Topic 3, Unit 8 - Transport in Plants Flashcards
(15 cards)
Features of phloem
- water travels both ways
- no lignin
- contain sieve plates
- made of living cells
Function of phloem
- transport nutrients (Sucrose and Glucose)
- Involved in translocation
Features of xylem
- water travels in one direction
- strengthened cellulose and lignin cell wall
- hollow lumen for more space
- made of dead cells
Functions of xylem
- transport water and minerals
- provides support
- transpiration
Difference between xylem and phloem
- Phloem made of living cells, Xylem made of dead cells
- Phloem contains sieve plates, xylem doesn’t
- Xylem has a one way flow, Phloem has a 2 way flow
- Xylem transports water and minerals, Phloem transports nutrients ( Sucrose & Glucose)
Definition Transpiration
- Process which moisture is carried
- through plants from roots to the stomata
- where changes to vapor
- released into the atmosphere
Water uptake pathway
Soil Particle -> Root hair cell -> Root cortex cell -> Xylem vessel
Soil particle at high WP then through osmosis becomes low WP at root hair cell
Factors affecting Transpiration
1) Wind speed - Higher windspeed, Increase transpiration rate (TR)
2) Humidity - Higher humidity, Decrease TR
3) Light intensity - Higher = Higher TR
4) Temperature - Higher = Higher TR
5) Water supply - Lower = Lower TR
Functions of transpiration stream
- transporting mineral ions
- providing water to keep cells turgid to support plants
- providing water to leaf cells for photosynthesis
- keeping leaves cool by evaporation
How plants are adapted for water uptake
- Root hair cells = high surface area
- Hollow Narrow Xylem - for easy pathway for water flow
- Many air spaces - increases rate of evaporation
- Stomata = Opens to allow transpiration
Tropism
Growth in response to stimulus
Positive tropism
Moving towards stimulus
Negative tropism
Moving away from stimulus
Phototropism
Move towards the sun
Geotropism
Move towards direction of gravity
