In vitro shoot multiplication of Lobelia cardinalis L., an aquatic ornamental plant

Abstract

Lobelia cardinalis L. is an underwater plant, used worldwide for aquarium ornamentation. A successful protocol is described for rapid and large-scale propagation of an ornamental aquatic plant, Lobelia cardinalis L. by in vitro culture of shoot tip explants. The shoots of an ornamental aquatic plant, Lobelia cardinalis L. from ex vitro were surface sterilized using 4% Clorox® (5.25% sodium hypochlorite, NaOCl) for 10 min followed by rinsing three times with sterile distilled water. They were again surface sterilized for another 2% Clorox® for 5 min. All aseptic shoot tip explants were cultured on MS basal medium augmented with various concentrations of N6-benzylaminopurine (BAP; 1.0-3.0 mg L-1) and α-naphthaleneacetic acid (NAA; 1.0-3.0 mg L-1) individually for shoot induction. Presence of BAP in the medium significantly increased shoot numbers. The maximum shoot formation (100%) and number of shoots per explant (5.8±0.74) was achieved on media containing 1.0 mg L-1 BAP after 60 d of culture. The highest frequency (100%) of root formation with maximum number of roots (11.4±0.20 roots explant-1) and root length (27.37±1.67 mm) was noticed on hormone-free MS medium. Regenerated plantlets were subsequently hardened, acclimatized and successfully established in aquariums after 60 d of transfer to the greenhouse with 95% survival rate. Acclimatized plantlets of Lobelia cardinalis L. were vigorously growing with normal phenotypes. A highly efficient and rapid regeneration system via multiple shoot formation was developed for Lobelia cardinalis L. Plant tissue culture is an alternative method of commercial propagation.