The transport of water Flashcards
The transport of water is…
passive and it is driven by evaporation from the leaves.
The process of transpiration starts in…
leaves.
Transpiration is the process of…
evaporation of water from the leaves by solar energy.
Transpiration from leaves reduces…
the water potential in the leaves and creates a water potential gradient throughout the plant.
The walls of the mesophyll are…
wet, so some of this water evaporates into the air spaces. The air inside the plant is saturated with water vapour.
The air inside the internal spaces of a plant has…
direct contact with the air outside, through stomata.
Stomata are…
small pores which allow CO2 to get inside.
As there is a water potential gradient between the leaf and air outside, the water…
vapour diffuses out of the plant.
Most of the water absorbed by plants…
evaporates by the process of transpiration.
Water moves through mesophyll cell…
wall or out of the mesophyll cytoplasm into the cell wall.
Water leaves xylem through…
a non-lignified area such as pit. It enters either the cytoplasm or the cell wall of a mesophyll cell.
Factors affecting transpiration:
- humidity
- wind speed and temperature
- light intensity
- very dry conditions
Humidity:
If the water potential between air and air spaces is steep, the rate of transpiration increases.
Wind speed and temperature:
Transpiration increases by an increase in wind speed or rises in temperature. As the water evaporates more and humid air is blown away.
Light intensity:
Stomata must open to allow CO2 to get inside for photosynthesis. During the day, the transpiration increases as stomata are open.
Very dry conditions:
If the water potential gradient is too steep, plants may close the stomata, even if it reduces the rate of photosynthesis.
Evaporation helps leaves to…
cool down, as it absorbs heat energy from the plant cells. This reduces the temperature.
If the plant loses more water than it can absorb…
the cells become less turgid, and the plant wilts.
