Plant regeneration from seedling explants of Juncus effusus

An in vitro plant regeneration method for Juncus effusus L. was established. Six to eight day old in vitro grown seedlings, cultured on Murashige and Skoog medium supplemented with benzyladenine (BA), 2-isopentenyladenine (2iP), or kinetin, showed multiple shoot regeneration within 4 weeks. Among the three cytokinins, BA and 2iP induced the highest (88 and 86%, respectively) regeneration frequency, while no significant differences were noticed in regeneration frequency between control (without cytokinin) and kinetin. The in vitro generated shoots, upon subculture to the same shoot induction medium, produced an average of 10 shoots on 2iP medium. The regenerated shoots turned brown at the base, and gradually turned black, resulting in reduced plantlet rooting. Addition of charcoal to the rooting medium resulted in increased rooting percentages, increased root and shoot growth and reduced browning, whereas addition of the antioxidants citrate and ascorbate did not. Rooted plants, transferred to a commercial soil mix, had a survival rate of >95% in the greenhouse. All the plants that were transferred to wetlands survived. This was the first tissue culture study on this ecologically important wetland plant.