Maintaining Water Balance In Plants

Question 1

What is cohesion

Answer 1

Force of attraction between water molecules themselves to maintain unbroken columns of water to be pulled upwards to leaves

Question 2

When is the stomata open

Answer 2

During the day

Question 3

When the stomata is open what happens ?

Answer 3

The guard cells gain water and swell as they become turgid

Question 4

What happens in darkness/ at night / closed in the stomata

Answer 4

The guard cells loose water and they become flaccid

Question 5

What are adaptations of xerophytes

Answer 5

Stomata sunken in pits to reduce air movement in stomata, hairs also reduce air movement, rolled leaves protects the stomata from air movements and reduces transpiration, waxy cuticles reduce water loss through epidermis and leaves reduced in size make a smaller surface area so transpiration rates are reduced.

Question 6

What are other xerophytes adaptations

Answer 6

Succulent storage tissue which allows water to be stored and used during dry periods,
Reversed stomatal opening means that the stomata is open at night and closed during the day to reduce transpiration,
Low growth habit means that the plants are sheltered from strong winds and avoid excessive transpiration

Question 7

What are adaptations of hydrophytes

Answer 7

Air spaces in stems and leaves increases buoyancy,
Reduced xylem means that the flexibility of the stem reduces the chance of damage by the surrounding water,
Restricted stomatal distribution means the stomata are missing from submerged leaves and only found on Upper surface

Question 8

What is adhesion

Answer 8

Force of attraction between water molecules and the inner walls of the xylem vessels to pull the water upwards.