Effect of Explant Type and Plant Growth Regulators On the Micropropagation of Echinacea Purpurea L

Echinacea purpurea L. is an indigenous plant of North America and occupies an important place among medicinal plants due to its immunostimulant properties. The increasing demand of high quality plant material has necessitated its true to type, disease-free propagation through tissue culture. Different types of explants and plant growth regulators effect the in vitro regeneration of Echinacea purpurea L. In vitro regeneration potential of different types of explants in different types of plant growth substances was investigated in this study. Leaf discs, adventitious root segments and petiole segments were compared for their morphogenic potential in different concentrations and combinations of plant growth regulators. Seeds of Echinacea purpurea were grown in magenta boxes contaning MS medium under controlled conditions. Explants were excised and cultured under aseptic conditions onto nutritional medium containing Murashige and Skoog (MS) salts and B5 vitamins mix with combinations of 1.0-5µΜ BAP, 1.0-5.0µΜ IBA and 0.1-1.0µΜ TDZ. The cultures were kept in growth cabinet with cool white light (40-60 mol.m-2.s-1) under 16-h photoperiod. Regeneration was quantified at 28 day based on the degree of callogenesis, organogenesis, and somatic embryogenesis. Root segment explants found to be more efficient for their morphogenic ability followed by leaf and petiole explants. Whereas maximum callogenesis was achieved in petiole explant followed by root and leaf explants. An interaction was found between the PGR and explant types. These investigations will aid in the development of a model system for clonal mass propagation and in vitro regeneration of Echinacea purpurea L.