Env Exp Biol (2013) 11: 59–67

Micropropagation, in vitro flowering and cytological studies of Bacopa chamaedryoides, an ethno-medicinal plant

Abstract

This is the first report of both establishment of micropropagation protocol as well as cytological studies of Bacopa chamaedryoides (Kunth) Wettst., an important Indian ethno-medicinal herb. Shoot-tips and nodal segments explants were inoculated on Murashige and Skoog basal medium containing 0.7% agar, 3.0% sucrose and different concentrations and combinations of cytokinins and auxins. Optimum multiplication was achieved on medium containing 6-benzyl-aminopurine (2.0 mg L^–1) and indole-3-acetic acid (0.2 mg L^–1). Shoot-tips proved to be a better explant in having a high rate of shoot multiplication (18.7 ± 0.17) in comparison to nodal segments (15.1 ± 0.18) in the same medium. In vitro rooting of multiplied individual shoots was achieved on half strength Murashige and Skoog medium supplemented with 50% of ‘Aloe vera gel’, with a maximum of 18.3 ± 0.17 roots. Up to 66.7% of these multiplied shoots induced healthy flowers in vitro on Murashige and Skoog medium containing low concentration of 6-benzyl-aminopurine (0.2 mg L^–1). In vitro produced flowers contained 96.54 % viable pollen, more or less same as the field grown mother plants. Micropropagated plants have shown normal diploid 2n = 22 chromosomes, same as that of the mother plant. These micropropagated plants were successfully established in soil after hardening them in submerged condition, with an 84% survival rate. In total, 88.9% of the survived plants flowered and fruited normally after 50 days of field transfer. More than 85% field-grown regenerated plants developed normal fruits and viable seeds. This work presents an efficient micropropagation method from node and shoot-tip culture for mass propagation and in vitro flowering of B. chamaedryoides.