Abstract: A carbon-based process for the selection of heterotrophically cultured plant cells is contemplated as are plants transformed using that process and a kit useful for effecting such a transformation. Plant cells are transformed with a heterologous DNA segment that contains two expression cassettes. The first cassette contains a gene that encodes a heterologous enzyme that on expression converts a growth-limiting (encrypted) carbon source that does not support growth and proliferation of non-transformed plant cells into a carbon source that supports growth and proliferation of transformed plant cells. The second cassette contains a second gene to be expressed in the transformed plant cells. A mixture transformed and non-transformed plant cells is cultured under heterotrophic culture conditions with the growth-limiting carbon source as the only carbon source.