Development of a regeneration system via nodal segment culture in Veronica anagallis-aquatica L. – an amphibious medicinal plant

Abstract

The present study describes an effective, reproducible and rapid regeneration protocol for in vitro shoot development of the medicinally important, semi-aquatic plant Veronica anagallis-aquatica L. through mature nodal segments on Murashige and Skoog (MS) medium. The most effective medium for shoot regeneration was MS medium fortified with 0.5 µM 6-benzyladenine (BA), on which the maximum number (43.7±1.85) of shoots per explant having a shoot length of 5.0±0.25 cm were produced. The addition of auxins along with optimal concentration (0.5 µM) of BA did not further improve the regeneration capacity of the explants; instead, it resulted in an adverse effect. Nodal segments cultured in MS liquid medium without agar provided a better and early response for efficient shoot regeneration, and simultaneous rooting as compared to solidified medium. The optimal liquid medium comprised of MS+BA (0.5 µM) on which a maximum 20.7±1.76 shoots per explant were produced and grew healthier. Both half strength MS and MS basal medium supplemented with α-naphthaleneacetic acid (NAA) responded equally for root induction. Rooted shoots were successfully transferred to field conditions with 80% survival. Histological studies revealed the de novo origin of shoots which would make this protocol suitable for transformation techniques.