ABSTRACT

The basic condition for somatic embryogenesis  through tissue culture was established by culturing the root segments of spinach (Spinacia Oleracea L.)seedlings. The explants efficiently produced embryogenic calli on a semi-solid medium containing half-strength of Murashige and Skoog’s (MS) inorganic salts, low concentrations of sugars and gibberellic acid together with auxin. The full composition of MS salts was rather toxic for the proliferation of embryogenic calli, and fructose proved to be preferentially utilized by the explants as a carbon source upon testing various concentrations and types of sugars included in the medium. The regeneration regime presented here required an exogenous supply of gibberellic acid; the addition of GA₃ seemed to be crucial not for development of embryo proper but for producing embrygenic calli. This technique was also applied to plant regeneration from the protoplasts of spinach. The calli derived from cotyledon protoplasts poorly produced somatic embryos but formed adventitious roots in abundance. These roots could produce many embryos by means of the methods for inducing embryos in the cultures of root explants from seedlings. The systems of somatic embryogenesis in spinach presented here would constitute an effective tool to understanding the somatic embryogenesis of plants.