Studies on the Induction of Nitrate Reductase by Nitrite in Bean‐Seed Cotyledons

Nitrate reductase of sterilized bean seed cotyledons is more readily induced by nitrite (10 mM) then by nitrate (100 mM) when incubated in these solutions for 24 h. Inhibition of induction by tungstate, dependence on NADH and presence in extracts of endogenous nitrate at effective substrate concentrations were observed with both inducers. Nitrite was oxidized to nitrate after absorption but the concentration produced thereby was less than 5% of that produced by direct absorption of nitrate from the incubation medium. Nitrite may be a direct inducer of nitrate reductase in bean seed cotyledons.