3.2 Xerophytes Flashcards
What is the term given to plants that are adapted to living in dry conditions where there is a limited supply of freshwater and give two examples
xerophytes: cacti, marram grass
what are xerophytes
they are plants adapted to living in dry conditions where there is a limited supply of freshwater
What are two adaptations that cacti have to reduce water loss
1 - Have spines instead of leaves, reduces surface area - reduces number of stomata - reducing water loss via transpiration
2 - Have a very thick, corrugated stem - water storage, when it absorbs lots of water it expands
What are two adaptations that cacti have to increase water uptake
1 - Has massive extensive root network close to surface to catch rainwater as soon as it falls
2 - Some have a very deep root that reaches water table
State 5 adaptations that marram grass have to reduce water loss
rolled leaves
leaf hairs
sunken stomata
fewer stomata
thick waxy cuticle
explain how rolled leaves help marram grass to live in dry conditions
rolled leaves trap moist air (high water potential) near the stomata as there is no wind to blow the vapour away, and so, lowering the water potential gradient between the stomata and the air surrounding it so that less water is lost via stomata
explain how leaf hairs help marram grass to live in dry conditions
traps moist air near the stomata to lower the water potential gradient between the stomata and the air surrounding it so that less water is lost via stomata
explain how a thick waxy cuticle help marram grass to live in dry conditions
reduces evaporation of water
explain how sunken stomata helps marram grass to live in dry conditions
reduces water loss as they are not on the surface of the leaf
how does having fewer stomata help xerophytes to live in a dry environment
number of stomata is less so SA:Vol is less and so reduces water loss
