NOX EVOLUTION BY SOYBEAN LEAVES TREATED WITH SALICYLIC-ACID AND SELECTED DERIVATIVES

Experiments were conducted using soybean (Glycine max [L.] Merr. var. "Hobbit") leaves to measure the effects of selected salicylate derivatives on nitrate and nitrite metabolism. Salicylic acid was previously shown to act as a powerful stimulator of nitrate reduction and a herbicide synergist when used in combination with a number of different photosynthetic inhibitor herbicides. The experiments presented in this paper offer evidence that the converse is true, i.e., that a number of salicylic acid derivatives can function as stimulators of nitrate reduction and as herbicide synergists when used in combination with a single photosynthetic inhibitor herbicide. Salicylic derivatives were compared with salicylic acid for their ability to stimulate nitrate reduction. The degree of stimulation of nitrate reduction was measured as rate of gaseous NOx evolved from soybean leaves. Salicylic acid and 17 salicylate derivatives were tested and only salicin failed to cause NOx evolution. The halogen derivatives were found to be the most effective, and 5-chlorosalicylanilide not only caused stimulation of nitrate reduction, but also apparently interfered with the photosynthetic electron flow necessary for nitrite reduction. © 1991.