Abstract
Nickel (Ni) electrodes were placed in a culture solution to release Ni, a component of urease. The growth of spinach (Spinacia oleracea L.) cultured in nutrient solutions containing urea (U solution) with Ni electrodes was superior to that cultured in nutrient solutions without electrodes; the best growth was observed when the nutrient concentration was 1 unit and a 3 μA current was applied. Urease activity of spinach leaves was higher in the U solution with Ni electrodes, and the activity that occurred 4 weeks after planting was the highest when 3 μA current was applied to Ni electrodes. The application of electric current to Ni electrodes in the U solution increased the urease activity and promoted the conversion of urea to ammonia, thereby promoting the growth of spinach.
