B11.10 Using plant hormones

Question 1

What is gibbereliins?

Answer 1

Plant hormones that initiate seed germination - trigger the breakdown of food store in the seed at the start of germination
- Stimulate the growth of plant stems

Question 2

What is Ethene?

Answer 2

Hormone that controls cell division - important in the ripening of fruits

Question 3

How can you use auxins to make more plants?

Answer 3

Take a small piece of stem and dip it into the rooting powders containing auxin(known as IAA)
Chances of success are greatly increased because the hormone stimulates the growth of new roots and helps the cutting to grow into a new plant

Question 4

How can auxin be used in weed killers?

Answer 4

If you spray auxin solution onto the leaves of plants - the hormone is absorbed - the extra auxin can send the plants into rapid - uncontrolled growth
Auxin naturally stimulates growth in plants

Question 5

What is one of the main reason of the increase in yield of cereal crops?

Answer 5

Hormone weed killers kill weds and removes competition for light and for mineral from the soil

Question 6

How can auxin be used to produce identical plants?

Answer 6

Used in modern tissue cultures as part of the plant cloning process
Stimulate growth and cell division in the tissue culture

Question 7

What are the uses of giberellins?

Answer 7

Used in the brewing industry to end seed dormancy - speeding up germination of the barely seeds to make malt

Promote flowering throughout the year

Increase the size of the fruit. Seedless grapes would be very small because seeds produce gibberellins to make fruit grow - commercial growers spray the fruit with gibberellins to replace natural hormones

Question 8

What are the uses of ethene?

Answer 8

Control ripening of fruit
Growers harvest fruit when it is not ripe - then transported chilled which ensure they are less likely to be damaged than rip fruit
Unripe fruit is stored then warmer temperatures and ethene added to the atmosphere to make it ripe