Plant Adaptations Flashcards
Plant adaptations we already know to reduce water loss
-close stomata at night
-waxy cuticle which reduces water loss by evaporation.
What are plant which have evolved to live in dry places called
Xerophytes
How have cacti been adapted
-leaves replaced by fibrous spines, with photosynthesis taking place in the stem of the cactus, and in these cacti the stomata are found on the surface of the stem.
-replacing the leaves with spines reduces the surface area to volume ratio of the cactus, reducing water loss.
-The spines also trap moist air near the cactus, reducing the rate of transpiration, as well as providing some shade for the stem from the heat of the sun
-cacti also have a thick waxy cuticle to reduce evaporation of water
-In cacti the stomata are sunken into pits, this traps a layer of moist air around the stomata, reducing water loss by transpiration.
-Cacti only open their stomata at night to absorb carbon dioxide when conditions are cool, co2 then used during day for photosynthesis.-reduced water loss only opening them at night.
-cacti often have extensive shallow roots, this allows the cacti to absorb water after a rain shower before the water evaporates.
-cacti can also have very deep roots to access water from lower levels of the soil.
-cacti can store water in their stem- cacti is a succulent.
How is marram grass adapted
-found in sand dunes-water is scarce, windy conditions can increase evaporation of water from plants.
-leaves of marram grass can roll into a tube with the stomata on the inside, moist air is trapped within the tube, rather than being blown away by the wind
-the stomata in marram grass are found in sunken pits, with fine hairs projecting inwards towards the centre. These adaptations ensure moist air is trapped around the stomata.
-have thick waxy cuticle to reduce evaporation from the surface
-roots of marram grass can be very long, extending deep into the sand to find water. Also have extensive roots which are closer to the surface, help sand retain water.
