Callus Formation, Plant Regeneration and Clonal Propagation in Vitro of Gynura aurantiaca (Blume) DC.

Methods for culture in vitro of Gynura aurantiaca (Blume) DC.are described. Callus formation from gynura explants was initiallydifficult in spite of the multiple combinations of plant growthregulators assayed. In order to induce high growth rate, incorporationof several organic addenda to a basal medium was necessary,the best of these being coconut milk. Unorganized cell linescould be obtained by subculturing on C medium supplemented with10% coconut milk, and transfers had to be done at short intervals. A morphogenetic cell line without apparent loss in its organogenicpotential through more than 8 months of subculturing was establishedfollowing a sequence of culture media. Methods for rapid and efficient clonal propagation in vitroof this plant species are also reported. The possible utilization of these tissue culture techniquesdeveloped for gynura, a suitable indicator host for Citrus ExocortisViroid, in further studies concerning pathogenesis and replicationof this viroid is discussed. (Received April 22, 1985; Accepted October 11, 1985)