Somatic embryogenesis is the formation of embryos in tissue culture from vegetative tissue.

Somatic embryos are clones or copies of the mother plant, while zygotic embryos show diversity from the fusion of sexual gametes.

Photo showing an example of a somatic embryo.

Somatic embryos differ from sexually derived zygotic embryos in several significant ways.

Somatic embryos also lack seed parts, like the endosperm, seed coat and any fruit parts.

Photo pointing out a developing somatic embryo.

However, somatic embryos still go through the recognizable stages of embryogenesis and synthesis of storage reserves.

The somatic embryos to the right show typical dicot embryogenesis including globular, heart and cotyledon stages of development.

Photo identifying globular and cotyledon stages of development.

Stages of somatic embryogenesis.

  1. Induction
  2. Development
  3. Conversion
  4. Germination

Photo of somatic embryo developing in medium within a flask.

The induction stage usually requires 2,4-D.

Photo of somatic ebryo in the induction stage.

Micrograph of somatic ebryo cells in the induction stage.

The development stage is inhibited by 2,4-D and is often enhanced by ABA.

Photo of somatic ebryo in the development stage.

Micrograph of somatic ebryo in the development stage.

Somatic embryos often arise from epidermal cells.

Photo showing a picture of a somatic embryo arising from epidermal cells. An enlarged micrograph view of the somatic embryo is beside it.

Conversion prepares the embryo for germination and can be aided by desiccation.

Embryos in a petri dish during the conversion stage.

Eventually, mature somatic embryos will germinate and form seedlings that can be transferred to a greenhouse medium and grown into whole plants.

Close up photo of somatic embryos.

Photo of a seedling germinated from a somatic embryo.