The aim of this Paper is the analysis of the spatiotemporal solutions of modified Oregonator model systems (modified incomplete Oregonator, MIO, and modified complete Oregonator, MCO) accounting for the oxygen- sensitivity and photosensitivity of Belousov-Zhabotinsky (BZ) reactions. Critical nuclei and velocities of autowaves of the bistable subsystem (MIO) were determined in dependence on an inhibition parameter phi representing the influences of oxyen and/or light. Shapes of critical nuclei and coexistent phases were constructed explicitly. In the oscillatory and the excitable domain of the complete system (MCO), the propagation of trigger waves was studied numerically. With increasing phi, trigger waves are continuously slowed down to a minimal velocity. They remain stable for sufficiently low values phi < phi(tr1) and turn over to so-called transient impulses in a small interval beyond phi(tr1). They are characterized by finite lifetimes with gradually vanishing amplitudes. Above that interval no waves occur. Furthermore,critical nuclei for the excitation of trigger waves and leading centers were determined in dependence on phi. In the Experimental Section, propagation of trigger waves in an excitable medium under light influence was studied with the Ru(dmby)(3)(2+)-catalyzed BZ system in a continuously fed gel reactor. Trigger waves are slowed down with increasing light intensity until complete extinguishing at supercritical intensities. Spiral waves widen under illumination. Incompletely extinguished single waves can be restarted by switching off the light and show the effect of wave splitting.