Micropropagation

Question 1

Micropropagation:

Answer 1

• A technique for producing many identical plant clones from a single parent plant through a tissue culture.
• It is a type of asexual reproduction on a very large scale.

Question 2

Tissue culture:

Answer 2

• Involves growing plant tissues in a sterile medium enriched with hormones like auxins and cytokinins that stimulate cell division and growth.

Question 3

Steps in micropropagation:

Answer 3

1. Explant collection
2. Sterilisation
3. Culture
4. Development
5. Transfer

Question 4

Explant collection:

Answer 4

• Small tissue samples called explants are taken from a parent plant to start the micropropagation process.
• Explants are typically taken from the stem and root tips as they have meristem cells. -> from shoot tips and exial buds
• Meristem cells are totipotent so can differentiate into any type of plant cell.

Question 5

Sterilisation:

Answer 5

• The explant’s cells are sterilised to remove and inhibit the growth of contaminants such as bacteria and fungi.
• This reduces the risk of widespread infection and helps to produce healthier crops.

Question 6

Culture:

Answer 6

• The sterilised explant cells are then cultured on a nutrient-rich medium.
• The medium supplies minerals, sugars, vitamins, and growth hormones like auxins that support rapid cell division and growth.

Question 7

Development:

Answer 7

• The cells in each explant divide to form an undifferentiated mass of cells called a callus.
• The callus cells are transferred to a new medium with specific conditions to encourage shoot and root formation.
• This allows the callus cells to differentiate and develop into plantlets.

Question 8

Transfer:

Answer 8

• Fully formed plantlets, complete with shoots and roots, are moved to a growth medium like soil.
• There, they can develop into mature plants that are identical to the parent plant.

Question 9

Application of micropropagation:

Answer 9

• It enables the rapid and large-scale propagation of plants that naturally reproduce slowly or are rare or endangered.
• It is used for producing disease-free clones of crops and preserving valuable genetic resources.
• It allows the mass production of genetically modified plants, such as those engineered for herbicide resistance.
• It can be used to produce seedless plants or those that are difficult to cultivate from seeds.

Question 10

Advantages of micropropagation:

Answer 10

• Produces plants that are genetically identical so there is a reliable inheritance of traits, such as those that produce high yields
• Produces plants without seeds
• Produces naturally infertile plans
• Disease free plants
• Produces plants after GM
• Rare / endangered plants grown in seed banks
• It can be carried out at all times of the year
• It is more space-efficient compared to conventional propagation methods
• It rapidly produces of a large number of mature plants

Question 11

Disadvantages of micropropagation:

Answer 11

• All plants are genetically identical (monoculture) so crops are vulnerable to diseases and environmental changes
• It may unintentionally propagate undesirable traits
• It is expensive and requires skilled technicians, making it less feasible on a small scale
• Explants and plantlets are vulnerable to infection, increasing the risk of total crop loss
• If parent plant has a disease -> all parents have a disease
• Explants and plantlets vulnerable to infection by moulds

Question 12

why is micropropagation important?

Answer 12

• Limits on number of plants that can be replicated via natural cloning
• Use the fact that plants are totipotent

Question 13

When is micropropagation used?

Answer 13

• Doesn’t readily produce seeds
• Rare
• Has been GM or selectively bred with difficulty
• Required to be pathogen free by growers
• Can’t natural clone

Question 14

Sodium dichloroisocyanurate

Answer 14

Used to make protocol pathogen free / sterile without having to sterilise lab

Question 15

Callus:

Answer 15

Ball of cells produced by micropropagation

Question 16

What can sterilise?

Answer 16

• Ethanol
• Bleach
• Sodium dichloroisocyanurate

Question 17

Why use aseptic techniques?

Answer 17

Prevent contamination by microorganisms