Clonal variability and light induction of betalain synthesis in red beet cell cultures

When calli from a green habituated cell culture of red beet (Beta vulgaris L.) are transfered from dim-light to high-light intensity, red colored spots appear on the surface. Not all cells express the pigmented phenotype, giving rise to variegated patches. The pattern of patch formation is different from one callus to another, although all calluses stem from the same original clone. This clonal variability is an intrinsic property of the tissue and is not affected by light which is only needed for the induction of pigment synthesis, and therefore acts as a revealing factor.