Plant Tissues — Question 3

The Conducting tissue has two elements:

1. Xylem — Xylem is the water-conducting tissue of plants. It is composed of vessels, tracheids, fibres and xylem parenchyma.
   1. A xylem vessel is not one cell but a series of cells joined from end to end to form a long tube.
   2. Tracheids are usually long and narrow cells that taper at the ends. Both tracheids and vessels do not have living protoplasm at maturity. They are involved in the transportation of water from the roots to the upper parts of the plant.
   3. Fibres provide strength to the tissue. They also lack living protoplasm at maturity.
   4. Xylem parenchyma is the only living component of xylem. It helps in the conduction of water and also stores food.

The below diagram shows the lateral section of Xylem tissue:

2. Phloem — Phloem is the food-conducting tissue of plants. It is composed of different types of cells namely, sieve cells, phloem fibres and phloem parenchyma. It consists of living cells with protoplasm in them.
   1. Sieve cells are elongated cells with minute pores. They do not have a nucleus at maturity. They help in the transportation of food prepared in the leaves to other parts of the plant.
   2. Phloem fibres provide mechanical strength to the plant.
   3. Phloem parenchyma cells are involved in the storage of reserve substances. Certain specialized parenchyma cells, closely associated with sieve cells are known as companion cells.

The below diagram shows the lateral section of Phloem tissue: