Artificial Plant Cloning: Microprop

Question 1

Why do we use micropropagation ( artificial )

Answer 1

1) when desirable plant doesn’t produce seeds
2) is very rare
3) doesn’t respond well to natural cloning
4) required to be pathogen free

Question 2

Steps of micropropagation

Answer 2

1) plant material cut from meristemic tissue into small pieces- called explants

2) dilute bleach and alcohol used to sterilise explants

3) placed on sterile growth medium containing glucose, amino acids, phosphates and growth hormones

4) forms a callus which divides into small clumps of undifferentiated cells

5) clumps moved to different growth medium, with less horomones
clumps are stimulated and differentiate to form different plant tissues

6) forms plantlets, transferred to a green house, acclimatised and grown in soil or compost

Question 3

Why do we cut from meristem tissue in step 1

Answer 3

• meristemic tissue are free from viral infections so clones are not infected

Question 4

Why do we sterilise explants in step 2

Answer 4

• kills bacteria that could thrive in plant growing conditions and prevent healthy growth

Question 5

Why is explant placed on agar plate with substances in step 3

Answer 5

• substances stimulate explants to divide by mitosis and forms a mass of totipotent cells- callus

Question 6

Why does the callus need to divide into smaller clumps in step 4

Answer 6

Because they have the ability to grow into a new plant from different tissues

Question 7

Why are the clumps transferred to different growth medium in step 5

Answer 7

Different ratios mean different growth directions

Question 8

Why are the plantlets formed transferred to green house in the last step

Answer 8

Has to acclimatise so it can adjust to growing conditions for optimum growth

Question 9

Advantages of micropropagation

Answer 9

• rapid production of large numbers of plants with known good genetic makeup
• culturing meristemic tissue produces disease free plants
• provides a way to produce large numbers of seedless plants which fits consumer taste
• provides a way to increase endangers plants

Question 10

Disadvantages of micropropagation

Answer 10

• monoculture- genetically identical so reduced gene pool, more susceptible to disease

-expensive due to equipment and training required

• if source is infected, all clones would be infected
• large numbers of new plants lost in the process