Effects of nitrate on in vivo nitrate reductase activity of seedlings from three open-pollinated families of Robinia pseudoacacia

In vivo NO5 reductase activity (NRA) was determined in eightand nine-week-old nodulated seedlings from three open-pollinated families of black locust (Robinia pseudoacacia L.) that were grown in sand culture and fertilized with 0,0.5, 1.0, 5.0, or 15.0 mM NO?. Nitrate reductase activity was induced by NO?. Unlike many temperate legumes, enzymatic activity was typically much higher in leaves than in roots. This may have energetic ramifications because of the potentially lower energy costs of NOT reduction in leaves than in roots.