Specialised Plant Cells Flashcards
What does the phloem contain that means there is a lot of space to transport nutrients? (2)
Sieve tube elements
Companion cells
What do companion cells do?
Supply energy for respiration for active transport of sucrose in and out of sieve tubes
What do companion cells contain?
Mitochondria that supply energy
What are xylem vessels?
Dead cells which have no cytoplasm or cell contents
Why do xylem contain dead cells?
Means there is more space for water containing mineral ions to move through
What are the holes in the xylem walls called?
Pits
What are pits?
Holes in the walls to allow water and mineral ions to move out
What strengthens xylem’s walls?
Ligin rings
What do ligin rings do?
Make the walls strong and prevents them from collapsing
Why do xylem have no end walls?
So they can from a long tube for water to flow through easily
What affect does light intensity have on plants?
Causes the stomach to open which increases the rate of evaporation of water from a leaf so more water is take up to replace it
What affect does air movement have on plants?
Wind blows most air away from the stoma keeping diffusion gradient high. More air movement, the higher the transpiration rate
What affect does temperature have on transpiration?
The higher the temperature the more energy water molecules have so the faster the rate of transpiration
What is a pot metre used for?
Measure the rate of transpiration
What is transpiration?
The loss of water by evaporation from leaves
