The commercial use of plant hormones

What hormone controls fruit ripening?

Ethene

What are climacteric fruits?

Fruits that continue to ripen after they have been harvested

Examples of climacteric fruits

- Bananas
- Tomatoes
- Mangoes
- Avocados

Examples of non-climacteric fruits

- Oranges
- Strawberries
- Watermelon

Difference between non-climacteric and climacteric fruits

Non-climacteric fruits do not:

- Produce large amounts of ethene
- Ripen much after picking

How can the effect of Ethene on climacteric fruits be seen?

Green bananas next to a ripe banana will ripen faster

- Ethene from the ripe banana stimulates rapid ripening of the green ones

Graph to show effect of Ethene on respiration rate of respiring fruit

How can synthetic auxins be used as weed killer?

- Auxin are absorbed by plants and affect their metabolism

- Growth rate increases, making the plant unstable and it dies

How can auxins be used in rooting powders?

- They help cuttings grow

- Adding rooting powder to the soil makes them produce roots rapidly and start growing as new plants

- This means many clones can be made very quickly

How can auxins be used commercially?

- Production of seedless fruit

- Weed killer

- Rooting powder

How can ethene be used commercially?

Promote fruit dropping in cotton, walnuts, cherries

How can cytokinins be used commercially?

- Prevent ageing of ripened fruit and lettuces

- Micropropagation to control tissue development

How can gibberellins be used commercially?

- Delay ripening and ageing in fruit

- Improve size and shape of fruits

- Speed up malting process in beer brewing