ADVERTISEMENTS:
In this article we will discuss about the classification of meristem based on the plane of cell division.
Mass meristem, plate meristem and rib meristem belong to this category.
Mass meristem (or block meristem):
ADVERTISEMENTS:
Ex. young embryos, endosperm, reproductive organs during the formation of spores and sperms etc. The cells of this meristem divide in all planes thus the tissue increases in volume. The derivative cells are isodiametric or spheroidal or have no definite shape.
Rib meristem (or file meristem):
Ex. cortex and pith of root and cortex of stem. The cells of this meristem divide at right angles to the longitudinal axis of the plant organ. As a result parallel files of cells (= ribs) are produced. Rib meristem is the characteristic of organs that have cylindrical form.
Plate meristem:
ADVERTISEMENTS:
Ex. flat blades of angiosperm leaves. The cells of this meristem divide by anticlinal division. Anticlinal division increases the number of cells in one layer only. This division causes the meristem to grow as a sheet but not in thickness. Plate meristem is the characteristic of plant organs that have flat forms. As a result a flat organ like leaf is produced.
Plate and rib meristem are the two growth forms exhibited by ground meristem. Plate meristem gives rise to the leaf like organs and rib meristem forms the elongated cylindrical structures like root, stem and petiole etc.
