STOMATAL GUARD-CELLS ARE TOTIPOTENT

It has been successfully demonstrated, using epidermis explants of sug ar beet (Beta vulgaris L.), that stomatal guard cells retain full toti potent capacity. Despite having one of the highest degrees of morpholo gical adaptation and a unique physiological specialization, it is poss ible to induce a re-expression of full (embryogenic) genetic potential in these cells in situ by reversing their highly differentiated natur e to produce regenerated plants via a callus stage. The importance of these findings both to stomatal research and to our understanding of c ytodifferentiation in plants is discussed.