Xerophytes Flashcards
What is a xerophyte?
Plant that is adapted to reduce water loss so it can survive in dry conditions
Why must stomata remain open during the day?
To take up CO2 for photosynthesis and to remove oxygen which is by-product of photosynthesis
What structural adaptations reduce water loss?
waxy cuticle on leaf reduces evaporation, stomata on under surface of leaf, most stomata closed at night, deciduous plants lose leaves in winter
What is the purpose of smaller leaves in reduction of water loss?
often needles, reduces SA, less water lost by transpiration
What is the purpose of densely packed spongy mesophyll in reduction of water loss?
reduces cell SA exposed to air inside leaves, less water will evaporate
What is the purpose of a thicker waxy cuticle in reduction of water loss?
Reduces evaporation e.g. holly leaves
What is the purpose of closing stomata in reduction of water loss?
when water availability is low will reduce water loss and then the need to take up water
What is the purpose of hairs on the surface of leaf in reduction of water loss?
Trap layer of air close to leaf surface, air becomes saturated reducing the water vapour potential diffusion gradient
What is the purpose of pits containing stomata in reduction of water loss?
Stomata at base of pit, air trapped saturated with water vapour, reduce water vapour potential gradient
What is the purpose of rolling leaves in the reduction of water loss?
lower epidermis is not exposed to atmosphere so can trap air which is saturated
How do cells maintain a low water potential inside their cells?
maintaining high salt concentration in cells, low water potential reduces evaporation from cell surfaces
How is marram grass adapted for living in sand dunes?
Leaf rolled, thick waxy cuticle, trapped air in centre (high vapour potential), hair on lower surface reduce air movement, stomata in pits
