Unit 2 - Key Area 5 - Transport Systems in Plants Flashcards
Why do plants require transport systems?
Plants require transport systems to transport sugar, water, and nutrients around the plant.
Which plant organs are used to transport substances?
The plant organs which are used to transport these substances are the roots, stems, and leaves.
What do xylem vessels do in a plant?
Water is transported through xylem vessels.
What is xylem made of?
Xylem is made of dead hollow tubes with rings of lignin.
Why are xylem cells lignified?
Xylem cells are lignified to withstand the pressure changes as water moves through the plant.
How does water move from the soil to the xylem vessel?
Water and minerals enter a plant through root hair cells.
Water moves by osmosis from the soil (higher water concentration) to the root hair cell (lower water concentration).
This continues through the root cell into the xylem vessel.
What do phloem cells do in plants?
Phloem cells transport sugar produced by photosynthesis up and down the plant.
What is phloem made of?
Phloem is living tissue made up of sieve tubes, sieve plates, and companion cells.
What do companion cells provide?
Companion cells provide the energy for the sieve cells
What do the sieve plates do?
The sieve tubes have pores through which sugar is transported from cell to cell.
What are stomata and where are they found?
Stomata are pores on the underside of a leaf.
What is the function of stomata?
They allow the entry of CO2 and the exit of O2 and water vapour.
What is the function of the guard cells?
Each stomata is surrounded by guard cells which change shape to open or close the stoma.
What is transpiration?
Transportation is the process of the water moving through a plant and it’s evaporating through the stomata.
The rate of transpiration is affected by wind speed, humidity, temperature, and surface area.
Soil to the root hair cells - Osmosis
Root cells to Xylem - Osmosis
Xylem to leaves - Transpiration
Leaves to air via stomata- Evaporation
Describe the experiment used to investigate the rate of transpiration
A bubble potometer is used to measure transpiration rate. An air bubble allows the measurement of water uptake by a leafy shoot. The water uptake is approximately equal to the transpiration rate. The potometer can be placed in different external conditions and their effect on transpiration measured.
