Silver nitrate induced rooting and flowering in vitro on rare rhoeophytic woody medicinal plant, Rotula aquatica Lour.

Abstract

Silver nitrate induced enhanced rooting and flowering in vitro was achieved on Rotula aquatica L., a rare rhoeophytic woody aromatic medicinal plant. Solid and liquid nature of the medium, and growth regulators significantly influenced in vitro rooting and flowering. Half-strength MS liquid medium fortified with 2.69 μM α-naphthaleneacetic acid (NAA) was effective among different auxins, which induced a mean of 7.3 roots per shoot. Plantlets acclimatized after auxin alone induced rooting exhibited 80% survival in field conditions. Nevertheless, the established plantlets exhibited 50% loss within 3 months. Addition of 11.7 μM silver nitrate to half-strength MS liquid medium containing 2.69 μM NAA increased the number of roots to 16.8 per shoot. Plantlets established after rooting in silver nitrate supplemented medium facilitated 95% survival, and the established plantlets did not exhibit loss even after 3 months. Dipping of the basal end of shoots developed in vitro in NAA (2.69 μM) and silver nitrate (11.7 μM) solution (made in water) for 25 days induced a mean of 12.4 roots per shoot. These plantlets transferred to small pots facilitated 90% survival. Half-strength MS liquid medium containing 2.69 μM NAA and 11.7 μM silver nitrate induced flowering earlier. The flowers were morphologically and structurally similar to that on plants growing in field conditions.