Question

Plate meristem shows
A) Anticlinal divisions in two planes at a right angle to each other.
B) Anticlinal divisions in one plane.
C) Both periclinal and anticlinal divisions in one plane.
D) Three-dimensional divisions.

Answer 1

Hint: Plants are multicellular eukaryotes with tissue systems made up different cell types. The plant tissue system is of two types: Meristem tissue and permanent tissue. Internally again these tissues are divided into different types.

Complete answer:
The meristem is a type of tissue found in plants and it consists of undifferentiated cells called meristematic cells capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants and thus form various parts of the plant.

To answer this question, we must know about the Classification of meristem based on the plane of cell division. Meristem is composed of cells that are capable of division. They can develop into any part of the plant.
- Mass meristem
- Plate meristem
- Rib meristem

The cells of the mass meristem divide in all planes thus the tissue increases in volume and the derivative cells are isodiametric or spheroidal or have no definite shape.

The cells of the rib meristem divide at right angles to the longitudinal axis of the plant organ thus as a result parallel files of cells called ribs are produced.

The cells of the plate meristem divide by anticlinal division. Anticlinal division increases the number of cells in one layer only and this division causes the meristem to grow as a sheet but not in thickness. Therefore, Plate meristem is the characteristic of plant organs that have flatforms. As a result, a flat organ-like leaf is formed.

Thus, the correct answer is an option ‘A’ i.e, Anticlinal divisions in two planes at a right angle to each other.

Note: Plate and rib meristem are the two growth forms exhibited by ground meristem whereas plate meristem gives rise to the leaf-like organs and rib meristem forms the elongated cylindrical structures like root, stem and petiole etc.