Edexcel iGCSE Biology-6.17B-6.18B Micropropagation- Study Notes- New Syllabus
Edexcel iGCSE Biology-6.17B-6.18B Micropropagation- Study Notes- New syllabus
Edexcel iGCSE Biology-6.17B-6.18B Micropropagation- Study Notes -Edexcel iGCSE Biology – per latest Syllabus.
Key Concepts:
6.17B describe the process of micropropagation (tissue culture) in which explants are grown in vitro
6.18B understand how micropropagation can be used to produce commercial quantities of genetically identical plants with desirable characteristics
Micropropagation (Tissue Culture)
📌 Introduction
Micropropagation is a method of producing large numbers of identical plants from a small piece of plant tissue called an explant.
It is done in vitro (in glass or controlled conditions outside the parent plant).
Useful for rapid multiplication, disease-free plants, and conserving rare species.
🧩 Step-by-Step Process
- Selection of Explant
A small piece of plant tissue is chosen: leaf, stem, bud, or root tip.
Explant should be healthy and disease-free. - Sterilization
Explants are sterilized to remove microorganisms using:- Alcohol
- Bleach or other disinfectants
This ensures aseptic conditions during culture.
- Inoculation into Growth Medium
Explant is placed on sterile nutrient agar medium containing:- Minerals and nutrients
- Plant hormones (auxins and cytokinins) to stimulate growth
Medium supports cell division and differentiation.
- Callus Formation
Explant cells divide and form an undifferentiated mass called a callus. - Shoot and Root Formation
By adjusting plant hormones, callus differentiates into:- Shoots (cytokinins dominant)
- Roots (auxins dominant)
- Transfer to Soil
Plantlets are hardened (gradually adapted to natural conditions) and then planted in soil.
These are now genetically identical clones of the parent plant.
⚡ Advantages
- Produces large numbers of identical plants quickly.
- Ensures disease-free plants.
- Can propagate rare or endangered species.
- Reduces space needed compared to traditional propagation.
⚡ Quick Recap
Micropropagation = in vitro cloning of plants
Steps: Explant → Sterilization → Nutrient medium → Callus → Shoots/roots → Soil
Uses: mass production, disease-free, rare plant conservation
Key hormones: Cytokinins → shoots, Auxins → roots
Micropropagation for Commercial Plant Production
📌 Introduction
Micropropagation is used not just for cloning, but also to produce large quantities of plants with desirable traits for commercial purposes.
Ensures genetically identical plants (clones) with consistent quality.
Useful in agriculture, horticulture, and forestry.
🧩 How Micropropagation Helps Commercial Production
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- Mass Production of Plants
From a single explant, thousands of plantlets can be produced in a short time.
Example: Orchids, bananas, and potatoes.
Reduces time and space compared to traditional methods. - Ensuring Desirable Traits
Only plants with high yield, disease resistance, or better fruit quality are cloned.
All offspring have exactly the same characteristics. - Producing Disease-Free Plants
Explants are sterilized and grown in controlled conditions, preventing disease spread.
Ensures healthy plants for commercial sales. - Conservation of Rare or High-Value Species
Micropropagation allows rapid multiplication of rare, endangered, or slow-growing plants.
Example: Rare orchids or medicinal plants. - Faster Market Supply
Shortens the time to produce large numbers of plants for planting or sale.
Farmers and companies can meet demand quickly.
⚡ Advantages
- Produces large quantities quickly
- Genetically identical plants → uniform quality
- Disease-free propagation
- Can propagate plants that do not produce seeds naturally
⚡ Quick Recap
Micropropagation = cloning in vitro
Commercial use: mass production, uniform quality, disease-free plants
Benefits: time-saving, high yield, rapid supply of plants with desirable traits
Examples: orchids, bananas, potatoes, medicinal plants