Structural aspects of the regulation of starch accumulation in stem pith explants of kale

Anatomical aspects were studied of starch deposition in primary explants of stem pith of marrow-stem kale. During cultivation on semisolid media containing glucose and growth substances starch is accumulated in the inner part of the explant but absent on its periphery. The starch localization pattern formed within originally quite homogeneous tissue seems to be caused both by gradients of substances absorbed from culture medium and by physiological gradients manifested in the explanted tissue. Strange enlarged grains were abundant in cells with high starch content.