Apical Meristem: Meaning and Function

The apical meristem is a group of cells that can divide and help in primary growth. These cells are found at the tips of growing roots and shoots. The apical meristems create the main parts of the plant and make the roots and shoots longer. The apical meristem is located at the root tip, shoot tip, and the tip of the leaves. The meristematic cell can transform into various cell types.

Meristem is the tissue found in the plant’s growth region. The term “apical” indicates that growth occurs at both the top and bottom of the plant. An intercalary meristem is situated between branches and a lateral meristem contributes to the plant’s width, particularly in woody plants.

What is Apical Meristem?

The apical meristem is a group of cells that can divide and grow a lot. Due to this growing property they are present at growing roots and shoot tips. The meristematic cells are generally small and nearly spherical, featuring dense cytoplasm and few vacuoles. The apical meristem goes through partial differentiation to give rise to primary meristems, which include the protoderm, ground meristem, and procambium.

Where Apical Meristem Can be Found?

The apical meristem is situated just below the root cap in the roots, consisting of a group of closely packed cells that have not yet specialized. These cells serve as the source for various cell structures required by the plant. An undifferentiated apical meristem cell continuously divides and gradually transforms into a specialized cell. The meristematic cells are generally small, nearly spherical, with dense cytoplasm and relatively fewer vacuoles.

Structure of Apical Meristem

The apical meristem is situated just below the root cap in the roots, consisting of a group of closely packed cells that have not yet specialized. These cells serve as the source for various cell structures required by the plant. An undifferentiated apical meristem cell continuously divides and gradually transforms into a specialized cell. The meristematic cells are generally small, nearly spherical, with dense cytoplasm and relatively fewer vacuoles.

Types of Apical Meristem

Several plants have two apical meristems: Root meristem and shoot meristem.

• Root Meristem: The meristem present in the root tip and tip of the leaves of the plant is known as the root apical meristem. It shows upward as well as downward movement.
• Shoot Meristem: The meristem present at the plant’s tips, known as the shoot apical meristem. The shoot apical meristem is situated at the ends of plants and shows only an upward direction.

Difference between root apical meristem and shoot apical meristem are shown below:

Type of apical meristem	Root apical meristem	Shoot apical meristem
Directions	Two directions.	Only one direction.
Location	At the tip of plants (dicots) or leaves (monocots).	At root tip.

Regulation of Apical Meristem

The process of cell diversification in the apical meristem is intricate and controlled by several genes, which play an essential role in shaping and structuring plants. As the apical meristem grows, it gives rise to smaller meristem locations, eventually developing into branches of the stems and roots. The timing and quantity of these branching events are regulated by a series of genes in plants. The diverse expressions of these genes result in various plant forms, contributing to the millions of different species seen today. The root apical meristem is integral for root development, with deep and focused roots, like taproots in many weeds, or more dispersed and fibrous root systems, as seen in corn and bamboo.

Functions of Apical Meristems

The apical meristem, positioned just below the surface of the outermost branches and roots, continually undergoes division. Some cells divide to produce more meristematic cells, while others divide and specialize into structural or vascular cells. Most plants have two apical meristem locations.

Shoot Apical Meristem

This meristem is found at the tips of plants and has the following responsibilities:

• Shoot growth.
• Phototropism (growth towards sunlight).

Root Apical Meristem

This meristem is located at the tips of roots and has the following functions:

• Sensing the soil conditions around the root.
• Hydrotropism (growth towards water).
• Protects root cap.

Conclusion

The apical meristem is a crucial group of cells situated at the tips of growing roots and shoots in plants. Found in the tips of roots, shoots, and leaves, it’s one of three types of tissues capable of transforming into different cell types. This meristem plays a vital role in plant growth, shaping the main body structure, and promoting the extension of roots and shoots. In summary, the apical meristem is a key contributor to plant growth, differentiation, and adaptation to environmental conditions.

FAQs on Apical Meristem

1. What are the three Apical Meristems?

Meristem is a plant tissue present in growth regions. There are three types of meristems: Apical meristems are present at the top and bottom of the plant. Intercalary meristem is present between branches. Lateral meristem is present on the lateral sides of the stem that grow wider, like in woody plants.

2. Where is Apical Meristem found?

Most plants have two apical meristems: root apical meristem and shoot apical meristem. The shoot apical meristem is situated at the tips of plants. The root apical meristem is present at the tips of roots.

3. What are the two functions of Apical Meristem?

The apical meristem is important for plants to grow, reach out for nutrients and water with their roots, and get sunlight with their leaves.

4. What is an example of Apical Meristem?

The example of apical meristems are as follows: root apex and shoot apex.

5. What is the Apical Meristem of a flowering plant?

The meristem that is responsible for growth of flowers is the shoot apical meristem and it generates the floral organ in predetermined positions is known as apical meristem in flowering plants.