Effect of broad‐band ultraviolet and visible radiation on hydrogen peroxide formation by cultured rose cells

Abstract

Broad‐band radiation from a high‐pressure Hg‐vapor lamp, including ultraviolet wavelengths from 290 to 400 nm, blue, green and red wavelengths, did not induce the synthesis of H2O2 in cultured rose cells. This was in contrast to the effects of shortwave (254 nm) ultraviolet radiation, even though, like shortwave ultraviolet radiation, the UV‐B component of the broadband radiation induced a striking K+ efflux from the cells, and this efflux has been associated with H2O2 synthesis in a previous report. The UV‐A and visible wavelengths were shown to inhibit the synthesis of H2O2. This effect was associated with inhibition of peroxidase, an enzyme reported to be involved in the synthesis of H2O2 in cell walls. UV‐B radiation inhibited the alternate pathway for mitochondrial electron transport, but there was no evidence that this effect contributed to the inhibition of H2O2 synthesis in cells treated with broad‐band radiation.