Increase in electrogenic membrane potential with washing of corn root tissue

Area of Science:

• Plant Physiology
• Cellular Electrophysiology
• Biochemistry

Background:

• Corn root epidermal cells exhibit electrical potential differences across their membranes.
• Cellular transport mechanisms are crucial for plant cell function and response to environmental stimuli.

Purpose of the Study:

• To investigate the effect of washing on the electrical potential difference in corn root epidermal cells.
• To elucidate the underlying electrogenic mechanisms and ion transport involved.

Main Methods:

• Measurement of electrical potential difference in corn root epidermal cells before and after washing.
• Application of the uncoupler (p-trifluoromethoxy)-carbonyl cyanide-phenylhydrazone to assess electrogenicity.
• Monitoring proton extrusion and its modulation by mersalyl, an inhibitor of the Pi-OH(-) antiporter.

Main Results:

• Washing corn root tissue significantly increased the electrical potential difference, negative inside.
• The observed increase in electrical potential was immediate and electrogenic, collapsing upon uncoupler addition.
• Proton extrusion decreased with washing but was restored by mersalyl, suggesting altered ion transport.

Conclusions:

• Washing enhances the activity of an electrogenic ion pump, likely a proton or cation efflux pump, in corn root epidermal cells.
• The proton motive force generated may augment an anion-OH(-) antiporter.
• These findings highlight the dynamic electrophysiological responses of plant cells to washing and altered transport activities.