20190108_Osmosis is not driven by water dilution


1. Title, Journal and Authors

Title : Osmosis is not driven by water dilution

Journal : Trends in Plant Science

Authors : Eric M. Kramera and David R. Myersb

a Department of Physics, Bard College at Simon’s Rock, Great Barrington, MA 01201, USA

b Department of Chemistry, Bard College at Simon’s Rock, Great Barrington, MA 01201, USA


2. Summary

 Osmosis, the flow of water across a semipermeable membrane from a region of lower to higher solute concentration, is of central importance to plant physiology, in particular for cell turgor, tissue growth, and phloem transport. There is misconception among plant scientists that osmosis is driven by the tendency of solutes to dilute water. So, if the degree to which solutes dilute water does not play a role in understanding osmosis, what is the explanation? Although osmotic flow is ultimately the response of water to an applied force, there is also a role for the diffusion of solute. Given that the water moving through the pore contains no solute, one effect of osmotic flow will be the dilution of solute near the downstream aperture and the concentration of solute at the upstream aperture. This will tend to decrease the force imbalance that drives osmosis. Thus, the continued flow of water relies on Brownian motion to carry solute molecules back into the region of the downstream aperture and away from the upstream aperture, maintaining the force imbalance.


3. Originality & Creativity 

 In this opinion article, Authors discuss the quantitative and qualitative failures of this view, and go on to review the correct kinetic picture of osmosis as it appears in physics textbooks.


4. Application to research 

  - It is possible to approach to osmosis in terms of various academics.

  - We can correct the misconception about osmosis.


5. Contact

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E-mail : mjwabc@naver.com

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