Structure Of Leaf, Plant Transport Tissue Flashcards
Function of waxy cuticle
Water proof protection layer, stops water being released too early.
Function of upper epidermis
Contains epidermal cells, which have no chloroplasts and are one cell thick. Transport layer, water moves through them
Function of palisade mesophyll layer
Tightly packed cells, receive the most light, therefore contain most chloroplasts. Where most photosynthesis takes place.
Function of xylem tissue
Transports water and minerals.
Transpiration.
Function of phloem tissue
Transports food around the plant as cell sap.
Translocation
Function of spongy mesophyll layer
Gives a large sa/v ratio for max absorption of gases. Air space for evaporated water for efficient gas exchange.
Function of the lower epidermis
Contains stomata, pore like cells that lets co2 in and o2 and H2o out. Guard cells open and close the stomata when turgid and controls water vapour loss.
Transpiration definition
The process by which water evaporates from the leaves, which results in more water being drawn up from the roots.
Why does a plant need water?
- Needs water to combine with co2 in photosynthesis to make glucose.
- Needs dissolved minerals
- Cooling effect, as water evaporates.
- Allows cells to become turgid by osmosis, supporting the plant.
How does water move through a plant?
- Absorption from soil through root hair cells by osmosis.
- Transported through root hair cells by osmosis.
- Evaporation of this water from the leaves (transpiration)
How do plants control the rate of transpiration?
- waxy cuticle
- Guard cells must become turgid before they open stomata.
- Very few stomata on upper layer.
Factors that increase the rate of transpiration.
- Light intensity
- Temperature increase.
- Increase air movement
- Decrease humidity.
