5.5.7 Commercial Use of Plant Hormones

Question 1

How can plant hormones be used commercially?

Answer 1

• Selective weed killers
• Rooting powders
• Control ripening

Question 2

Selective week killing :

Answer 2

• In high concentrations auxins can cause such rapid plant growth that plant tissues (eg. Roots) become distorted and damaged
• This allows pathogens to enter the plant
• Synthetic auxins with 100x the concentration of the natural hormone can be used
• Effective in treatment against weeds occurring in fields of cereal crops or grass lawns. Grass is significantly less sensitive to these weed killers

Question 3

What are rooting powders?

Answer 3

• Low doses, auxins can be used to stimulate cuttings to grow new roots
• Lower end of cutting dipped into powder and planted in compost
• With correct conditions roots grow after
• Commonly used by commercial flower sellers

Question 4

What is controlled ripening?

Answer 4

• Ethene used to stimulate fruit to ripen
• Used with delicate fruits that are soft when ripe
• So can be easily damaged during transport
• Instead, fruits are harvested when unripe, so are hard and don’t get damaged during transportation, then ripened artificially using ethene at their destination

Question 5

What are pathenocarpic fruits?

Answer 5

• Fruits that form without fertilisation
• So seedless fruits