A reliable protocol for micropropagation of an ornamental aquatic plant, Staurogyne repens

Staurogyne repens is a commercially important ornamental aquatic plant species with traditional uses. Due to the low growth of plantlets, propagation by conventional means has been met with many difficulties. In this study, a reliable protocol for micropropagation of an ornamental aquatic plant Staurogyne repens was established. The explants were surface sterilized using 15% Clorox^® (5.25% sodium hypochlorite, NaOCl) for 5 min followed by rinsing 3 times with autoclaved double distilled water. The surface sterilization of explants was rendered by 10% Clorox^® for 10 min and 5% Clorox^® for 15 min. The aseptic nodal segments (1.5 cm in length) were transferred to MS medium supplemented with varying level of 6-benzylaminopurine (BAP; 0, 1.0, 3.0, 5.0 or 7.0 mg L^‑1) alone or in combination with 1-naphthalene acetic acid (NAA; 0.15 mg L^‑1). A maximum mean number of shoots explant^‑1 (48.75±0.27) and mean shoot length (21.42±0.70 mm) were induced from about 1 aseptic nodal segments within 45 days in the presence of 0.15 mg L^‑1 NAA and 1.0 mg L^‑1 BAP. In vitro regenerated shoots were rooted on full strength MS medium conjunct with 3-indolebutyric acid (IBA) singly at different concentrations. The best rooting response was observed on full strength MS medium containing IBA at 3.0 mg L^‑1. This medium yielded maximum number of roots (26.20±0.32 roots shoot^‑1) with 9.53±0.44 mm average length. In vitro grown plantlets were successfully acclimatized in pots containing rock wool under greenhouse conditions at 100% survival and grew vigorously without any morphological abnormalities during acclimatization in the greenhouse. The current protocol was the first report on successful establishment of in vitro clonal propagation of Staurogyne repens.