Somatic Embryogenesis
It has been demonstrated that embryo development is not the monopoly of egg cell and that any cell of the embryo sac or any other part of the sporophyte may give rise to an embryo. However, embryos can not develop outside the ovules, although in several species (Citrus, Mangifera), adventive embryos (embryos developing from sporophytic tissue) may develop from nucellar cells or integuments of the ovule, outside the embryo sac.

These embryos, however, mature, only when Pushed into the embryo sac, suggesting that embryo sac should have a special environment, which facilitates the development of embryo and the same should be made available in culture if somatic embryogenesis needs to be induced.

Somatic embryogenesis in culture was demonstrated for the time in carrots (Daucus carota), where bipolar embryos developed from single cells. Further, tissue derived from these somatic embryos spontaneously developed into embryos again. However, somatic embryogenesis is influenced by plant extracts, growth regulators and by the physiological state of calli. For instance, 2, 4-D in the medium is least conducive for embryogenesis in plants like cabbage or carrot.

Embryogenesis is easy in suspension cultures, which are derived from explants grown on auxin containing medium. On the other hand, cytokinins and gibberellins caused a partial or complete inhibition of growth of the potential embryonic cells. It has also have shown that nitrogen supplied in the form of NH₄⁺ ions or as casein hydrolysates (rather than as nitrate), stimulates somatic embryogenesis.