A number of interdisciplinary fields related to Plant Cell Biotechnology are discussed. The two main directions are: Plant cell culture in agricultural applications for the improvement of crops and industrial applications in the production of secondary metabolites. A number of areas such as physiological and biochemical aspects of autotrophic cells, gene characterization in higher plants, transformation of plant cells, genetic stability in plant cell cultures, somatic hybridization and somatic embryogenesis are treated. Recent knowledge on somaclonal and gametoclonal variation as well as on the obtainment of protoplasts and their use for the isolation and culture of heterocaryons as tools for plant breeding are considered. Furthermore, the