2. Artificial Cloning In Plants

Question 1

Many plant cells are totipotent
What does this mean?

Answer 1

They can differentiate into all of the different types of cells in the plant

Scientists have developed ways of using this property to produce huge numbers of identical clones from one desirable plant

Question 2

What is micropropagation?

Answer 2

The process of making large numbers of genetically identical offspring from a single parent plant using tissue culture techniques

Question 3

When is micropropagation used?

Answer 3

When the plant:
- doesn’t readily produce seeds
- doesn’t respond well to natural cloning
- is very rare
- genetically modified of selectively bred with difficulty
- is required to be pathogen free by growers- eg strawberries and bananas

Question 4

Give an example of how plants can be micropropogated

Answer 4

Take sample of tissue from plant you want to clone- usually meristem tissue from shoot tips, dissected in sterile conditions. This is called the explant

Sample is sterilised- immersing it in sterilising agents- EG bleach. Doesn’t need to be washed of= remain sterile

Explant placed in sterile culture medium containing balance of plant hormones which stimulate mitosis {including auxins). Cells proliferate= mass of identical cells known as callus

Callus divided, individual cells/clumps transferred to new culture medium containing diff mixture of hormones, atom development of genetically identical plantlets

Plantlets potted and grow

Question 5

What are the advantages of micropropagation?

Answer 5

Rapid production of large numbers of plants which have known genetic make-up= yield good crops

Culturing meristems= disease-free

Way of reliably increasing numbers of rare/endangered plant species which may be infertile or difficult to grow from seeds

Question 6

What are disadvantages of using micropropagation

Answer 6

Monoculture- many plants are genetically identical- susceptible to same diseases or changes in conditions

Expensive- requires skill

If source is infected with virus, all clones will also be infected

Question 7

How are bananas produced using micropropagation?

Answer 7

Initially inedible, mutation made them parthenocarpic (produce fruit without fertile seeds), making them good to eat but also making them infertile

Initially naturally cloned

Early 20th century- fungal panama disease wiped them out in major banana growing countries, none of the clones had any resistance
Different type of banana took over- also clones- being destroyed by black Sigatoka

New biotechnologies- genetic engineering and micropropagation= hope