Transport in plants 2 Flashcards
How does plants roots maximize absoprtion
root hair cells increase surface area
What process is the uptake of water?
Its a passive process and occurs by ossmosis
What process is the uptake of minerals?
Its a passive and an active process, can occur either by diffusion or active transport
State the two pathways water & dissolved solutes can take in order to move across the cortex
-Apoplastic
-Symplastic
Describe apoplastic pathway
-Most water travels through this pathway.
-It occurs faster than symplastic pathway
Moves from cell wall to cell wall, by diffusion. Until it reaches the endodermis, which blocks the water due to the casparian strip (made up of suberin which is waterproof). From here the water continues through symplastic pathway
Desribe symplastic pathway
Water travels through the cytoplasm and the plasmodesmata. Water travels by osmosis into the cell . It is slower than apoplastic pathway
What happens when the plant ages in relation to the apoplastic pathway?
The casparian band thickens. Which helps control which mineral ions must move into the xylem.
Where does apoplast and symplast pathways matter and occur?
Root and leaves of the plant
Define transpiration
Loss of water vapour from the plant to its environment by diffusion.
What is transpiration stream
movement of water from the roots to its leaves
Roles of transpiration
- Provides cooling for the plant
- Uptake of mineral ions
- Turgor pressure of cells provide support to leaves and non woody stems
How are xerophytes adapted to dry conditions?
Sunken stomata
- Traps moist air, transpiration decreases
Trichomes present
- Traps moist air, reduces water p. gradient, transpiration decreases
Hinge cells
- When flaccid they cause leaves to roll, creating a humid space
Lower epidermis
- No stomata present
- Thick waterproof cuticle
Leaves reduced, to scales, spines or needles
- Surface area is less, transpiration decreases
Multilayered epidermis
Prevents loss of water vapor
Helps protect from heat
Outline the importance of water as solvent in plants
- Mineral ions dissolved in water providing energy
- Transports solutes in xylem or phloem
- Metabolic reactions occur in water
- Dissolves Co2 / O2 for respiration
Difference between source and sink
Source is the site of synthesis I
Sink is the site at which the assimilates are used for growth and energy
