TRSPT in Plants 2013.5
TRSPT in Plants 2013.5
TRSPT in Plants 2013.5
Increase SA
to Vol.
Ratio
Increase
rate of
absorption
;)
1. Since sap is concentrated, has a lower WP than soil solution > water
enters root cell (from soil soln) by osmosis (down a concentration
gradient)
2. This lucky root hair cell sap becomes diluted and has a HWP than the
inner cell > Water moves into inner cell through pp plasma
membrane by osmosis
3. Process continues and water passes through cortex cells until water
reaches xylem and moves up the plant
3 Anti-Gravity Techniques
1. Root pressure
-
Living cells around xylem uses active transport to pump ions into
vessels
Lowers water potential in xylem & water can pass into xylem by osmosis
The build up of water forces the water up out
3. Transpiration pull
Water moves out of mesophyll cells
Importance of Transpiration
-
4 Factors
-
Humidity
o Difference in concentration gradient
Wind
o Blows away water vapour
o Maintain concentration gradient
Temperature
o Rate of evaporation from mesophyll increases > Rate of
transpiration increases
Light intensity
o Causes stomata to open and widen
Xylem
- Carry water and mineral salts
- Mechanical support (Lignin)
Adaptations
- Empty lumen, no protoplasm
o Reduces water resistance
o Efficient water support
- Walls thickened with lignin
o Prevents collapse of vessel
- Vessels bundled together
o Mechanical support to plant
How to remember adaptations:
Lestrade Promised Loki Books
Phloem
-
Fandom analogy:
Sieve tubes > The Doctor
Companion cells > Donna
After many cycles of regeneration, the doctor is empty (like the sieve cells) and need somebody to support them. Then comes Donna
the companion to provide nutrients to him and helps him carry out his duties.
Adaptations
- Small holes in sieve plates
o Allows rapid flow of manufactured food
- Mitochondria in companion cells
o Provides energy for transport of sugars from mesophyll to sieve tubes
(active transport)
o Carries out metabolic processes to keep sieve tubes alive
o Provides nutrients
How to remember:
Sherlocks Reichenbach Fall & Moriartys End Made Peter Numb