Embryogenesis and Plantlet Regeneration from Callus of Hibiscus acetosella1

Abstract

Abstract Plantlets have been produced by germination of somatic embryos derived from callus of Hibiscus acetosella Welw. ex. Hiern. Five of the media used were based on Nitsch and Nitsch's Medium H (purchased formulated without IAA or sucrose). To this base were added, per liter: 40 g glucose for NH; 10 g sucrose for NH-1; 40 g sucrose, 1 mg 2,4-dichlorophenoxyacetic acid (2,4-D), and 1 mg 6-furfurylaminopurine (kinetin) for RM-1; 40 g glucose, 250 mg NaH2PO4·H2O, 28 mg FeC6H5O7·nH2O, 100 mg i-inositol, 30 mg adenine, 0.1 mg (2-chloroethyl)trimethylammonium chloride (chlormequat), and 4 mg 2,4-D for SEM-1; and 40 g glucose, 0.1 mg chlormequat, 0.05 mg B-napthoxyacetic acid (NOA), and 10 mg 2-isopentyladenine (2iP) for HC. The B5 medium was Gamborg's B5 without 2,4-D. All media contained 8 g agar and had the pH adjusted to 5.7 prior to autoclaving. Primary explants placed on HC produced adventitious shoots and callus. When callus explants from HC or primary explants of roots were placed on RM-1, a callus containing embryoid-like structures was produced. Torpedo stage embryos were induced by subculturing this callus from RM-1 on SEM-1 and could be proliferated by sequential transfer from SEM-1 to RM-1, then back to SEM-1. When callus containing torpedo-stage embryos was transferred to B5, the embryos germinated and produced rudimentary plantlets with elongated hypocotyls, short roots, and small cotyledons. These developed into plants when transferred to NH-1.