| Stem transverse thin cell layers (tTCLs) from leading Japanese chrysanthemum (Dendranthema X grandiflora Ramat. Kitamura) ‘Shuhou-no-chikara’ cultivar were used to obtain defined morphogenic programs when select plant growth regulators (PGRs) were used, superior to the use of conventional explant sources. A single auxin or cytokinin, or numerous permutations of each, in conjunction with tTCLs, were utilized to manipulate the callogenic, caulogenic, rhizogenic and somatic embryogenic pathways/programs in vitro. Light or darkness played a significant role. Single PGRs were capable of activating morphogenic programs in chrysanthemum tTCLs: callus induction by TDZ, axillary shoots by BA, roots by 2,4-D or NAA and somatic embryos by IAA, while multiple PGR applications resulted in a multiple organogenic outcome. |