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7 Cards in this Set
- Front
- Back
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How do terrestrial plants balance the need for gas-exchange and the need to conserve water?
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They must limit their water loss without compromising the efficiency of their gas-exchange system.
Many plants can obtain enough water from the soil to enable them to survive without too many adaptations for reducing water loss. A waterproof covering over parts of the leaves and the ability to close the stomata when necessary are sufficient for them to survive. |
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How do plants adapt to living in areas where water loss from transpiration may exceed their water intake?
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Xerophytic plants have modifications designed to increase water uptake, to store water and to reduce transpiration
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(xerophytic features)
How does a thick cuticle of a plant help protect against water loss? |
a thick cuticle which forms a waterproof barrier, so the thicker the cuticle, the less water that can escape
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(xerophytic features)
How does the rolling up of leaves help protect against water loss? |
The rolling of leaves to protect the lower epidermis from the outside helps to trap still air within the rolled leaf
This region becomes saturated with water vapour and so there is no water potential gradient between the inside and outside of the leaf Transpiration is reduced as it cannot go down a water potential gradient |
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(xerophytic features)
How do hairy leaves on plants help protect against water loss? |
A thick layer of hairs on leaves traps moist air next to the leaf surface
The water potential gradient between the inside and the outside of the leaves is reduced because of this and therefore less water is lost by transpiration |
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(xerophytic features)
How do the stomata in pits or grooves help protect against water loss? |
These also trap moist air next to the leaf and reduce the water potential gradient
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How does a reduced surface area to volume ratio of the leaves help protect against water loss?
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By having leaves that are small and circular, rather than leaves that are broad and flat, the rate of water loss can be considerably reduced
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