Some Effects of Environment on the Development of Embryos from Cultured Free Cells

Populations of cultured cells from carrot root (Daucus carota) and water parsnip embryos (Sium suave) have been brought to, and maintained in, a proembryonic state. Aliquots of these stock cultures were inoculated into experimental cultures in which the composition of the medium was manipulated to induce growth and production of somatic embryos in large numbers. The effects of light and darkness and of total osmotic concentration of the medium were investigated. Growth in darkness and at relatively high solute concentrations, conditions compatible with those in ovular fluids, permits morphogenesis to occur and causes the resultant embryos to remain small. The effects of other conditions on the enlargement of shoots, roots, or hypocotyls are described. The effects of concentration of the medium on the first growth of free cells and on the later growth of cell clusters organized as proembryos are contrasted. The role of nitrogen supply in the development of green cotyledons is also emphasized. The investigation as reported contributes to knowledge of embryogenesis in cultured cells.