mass transport in plants
- Created by: Margaret Hobart
- Created on: 15-05-21 15:21
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- mass transport in plants
- Xylem
- transports water up stem and leaves
- passive
- cohesion and tension help the water move up, against gravity
- transpiration creates tension which pulls water up the leaf
- water molecules are cohesive
- continuous column of water
- water molecules are cohesive
- factors affecting transpiration
- the lighter it is the faster rate
- stomata open when it's light
- the hotter the faster rate
- water evaporates faster which increases concentrationgradient
- the lower the humidity the faster the rate
- the windier it is the faster the rate
- blows away water, increasing gradient
- the lighter it is the faster rate
- transports water up stem and leaves
- phloem
- transports organic substances and ions (solutes)
- translocation:movement of solutes (assimilates)
- needs energy (ATP)
- from 'source' to 'sink'
- enzymes maintain concentrationgradient by changing solutes at the sink into something else
- sieve tube elements
- living cells that form the tube for transporting solutes
- no nucleus or organelles
- companion cells
- 1 companion cell per sieve tube element
- carries out living functions for sieve tube elements
- living cells that form the tube for transporting solutes
- mass flow hypothesis
- supporting : active transport of sugars
- against: solutes move at different speeds
- Xylem
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