Tuesday 31 January 2017

Adaptations to dry habitats

 

Plants in different habitats are adapted to cope with different problems of water availability.
Mesophytes      plants adapted to a habitat with adequate water
Xerophytes        plants adapted to a dry habitat
Halophytes        plants adapted to a salty habitat
Hydrophytes      plants adapted to a freshwater habitat
Some adaptations of xerophytes are:
Adaptation
How it works
Example
thick cuticle
stops uncontrolled evaporation through leaf cells
most dicots
small leaf surface area
less area for evaporation
conifer needles, cactus spines
low stomata density
fewer gaps in leaves

stomata on lower surface of leaf only
more humid air on lower surface, so less evaporation
most dicots
shedding leaves in dry/cold season
reduce water loss at certain times of year
deciduous plants
sunken stomata
maintains humid air around stomata
marram grass, pine
stomatal hairs
maintains humid air around stomata
marram grass, couch grass
folded leaves
maintains humid air around stomata
marram grass,

succulent leaves and stem

stores water
cacti
extensive roots
maximise water uptake
cacti

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