Adaptations in Xerophytes

• Xerophytes:

  Leaving stomata open to exchange gases during the day causes plants to also lose water

  • For plants in hot, windy or dry climates they have to have extra adaptations to prevent too much water loss when their stomata are open
  • These plants are known as xerophytes
  • Most adaptations reduce the factors that can increase transpiration
• Xerophytes adaptations: Small leaf surface area

  • Reduced surface area for evaporation/ fewer stomata
  • Eg: Conifer needles, cactus spines
• Xerophytes adaptations: Sunken stomata

  • Maintains humid air around the stomata to reduce the water potential gradient
  • Eg: Marram grass, cacti
• Xerophytes adaptations: Stomatal hairs

  • Maintains humid air around the stomata to reduce the water potential gradient and reduce evaporation
  • Eg: Marram grass
• Xerophytes adaptations: Rolled leaves

  • Reduces the effects of wind to reduce the water potential gradient and reduce evaporation
  • Eg: Marram grass
• Xerophytes adaptations: Extensive root systems

  • Maximises water uptake - helps to increase chances of contact with water, often shallow but wide area to absorb rainfall
  • Succulents - Often have swollen stems to store the collected water
  • Eg: Cacti
• Xerophytes adaptations: Reduced number of stomata

  • Reduce the amount of places water can evaporate from
• Xerophytes adaptations: Thicker, waxy cuticle

  • Waterproof leaves and stems reduce evaporation
  • Eg: agave