Temporary, fast responses to a stimulus that are not determined by the direction
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What is tropism
A permanent, slow response to a stimulus that is determined by it's direction
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How can auxins be used commercially?
Stimulates root growth so in rooting powder, prevents fruit and leaf drop in high concentrations, in herbicides promotes fast growth in weeds so they grow too quickly and die, promotes growth of seedless fruit
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How can gibberellin be used commercially?
Increases the length of grapes and apples, slows senescence in citrus fruits (ageing), elongates stalks
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How can ethene be used commercially?
Causes the ripening of fruits in transit, promotes lateral growth and fruit drop
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How are hormones involved in leaf loss in deciduous plants?
Ethene is produced as the leaf ages, inhibiting auxin production. This initiates leaf abscission. An abscission layer grows at the base of the petiole. Cellulose hydrolyses the polysaccharides in the cell wall.
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Explain how plants can bend towards sunlight.
Blue light is absorbed by phototrophin, which is phosphorylated. This causes the auxin to be transported sideways. The auxin causes stem elongation making it bend towards the light.
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What is the experimental evidence for the role of auxins in apical dominance?
When the meristem is removed and an agar block containing auxin replaces it the lateral buds do not grow. If the meristem is removed and this is not done, the lateral buds will begin to grow. If the shoot is upside down, the lateral buds will grow.
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Other cards in this set
Card 2
Front
What is tropism
Back
A permanent, slow response to a stimulus that is determined by it's direction
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