Difference Between Micropropagation and Tissue Culture

The main difference between micropropagation and tissue culture is that the micropropagation is the production of a large number of plants from a small plant material whereas tissue culture is the initial step of micropropagation where plant cells are grown in an artificial medium, developing them into a large number of plantlets. Furthermore, micropropagation requires tissue culture for the multiplication of plantlets.

Micropropagation and tissue culture are two types of techniques involved in the production of a large number of identical plants.

Key Areas Covered

1. What is Micropropagation
     – Definition, Steps, Advantages
2. What is Tissue Culture
     – Definition, Types, Steps
3. What are the Similarities Between Micropropagation and Tissue Culture
     – Outline of Common Features
4. What is the Difference Between Micropropagation and Tissue Culture
     – Comparison of Key Differences

Key Terms

Explant, Meristem, Micropropagation, Tissue Culture, Vegetative Propagation

What is Micropropagation

Micropropagation is an in vitro technique of tissue culture in which high-quality, clone plants are developed in large scale. In micropropagation, the apex of the shoot is grown in a nutrient agar medium under the influence of plant hormones. The shoot apex consists of undifferentiated meristematic tissue, which has indeterminate growth. The two main stages of micropropagation are tissue culture and the introduction of new plants to the soil.

Figure 1: Banana Plantlets Transferred to Soil

The three main benefits of micropropagation are:

1. Bulking up new plants – Micropropagation allows the production of a large number of clonal plants by means of tissue culture. Other vegetative propagation methods can generate only a few plants at a time.
2. Production of disease-free plants – Micropropagation uses the meristem, which cannot be infected by plant viruses in general. Typically, plant viruses spread through vascular tissue, which is not connected to the meristem.
3. Propagation of rare species – Micropropagation can be used in the propagation of rare and endangered plants as well as plants with difficulties in seed germination and seed dormancy.

What is Tissue Culture

Tissue culture is the technique in which a small fragment of a plant (explant) is introduced into an artificial, nutrient medium, which allows its functioning or growth. There are several types of tissue culture methods based on the type of plant material used. Some of the include seed culture, embryo culture, callus culture, organ culture, and protoplast culture.

1. Seed culture – It is used for the plants that face difficulties in seed germination such as Orchids. Seeds are cultured to generate seedlings under ascetic conditions.
2. Embryo culture – Both mature and immature embryos can be cultured in order to obtain seedlings. This method eliminates the seed dormancy due to various structures of the seed such as chemical inhibitors or the structures that over covers the embryo.
3. Callus culture – Callus is an undifferentiated mass of cells generated when the explant is cultured in a tissue culture medium. The cells of a callus can develop into shoot primordial or somatic embryo.
   

   Figure 2: Callus

4. Organ culture – Plant organs such as shoots, roots, leaves or flowers can be used as the explant to preserve the structures or their function.
5. Protoplast culture – Protoplasts are the cells without a cell wall generated mainly for the production of transgenic plants. Once these cells regenerate their cell walls, they become callus.

The three main steps of plant tissue culture are:

1. Initial phase – The introduction of an explant to the tissue culture medium under sterile conditions.
2. Multiplication phase – Re-division of the explant in the tissue culture medium, producing multiple shoots. This step can be repeated for several times in order to obtain a large number of plantlets.
   

   Figure 3: Physcomitrella patens Plants on an Agar Plate

3. Root formation – Induction of the formation of roots by introducing plant hormones to the tissue culture medium.

Similarities Between Micropropagation and Tissue Culture

• Micropropagation and tissue culture are two types of techniques involved in the production of a large number of genetically-identical plants.
• They are methods of vegetative propagation.
• Both are involved in the growth of plant cells into plantlets in a nutrient medium.

Difference Between Micropropagation and Tissue Culture

Definition

Micropropagation refers to the propagation of plants by growing plantlets in tissue culture and then planting them out while tissue culture refers to the technique of maintaining and growing plant cells, tissues or organs especially on artificial medium in suitable containers under controlled environmental conditions.

Steps

The two steps of micropropagation are tissue culture and the introduction of new plants to the soil while the three steps of tissue culture are the explant introduction to the tissue culture medium, multiplication, and induction of the formation of roots.

Importance

While micropropagation can be used to produce a large number of clonal plants, tissue culture also allows transgenic studies that produce new plant strains.

Conclusion

Micropropagation is a practical aspect of tissue culture in which a large number of clonal plants are produced. It can also produce clones of the rare plants or the plants with difficulties in undergoing sexual reproduction. On the other hand, tissue culture is a technique used by micropropagation to produce new plantlets from a small piece of explant. The main difference between micropropagation and tissue culture is their purpose.

Reference:

1. Cornell, Brent. “Micropropagation.” BioNinja, Available Here
2. Anderson, Hayley. “Tissue Culture – Types, Techniques and Process.” MicroscopeMaster, Available Here

Image Courtesy:

1. “Banana plantlets transferred to soil (with vermicompost) from plant media” By Joydeep – Own work (CC BY-SA 3.0) via Commons Wikimedia    
2. “Callus1” By Igge – Own work (CC BY-SA 3.0) Available Here    
3. “Physcomitrella growing on agar plates” Von Sabisteb – Anja Martin from the Ralf Reski lab (CC BY-SA 1.0) Available Here