PLANT BIOTECHNOLOGY IS FOUNDED ON THE DEMONSTRATED TOTIPOTENCY OF PLANT CELLS

combined with the delivery, stable integration, and expression of transgenes in plant cells, the regeneration of transformed plants, and the Mendelian transmission of transgenes to the progeny. The concept of totipotency itself is inherent in the Cell Theory of Schleiden (1838) and Schwann (1839), which forms the basis of modern biology by recognizing the cell as the primary unit of all living organisms. The Cell Theory received much impetus from the famous aphorism of Virchow (1858), “Omnis cellula a cellula” (All cells arise from cells), and by the very prescient observation of Vöchting (1878) that the whole plant body can be built up from ever so small fragments of plant organs. However, no sustained attempts were made to test the validity of these observations until the beginning of the 20th century because the required technologies did not exist and the nutritional requirements of cultured cells were not fully understood (see Gautheret 1985). Haberlandt (1902) was the first to conduct experiments designed to demonstrate totipotency of plant cells by culturing isolated leaf cells in diluted Knop’s (1865) nutrient solution. He failed largely because of the poor choice of experimental materials (even now, more than 100 years later, there are only rare instances where intact leaf cells have been cultured successfully), inadequate nutrients, and infection (see Vasil and Vasil 1972). Nevertheless, he boldly predicted that it should be possible to generate artificial embryos (somatic embryos) from vegetative cells, which encouraged subsequent attempts to regenerate whole plants from cultured cells.
The following pages provide a short history of the evolution of a variety of ideas and technologies that are now routinely used for the genetic improvement of plants, and celebrate the many pioneering men and women who played key roles in the development of plant biotechnology. It does not include the history of plant tissue culture, which can be found elsewhere (White 1943; Gautheret 1985), and the use of plant cell cultures or transgenic plants for the production of pharmaceuticals, vaccines, etc., as these subjects are covered adequately elsewhere in this volume.
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