The Need For Transport Flashcards
Different parts of the leaf
Upper epidermis Palisade mesophyll Spongy mesophyll Vein Lower epidermis Guard cells Stomata
State why water is required in plants
Needed to transport materials e.g. Nitrates
And as a raw material for photosynthesis
Name the tissue that transports water and minerals in a plant
Xylem
Explain how xylem vessels are specialised to their function
Xylem are lignified for support, to withstand the pressure changes as water moves through a plant ( this stops them bursting)
Define transpiration
Transpiration is the process by which water is lost by evaporation from the leaves of a plant
Describe the movement of water through a plant from the root to the leaf
Water absorption
Water moves from a region of high (soil) concentration to a region of low concentration (root hair cells) by osmosis
Water then continues to move through the root cells into the xylem vessel by osmosis.
Transport up the stem
Water and mineral salts are transported by the xylem up the stem to the top of the plant.
There is also lateral (sideways) movement of water to side branches.
Water then evaporates from the surrounding cells into the air space in the leaf
The waters is then lost through tiny openings in the leaf called stomata by transpiration
Give examples of environmental factors that could increase transpiration rate.
High temperatures
Wind
Low humidity
Give examples of environmental factors that could decrease transpiration rate.
Low temperatures
Low wind
High humidity
Explain how phloem tissue is specialised for its function.
Sieve tube (cytoplasmic strands and sieve plates) with a companion cell
Sugar is transported up and down the plant through cytoplasmic strands
Name the tissue responsible for sugar transport.
Phloem
Upper epidermis function
Protective layer of cells which is transparent to let light through.
Palisade mesophyll function
Rectangular cells which contain many chloroplasts for photosynthesis
Spongy mesophyll function
Loosely packed contains chloroplasts airspaces between the cells to allow gas exchange
Vein function
Part of the transport system. Contains xylem and phloem
Lower epidermis function
Protective layer of cells on the underside of a leaf. Made up of epidermal cells, guard cells and stomata.
Guard cells function
Lots of cells which change shape to open and close the stomata.
Stomata function
Pore on the lower leaf surface which allows entry to CO2 and exit of O2
When do the stoma open and close.
Open
When guard cells are turgid (swollen) - day time
Close
When guard cells flaccid (shrunken) - nigh time