The influence of different concentration of nitrogen in nutrient solution on plant growth and nitrate accumulation in aeroponically grown lettuce (Lactuca sativa L.)

The lettuce plants cv. Vanity were grown in aeroponics using four different amounts of nitrogen in nutrient solutions. Differences among averages of fresh shoot weights were statistically significant in all three experiments. In the first experiment, the maximum final fresh weight average was 999.0 g in treatment 8 mM. In the second experiment the largest amount of nitrogen 12 mM NO 3 -N significantly (p < 0.05) increased the fresh shoot weight of lettuce plants. The low level of nitrate in the nutrient solution (4 mM NO 3 -N) significantly (p < 0.05) increased the fresh weight of the final roots regarding the level of nitrate in standard nutrient solution (12 mM NO 3 -N). The highest NO 3 concentration in lettuce leaves was recorded in plants grown in nutrient solutions with the highest NO 3 -N concentration (12 mM NO 3 -N). The low enough NO 3 -concentration was found in leaves of lettuce treated with nutrient solution with 4 mM NO 3 -N in both two experiments.