Water and Solute movement Flashcards
What are examples of drought sensitive plants?
Rice. wheat
What are some examples of drought tolerant plants?
Cacti, succulents
What is an example of a resurrection plant?
Tripogon
What is the category of plants that can survive even lith <5% relative water content?
Desiccation tolerant or resurrection plants.
Why is water so important for plants?
- Makes up 80-95% of tissues
- Helps transfer food, essential nutrients around the plant
What is the process that induces the opening of stomata?
- Detection of blue light/shade or non intense light
- Influx of potassium
- Accumulation of solutes in the guard cells
- Stomata opens
What is the process that induces the closing of stomata?
- Water loss stres and abscisic acid
- Efflux of postassium
- Decline in solutes in guard cells
- Closing of stomata
What are some influences that cause stomatal closure?
- Increased CO2 concentration
- High temp
What is bulk flow?
The movement of water as being pulled by other moving water molecules.
What are aquaporins?
Regulated, membrane-bound water channels.
What do aquaporins do?
Help facilitate rapid plant movements, such as motor cells.
Apoplastic pathway?
water moves through cells walls but remains outside the cell membrane
Symplastic pathway?
water travels inside cells and moves to the next cell via plasmodesmata
Transcellular pathway?
water moves sequentially from one cell to the next by crossing membranes
What is the endodermis?
band of cells around the vascular tissue of the roots.
Water and solutes must cross endodermis cell membranes to reach the xylem.
What is the Casparian strip?
cell walls of endodermis impregnated with suberin to form a barrier to water and solute movement
What are the two functions of companion cells?
Responsible for loading and unloading sugars and other compounds from sieve elements/to sink
Takes over critical metabolic functions that are reduced or lost in sieve elements
What is translocation?
The process whereby the products of photosynthesis are transported through phloem.
What is a sugar source?
An organ that produces sugar, such as mature leaves.
What is a sugar sink?
An organ that is a consumer of sugar yet does not produce such as a tuber or bulb or fruit.
What is phloem loading?
The movement of photosynthates from mesophyll chloroplasts to sieve elements of mature leaves.
What are the 3 steps in phloem loading?
(i) Sucrose synthesis
(ii) Short-distance transport
(iii) Sieve element loading
