Phytoluminographic detection of dynamic variations in leaf gaseous conductivity

Gas exchange and plant luminescence (delayed light emission) of a single red kidney bean leaf undergoing synchronous oscillations in gas exchange were recorded and analyzed. Introduction of 1.1 microliter per liter SO(2) during these oscillations produced increases in plant luminescence that, when averaged over a portion of the leaf, oscillated in phase with the gas exchange oscillations. However, examination of a video record of the plant luminescence showed not only that luminescence intensities tended to be localized within discrete areas of the leaf, but that the time-dependence of luminescence intensities within these regions varied considerably from the period, amplitude, and often phase of the overall gas exchange oscillations. The video recording also showed that changes in luminescence intensities appeared to migrate across the leaf in wave-like patterns. These data are interpreted in terms of localized fluctuations in gaseous conductances of the leaf.