ABSTRACT
It is not more than 100 years ago that chemical synthesis started to replace plants as the major source of organic compounds for human use. Today, plants serve as an important source of secondary metabolites used in pharmacy, biotechnology and food technology. The first practical applications of in vitro techniques to plants occurred in the 1920s, with differentiated structures such as zygotic embryos. Efforts to grow dedifferentiated, isolated plant cells in vitro were unsuccessful until 1939 and it was the discovery of auxin in 1930 that finally led to success in achieving the production of continuously growing plant cell cultures.
