Research Progress on the Application of Plant Growth Regulators in the Rapid Propagation of Jujube by In Vitro Culture

Jujube (Ziziphus jujuba Mill.) is an important economic fruit tree in China, and its in vitro culture technology is the key to achieving large-scale seedling cultivation. PGRs (Plant growth regulators) play a central regulatory role in all stages of jujube micropropagation, including explant initiation, proliferation, and rooting. This article provides a comprehensive overview of recent advances in in vitro culture of jujube, with a focus on the recommended exogenous phytohormone ratios, their effects, and underlying regulatory mechanisms across distinct varieties during the key stages such as in vitro culture, shoot proliferation, and root formation. The primary culture of most jujube varieties usually employs the MS medium, and it is recommended that auxin and cytokinin be used in combination. During the initial cultivation stage, the use of NAA (1-naphthaleneacetic acid) or IBA (indole butyric acid) is recommended at concentrations ranging from 0.1 to 1.0 mg/L. At the same time, 6-BA (6-benzylaminopurine) is suggested, with a concentration range of 0.5 to 2.5 mg/L. In the subculture multiplication of most jujube varieties, MS medium is used, and auxin (such as NAA, IBA), and TDZ (thidiazuron) and cytokinin (e.g., 6-BA) are used in combination. The recommended concentration range for auxin remains between 0.1 and 1.0 mg/L, and for cytokinin 6-BA between 0.5 and 2.5 mg/L, while the recommended concentration of TDZ is suggested to be below 0.01 mg/L. Rooting induction for most jujube varieties has predominantly been achieved using 1/2 MS medium, with growth regulator concentrations typically ranging from 0.5 to 3.0 mg/L.