Transport In Plants Flashcards
What are the two types of transport vessels in plants?
Xylem vessels and phloem vessels.
What do xylem vessels transport?
Water and minerals from the roots to the stem and leaves.
What do phloem vessels transport?
Food materials (mainly sucrose and amino acids) from photosynthesising leaves to non-photosynthesising regions in the roots and stem.
What are vascular bundles?
Groups of xylem and phloem vessels arranged throughout the root, stem, and leaves.
What is the function of xylem?
Transport tissue for water and dissolved mineral ions.
What are the adaptations of xylem vessels?
Cells joined end to end with no cross walls, essentially dead cells, and outer walls thickened with lignin.
Why are xylem cells dead?
To allow free passage of water.
What is lignin?
A substance that thickens the outer walls of xylem vessels, strengthening the tubes.
Xylem and Phloem diagram
Xylem diagram
What are root hair cells?
Root hairs are single-celled extensions of epidermis cells in the root.
How do root hair cells absorb water?
They absorb water and minerals from the soil by osmosis.
Why does water enter root hair cells by osmosis?
Because soil water has a higher water potential than the cytoplasm of the root hair cell.
What is the significance of the large surface area of root hair cells?
It increases the rate of absorption of water by osmosis and mineral ions by active transport.
What is the pathway of water movement in plants?
Root hair cell → root cortex cells → xylem → leaf mesophyll cells.
How can the pathway of water through a plant be studied?
By placing a plant stem in dyed water and observing the color change in the leaves.
What is transpiration?
The loss of water vapour from plant leaves by evaporation followed by diffusion through the stomata.
How is xylem adapted for water transport?
Xylem cells become hollow and form a continuous tube for water and mineral ions to travel through.
What are the functions of transpiration in plants?
Transporting mineral ions, providing water for turgidity, photosynthesis, and cooling the leaves.
How can the effect of temperature on transpiration rate be investigated?
By comparing transpiration rates in a cold room and a warm room.
What happens to the rate of transpiration as temperature increases?
The rate of transpiration also increases.
How can wind speed affect transpiration rate?
Using an electric fan to mimic different wind speeds; as wind speed increases, the rate of transpiration increases.
What are root hair cells?
Root hairs are single-celled extensions of epidermis cells in the root.
How do root hair cells absorb water?
They absorb water and minerals from the soil by osmosis.
