Inhibition of Nitrite Reduction with Photosynthetic Inhibitors

Using a modified in vivo nitrate reductase assay, all photosynthetic inhibitors tested were shown to effectively block light-dependent nitrite reduction in green leaf tissue. Nitrate reduction continued so that nitrite accumulated. Nitrite, vacuum infiltrated into leaf tissue, disappeared linearly with time when incubated in the light. Nitrite, vacuum infiltrated with a photosynthetic inhibitor, did not disappear but accumulated to even higher levels. The degree of inhibition of nitrite reduction was a function of herbicide concentration and time of incubation.