A mercury holder for electric discharge lamps, such as tubular fluorescent lamps, is mounted within the lamp envelope so as to serve as a target for bombardment by electrons and ions. The source of the bombardment may be the electrons emitted by one of the cathodes which impinge on the holder and which generate ions by collision with the gas fill in the lamp envelope. Alternatively, the source of the bombardment may be an arc discharge induced by a radio-frequency source across a gap between the holder and a lead-in conductor.