Influence of explants type and phytohormones on In vitro callogenesis and plantlet regeneration of patharchur (Coleus barbatus L.), an endangered ethnomedicinal plant

Abstract

The present study was conceptualized to study the effect of explants and plant growth regulators on organogenesis to establish an efficient regeneration protocol for Coleus barbatus, an endangered ethnomedicinal Plant. In course of this, sterilized explants were cultured onto MS medium augmented with different concentrations and combinations of auxin (IAA) and cytokinin (BAP). The best callogenic response was observed on media M4 followed by M9 and M5 in terms of Days of callogenesis, degree of response, colour and texture, considering all the three explants. Regenerated shoots from embryogenic calli were further multiplied on fresh media. Highest per cent shoot regeneration response was obtained on medium M12 (84.7%) and M7 (84.7%) followed by media M6 (81.4%), whereas in terms of number of shoots per culture, shoot apex (0.0-3.7) and internodal stem (0.0-3.7) exhibited as better explant then young leaf (0.0-1.7). The long and healthy shoots were harvested and subcultured on rooting media for root induction. Maximum per cent response of root proliferation were obtained on medium M13 (85.2%) followed by media M9 (84.4%) and M8 (84.1%), whereas for highest frequency of root per elongated shoot, shoot apex (0.0-10.3) exhibited as better explant then internodal stem (0.0-9.7) and leaf explants (0.0-7.3). Hence, the In vitro regenerated plantlets using this established micropropagation protocol can be used for large-scale commercial cultivation, in situ conservation, and genetic characterization of this endangered medicinal plant.