Somatic embryogenesis and plant regeneration from immature embryos of saw palmetto, an important landscape and medicinal plant

Abstract

Somatic embryogenesis and plant regeneration from immature zygotic embryos was achieved for saw palmetto (Serenoa repens (Bartr.) Small). Embryos, isolated from immature fruit of native-grown plants, were cultured on Murashige and Skoog medium plus 0.15% (w/v) activated charcoal and supplemented with 452 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 14.7 μM N6-(2-isopentenyl)adenine (2iP). Clusters of somatic embryos developed from all immature zygotic embryos 5 weeks after culture initiation. After 12 weeks, explants were transferred to the same medium with the amount of 2,4-D reduced to 90.4 μM which resulted in somatic embryo proliferation. Somatic embryos were then transferred to the basal medium containing 0.9, 9 μM thidiazuron (TDZ), or no growth regulator for conversion into plantlets. The 9 μM TDZ treatment was ineffective for plant regeneration. However, 12% of the embryos subcultured on 0.9 μM TDZ were able to produce complete plantlets. Shoot production was obtained from 35% of the embryos subcultured in the absence of growth regulators. Rooting (100%) was achieved when these shoots were transferred onto medium containing 22.2 μM α-naphthaleneacetic acid (NAA).