Somatic embryogenesis in Hypoxis hemerocallidea: An important African medicinal plant

Abstract

An efficient in vitro plant regeneration system was established via somatic embryogenesis of Hypoxis hemerocallidea, an extensively utilized medicinal plant in South African traditional medicine. Embryogenic callus was obtained on Murashige and Skoog (MS) basal medium supplemented with 15μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.5μM N6-benzyladenine (BA). Different developmental stages of somatic embryos (SEs: globular embryos, torpedo-shaped embryos and cotyledonary embryos) were obtained and further matured from the embryogenic callus by subsequent subculture on the same medium. Highest frequency of somatic embryos (30.56±1.15) was recovered after 6weeks. Scanning electron micrographs revealed the presence of somatic embryos. Mature somatic embryos germinated and developed into plantlets after 4weeks on half strength MS basal agar medium. The germination frequency reached 88.9% when using half strength MS basal agar medium supplemented with 1.44μM gibberellic acid (GA3). Rooted plantlets were successfully acclimatized in the greenhouse with a survival rate of 90%. This is the first report on the establishment of H. hemerocallidea somatic embryogenesis. The protocol developed would be helpful in reducing stress on natural populations, provide a system for germplasm conservation, regeneration of large numbers of high value clonal plants for commercial production, genetic transformational studies and provides a system for analysis of bioactive compounds.