Objective ‘Jingzao 39’ is a new high-quality jujube variety. There is no effective regeneration system in vitro at present, which affects the cultivation of self-rooted seedlings and the purity of seedlings. In order to solve the problems of low genetic transformation efficiency of jujube, different influencing factors of jujube leaf regeneration were explored in this study, in order to establish an efficient leaf regeneration system.
Method Using the leaves of tissue cultured seedlings of ‘Jingzao 39’ as experimental materials, the effects of different inoculation methods, types of basic culture medium, types and concentration ratio of plant growth regulators on the direct induction of adventitious bud regeneration from detached leaves were studied.
Result The results showed that the regeneration rate of the inoculation method with the leaves being placed upward was much higher than that of back up, which was the best placement method for the regeneration of adventitious buds from leaves of ‘Jingzao 39’. The effect of basic culture medium on leaf regeneration of ‘Jingzao 39’ was greater than that of plant growth regulator, and the optimal basic medium and plant growth regulator were 1/2 MS and cytokinin 6-BA, respectively. The optimal regeneration system for leaves of ‘Jingzao 39’ tissue cultured seedlings established in this study was 1/2 MS medium + 1.0 mg/L thiabenduron + 0.5 mg/L 6-BA + 0.2 mg/L NAA + 30 g/L maltose + 6 g/L agar, an average of 4.67 adventitious buds could be regenerated for each leaf. Then, the optimal propagation system of ‘Jingzao 39’ tissue culture seedlings was initially explored and established: MS + 20 g/L maltose + 6 g/L agar + 3.00 mg/L 6-BA + 0.10 mg/L NAA, with the branching rate up to 88%, and the average branch number of 2.76; the most suitable rooting medium was: 1/2MS + 20 g/L sucrose + 8 g/L agar + 1.50 mg/L IBA + 0.30 mg/L NAA, with rooting rate of 90.91%, and the average root length up to 4.08 cm.
Conclusion The leaf regeneration efficiency of ‘Jingzao 39’ is greatly influenced by external factors, especially the basic medium type and inoculation method, and each factor does not play an independent role. This study establishes a complete cultivation system for the functional verification of interested gene with the leaves of ‘Jingzao 39’ as transgenic materials, and lays a foundation for accelerating the jujube research process.
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