Summary
Highlights
Plants require water for photosynthesis, and they absorb it through their roots. The water in the soil contains various nutrients that are absorbed along with the water. The primary site for water absorption is the root hairs, which account for about 95% of water uptake. Areas with a high concentration of root hairs are called root hair zones, where water absorption is maximal.
Two tissues are responsible for conduction in roots: xylem and phloem. Xylem conducts water throughout the plant, while phloem conducts food. In the root, the central red-colored portion represents the xylem, and the surrounding yellow portion is the phloem. Xylem transports water to the plant for photosynthesis.
Water absorption in plants occurs through two main methods: active absorption and passive absorption. Active absorption requires the plant to expend energy (ATP) to absorb water, typically when water moves from a lower concentration to a higher concentration area. Passive absorption does not require energy, as water moves from a higher concentration to a lower concentration, similar to diffusion.
Water moves within the plant cells via two pathways: apoplast and symplast. In the apoplast pathway, water travels through the cell walls and intercellular spaces (cell wall to cell wall movement) without entering the cytoplasm. In the symplast pathway, water moves from cell to cell through the cytoplasm and plasmodesmata, filling one cell before moving to the next through cytoplasmic connections.