Effect of different nitrogen amounts in nutrient solution on plant growth and nitrate accumulation in aeroponically grown lettuce (Lactuca sativa L.)
2001
Kacjan Marsic | N. | Osvald, J. (Ljubljana Univ. (Slovenia). Biotechnical Fac., Agronomy Dept.)
The influence of different nitrogen amounts in nutrient solution on growth, development and nitrate content was studied in aeroponically grown lettuce (Lactuca sativa L.). Three successive experiments were conducted in 1999 from April to September, in an aeroponic system. The lettuce plants cv. Vanity were grown in aeroponics using four different amounts of nitrogen in nutrient solutions. The pH level was maintained between 5.5 and 6.5, and the EC between 1.8 in 2.2 mS/cm. Fresh weight measurements were made on all the material. Differences among averages of fresh weight were statistically significant in the first experiment. The maximum final fresh weight average in treatment 8 mM was 1000 g. In the second and the third experiment, the largest amount of nitrogen 12 mM NO3-N, also affected the growth of lettuce plants. The low level of nitrate in the nutrient solution significantly increased the fresh weight of the final roots regarding the level of nitrate in standard nutrient solution (12 mM NO3-N). The highest NO3- concentration in older leaves was recored in plants grown in nutrient solutions with 8 mM and 12 mM NO3-N. The low enough NO3- concentration was found in leaves of lettuce treated with nutrient solution with 4 mM NO3-N, in all three experiment.
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