Botany lecture notes

Apical Meristem in Shoot: Structure and Organization


Shoot Apical Meristem
Apical Organization of Shoot Meristem

Apical meristem

Ø  Apical meristem is a patch of meristematic tissue present in the apex (tips) of shoot and roots in plants.  

Shoot apex:

Ø  Shoot apex is the growing tip of the stem.

Ø  It is an undifferentiated region with meristematic cells.

Ø  From this region the plant growth proceeds.

Ø  The shoot apex also produces lateral organs such as leaves, branches and flowers.

Ø  Below the apical meristem, different tissue zones are progressively differentiated.


Tissue zones in the shoot apex

Ø  Three main tissue zones are present on the shoot apex of plants, they are:

$.  Protoderm: Protoderm gives rise to the epidermis of the plant.

$.   Procambium: Procambium gives rise to primary vascular tissue (xylem & phloem).

$.   Ground meristem (fundamental meristem): The ground meristem gives rise endodermis, pericycle, cortex, medulla and pith.

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Botany lecture notes

What are the Characteristics of Meristems & Meristematic Cells?

Mitosis (261 14) Pressed; root meristem of onion (cells in prophase, anaphase)

Meristematic Cells of Root Apex Showing Cell Division (source wikipedia)

What are Meristems?

Meristem is a group of plant cells that remain in a continuous state of division. It is a tissue system in plants called meristematic tissue. The term meristem was proposed by Karl Nägeli from a Greek word ‘merizein’ which means ‘to divide’. The meristem composed of rapidly dividing undifferentiated mass of cells. Meristems are usually found in the growing region of plant organs such as shoot apex and root apex. Usually meristem originates from the embryonic cells.

The primary function of meristem is to assist in plant growth and development. Meristematic cells are characteristically different from other differentiated cells in terms of many aspects. This post describes the characteristic features of meristematic cells in plants.

What are Characteristics of Meristems / Meristematic Tissues?

§.  Meristem composed of rapidly dividing cells

§.  Usually situated at the growing apex of plant parts (root apex or shoot apex)

§.  Meristematic cells are undifferentiated

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