Shoots are generally separated every four weeks and transferred onto a fresh proliferation medium. Induction of the root system on indivifual shoot may be induced on appropriate medium. The meristem is a dome of activelly dividing cells, about 0.1 mm in diameter. Endogeneous contaminants do not easily invade in the meristem, often resulting in the formation of a disease-free plant. When combined with micropropagation techniques, large numbers of disease-free plants may be produced from meristematic explants.
Somatic embryo occurs either directly on the explant or more often in callus culture.
There are several advantages of recovery of plants from cells via somatic embryogenesis compared to micropropagation. Somatic embryos can be produced from cells growing in suspension, thereby making possible batch culture techniques which can be scaled-up with minimum handlings costs. The multiplication rate is very high and, in some species like carrot, celery or tomato, the embryos can be encapsulated and treated as an artificial seeds. Whole plants develop from the somatic embryos and only require growth to maturity. When organogenesis occurs, shoots or roots develop and the induction of the complementary structures frequently requires different culture media formulations.