Lecture 20 Transport in plants Flashcards
Abscisic Acid (ABA)
- Slows growth
- Encourages seed dormancy
– Under high ABA concentrations - Drought tolerance
ABA – Drought Tolerance
- Causes stomatal closure during drought stress
Fig. 36.14 - ABA causes potassium channels in the plasma membrane of guard
cells to open, potassium ions diffuse out - Water follows osmotically
- The accompanying osmotic loss of water reduces guard cell turgor
and leads to closing of the stomatal pores
Is transport within the xylem
apoplastic or symplastic?
Apoplastic
(transports water and minerals)
Is transport within the phloem
apoplastic or symplastic?
Symplastic
(transports sugars + mostly sucrose for transport)
The Casparian strip
closes off the…
A. Apoplastic route
B. Symplastic route
C. Transmembrane
route
A.
Boron
- Micronutrient for plants
– Boron deficiency causes stunted growth - Excessive boron toxic
Plant hormonal regulation differs from
animal hormonal regulation in
that _____.
There are no dedicated hormone-producing
organs in plants as there are in animals
what is symplastic transport
symplast - cytoplasm, transport within cytoplasm from cell to cell using plasmodesma bridges
What is apoplastic transport
transport outside of cell membrane.
Casparian strip
water-proof, prevents apoplastic transport to allow symplastic transport through xylem with selective resources
Endodermis cells
inner layer of cells protecting vascular tissue, contains casparian strip (inner skin)
What mechanism connects casparian strip to xylem cells
ions go through protein channel
How does casparian stip affect boron concentration in the plant?
regulates optimal levels of boron for plant tissues.
How is sucrose transported across the membrane
Active transport
Hydrogen ion facilitates the diffusion after being actively diffused with ATP to create a conc. gradient
In an apple tree that is producing sugars, sugar might flow from __________ to ___________.
leaf to apple
