The Wave Form of Luminescence Emitted by Noctiluca

The wave shape, intensity, and time course of the flash were examined with the aid of electronic operations in order to characterize the luminescence response and examine the in vivo dynamics of the light reaction. The most prominent single component of the flash shape is its exponential decay, beginning several milliseconds after the intensity maximum, with a mean rate constant at 23°C of -0.088 msec^-1. Earlier components of the flash curve are more complex, exhibiting no pure exponentials with time. As predicted from previous observations, the time course of the flash triggered by a propagated action potential, and therefore influenced by the conduction time of the triggering potential, is measurably slower than that of the synchronously triggered flash. The time course of emission from individual specimens is otherwise quite stable, undergoing only limited slowing with short-interval fatigue or specimen deterioration in spite of marked changes in the amplitude of the wave form. Relative stability of amplitude is obtained when flashes are elicited at regular intervals greater than 10 sec. On the basis of an analogue computer simulation (Appendix) the dynamics of the luminescence wave shape were found to be compatible with a short sequence of first order processes acting on an initial brief transient.