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BIOL V03: Transport in Plants (Campbell-10: Ch 36)
©2014 copyright Marta D. de Jesus
(Skip section 36.1, 36.2 past left column on p782, 36.6)
I. Movement through membranes (look also at Ch 7)
A. cell membranes
1. diffusion
osmosis
2. facilitated diffusion
B. active transport
II. Water in a plant
A. balance
B. xylem
C. 3 compartments at cell level
1.
2.
3.
D. ways of moving water up a plant
1. in the roots
guttation
c. 2 main routes for water flow
1) apoplast
2) symplast
3) transmembrane route
2. up the entire plant
a. first proposed mechanism: air pressure / capillary flow
b. cohesion-tension theory
1) cohesion
adhesion
2) tension
3) water potential (
c. in different compartments
1) in soil
2) enters roots
mycorrhizal fungus
(i) can now travel into plant by:
- apoplast
- symplast
- transmembrane route
(ii) when get to endodermis
Casparian strip)
(iii) then enters vasc. cylinder
3) up in trunk
4) up in leaves
5) air outside of leaves
(i) at 90% humidity
(ii) at 50% humidity
d. theoretically possible
e. as water molecules leave
f. ultimately powered
E. can’t lose water too fast but do need openings to get CO2
1. guard cells
2. plant controls this by regulating
3. generally open
circadian rhythm
4. emergency closing
abscisic acid
III. Moving sugars
A. phloem
B. sugars made
C. companion/transfer cells
D. sieve-tube members
E. sink