| Popis: |
Summary On axenic, photoautotrophic cell suspension cultures of Chenopodium rubrum L. the electrical membrane potential ψ m , membrane conductance g m , and the cellular ATP level have been measures upon addition of 10 -5 to 10 -3 M fusaric acid (FA). 10 -5 M FA hardly affects ψ m , but decreases g m from 0.4 to 0.26 S m -2 , whereas at 10 -4 M FA, ψ m of about -160 mV decreases by about 50 mV and g m increases from 0.4 to 0.8 S m -2 . A transient (3 min) addition of 10 -4 MFA causes the ATP level to drop to 13% of its normal value of about one μmol g dw -1 . The results which include a current-voltage analysis and additional experiments with the uncoupler CCCP, are consistent with the idea that FA acts as a protonophor on both cell and organell membranes. Thus FA would effectively block the ATP-fueled electrogenic pump at the plasmalemma. |
