MOVEMENT OF WATER IN THE ROOT
1. Water first enters the root hair cell by osmosis, as the water potential of the soil is much greater than that of the root hair cell. This is due to the solution of organic and inorganic ions in the cytoplasm and vacuole of the root hair cell, making the solute potential more negative.
2.The root hair cells also provide a large surface area for the uptake of water.
3.The water that is taken in moves across the cortex of the root via the apoplast pathway or the symplast pathway.
4. The root hair cell always has a greater water potential than the cell next to it, so water diffuses from cell to cell until it reaches the centre of the root.
5. At the centre of the root, the vascular tissue is surrounded by a region called the pericycle. The pericycle is surrounded by a layer of cells called the endodermis, which have cell walls lined with suberin, forming the Casparian strip. The Casparian strip in impenetrable.
6. In order for water to enter the xylem, the water in the apoplast pathway is forced into the cytoplasm.
7. The water then diffuses into the base of the xylem by osmosis from the endodermal cells, down a water potential gradient.…