AQA AS Biology Xerophytes Revision.

  • Created by: Chloe
  • Created on: 30-05-13 17:14

Xerophytes

Adaptations

  • Conserve water while maximising gas exchange efficiency.
  • Deep or wide spread roots suffice for many but plants without plentiful water supply develop adaptions to limit water loss.Adaptions help; water uptake, store water, reduce transpiration.
  • STOMATA IN PITS: Trap moist air next to leaf, reduce water potential gradient. Reduce water lost via transpiration.
  • REDUCED SA:V RATIO OF LEAVES: Having small and cylindrical leaves as opposed to flat and broad, rate of water loss can be reduced. As smaller SA:V the slower the rate of diffusion, water moves out of plant slower.

Adaptions

Other information              

  • A THICK CUTICLE: thicker waxy cuticles reduce water lost across waxy cuticle.
  • ROLLING LEAVES: rolled leaves create still water saturated air around the stomata reducing water potential gradient and reducing transpiration.
  • HAIRY LEAVES: thick layers of hair trap moist air next to leaf, reducing water potential gradient between inside + outside of leaf, so less water lost via Transp.
  • Transpiration occurs through stomata and can be increased/decreased by environmental factors eg heat, wind, sun etc. humidity and water potential gradients can help reduce rate of transpiration and therefore water loss.

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AQA AS Biology Xerophytes Revision.

  • Created by: Chloe
  • Created on: 30-05-13 17:14

Xerophytes

Adaptations

  • Conserve water while maximising gas exchange efficiency.
  • Deep or wide spread roots suffice for many but plants without plentiful water supply develop adaptions to limit water loss.Adaptions help; water uptake, store water, reduce transpiration.
  • STOMATA IN PITS: Trap moist air next to leaf, reduce water potential gradient. Reduce water lost via transpiration.
  • REDUCED SA:V RATIO OF LEAVES: Having small and cylindrical leaves as opposed to flat and broad, rate of water loss can be reduced. As smaller SA:V the slower the rate of diffusion, water moves out of plant slower.

Adaptions

Other information              

  • A THICK CUTICLE: thicker waxy cuticles reduce water lost across waxy cuticle.
  • ROLLING LEAVES: rolled leaves create still water saturated air around the stomata reducing water potential gradient and reducing transpiration.
  • HAIRY LEAVES: thick layers of hair trap moist air next to leaf, reducing water potential gradient between inside + outside of leaf, so less water lost via Transp.
  • Transpiration occurs through stomata and can be increased/decreased by environmental factors eg heat, wind, sun etc. humidity and water potential gradients can help reduce rate of transpiration and therefore water loss.

Comments

No comments have yet been made