Adaptations for transport in plants Flashcards
(24 cards)
Why would the blockage of xylem vessels cause the wilting of plants and the death of trees?
Xylem transports water from the roots up to the plant to the leaves
A lack of water causes the leaf to lose turgor and become flaccid
This reduces the surface area, and there is less water for photosynthesis
This means that less products of photosynthesis conform for respiration and growth
Why do the symptoms occur in both roots and leaves in the phloem but not in the xylem?
Phloem transport is bidirectional up and down the plant
Why is a plasmodesmata important in the phloem
It transports sucrose and ATP
How is a palisade mesphyl adapted for photosynthesis?
High Number of chloroplasts
Benefits of having a sunken stomata a thick cuticle and fewer stomata
Sunken stomata -trap water vapour to reduce diffusion gradient
Thick cuticle - waterproof
Fewer stomata - fewer spaces through which water vapour can be lost
In a potometer experiment, why is the plant cut underwater?
Prevents air bubbles entering the xylem which would break hydrogen bonds affecting cohesive forces between water molecules
Apoplast root
Along cell walls
Symplast root
Through cytoplasm via the plasmodesmata
Vacuole pathway
Through the tonoplast
Route into the vascular tissue
Endothermic has Casperian strip which is waterproof and blocks the Apoplast pathway
Water is forced into Symplast
Active transport of minerals into xylem lowest water potential in xylem so water enters by osmosis
Why would a plant growing in waterlogged soil experience a reduction in root pressure?
Less oxygen for respiration
Less respiration so less ATP for active transport of minerals into the endodermis
This lowers the water potential as a result of less active transport of minerals into xylem
Less water enters xylem which lowers root pressure
What happens to transpiration if wind speed decreases?
Transpiration rate decreases
Humidity increases which decreases the steepness of the diffusion gradient
Why is the water uptake from the photometer not the exact transpiration rate?
Water is used in photosynthesis and water is produced in respiration
Why would the distribution of stomata differ if there is shading?
if the surface is shaded, there will be a higher density of stomata to reduce water loss
if neither surface is shaded, there will be equal distributions of stomata and water loss will be equal on both sides
Stomata open when potassium ions are actively transported into the cell explain why this would cause this tomato to open
Potassium ions reduce water potential in guard cell
water moves in by osmosis down a water potential gradient
cells become turgid
end of guard cells have a thinner wall than centre so ends of guard cell expand and stomata opens
Use the mass flow model to explain how the sugars are transported to the potato to be stored as starch
Leaves photosynthesis to make sugars and are moved into the phloem
water potential falls and water is absorbed by osmosis due to hydrostatic pressure
Flow from high to low pressure regions
sucrose is converted into starch
Water potential rises and water is lost
Why is it an advantage for the tuber to act as a source?
Sugars allow rapid growth as they are used to form cellulose for growth and sugars are used for respiration
What tissue are root hair cells located in?
Epidermis
Cyanide was added to the soil and the water level in the tube remained constant in a root pressure experiment. Why is this?
Cyanide prevents aerobic respiration as it is a respiratory inhibitor
No ATP means no active transport of ions
Water potential of the endodermis is not lowered so water is not taken up by the xylem
Two mineral ions that plants take up through the root hair cells
Nitrates and phosphates
Why would having a thin wall being adaptation for root hair cells?
Shorter pathway to reach cell membrane
Why would having a thin cuticle increase the efficiency of uptake of ions in root hair cell?
Ions can come into contact more easily with transport proteins in cell membrane
Why does Apple route go into Simlat route?
The Casperian strip in endodermal cells is waterproof
How can plants and fungus both benefit from having a mutualistic relationship?
Fungi can absorb mineral ions from a larger volume of soil than root hair
Fungi carry more ions to plants than it could otherwise take up
Fungi within plant tissues have more protection than those in soil
Fungi can absorb nutrients from plant cells
