Xerophytes Flashcards
What adaptations do most terrestrial plants have to help them preserve water?
-Waxy cuticle
-Stomata on the under/shady side that close at night
-Lose their leaves in winter
What are xerophytes?
Plants with the ability to live in arid climates which have extra adaptations to help them preserve as much water as possible.
What is the first adaptation of cacti that allows them to live in deserts?
Spines instead of leaves which reduces the SA over which transpiration can happen.
-Also prevent herbivores from eating them
What is the second adaptation of cacti that allows them to live in deserts?
Very thick waxy cuticle that’s impermeable to water so reduces evaporation more effectively
What is the third adaptation of cacti that allows them to live in deserts?
Sunken stomata which traps a pocket of still, moist air above the stomata reducing the ψ gradient
What is the fourth adaptation of cacti that allows them to live in deserts?
Large girth which reduces the SA:Vol ratio
What is the fifth adaptation of cacti that allows them to live in deserts?
They have fewer stomata and close them when it’s hot so water vapour can’t diffuse out of the leaf
What is the sixth adaptation of cacti that allows them to live in deserts?
They’re succulents meaning they can store water in specialised parenchyma tissue meaning they can use during long,dry conditions
What is marram grass adapted for?
To live in sand dunes
What is the first adaptation of marram grass?
Thick waxy cuticle on outside of leaf which is impermeable to water so reduces evaporation
What is the second adaptation of marram grass?
Sunken stomata on inside of leaf which traps a pocket of still, moist air above the stomata reducing the ψ gradient
What is the third adaptation of marram grass?
Stomata only open at night meaning there is less evaporation at night as its cooler
What is the fourth adaptation of marram grass?
Hairs (trichomes) around stomata traps a pocket of still, moist air above the stomata reducing the ψ gradient
What is the fifth adaptation of marram grass?
Rolled leaf which traps moist air inside the leaf and protects the stomata
What does marram grass also have?
A tap root and horizontal stems called rhizomes
