A process for producing multicellular plants, plant organs or plant tissues transformed on their plastome by the following steps is provided: (a) altering or disrupting the function of a gene in a plastid genome for producing a selectable or recognizable phenotype; (b) separating or selecting plants or cells having plastids expressing said phenotype; (c) transforming said plastid genome of said separated or selected plant, plant organ or plant tissue with at least one transformation vector having a restoring sequence capable of restoring said function; and (d) separating or selecting said transformed plant, plant organ or plant tissue having plastids expressing said restored function.