Potato crops are normally planted using small whole tubers or portions of the tuber. These whole or partial tubers are referred to as seed, although they do not resemble true botanical seed. A potato as it is used in commerce is botanically a tuber. The tuber is an enlarged stolon, which is an underground stem. The dormancy and sprouting processes of potato tubers need to be understood in order to manage production practices such as seed storage, planting, and sprout inhibition for marketing or long-term storage of fresh or processing potatoes. Stolons are underground stems that develop first at the basal nodes of the stem and then develop progressively upward. The developing stolons can be converted to leafy shoots by exposure to light. Tuberization of potato plants is promoted by relatively low night temperatures, short days, or stress conditions such as low or interrupted fertilizer supply.