Transport in plants - xylem Flashcards
What is the function of the xylem?
To transport water and mineral ions in solution up the plant
Which part of the xylem actually transports the water and mineral ions?
Xylem vessel
What is the structure of the xylem vessels?
Long, tube-like structure
What are xylem vessels made from?
Dead cells
How are xylem vessels joined?
End to end with no end walls
What is the benefit of the xylem vessels having no end walls?
The water can move uninterrupted up the plant
Does water move with gravity or against gravity?
Against
What combined action of two things cause the water to move up the plant?
Cohesion
Tension
What is transpiration?
The water evaporating out of the top of the plant out of the leaves
What does transpiration create in the plant? What does this cause to happen?
Tension
More water molecules being pulled into the plant
How does cohesion help water move up a plant?
When some water molecules move, other follow so the whole column of water moves up
Where does the water move into the plant from? Where does it go?
From the roots into the stem
What happens during transpiration when the stomata open?
The water evaporates out of the leaves down the water potential gradient as theres more water inside the plant than outside
What are the 4 main factors which affect the rate of transpiration?
Humidity
Wind
Temperature
Light intensity
How does humidity affect the transpiration rate?
The lower the humidity, the faster the rate of transpiration
The air outside is dryer so theres a steeper water potential gradient
How does wind affect the transpiration rate?
The windier it is, the faster the transpiration rate
The wind blows any water molecules away from the leaves which steepens the water potential gradient
How does temperature affect the rate of transpiration?
The higher the temperature, the faster the transpiration rate
The water molecules have more energy so they evaporate faster out of the leaf
How does light intensity affect the rate of transpiration?
The lighter it is, the faster the rate
When its lighter, the stomata open to allow the water molecules to leave
What piece of equipment is used to measure the transpiration rate?
Potometer
