Ion induced changes in the structure of bordered pit membranes
Jinkee Lee1, N Michele Holbrook, Maciej A Zwieniecki
1School of Mechanical Engineering, Sungkyunkwan University Suwon, South Korea.
Frontiers in Plant Science
|May 31, 2012
Summary
Ion concentration affects plant xylem hydraulic resistance by altering bordered pit membrane structure. Atomic force microscopy revealed that ion exposure hardens and roughens these membranes, impacting water flow.
Area of Science:
- Plant Biology
- Biophysics
- Materials Science
Background:
- Xylem hydraulic resistance is crucial for water transport in plants.
- Ion-mediated changes in resistance are linked to pectin properties in pit membranes.
- Direct evidence for these structural changes has been lacking.
Purpose of the Study:
- To investigate structural changes in bordered pit membranes using atomic force microscopy (AFM).
- To correlate these structural changes with varying ionic concentrations.
Main Methods:
- Atomic Force Microscopy (AFM) was used to image bordered pit membranes.
- Membranes were exposed to de-ionized water and 50 mM KCl solutions.
- Surface physical properties and elevation features were analyzed.
Main Results:
- In de-ionized water, membranes appeared smooth and soft.
- Exposure to KCl caused membranes to become harder, rougher, and contract.
- No discrete pores were observed; changes in permeability and thickness are suggested.
Conclusions:
- Ion concentration significantly alters bordered pit membrane structure and physical properties.
- These ion-induced structural changes likely explain variable xylem hydraulic resistance.
- The findings support the hydrogel-like behavior of pectins in pit membranes.
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