Plant stems are multitaskers: they support the growth of leaves and buds and serve as transportation routes for water, food and minerals. Plant stems are among the most recognizable physical features of plants; they also hold leaves, buds and flowers upright and keep them from toppling over in heavy winds and rain. Although stems do not appear at first glance to be doing much of anything, plenty of activity takes place beneath their surfaces.
Stems contain three main structural components: xylem, cambium and phloem. The phloem and xylem are primary components of plants' vascular systems and play leading roles in enabling the movement of minerals and nutrients to all areas of the plant. Plant stems function much like highways. They contain wide, straight tunnels and tubes that enable the rapid movement of essential fluids and foods throughout the plant. At all hours of the day and night, the vascular systems of stems are crawling with activity. Xylem vessels secrete fluids that facilitate the movement of water and minerals while food is digested and transported through the phloem. The last stem component, which is the cambium, is also a hotspot for activity. In this region, critical cell division takes place, which signals the plant to keep growing.