ADAPTIONS OF FLOWERING PLANTS TO WATER AVAILABILITY Flashcards
1
Q
mesophyte
A
plants in conditions with adequate water
2
Q
xerophytes
A
plants in low-water conditions
3
Q
hydrophytes
A
water plants
4
Q
why are most crop plants mesophytes? (3)
A
- grow best in well-drained soils and dry air
- water during night replaces water lost during day
- excessive water loss prevented because stomata close at night
5
Q
how are mesophytes adapted to frozen conditions (3)
A
- shed leaves before winter so no water is lost via transpiration
- aerial of plants die in winter so not exposed (e.g potatoes) but underground organs survive
- annual mesophytes (flower & seed and die in 1 year) pass winter as dormant seeds with a low metabolic rate so little water is needed
6
Q
how are xerophytes adapted to harsh, dry conditions? (5)
A
- rolled leaves - reduce area exposed to air, so reduce transpiration
- sunken stomata - humid air trapped in pits so reduces gradient between inside of leaf and outside, reducing transpiration
- hairs - stiff, interlocking hairs trap water vapour and reduce gradient between leaf and outside
- thick cuticle - waxy convering is waterproof so reduces water loss
- sclerenchyma fibres are stiff and maintain leaf shape even when flaccid
7
Q
hydrophytes adaptions (5)
A
- few supportive tissues - because water is a supportive medium
- poorly developed xylem - surrounded by water
- little/no cuticle - no need to prevent water loss
- stomata on upper surface - because lower is in water
- large air spaces from leaves to roots forming co2/o2 reservoir, providing buoyancy
