Plant regeneration and encapsulation of somatic embryos of horseradish

Abstract

Callus with a potential for somatic embryogenesis was obtained from in vitro grown explants of horseradish, Armoracia lapathifolia. Embryogenic callus was induced on solid MS medium supplemented with 0.1–2.0 mg/l, 2,4-dichlorophenoxyacetic acid and either 0.1 or 0.5 mg/l 6-benzyladenine. After transferring the callus to liquid medium having the same concentrations of growth regulators as used in the solid medium, small green clumps, representing the early embryogenic stage were obtained after one month. These small clumps were separated into several fractional sizes and transferred to growth regulator-free liquid MS medium in order to mature the embryos. Small globular clumps, 100 μm-1 mm, produced somatic embryos. These embryos were transferred to growth regulator-free solid Murashige and Skoog medium. Normal shoots developed within one month. The somatic embryos were then encapsulated in alginate calcium gel and placed on gelled MS medium without growth regulators. The conversion frequency of the encapsulated embryos was higher than that of non-encapsulated embryos. The regenerated plantlets have grown well in a greenhouse.