Optimisation of a highly efficient shoot regeneration system using leaf explants of Chinese jujube (Ziziphus jujuba Mill.) by response surface methodology
Chinese jujube (Ziziphus jujuba Mill.) is a major fruit crop in Asia. In this study, response surface methodology (RSM) was successfully employed to establish a highly efficient in vitro propagation and regeneration system for the ‘Teapot’ jujube via shoot organogenesis. Among the tested factors, gibberellic acid (GA3) concentration showed the most significant positive effect. The pre-culture darkness timing and medium were also important factors for highly efficient shoot regeneration of the ‘Teapot’ jujube. The highest regeneration (> 75%) was achieved by 1 week in darkness and culture on wood plant medium (WPM) containing 0.25 mg·L−1 GA3, 0.5 mg·L−1 6-benzylaminopurine (BAP) and 0.1 mg·L−1 3-indoleacetic acid (IAA). In vitro-derived shoots rooted very well in the modified 1/2 Murashige and Skoog (MS) medium containing 0.4 mg·L−1 3-indolebutyric acid (IBA), resulting in a 100% rooting rate. These findings suggest that the RSM can be employed to optimise the protocols needed for successful in vitro plant regeneration of jujube cultivars, with potential applications in plant genetic transformation practices, polyploidy induction and germplasm preservation.