B3.2.7 Uses of Plant Hormones Flashcards
Function of auxin
Stimulate growth by causing cell elongation
Also help to regulate fruit development
Without auxins fruit are often too small
Function of ethene
Causes plant fruits to ripen by stimulating the conversion of starch into sugar
This is why a ripe fruit tastes sweeter than an unripe one
The only plant hormone that exists as a gas
Gibberellins function
Promote growth, particularly stem elongation
End dormancy periods of seeds and buds
This leads to shoots and flowers opening
How is auxin used as weed killer
Auxin weed killer makes the weeds grow too fast
This rapid uncontrolled growth kills the plant
How do auxin promote root growth
Rooting powder contains auxin
Gardeners use auxin to produce identical plants from cuttings
They cut off a plant from a shoot, dip it into rooting powder and plant it
After a few days, rooots develop from the cut stem
The new roots anchor into the soil and take up water and minerals
How does auxin delay ripening
Sprayed on fruit trees
Allows a harvest to all be collected at the same time
Can prevent fruit from dropping too early
How is ethene used to ripen fruit
Sprayed onto fruit trees and plants so their fruits ripen quicker
Allows fruit to be ready earlier in the growing season
How do auxins produce seedless fruit
Seeds are produced after a plant is pollinated by insects or the wind
If auxins are applied to unpollinated flowers, the plant produces seedless fruit
How do gibberellins / auxins control dormancy
Seeds remain dormant until conditions are ideal for growth so they don’t germinate at the end of summer
Commercial growers trigger seed germination in winter by spraying them with g/a in the greenhouse