Xylem and Phloem - Part 2 - Transpiration - Transport in Plants

Transpiration is the evaporation of water from the aerial parts of a plant (so the leaves and stems). By water evaporating out of these parts - mostly the leaves, a suction pressure is created which draws water up through the plant. This is called the transpiration pull. Water passes in from the soil by osmosis, passing down the concentration gradient, and into the root hair cell’s cytoplasm, and then on to the xylem vessels. Water moves through the xylem vessels from the root to the stem to the leaf. As well as the leaf cells needing water for photosynthesis, water also keeps the cells turgid which supports the plant. Inside the leaves, water is drawn out of the xylem cells to replace the water lost through transpiration.