Transpiration and Translocation Flashcards
Name the two tissues that transport substances around the plant.
Xylem
Phloem
What structure do they form?
Tubes
Phloem’s structure
The phloem is made from columns of elongated living cells.
They have small air pores in the end walls of their structure to allow cell saps to move through.
Phloem’s function
The phloem transports food substances, especially sugars, from the leaves to the rest of the plant.
The transport goes in both directions: from the roots to the leaves and from the leaves to the roots.
Translocation
The transportation of food substances in the phloem from the leaves to the roots and back
Xylem’s Structure
The xylem is made from columns of dead xylem cells.
They have no end walls so they join together to create a hollow tube that is strengthened by lignin
Xylem’s function
They carry Water and mineral ions from the roots to the stem and then to the leaves
Transpiration stream
The movement of water from the roots to the leaves
Transpiration
The loss of water from a plant
Process of Transpiration
- Water evaporates from the plants and diffuses out through the stomata.
- This creates a shortage of water in the plants, so water is drawn up from the roots to replace it.
- This creates a constant transpiration stream of water
What are the 4 factors that affect the rate of transpiration
Temperature
Light intensity
Air flow
Humidity
Temperature
As temp. increases, the rate of transpiration gets faster.
Light Intensity
The brighter the light, the greater the rate of transpiration.
This is because the stomata closes in the dark and photosynthesis will not occur. If the stomata is closed, very little water will be able to escape
More evaporation of water
Airflow
The greater the air flow, the higher the rate of transpiration, because more water will be swept away creating a better concentration for the plants
Humidity
The drier the air,the greater the rate of transpiration.
