Proteolytic activity within the starchy endosperm results in the production of amino acids, dipeptides, and a number of small oligopeptides. These soluble products are rapidly absorbed by the embryo, via the scutellum. Although this uptake of peptides does not appear to involve or require their hydrolysis, they are eventually cleaved by peptidases within the scutellum, and only free amino acids accumulate to any extent in the growing embryo. Active, i.e., energy-dependent, uptake mechanisms within the scutellum can distinguish between peptides and amino acids. Several uptake systems have been identified in cereal grain scutella In those of wheat and barley there are at least four systems for amino acids alone: two nonspecific amino acid systems, one specific for proline, and another specific for basic amino acids. Maize and rice also possess multiple uptake systems, but with some differences in specificity. The efficiency with which scutella take up certain