jatropha curcas L.

The in vitro regeneration frequency was commonly low, and the quality of adventitious buds was poor, when the traditional methods were used to induce adventitious buds from leaf explants of Jatropha curcas L. through the medium containing low concentration of thidiazuron (TDZ). When treated with high concentrations (6.5-104 mg/L) of TDZ for a certain time (7-120 min), the regeneration frequency and quality of adventitious buds were significantly increased. The best induction rate of adventitious buds (78.58%) and the average number of buds per explant (7.26) were obtained by soaking leaf explants in 26 mg/L TDZ solution for 30 min and then transferring them onto MS medium without hormone for 30 days. Furthermore, the adventitious bud regeneration was affected obviously by source of explants, sterilization time, illumination time and genotype. The subsequent elongation and rooting experiments showed that adventitious bud elongation could be improved by adding diethyl aminoethyl hexanoate (DA-6) in the medium, and the best elongation effect could be gained when the concentration of DA-6 was 1.2 mg/L. The elongated shoots induced the roots and developed into small intact plants on the MS medium with 1.5 mg/L sodium nitroprusside (SNP). After domestication, these small plants could be transplanted into the soil and growing normally. Therefore, the method established in this study was helpful to improve the plant regeneration efficiency of leaf explants in J. curcas.