1. Introduction
Plant tissue culture depends on the ability of plant cells to divide, differentiate, and regenerate under controlled conditions. Unlike animal cells, many plant cells retain totipotency, meaning they can develop into entire plants when given the right conditions.
This lesson explores plant cell structures, totipotency, and cell division, providing the foundation for understanding how plants grow in vitro.
2. Structure and Function of Plant Cells
Plant cells have unique features that make tissue culture possible.
2.1 Major Components of a Plant Cell
| Organelle | Function |
|---|---|
| Cell Wall | Provides support & protection. |
| Plasma Membrane | Controls movement of molecules in & out. |
| Cytoplasm | Contains essential organelles. |
| Nucleus | Stores genetic material (DNA) & directs growth. |
| Vacuole | Stores water, nutrients, & maintains cell pressure. |
| Chloroplasts | Perform photosynthesis (not always needed in vitro). |
📌 Further Reading: Plant Cell Structure & Function
3. Totipotency: The Foundation of Tissue Culture
Totipotency refers to a plant cell’s ability to regenerate into a complete plant.
3.1 Historical Perspective
- Introduced by Gottlieb Haberlandt (1902).
- Proved that individual cells contain all genetic instructions to form a new plant.
3.2 Role in Tissue Culture
- Allows propagation from small tissue samples (explants).
- Enables the creation of genetically identical clones.
- Requires plant hormones to stimulate root & shoot formation.
📌 Further Reading: Totipotency in Plant Cells
4. How Plant Cells Grow and Divide
Successful plant tissue culture relies on cell division and differentiation.
4.1 Mitosis – Cell Division for Growth
- Cells divide identically to create more cells.
- Essential for callus formation and shoot induction.
4.2 Callus Formation
- Callus = a mass of undifferentiated plant cells.
- Can be triggered using auxins and cytokinins.
4.3 Differentiation into Plant Organs
- Under the right conditions, cells differentiate into shoots, roots, or embryos.
- Controlled by plant growth regulators (PGRs).
📌 Further Reading: Mitosis and Cell Differentiation in Plants
5. Factors Affecting Cell Growth in Tissue Culture
Successful plant regeneration depends on:
- Nutrient Medium (MS Medium)
- Provides macronutrients, micronutrients, and vitamins.
- Plant Growth Regulators (PGRs)
- Auxins (IAA, IBA) → Promote root development.
- Cytokinins (BAP, Kinetin) → Promote shoot multiplication.
- Environmental Conditions
- Light: Affects photosynthesis and development.
- Temperature: Must be optimized for cell growth.
- pH Balance: Controls nutrient availability.
📌 Further Reading: Factors Affecting Plant Cell Growth