The induction of bacterial bioluminescence system on solid medium

Induction of the luminescence system of the marine luminous bacteriumVibrio harveyi growing on a solid medium was studied. The induction occurred when the total number of cells per square centimeter of solid medium approached 10⁴ cells (i.e., either 100 colonies consisting of 100 cells per each colony or 1 colony with about 10⁴ cells). The preinduction period and number of cells per colony at the time of induction decreased as the number of colonies per cm² increased. The ecological significance of the induction of the luminescence system on solid medium is discussed.