3.1.3: Transport In Plants Flashcards
What is a potometer used for?
A potometer measures the rate of transpiration
It can investigate the effect of environmental variables on the rate of transpiration.
What must be done to a plant sample before using a potometer?
The plant must be cut underwater
This prevents air from entering the xylem and breaking the water column.
How is the potometer prepared before measuring transpiration?
The potometer is filled with water and all air bubbles are removed
The cut leafy plant is attached using rubber seals and petroleum jelly to make it air-tight.
What is recorded to estimate the transpiration rate using a potometer?
The distance that an air bubble has moved towards the plant
This distance is used to calculate the volume of water evaporated.
How is the transpiration rate calculated?
The volume of water evaporated is divided by the time it took to lose that volume
This gives an estimate of the transpiration rate.
What environmental conditions can be varied in a potometer experiment?
Conditions such as light, wind, and humidity
For example, a lamp can replicate sunlight, a fan can replicate wind, and a plastic bag can increase humidity.
How do root hair cells absorb water?
Root hair cells absorb water through osmosis
They are adapted with thin walls and a large surface area to maximize osmosis.
What are the two pathways for water transport in plants?
Apoplastic pathway and symplastic pathway
The apoplastic pathway involves movement through the cell wall, while the symplastic pathway involves movement through the cytoplasm.
What is the symplast pathway?
The symplast pathway is through the cytoplasm of a cell
Water moves from cell to cell by osmosis through plasmodesmata.
What are plasmodesmata?
Gaps in each cell wall that allow water to move between cells
They are crucial for the symplastic pathway of water transport.
What happens to the water potential as water moves from cell to cell in the symplastic pathway?
Each successive cell’s cytoplasm has a lower water potential
This gradient allows water to move by osmosis.
Fill in the blank: Water is absorbed into plants through the _______.
root hair cells
True or False: The apoplast pathway involves movement through the cytoplasm.
False
The apoplast pathway involves movement through the cell wall.
What is the role of vacuoles in root hair cells?
Vacuoles help maintain turgor pressure
They store water and contribute to the osmotic potential of the cell.
