Plant Hormones Flashcards
How is ethene used in commercial fruit production
Developed but unripe(hard) fruits harvested so they can be easily transported
When needed for sale, they are exposed to ethene to ripen them. This increases shelf life; reduces waste and ensures all ripen at the same rate
How is auxin used in micropropagation?
If a cutting is placed in hormone rooting powder before being placed in soil, it is more likely to form roots and therefore successfully propagate
How are synthetic auxins used to help us increase yield?
They interrupt metabolism of weeds, causing unsustainable growth and causing them to die. They are cheap and safe for mammals, and are selective
What other ways can hormones be used commercially in plants ?
Auxins used in making seedless fruits
Ethene used to promote fruit droppings (cherries or cotton)
Cytokines used to prevent ageing of ripened fruits
Gibberellins improve shape and size of fruits, and speed up malting process in beer making
What do these hormones do? Auxins Gibberellin Ethene ABA
Control cell elongation, prevents abscission, maintain apical dominance, stimulated release of ethene
Causes cell elongation, triggers germination, stimulates pollen tube growth
Causes ripening, promotes abscission,
Maintains dormancy of seeds and buds, protects against cold (antifreeze)
How does germination work?
When a seed absorbs water, embryo is activated and produces gibberellins. These stimulate production of enzymes that break down food stores, giving the plant energy to start building.
What evidence do we have for the role of gibberellins in germination?
Mutants variants of seeds with no gene to make gibberellins do not germinate, but do when external gibberellins applied
They also don’t germinated when they external gibberellin inhibitors are applied, but do when they are removed
