Question

Root hair helps in better absorption of air and water
A) It increases the surface area for absorption
B) It helps in growth and development
C) It increases the rate of flowering in plants.
D) All of the above

Answer 1

Hint: Root hair plays a vital role between plants and soil to absorb minerals and water. Root hair is also known as absorbent hair. They are long in size so that they can prevent the entry of harmful bacterial organisms into the plant through xylem vessels.

Complete answer: Root hair is the rhizoid of a vascular plant which is a tubular outgrowth of the trichoblast. These are mainly single-celled or rarely branched. These are only found in the maturation region of the root. In root hairs, another adaptation is the large permanent vacuole. Plants absorb water from the soil by osmosis with the help of root hairs. A root hair is long so that they can interact between the soil and the plant. Root hair has a small diameter (5-17micrometers) and of greater length (80-1500 micrometre), so root hair has a large surface area for the absorption of water. Water is found in the space between soil particles. Water first enters the cell wall and the cell membrane of root hair through the process of osmosis. Water fills and stores in the vacuole of the root hair. It increases the surface area for the absorption of water.
Hence, the correct answer is option A.

Note: Root hair grows quickly, i.e. the rate of the growth is one micrometre per minute. It also helps in the formation of root nodules in legume plants. Root hair secretes acid (malic acid) which is used for taking minerals in ionic forms from the soil. Root hair can survive for 2 to 3 weeks after they die and immediately new root hair is formed by root tip.