A microscopic examination of starch depletion in tubers of cv. Maris Piper during sprouting

Summary Optical microscopy of starch distribution in sprouting tubers showed certain tissue types to be devoid of starch even before the onset of starch breakdown (Figs 2 and 3). These included the periderm, vascular ring and phloem bundles. Cortical cells contained less starch than adjacent cells in the outer parenchyma. Similarly, cells in areas occupied by pith contained less starch than adjacent cells in the perimedulla. With the onset of reserve mobilization there was a general decrease in starch in all tissue types, and the zones of depletion in parenchymatous tissue around the vascular ring and phloem bundles became more extensive. Cells in the outer parenchyma were the last to lose their starch.