Exam 2 Transport In Plants Flashcards
¥w=¥p+¥s
Total water potential of a plant = pressure potential and solute potential
Transpiration
Process where plants absorb water through roots and give off water vapor through pores in their leaves.
Water moves from areas
High to low ¥w
Adhesion
Attraction between water and polar groups of other molecules
Cohesion
Attraction between molecules
Water movement through xylem is…
Passive
Neg. pressure in xylem
Water evaporates into intracellular spaces and exits the stomatal pores by diffusion :
The concentration of water vapor inside the lead is higher than that of the atmosphere.
Opening and closing of the stomata…
Regulates transpiration
ABA (abscisic acid)
Plant hormone that triggers closure of stomata.
Soil solution
[K+] plant cells»_space;[K+] in the soil solution
When they reach xylem,
Minerals move to the shoot with the transpiration stream and are incorporated into the tissues of the shoot
Phloem transports organic molecules:
Sucrose, amino acids, and some hormones
Movement is from sources to sinks.
Movement only in one direction.
Sources:
Places from where molecules are exported.
Eg. Mature leaves
Sinks
Places where import of substance occurs.
Eg. Roots, young leaves, fruits, seeds, growing parts of the plant.
Mass flow
Substances move by a difference in hydrostatic pressure between the source (high pressure) and the sink(low pressure).