Plant responses to abiotic stress

Created by: TaraCBeckworth
Created on: 31-05-17 14:00

What is photoperiodism?

The fact that plants are sensitive to the lack of light so they make certain changes to adapt as the seasons are changing (lack of light is a trigger for change)

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Give a few examples of plant responses affected by the photoperiod

The breaking of dormancy in leaf buds causing them to open up, tubers are formed in preparation of long winters

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What light pigment causes the sensitivity to day length in plants? & describe it

Phytochrome, which comes in 2 forms Pr and Pfr, these different forms absorb different lengths of light and come in different ratios depending on the levels of light (seasonal)

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How does the plant prepare for abscission?

Levels of auxin fall as light does, this triggers release of ethene, at the abscission zone 2 layers are formed, separation zone- enzymes triggered by ethene to weaken cell walls, protective layer- fatty material deposited there to form a scab`

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What actually causes the leaf to fall off?

Cells deep in the separation zone swell and retain water putting more strain on the separation zone, if this doesnt cause the leaf to drop off abiotic factors will, like wind or low temperatures

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How do plants protect themselves from freezing?

High solutes in the vacuole and sap, lowering freezing point, some plants produce biological molecules like amino acids and polysaccharides to protect cell if they do freeze, most species produce chemicals which make them hardy and frost resistant

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Leaf cells produce ABA to trigger stomatal closure, however what other way have scientists found that causes stomatal closure?

In the roots they detect low water levels and produce ABA which is transported up to the leaves, they bind to receptors on guard cells, they change the ionic concentrations of guard cells, reducing ψ making them less turgid causing closing of stomata

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Other cards in this set

Card 2

Front

Give a few examples of plant responses affected by the photoperiod

Back

The breaking of dormancy in leaf buds causing them to open up, tubers are formed in preparation of long winters

Card 3

Front

What light pigment causes the sensitivity to day length in plants? & describe it

Back

Card 4

Front

How does the plant prepare for abscission?

Back

Card 5

Front

What actually causes the leaf to fall off?

Back

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Plant responses to abiotic stress