967620
Description
Mind Map by charl.mallon, updated more than 1 year ago
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Created by charl.mallon
almost 10 years ago
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BIOLOGY 4.2
- Root hairs take in water by osmosis
- Root hairs give the plant a large surface
area for absorbing water from the soil
- There's usually a higher concentration of
water in the soil than in the plant, so water
is drawn in to the root hair cell by osmosis
- Root hairs give the plant a large surface
area for absorbing water from the soil
- TRANSPIRATION
- The loss of water from a leaf as it
diffuses out of the stomata by evaporation
- Creates a slight shortage of water in the leaf,
so more water is drawn up from the rest of
the plant through the xylem vessels
- This means more water is drawn up from the
roots & there is a constant transpiration stream
- This means more water is drawn up from the
roots & there is a constant transpiration stream
- Benefits of transpiration
stream/provides water for
- Keeping the plant cool
- Provides water for
photosynthesis constantly
- Creates turgor pressure - supports plant
- Minerals needed by the plant can be brought
in from the soil along with the water
- Keeping the plant cool
- Factors that increase
transpiration:
- Increased light
- Stomata close in the dark: no
photosynthesis, no CO2
needed, no water escaping
- Stomata close in the dark: no
photosynthesis, no CO2
needed, no water escaping
- Increased temp
- Water particles have more energy to
evaporate & diffuse out of the stomata
- Water particles have more energy to
evaporate & diffuse out of the stomata
- Increased air movement
- Windy: water vapour swept away, low
conc of water outside leaf = lots of diffusion
- Windy: water vapour swept away, low
conc of water outside leaf = lots of diffusion
- DECREASED humidity
- Humid air has lots of water in it - not a big
difference in conc in/out = less diffusion
- Humid air has lots of water in it - not a big
difference in conc in/out = less diffusion
- Increased light
- The loss of water from a leaf as it
diffuses out of the stomata by evaporation
- Leaf adaptations for reducing water loss
- Waxy cuticle covering
the upper epidermis
- Makes the upper surface
of the leaf waterproof
- Makes the upper surface
of the leaf waterproof
- Stomata are found on the lower
surface where it is darker & cooler
- Slow diffusion of water out of the leaf
- Slow diffusion of water out of the leaf
- Stomata size & number
- The more stomata, the more water loss
- Fewer & smaller on the underside,
none on upper epidermis
- Fewer & smaller on the underside,
none on upper epidermis
- The more stomata, the more water loss
- Waxy cuticle covering
the upper epidermis
- Transport vessels: xylem & phloem
- Deliver water and nutrients to every part of the leaf
- Help support leaf's structure
- Take away glucose produced by photosynthesis
- XYLEM vessels
- Made of dead cells joined end to end
with no end walls between them and
a hole down the middle (lumen)
- Thick side walls
made of cellulose:
strong & stiff - support
- Carry water & minerals FROM the
ROOTS up the shoot TO the
LEAVES in the transpiration stream
- Made of dead cells joined end to end
with no end walls between them and
a hole down the middle (lumen)
- PHLOEM tubes
- Made of columns of living cells
with perforated end plates to
allow stuff to flow through
- Transport food substances made with sugars both UP and
DOWN the STEM - TO growing and storage TISSUES
- This movement of food
substances around the plant is
known as TRANSLOCATION
- Made of columns of living cells
with perforated end plates to
allow stuff to flow through
- Deliver water and nutrients to every part of the leaf
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