xerophytes

Question 1

what is a xerophyte

Answer 1

plants well adapted to living in dry and arid conditions e.g cactus, marram grass

Question 2

stomata in sunken pits

Answer 2

trap air which can become saturated with water vapour
reducing gradient in water potential inside and out of plants
less water lost via diffusion (gentler gradient)
e.g marram grass

Question 3

rolled leaves

Answer 3

lower epidermis not exposed so air can become trapped and saturated
reducing gradient in water potential inside and out of plants
less water lost via diffusion (gentler gradient)
e.g marram grass

Question 4

hairy leaves

Answer 4

trap layer of air close to surface which can become saturated
reducing gradient in water potential inside and out of plants
less water lost via diffusion (gentler gradient)
e.g marram grass

Question 5

thick waxy cuticle

Answer 5

reduces evaporation due to heating
e.g holly leaves, marram grass

Question 6

spines

Answer 6

reduce surface area
reduces water loss via diffusion
e.g cacti

Question 7

why might plants living in sand dunes require xerophyric features

Answer 7

1. high wind speeds- increase
   evapotranspiration
2. ground drains quickly- need to conserve
   water for photosynthesis

Question 8

why might plants living in salt marshes require xerophyric features

Answer 8

high salinity water- low water potential and hard for plants to absorb so need to conserve fresh water

Question 9

why might plants living in cold regions require xerophyric features

Answer 9

ground is often frozen so water cannot be absorbed via osmosis