The tuber is produced in one growing season and used to perennate the plant and as a means of propagation. When fall comes, the above-ground structure of the plant dies, but the tubers survive underground over winter until spring, when they regenerate new shoots that use the stored food in the tuber to grow. As the main shoot develops from the tuber, the base of the shoot close to the tuber produces adventitious roots and lateral buds on the shoot. The shoot also produces stolons that are long etiolated stems. The stolon elongates during long days with the presence of high auxins levels that prevent root growth off of the stolon. Before new tuber formation begins, the stolon must be a certain age. The enzyme lipoxygenase makes a hormone, jasmonic acid, which is involved in the control of potato tuber development.