Tetcyclacis and Abscisic Acid-Sensitive Reduction of Extracellular Ferricyanide by Mesophyll Cells of Valerianella locusta and Lemna gibba

Electron transport across the plasma membrane of Valerianella locusta mesophyll cells and intact fronds of Lemna gibba, induced by 10 -3 M ferricyanide, was inhibited by tetcyclacis, an inhibitor regarded to be specific for cytochrome P-450 mono-oxygenases. The effect was dependent on the concentration of tetcyclacis and the duration of preincubation. The apparent rate of transmembrane electron transport increased in the presence of catalase, indicating tetcyclacis-induced H 2 O 2 -production or additional tetcyclacis-independent H 2 O 2 release