Water Potential

Question 0

Hydrostatic pressure (P) is: (3)

Answer 0

Normal pressure.
Positive component.
Water with high P tents to move to zones of low P.

Question 1

Water potential ψ is a measure of

Answer 1

Waters capacity to move through the hydrological system.

Question 2

Osmotic pressure (TT) is: (3)

Answer 2

Component that accounts for the presence of solutes.
Negative component.
Solutions with high TT tend to attract water towards them.

Question 3

Matric pressure (m) is: (3)

Answer 3

The tendency of water to cling to solid surfaces by adhesion.
Negative component.
High m tends to attract water.

Question 4

Water will move from a zone of:

Answer 4

High ψ to low ψ

Question 5

Water pressure of freely draining soil:

Answer 5

-5 kPa

Question 6

Water pressure of plant tissue:

Answer 6

-50 kPa ➡️ -200 kPa

Question 7

Water pressure of atmosphere:

Answer 7

-100’000 kPa

Question 8

Evapotranspiration is caused when

Answer 8

Water moves from soil ➡️ plant ➡️ atmosphere because of the ψ gradient.

Question 9

If the air were saturated, water could be

Answer 9

Absorbed from the atmosphere to the soil - The ψ gradient is reversed.

Question 10

Transpiration in reverse can occur when

Answer 10

The ψ gradient is reversed

Air / atmosphere 0 kPa ➡️ plant -50 kPa ➡️ soil -100 kPa