02. Stems

Stems do two things. First, they hold up the plant, lifting the leaves toward the sun. Second, they act as a nutrient throughway: Stems contain the veins through which nutrients stored in the root move up to the leaves, fruits, and flowers, and through which sugars manufactured in the leaves descend back down for storage in the roots. To perform these functions, stems are structured a lot like roots. They have rigid support fibers interspersed with hollow veins, but unlike roots, stem fibers are not tough enough to do the job alone. They must be helped by a steady flow of fluid in the veins in order to have the snap (a brief resistance followed by a burst of juice) that indicates quality in a stem vegetable. If the vascular tissue dehydrates, the stem will lose its crispness, and the vegetable will become limp.