Problem Set 3 Question 2 d

Problem Set 3 Question 2 d

Hello everyone!

  I am a bit confused of what is meant by osmotic potential of water. Do we assume high osmotic potential in water means high solute concentration in the soil water and low osmotic potential means low solute concentration in soil water? Do we then assume solute concentration in plants is very low then?
  Or does osmotic potential mean the difference in solute concentration between the soil water and in the plant (with high potential meaning a large difference and low osmotic potential meaning a low difference)? If this were the case, do we also assume plants have a low solute concentration so that we can comment on the direction in which water could be moving? 

I guess I would like a clarification of osmotic potential and if plants are only low in salts, or if there could be scenarios if plants carrying more salts than in soils.

CareyYan (talk)22:57, 31 March 2018

As covered back in January, presence of solutes (or salts) reduces the total potential energy of water molecules, primarily because of the reduced freedom of movement of the water molecules that cluster around each solute ion. The greater the concentration of solutes the more the osmotic potential of water molecules is lowered. Or in other words, the more saline soil is, the lower the osmotic potential of water molecules in that soil.

MajaKrzic (talk)22:07, 1 April 2018

Thank you!

CareyYan (talk)17:51, 4 April 2018