Chapter 36-Transport in Vascular Plants Flashcards
What does the apoplast consist of?
everything external like the plasma membrane, cell walls, extracellular spaces, and interior dead cells like vessel elements and tracheids.
What does they symplast consist of
entire man of cytosol in living cells as well as the plasmodesmata
What is the apoplastic route
moving water and solutes through the cell wall and extracellular spaces
What is the symplastic route
moving water and solutes through the continuous cytosol
What do plants cotransport with
hydrogen ions
What is the Casparian strip
A barrier made of waxy material to prevent water and minerals from passing through the deepest part of the plant via the apoplastic route.
How do plants generate root pressure
roots pump minerals into the xylem so water can be pumped in. minerals don’t escape because of the casparian strip.
explain the cohesion-tension hypothesis
transpiration, the loss of water vapor form leaves and other aerial parts of the plant, causes water vapor to move out of the plant via the stomata. This causes a dip in the water. In order to fill in these dip, water from the surround cells(xylem) is pulled to these dips.
Which hormone signals the stomata to close
abscisic acid ABA
How does the stomata open and close
blue light stimulates the proton to pump out H+ . This causes K+ to be pumped in along with cotransport H+/Cl . The change in solute concentration makes water rush it and swell open the stomata. ABA signals the sopping of H+pumping and opens the Cl channels to flow out. This causes the K+ channels to open and flow out of the stomata.
How do plants get sugar into the sugar sinks
Some species move it form the mesophyll cells to sieve tube elements via the symplastic route. Others use both symplastic and apoplastic route where much of it is moved by apoplastic route and accumulates in the sieve tube elements.
Explain the process of pressure flow
Source cell(leaf) moves the sugar and water to the sieve tube and reduces water potential by unloading the vessel’s water into the sieve tube. This cause a bulk flow of positive pressure to flow down into a sink cell(storage root) and the water is translocated to the xylem to be recycled.
