Adaptations for transport: plants
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- Created by: chloesrevising
- Created on: 28-02-22 18:18
What is the word equation for photosynthesis
carbon dioxide + water -> (light, chlorephyll) glucose + oxygen
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What is the transport system in plants for transport of water and mineral ions
need water and mineral ions only available in soil
from roots to leaves
transported upwards in hollow tubes = xylem tissue
from roots to leaves
transported upwards in hollow tubes = xylem tissue
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What is the transport system in plants for transport of the products of photosynthesis - photsynthates
photosyhtnates are sucrose and amino acids made by glucose produced
must be moved from leaves to other organs e.g. root, flower
transported upwards and downwards in phloem tissue in a bidirectional movement
must be moved from leaves to other organs e.g. root, flower
transported upwards and downwards in phloem tissue in a bidirectional movement
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Leaf
Vascular bundle arranged as vein or midrib
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Stem
Vascular bundle a
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how are mineral ions e.g. nitrate transported from the soil into root hair cells
what happens to the water potential
how does water enter
what happens to the water potential
how does water enter
actively transported
lowered inside root hair cell
by osmosis
lowered inside root hair cell
by osmosis
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what does oxygen enter the roots from the soil to be used in
what does this provide
why do waterlogged soils struggle with uptake of ions
what does this provide
why do waterlogged soils struggle with uptake of ions
aerobic respiration
ATP for active transport
lack oxygen
ATP for active transport
lack oxygen
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what do water and dissolved materials then travel
-through
-to
down
what three routes can be taken
-through
-to
down
what three routes can be taken
root cells of cortex
endodermis
water potential gradient
symplast, apoplast, vacuolar
endodermis
water potential gradient
symplast, apoplast, vacuolar
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What form of transport is needed to move ions into the cytoplasm of the endodermal cells
Where do mineral ions then diffuse to
Where do mineral ions then diffuse to
active transport
into percicycle and then into xylem
into percicycle and then into xylem
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therefore, what is the only path that water and mineral ions can pass through the enderderims to the percicycle and into the xylem via
what form of transport does water follow by
what form of transport does water follow by
symplast
osmosis down water potential gradient
osmosis down water potential gradient
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what does this give the plant
greater control over which ions enter the xylem and are transported to the rest of the plant
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what is root pressure
when water moves from the endodermal cells of the root and into the xylem by osmosis this generates hydrostatic pressure and forces water up a small distance by the xylem
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How would cyanide result in a reduction of root pressure
casparian ***** stops apoplast path forcing ions into symplast path
ions into xylem needs active transport
cyanide is respiratory inhibitor so stops ATP synthesis
lower water potential gradient reduces root pressure
ions into xylem needs active transport
cyanide is respiratory inhibitor so stops ATP synthesis
lower water potential gradient reduces root pressure
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Why does the plant need to have control over what mineral ions enter the xylem
How does the plant ensure toxic ions dont enter its cells
How does the plant ensure toxic ions dont enter its cells
Some mineral ions are toxic if absorbed and accumulate inside plant tissues e.g. copper ions
no carrier proteins specific to these ions on the membrane so ions cannot enter via facilitated diffusion
no carrier proteins specific to these ions on the membrane so ions cannot enter via facilitated diffusion
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Why do plants need to absorb nitrates from the soil
Name some mineral ions absorbed by plants with their uses
Name some mineral ions absorbed by plants with their uses
required for synthesis of amino acids, proteins, DNA, RNA, ATP, nucelotides, nitrogeneous bases
R+ required for stomatal opening
Mg constituent of chlorophyll
PO43- synthesis of phospholipids and constituent of ATP
R+ required for stomatal opening
Mg constituent of chlorophyll
PO43- synthesis of phospholipids and constituent of ATP
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give two features of root hair cells that are adaptations for uptake of water and mineral ions
large SA - absorption of water + mineral ions
Large numbers of mitochondria - atp required for active transport of ions
Large numbers of mitochondria - atp required for active transport of ions
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what is transpiration
the evaporation of water vapour from inside the leaves, out through the stomata into the atmosphere
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how does the transpiration stream work/what happens in the transpiration stream
-water absorbed by root hair cells
-water moves through root tissue, into xylem and transported up xylem in stem to leaf
-water transported by osmosis from xylem to spongy mesophyll where it evaporates from surface to air spaces
-water vapour diffuses fro
-water moves through root tissue, into xylem and transported up xylem in stem to leaf
-water transported by osmosis from xylem to spongy mesophyll where it evaporates from surface to air spaces
-water vapour diffuses fro
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What does cohesion mean
What does adhesion mean
What does adhesion mean
water molecules attracted to each other by hydrogen bonds
water molecules attracted to hydrophilic lining of lignified xylem vessel walls
water molecules attracted to hydrophilic lining of lignified xylem vessel walls
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How does water travel up to the xylem to the leaves of the plant
The cohesion-tension theory (transpiration pull)
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How does the transpiration pull work
-water vapour diffuses out of leaf stomata by transpiration + water molecules drawn up from behind to replace those lost
-water molecules drawn across leaf and up xylem by cohesion + adhesion
-upward movement of water creates tension on xylem vessel wall
-water molecules drawn across leaf and up xylem by cohesion + adhesion
-upward movement of water creates tension on xylem vessel wall
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what 2 other processes help water move up the xylem a small amount
what is capillarity
why is capillarity not useful in large trees
what is capillarity
why is capillarity not useful in large trees
capillarity + root pressure
forces of adhesion and cohesion let water molecules rise up narrow tubes for short distance useful in small amounts e.g. moss
after short distance, capillary action is opposed by gravity
forces of adhesion and cohesion let water molecules rise up narrow tubes for short distance useful in small amounts e.g. moss
after short distance, capillary action is opposed by gravity
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How does high temperature affect transpiration rate
-increases kinetic energy(KE) of water molecules increasing evaporation rate and diffusion of water vapour into atmosphere
-atmospheres water potential is lower in high temps - increasing water potential gradient
-increases transpiration rate
-atmospheres water potential is lower in high temps - increasing water potential gradient
-increases transpiration rate
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How does high wind speed affect transpiration rate
-still air = layer of water vapour around leafs stomata - diffusion shell
-reduces water potential gradient between inside and outside of leaf
-air movement blows away diffusion shell increasing rate of transpiration from leaf
-reduces water potential gradient between inside and outside of leaf
-air movement blows away diffusion shell increasing rate of transpiration from leaf
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How does high humidity affect transpiration rate
-water potential gradient between inside + outside of leaf decreases with more water vapour in atmosphere
-however, usually a steep water potential gradient between inside of leaf + atmosphere as leaf is saturated with water vapour
-slows rate of transpir
-however, usually a steep water potential gradient between inside of leaf + atmosphere as leaf is saturated with water vapour
-slows rate of transpir
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How does high light intensity affect transpiration rate
-light causes stomata to open to allow gas exchange for photosynthesis
-increases rate of transpiration
-increases rate of transpiration
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What does a potometer measure
What units is this measured in
Why is the rate of uptake only an estimate of the transpiration rate
What units is this measured in
Why is the rate of uptake only an estimate of the transpiration rate
rate of uptake of water by shoot which indicates transpiration rate
mm2/mm3/min
some water used by plant as a reactant in photsynthesis
mm2/mm3/min
some water used by plant as a reactant in photsynthesis
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What is steps 1-3 of setting up the potometer
1. cut leafy shoot under water to prevent entry of air bubbles into xylem vessels which would break hydrogen bonds affecting cohesion
2. fully fill apparatus with water to avoid bringing air bubbles into glass
3. fit leafy shoot+seal all joints with vas
2. fully fill apparatus with water to avoid bringing air bubbles into glass
3. fit leafy shoot+seal all joints with vas
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What are steps 4-6 in setting up the potometer
4. pat leaves dry otherwise water potential gradient will be reduced and could affect results
5. introduce one air bubble into capillary tube / open tap
6. measure distance the air bubble moves along scale in specific time
5. introduce one air bubble into capillary tube / open tap
6. measure distance the air bubble moves along scale in specific time
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How would you calculate the volume of water in capillary tube
what two ways could you improve the reliability of the data collected
what two ways could you improve the reliability of the data collected
pi x r squared x l
r = radius of capillary tube
l = distance moved by air bubble
repeat experiment 3 times
calculate the mean
r = radius of capillary tube
l = distance moved by air bubble
repeat experiment 3 times
calculate the mean
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what is the standard deviation
what does a low standard deviation indicate
what does a high standard deviation indicate
what does a low standard deviation indicate
what does a high standard deviation indicate
measure of spread of data, indicating amount of variation/dispersion in data set
values close to mean = more consistent + more reliable
values further from mean so more spread out = less consistent + less reliable
values close to mean = more consistent + more reliable
values further from mean so more spread out = less consistent + less reliable
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What 6 steps do you follow to calculate the standard deviation
1. calculate mean for data set
2. subtract mean from each value
3. square each answer
4. add up all squares
5. divide total by number of peices of data minus 1
6. find square root of that value
2. subtract mean from each value
3. square each answer
4. add up all squares
5. divide total by number of peices of data minus 1
6. find square root of that value
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what does xylem tissue transport
what four cells is it composed of and their roles
what four cells is it composed of and their roles
water and mineral ions
vessels - main cells that conduct water
tracheids - conduct water but less efficient than vessels
fibres - only support, not transport
xylem parenchyma - living tissue
vessels - main cells that conduct water
tracheids - conduct water but less efficient than vessels
fibres - only support, not transport
xylem parenchyma - living tissue
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what shape are vessels
what are their walls thickened with and what does this mean for the plant
what are their walls thickened with and what does this mean for the plant
continuous column of dead cells arranged end-end with completely dissolved cross walls to form long hollow tubes that transport water from roots to leaves
lignin = impermeable to water strengthening and supporting plant + stops vessels collapsing under p
lignin = impermeable to water strengthening and supporting plant + stops vessels collapsing under p
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What shape are the tracheids
What do they have in their side walls, what do they allow and what are they involved in
What do they have in their side walls, what do they allow and what are they involved in
similar to vessels but more elongated with tapering ends with thickened walls and lignin on the walls
pits,
movement of water between adjacent vessels
movement of water to nearby living tissue
pits,
movement of water between adjacent vessels
movement of water to nearby living tissue
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Why is it important vessel walls are impermeable to water and solutes
why is lignin being hydrophilic and not hydrophobic important for xylem function
why is lignin being hydrophilic and not hydrophobic important for xylem function
vessels transport water-dont want water to leave vessel until it reaches leaf
water not attracted to hydrophobic walls so wouldnt stick but air would creating air bubbles
water not attracted to hydrophobic walls so wouldnt stick but air would creating air bubbles
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what does phloem tissue transport
what 4 types of cell is phloem tissue mad of and their roles
what 4 types of cell is phloem tissue mad of and their roles
sucrose and amino acids
sieve tubes - transport sucrose + amino acids up/down plant step
companion cells - connect to sieve tubes via plasmodesmata
phloem fibres - for support
phloem paranchyma - living tissue
sieve tubes - transport sucrose + amino acids up/down plant step
companion cells - connect to sieve tubes via plasmodesmata
phloem fibres - for support
phloem paranchyma - living tissue
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What are the sieve tubes formed from
what forms sieve plates and what do the sieve plates allow
what forms sieve plates and what do the sieve plates allow
cells called sieve elements placed end to end
thin cellulose wall at ends of cells that are perforated
cytoplasm from one cell to run into an adjacent cell
thin cellulose wall at ends of cells that are perforated
cytoplasm from one cell to run into an adjacent cell
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what are the phloem proteins filaments in
what do phloem proteins run through
what runs into adjacent companion cells through the plasmodesmata
what do phloem proteins run through
what runs into adjacent companion cells through the plasmodesmata
the cytoplasm
sieve plates
smaller strands of cytoplasm run through side walls of sieve tube cells
sieve plates
smaller strands of cytoplasm run through side walls of sieve tube cells
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what do the companion cells not transport
what does the prescenece of a nucleus in a companion cell provide
why is this important
what does the prescenece of a nucleus in a companion cell provide
why is this important
organic materials
ATP for active transport of sugars into/out of the sieve tubes
sieve tubes lose their nucleus and other organelles as they mature
ATP for active transport of sugars into/out of the sieve tubes
sieve tubes lose their nucleus and other organelles as they mature
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how are sieve tube elements adapted to their function
1. organelles+nucleus disintegrate in development, less resistance to flow in phloem
2. sieve tubes associated+linked by plasmodesmata with companion cells that provide energy in ATP form
3. sieve plate pores allow cytoplasm+phloem protein to move between
2. sieve tubes associated+linked by plasmodesmata with companion cells that provide energy in ATP form
3. sieve plate pores allow cytoplasm+phloem protein to move between
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what is translocation
what is the movement of these molecules called
what is the liquid inside the phloem tubes called
what is the movement of these molecules called
what is the liquid inside the phloem tubes called
transport of soluble organic materials produced by photsynthesis e.g. sucrose, amino acids in phloem
bi-directional
sap
bi-directional
sap
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what is the source
what is the sink
what are examples of both of these in a plant
what is the sink
what are examples of both of these in a plant
region where products of photosynthesis(photosynthates) are produced + exported
region where photosnythates are stored/use for growth
SOURCE: leaf
SINK: root, flower, seeds, shoot tips
region where photosnythates are stored/use for growth
SOURCE: leaf
SINK: root, flower, seeds, shoot tips
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what happens in a ringing experiment
what does this result show
what does this result show
-removal of ring of outer bark tissue from woody stem removes phloem
-analysis of phloem contents just above and below ring shows organic compounds cannot be transported past region where bark has been removed
phloem is under bark so sucrose must be tran
-analysis of phloem contents just above and below ring shows organic compounds cannot be transported past region where bark has been removed
phloem is under bark so sucrose must be tran
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what is an aphid and what can they be used to collect
give an example of an aphid
what can they use their specialised mouthparts/stylets to do
give an example of an aphid
what can they use their specialised mouthparts/stylets to do
small insects, can be used to collect contents of individual phloem sieve tube cells
greenfly
penetrate sieve tubes to feed on sap
greenfly
penetrate sieve tubes to feed on sap
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what does an aphid being anaesthatised with c02 allow to happen
what does this mean the pure phloem sap can be
why is this technique more accurate than a human with a syringe
what does this mean the pure phloem sap can be
why is this technique more accurate than a human with a syringe
stylet can be cut off and left in stem
collected through stylet for analysis
aphids enzymes ensure stylet doesnt get blocked
collected through stylet for analysis
aphids enzymes ensure stylet doesnt get blocked
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what does FIX mean in context of : fix it during photosynthesis to form photysnthates
convert into organic compound
e.g. C02 -> glucose
e.g. C02 -> glucose
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what is the mass flow hypothesis as an attempt of explaining transolcation
sugars flow passively from areas of high concentration in the leaf (source) to areas of low concentration e.g. growing tissue (sinj), down a pressure gradient
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how does this theory work
-sucrose,photosynthate,loaded by active transport into sieve tubes with ATP
-water enters sieve tubes along water pot. gradient by osmosis
-sieve tube pressure increases+sucrose moves down pressure gradient through phloem to sinks
-water enters sieve tubes along water pot. gradient by osmosis
-sieve tube pressure increases+sucrose moves down pressure gradient through phloem to sinks
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continued
-sucrose unloaded by active transport into cells at sinks
-water moves by osmosis out of phloem as sucrose is removed and pressure in phloem tissue gets lower at sink
-water moves by osmosis out of phloem as sucrose is removed and pressure in phloem tissue gets lower at sink
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What are some arguments against the mass flow theory
-doesnt explain sieve plated that seem to act as barriers to flow
-sucrose and amino acids have been observed moving at different rates and in different directions
-sieve tubes have high rate of ATP consumption + translocation is slowed/stopped if respiat
-sucrose and amino acids have been observed moving at different rates and in different directions
-sieve tubes have high rate of ATP consumption + translocation is slowed/stopped if respiat
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what are three alternative theories of the mass flow theory in explaining translocation
-streaming in cytoplasm of sieve tubes could be responsible for bidirectional movements
-protein filaments observed passing through sieve pores suggesting different solutes are transported by different filaments
-active process: cyanide + low temp slow tr
-protein filaments observed passing through sieve pores suggesting different solutes are transported by different filaments
-active process: cyanide + low temp slow tr
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What is a mesophyte
Where do they grow best
What are three examples of mesophytes
Where do they grow best
What are three examples of mesophytes
most plants in temperate regions and most crop plants
well drained soils
moderately dry airs
decidous trees, bulbs and corms, annual plants
well drained soils
moderately dry airs
decidous trees, bulbs and corms, annual plants
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How are decidous trees adapted to survive at unfavourable times of the year
How are bulbs+corms adapted to survive at unfavourable times of the year
How are annual plants adapted to survive at unfavourable times of the year
How are bulbs+corms adapted to survive at unfavourable times of the year
How are annual plants adapted to survive at unfavourable times of the year
shed leaves in autumn for winter and grow new leaves in spring
produced by non woody plants to survive underground in winter
produce seeds+die in same year: seeds survive winter frost+germinate next spring when conditions are better
produced by non woody plants to survive underground in winter
produce seeds+die in same year: seeds survive winter frost+germinate next spring when conditions are better
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What are hydrophytes and what is their environment
Give an example of a hydrophyte
Give an example of a hydrophyte
water plants that live submerged/partially submerged in water
water lily
water lily
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what does stomata being on the upper epidermis do for hydrophyte
what do the very large air spaces on the stems and leaves provide the hydrophyte with
why do the leaves have a thin or non existent cuticle
what do the very large air spaces on the stems and leaves provide the hydrophyte with
why do the leaves have a thin or non existent cuticle
allow gas exchange with air above
buyoancy for leaves and act as resovoir of oxygen and carbon dioxide
no need to reduce water loss as they already live in or on water
buyoancy for leaves and act as resovoir of oxygen and carbon dioxide
no need to reduce water loss as they already live in or on water
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why is the xylem tissue of a hydrophyte poorly developed
why is their little lignin in the plant tissues
why is their little lignin in the plant tissues
no need to transport large quantites of water as the plant is aquatic
water is a supportive medium so little lignin is needed to support the xylem tissue
water is a supportive medium so little lignin is needed to support the xylem tissue
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what is a xerophyte and what is its environment
give an example
why are sand dunes a location xerophytes would be
give an example
why are sand dunes a location xerophytes would be
adapted to conditions of low water availability, hot dry desert conditions or exposed windy conditions
marram grass
dry and windy as at the coast and wind comes off the sea
marram grass
dry and windy as at the coast and wind comes off the sea
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Why does the xerophyte having sunken stomata in pits cause less water to be lost by transpiration
Why is less water lost by transpiration due to hairs on the surface of the xerophytes leaf
Why is less water lost by transpiration due to hairs on the surface of the xerophytes leaf
water vapour trapped in pits, decreases water potential gradient between inside and outside of leaf
water vapour trapped between hairs, decreases water potential gradient between inside and outside of leaf
water vapour trapped between hairs, decreases water potential gradient between inside and outside of leaf
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what does the thick waxy cuticle mean for the xerophyte
why do the xerophyte's rolled leaves result in less water being lost by transpiration
what does the reduced leafsize/spines mean for the xerophyte
why do the xerophyte's rolled leaves result in less water being lost by transpiration
what does the reduced leafsize/spines mean for the xerophyte
reduce water loss from epidermis
stomata less exposed to atmosphere, vapour trapped and so water potential gradient between inside and outside of leaf decreases
reduces SA from which transpiration can occur
stomata less exposed to atmosphere, vapour trapped and so water potential gradient between inside and outside of leaf decreases
reduces SA from which transpiration can occur
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Other cards in this set
Card 2
Front
What is the transport system in plants for transport of water and mineral ions
Back
need water and mineral ions only available in soil
from roots to leaves
transported upwards in hollow tubes = xylem tissue
from roots to leaves
transported upwards in hollow tubes = xylem tissue
Card 3
Front
What is the transport system in plants for transport of the products of photosynthesis - photsynthates
Back
Card 4
Front
Leaf
Back
Card 5
Front
Stem
Back
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