Plant Transport Flashcards
What do plants need to be transported
Transport system of a plant consists of specialised tissues to transport specific substances e.g in water it’s transported from the roots up the stem in the xylem .
In minerals, roots up the stem to leaves in the xylem.
In glucose transported from the leaves to roots (no light no photosynthesis ) , young leaves and other growing points ( need energy ) in the phloem
Example of a mineral
Magnesium , found in chloroplasts
What are xylem like
Dead cells , thick rings of lignin to support the plants and stop it collapsing, cells walls are made of lignin , impermeable , it transports water and ions from roots to leaves up the plant
Why are xylem lignified
Water proof strong
What are phloem like
Living , cell walls are made of cellulose , it’s permeable , transports sugars and amino acids and materials carried from leaves to roots down the plant
Where is xylem
In root makes an X in cross section closer to the inside
What are phloem and xylem called
The vascular bundle
Why does a plant not watered wilt
Cells lose water and become flaccid so the leaf is no longer upright and turgid.
Why does a plant watered too much wilt
Roots need oxygen but thy are drowned can’t respire and die
What happens if transpiration is stopped
No water exits no movement in xylem no uptake of minerals plants have nitrate deficiency and then yellow
What are the different variables
Independent - change
Dependent - measure
-control - the same
How do you calculate % change
Initial value. X 100
What are root cells adapted to do
Adapted to get water and mineral ions into the plant through osmosis have a large surface area
How to reduce transpiration
Stems instead of leaves minimises surface area reduces transpiration
Thick waxy skin reduces water loss through stomata
Round or hairy to stop wing reducing humidity or to trap water vapour outside the plant making it humid
How does temperature effect transpiration
Increases because molecules have more kinetic energy
How do atmospheric humidity levels affect transpiration
Decrease , concentration gradient air has more water vapour slower rates
Stomata density
Increase more stomata more places for water to get out
Thickness of waxy cuticle
Decrease thickness makes it harder for water vapour to get out
Wind speed
Increase wind moves water vapour away increasing concentration gradient
Why do plants need a transport system
Diffusion is to slow and does not meet their metabolic needs . Transport system takes substances into the middle of the organism where they can diffuse into cell
Where are stomata
On lower surface
How do stomata open
Water moves and causes them to swell opening the stomata and allow gas exchange and transpiration
How does water get into plant
From soil osmosis into root hair cells providing water to the plant
What is the evaporation of water known as
Transpiration
Why do roots have hairs
Increase surface area
Why do roots have solutes dissolved in them
Have concentration gradients so water can go from soil to root so root has a low water water potential
Why are roots shaped like that
Long thin outer projection of the root cell or treated between soil particles reaching the soil water
Where is epidermis
Surrounds stomata covered in waxy cuticle impermeable to water
How does water pass out of leaves
Diffusss out As water vapour through stomata . Water leaves cells of the leaf mesothelioma and evaporates into the air spaces between the spongy Mesophyll cells
What is the transpiration stream
Supplies water from the leaf cells to carry out photosynthesis
Carries mineral ions dissolved in the water
Provides water keeps the pant cells tithi
Allow evaporation from the leaf surface which cools the leaf
Do phloem and xylem have cytoplasm
Phloem yes , it is a sieve tube , xylem no
Why are stomata on the lower surface
If they were on upper leaf surface leaf would loose to much water because the stomata are exposed to direct sunlight which produces a high rate evaporation. Also less air movement on the underside of leaves
How does light intensity affect transpiration
Opening of stomata in light
How do minerals enter the cell
By active transport
