Question

Give reasons.
Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole.

Answer 1

Meristem is a type of tissue that is found in plants. It consists of undifferentiated meristematic cells capable of cell division.

Complete answer:
Plant growth happens only in particular areas. This is because the dividing tissue, also known as meristematic tissue, is found only at these locations.

In a plant, we can see three types of meristematic tissues: apical meristem, intercalary meristem and lateral meristem. Apical meristem is found in the tips of roots and shoots. Intercalary meristem is located at the leaf blades and base of nods in stems. Lateral meristem is found in the woody part of the plants. They are cylindrical meristems.

Since meristematic tissue cells are very active, they have thick cytoplasm, thin cellulose walls, and prominent nucleus. Vacuoles are full of cell sap in plant cells and provide the cell with turgidity and stiffness. Meristematic cells are therefore deficient in vacuoles since they are actively dividing the cells. Initially, the new cells formed by the meristem resemble the meristem itself, but as they develop and mature, their characteristics steadily change and differentiate into components of other tissues. After cell divisions in the meristems, the newly formed cells become specialised in structure and function and lose the capacity to differentiate. These cells are called permanent or mature cells which form permanent tissues.

Note: Meristematic tissue cells divide to form various forms of permanent tissue. During the development of the primary plant body, apical meristem regions develop dermal tissues, ground tissues and vascular tissues.