Topic 8: Transport in plants Flashcards
(18 cards)
What is the function of xylem?
Transport water and mineral ions; provide support.
What is the function of phloem?
Transport sucrose and amino acids.
What are adaptations of xylem?
Thick lignin walls, dead cells, no cross walls, continuous tube.
Where are xylem and phloem found?
In roots, stems, and leaves of non-woody dicotyledonous plants.
What is the function of root hair cells?
Absorb water and minerals from the soil.
Why do root hair cells have a large surface area?
To increase the rate of water and mineral ion uptake.
Describe the pathway of water through a plant.
Root hair cells → Root cortex cells → Xylem → Mesophyll cells.
What is transpiration?
The loss of water vapour from leaves.
How does water vapour leave the leaf?
Water evaporates from mesophyll cells into air spaces, then diffuses out through stomata.
What causes transpiration pull?
Cohesive and adhesive forces between water molecules.
What happens when a plant wilts?
Cells lose water, become flaccid, and tissues collapse.
How does temperature affect transpiration?
Higher temperature increases evaporation, speeding up transpiration.
How does humidity affect transpiration?
Low humidity increases transpiration; high humidity decreases it.
How does wind speed affect transpiration?
Higher wind speed increases transpiration by removing water vapour.
What is translocation?
Movement of sucrose and amino acids in the phloem from sources to sinks.
What are sources in translocation?
Parts of plants that release sucrose and amino acids.
What are sinks in translocation?
Parts of plants that use or store sucrose and amino acids.
Give examples of sources and sinks depending on the season.
Spring: Roots to leaves.
Summer/Autumn: Leaves to roots.
