False-colour scanning electron micrograph of starch grains, or amyloplasts (large dark bodies, 4-6 per cell), in cells of a cotyledon (seed leaf) of a mature Jack bean, Canavalia ensiformis. Bean cotyledons are storage organs in the seed contain- ing reserves of starch, from which the germinating seed draws nourishment. Beans (legumes) are a source of protein in the human diet. The protein is stored in small vacuoles called protein bodies