FERRICYANIDE REDUCTASE OF ROSE PLASMA-MEMBRANES IS REGULATED BY NITROGEN SUPPLY

The ability of suspension-cultured rose (Rosa damascena Mill. cv Gloir e de Guilan) cells to reduce ferricyanide is decreased by 50% during a n overnight incubation in a low-nutrient (1 mM CaCl2, 0.1 mM KCl) solu tion. This loss is not observed when nitrate and/or glutamate is added to the low-nutrient medium, but it occurs in medium containing all th e components needed for normal growth except nitrate plus glutamate. T hus, the cells possess both constitutive and inducible enzymes for the reduction of ferricyanide, and nitrate or glutamate is both necessary and sufficient to stimulate the production of the inducible enzyme.