Maturation

Maturation is the terminal event of embryogenesis. In zygotic embryogenesis, maturation is characterized by attainment of mature embryo morphology, accumulation of storage carbohydrates, lipids and proteins, reduction in water content and a gradual decline or cessation of metabolism. Somatic embryos usually do not mature properly. Instead, due to environmental factors such as keeping a constant contact with inducing medium, somatic embryos often deviate from the normal developmental pattern by bypassing embryo maturation producing callus, undergoing direct secondary embryogenesis and/or germinating precociously. Somatic embryos growing from proembryonal complexes tend to develop asynchronously so that several stages are present in culture at any given time.

Therefore, the most obvious developmental difference between zygotic and somatic embryos is perhaps that the latter lacks a quiescent resting phase.