The foliar feeding of soil-grown plants with essential elements such as molybdate can
restore their Nitrate reductase activity. However, the activity of nitrate reductase under the foliar
feeding of plants with molybdate and nitrate in hydroponic conditions has not been investigated.
Thus, we wanted to investigate the effect of the foliar feeding of molybdate and nitrate on the nitrate
reductase activity in the leaves of lemon balm plants under hydroponic conditions. Nitrate and
molybdate solutions were applied by spraying the leaves of lemon balm plants and the nitrate
reductase activity was determined by the colorimetric method. The results of our study demonstrated
that the application of molybdate and KNO3 solution enhanced the nitrate reductase activity in the
leaves of lemon balm plants. Importantly, our results indicate that foliar fertilization with nitrate and
molybdate can improve nitrogen metabolism and carbon fixation in the leaves of lemon balm plants
under hydroponic conditions.