in botany, the repeated use by a plant of the mineral substances absorbed by the roots. The substances in the plant are constantly being redistributed, moving from organs whose growth is completed to young organs, where they are assimilated again. The reutilization of mineral substances stored in the leaves is particularly intense during fruit and seed ripening. Toward autumn the mineral substances in perennial deciduous plants move from the leaves to the stems and roots; in the spring these substances make possible the growth of the young shoots.

The ability of a plant to reutilize an element is detected by excluding one of the elements from the nutrient mixture. The oldest leaves are harmed first if there is a deficiency of nitrogen, phosphorous, potassium, or magnesium—which are highly capable of being reutilized. A deficiency of calcium, boron, iron, sulfur, or manganese—which are hardly reutilized at all—harms newly forming young organs.