Transport in Plants Flashcards
What does the xylem transport?
transport water and minerals from the roots to the stem and leaves
What are the adaptations of xylem?
Dead Cells - allows free passage of water
Lignin - strength to support the plant
No end walls - continous flow
Pits - lateral movement
What does the phloem transport?
transport food materials (mainly sucrose and amino acids) made by the plant from leaves to other regions
Describe the pathway of water through a plant
Osmosis causes water to pass into the root hair cells, through the root cortex and into the xylem vessels:
root hair cell → root cortex cells → xylem → leaf mesophyll cells
How Root hair cells are adapted for efficient water uptake?
Large surface area
it increases the rate of the absorption of water by osmosis and mineral ions by active transport
What is Transpiration?
Loss of water vapor from plant leaves by evaporation of water at the surface of mesophyll cells followed by diffusion of water vapor through the stomata
What is a transpiration stream?
the flow of water through a plant
How temperature effects transpiration rate?
The higher the temp, the kinetic energy of water molecules increase so they diffuse faster which increases the rate of transpiration.
How does wind speed effects rate of transpiration?
The faster the air movement, the faster the water is moved away from the plant, creating steeper gradient
How humidity effects rate of transpiration?
As the humidity is less, the concentration of water molecules outside the leaf decreases and rate increases
Translocation
The movement of sugars up & down a plant, from sources to sinks, via the phloem (requires energy)
Source
part of plant that release sucrose or amino acids
Sink
part of plants that use or store sucrose or amino acids
Active Transport
the movement of molecules in or out of a cell through the cell membrane, from region of lower concentration to higher concentration (requires energy)
Osmosis/Passive Transport
the movement of water molecules in or out of a cell through the cell membrane, from region of lower concentration to higher concentration (no energy required)
