Starch grains in raw potato cells, animated coloured scanning electron micrograph (SEM). A slice through a raw potato tuber (Solanum tuberosum) showing starch grains within the cellulose cell wall compartments. The stored starch grains are called amyloplasts. Starch is the predominant form of carbohydrate found in potatoes. Starch is synthesized from sucrose, a sugar formed in the leaves during photosynthesis & transported to the tuber (potato) via the phloem (vascular tissue). It is used as a store of energy for the later development of buds on the surface of the potato. Starch grains are can be larger than most plant cells (up to 50 microns across). All plant seeds and tubers contain starch that is predominantly present as amylose and amylopectin. Starch is an important food resource for humans and is cultivated as a crop.