Effect of cytokinin on the regeneration and proliferation of in vitro cultures of the endemic plant Arabis takesimana Nakai

Abstract

Arabis takesimana Nakai, an endemic plant native to Korea, possesses substantial potential as a resource in the bioeconomy sector. This study aimed to establish an efficient in vitro culture system for the mass propagation and biomass production of A. takesimana by investigating its regeneration attributes and capacity under various cytokinin treatments. Five cytokinin types - 2ip, zeatin, kinetin, BAP, and TDZ - were evaluated at the same concentration (1.0 mg/L) to assess their effects on biomass production, leaf development, and multiple shoot formation (growth of auxiliary buds). TDZ and BAP exhibited the highest efficacy, significantly increasing fresh biomass production, leaf production, and shoot differentiation compared to the other cytokinin types. Exmining the cross-sectional structure of the callus, the TDZ and BAP treatments resulted in an expanded meristematic zone and a reduced pith compared to the other cytokinin treatments. Optimal results were attained at 0.5 mg/L TDZ, which yielded the highest biomass (3.31 ± 0.9 g), number of leaves (136.6 ± 45), and number of shoots (18.4 ± 5.1) and minimal abnormal leaf development. High TDZ concentrations (≥ 0.5 mg/L) resulted in irregular leaf differentiation, while lower concentrations resulted in morphologies similar to those of the control group. These findings establish TDZ at 0.5 mg/L as the most effective cytokinin treatment for A. takesimana propagation and biomass production at an industrial scale. The study underscores the potential and effectiveness of in vitro culture for the sustainable propagation and commercialization of endemic plants.