Effective Combinations of Plant Growth Regulators for Somatic Embryogenesis from Spinach Root Segments

Abstract

To establish a plant-regenerating system through frequent somatic embryogenesis, a detailed investigation was undertaken on the effects of kinds, concentrations, and combinations of growth regulators on callus and somatic embryo formation from spinach root segments. Although no somatic embryogenesis occurred on the culture medium containing auxins alone, a low frequency of somatic embryo formation was shown on culture media containing auxins combined with natural cytokinins, namely 10 μM NAA with 10 μM zeatin, 30 μM NAA with 10 μM 2-iP, and 1μM 2.4-D with 0.1 μM zeatin or 10μM 2-iP. Somatic embryos also formed on culture madia containing auxins combined with GA₃. From 50 to 70% of the root segment differentiated somatic embryos on culture media containing 10 to 30 μM NAA combined with 1 to 100 μM GA₃. These results show that spinach somatic embryogenesis is most facilitated by NAA combined with GA₃.