Question

Explain how plants get water from soil through their root hairs.

Answer 1

Hint: When the epidermis differentiates, root hairs appear. The epidermis has root hair cells that are advanced cells. Due to their presumed significance as absorbing surfaces, much focus has been paid to root hairs. Typically, the epidermis consists of relatively thin-walled, elongated cells that form a compact layer covering the young roots' exterior.

Complete answer:
The flow of water from the root hairs to the cortical cells and then eventually to the xylem vessels is responsible for osmotic pressure. It is the force needed to resist water's movement down the concentration gradient through a semipermeable membrane. In the gaps between the soil particles, there are water molecules present. For the plants, this water is available. The first water and root hair cell contact is due to water imbibition. This is the adsorption method for water.
By osmosis, the water then reaches the cells of the root hair. The water movement is due to the osmotic pressure differential. The water's osmotic pressure in the roots is strong and so the water reaches the cells of the root hair. The water is transferred by osmosis to the other cells in the root area. The flow of water to the cortical cells is through the root hairs and then to the endodermis layer through the osmosis phase down the concentration gradient. Mostly through apoplast pathway, the water reaches the cortex and then crosses endodermis by symplast to reach xylem vessels.

Note: When they mature, the roots of woody plants develop bark, much like the trunks of large trees. While bark formation reduces the permeability of the older roots, substantial quantities of water can still be absorbed. Roots have the remarkable ability to grow away from dry areas into wetter soil patches, a phenomenon called hydrotropism.