Optimizing Lettuce Growth in Nutrient Film Technique Hydroponics: Evaluating the Impact of Elevated Oxygen Concentrations in the Root Zone under LED Illumination
Abstract
:1. Introduction
2. Materials and Methods
2.1. Experimental Site and Greenhouse Management
2.2. Biological Sample, Treatments, and Cultivation Methods
2.3. Experimental Design and Statistical Analysis
2.4. Data Collection
2.4.1. Oxygen Concentration Calculation and Percentage Change
- Utilized concentration = A;
- Oxygen concentration at inlet = X;
- Oxygen concentration at outlet = Z.
2.4.2. Growth Parameters
2.4.3. Physiological Parameters
2.4.4. Biochemical Parameters
3. Results
4. Discussion
5. Conclusions
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Month | Week | Average | Minimum | Maximum | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Temperature (°C) | Relative Humidity (%) | CO2 (ppm) | Temperature (°C) | Relative Humidity (%) | CO2 (ppm) | Temperature (°C) | Relative Humidity (%) | CO2 (ppm) | ||
December | 1 | 17.50 ± 0.40 | 56.50 ± 0.40 | 600.00 ± 45.00 | 16.00 ± 1.80 | 35.30 ± 6.50 | 450.00 ± 81.00 | 20.40 ± 1.84 | 84.83 ± 3.20 | 768.52 ± 55.65 |
2 | 17.30 ± 0.40 | 58.20 ± 3.30 | 650.00 ± 65.00 | 15.20 ± 1.85 | 36.50 ± 5.40 | 460.00 ± 75.00 | 20.72 ± 1.21 | 95.83 ± 6.21 | 858.29 ± 174.35 | |
3 | 16.20 ± 0.50 | 58.50 ± 2.70 | 650.00 ± 90.00 | 14.50 ± 0.65 | 30.20 ± 3.20 | 410.00 ± 25.00 | 20.46 ± 0.52 | 86.15 ± 3.86 | 825.96 ± 183.55 | |
4 | 16.00 ± 0.50 | 57.00 ± 2.50 | 640.00 ± 80.00 | 16.10 ± 1.92 | 34.50 ± 6.00 | 455.00 ± 135 | 20.53 ± 1.20 | 95.61 ± 5.75 | 817.92 ± 138.52 | |
January | 1 | 16.50 ± 0.47 | 57.90 ± 2.83 | 646.66 ± 78.33 | 15.26 ± 1.47 | 33.73 ± 4.87 | 441.66 ± 78.00 | 20.57 ± 0.98 | 95.86 ± 5.61 | 834.05 ± 165.47 |
2 | 18.42 ± 0.39 | 56.20 ± 0.36 | 605.20 ± 46.69 | 16.14 ± 1.85 | 35.30 ± 6.63 | 455.16 ± 137 | 20.39 ± 1.84 | 81.83 ± 3.20 | 768.52 ± 55.65 | |
3 | 18.20 ± 0.39 | 58.20 ± 3.32 | 653.47 ± 65.63 | 15.37 ± 1.87 | 36.86 ± 5.42 | 463.82 ± 77.58 | 20.72 ± 1.21 | 85.82 ± 4.21 | 858.28 ± 174.35 | |
4 | 17.00 ± 0.54 | 58.50 ± 2.70 | 652.65 ± 88.82 | 14.66 ± 0.64 | 30.21 ± 3.24 | 410.60 ± 23.52 | 20.45 ± 0.52 | 96.14 ± 6.86 | 825.96 ± 183.55 |
Plant Varieties | Oxygen Treatments | Photosynthetic Rate (µmol CO2 m−2 s−1) | Stomatal Conductance of (mol H2O m−2 s−1) | Transpiration Rate (µmol H2O m−2 s−1) | Temperature (°C) | Respiration Rate (µmol CO2 m−2 s−1) |
---|---|---|---|---|---|---|
Lugano | Natural oxygen concentration (NOC) | 6.19 ± 0.22 | 0.11 ± 0.40 | 2.92 ± 1.37 | 32.13 ± 0.69 | 3.81 ± 1.40 |
Elevated oxygen concentration (EOC) | 7.16 ± 0.91 | 0.09 ± 0.75 | 2.70 ± 0.94 | 33.55 ± 1.13 | 3.46 ± 0.19 | |
LED + elevated oxygen concentration (LED + EOC) | 7.11 ± 1.24 | 0.14 ± 0.72 | 3.96 ± 0.77 | 33.63 ± 1.12 | 4.54 ± 1.36 | |
Total (all treatments’ mean) | 6.82 ± 0.84 | 0.11 ± 0.21 | 3.19 ± 1.39 | 33.10 ± 0.75 | 3.94 ± 0.43 | |
Carmesi | Natural oxygen concentration (NOC) | 6.25 ± 0.398 | 0.12 ± 0.35 | 3.10 ± 1.21 | 30.57 ± 1.11 | 3.91 ± 1.24 |
Elevated oxygen concentration (EOC) | 6.93 ± 1.18 | 0.05 ± 0.31 | 5.60 ± 1.01 | 34.00 ± 1.26 | 3.60 ± 0.62 | |
LED + elevated oxygen concentration (LED + EOC) | 6.97 ± 1.24 | 0.10 ± 0.67 | 3.14 ± 1.13 | 32.35 ± 0.84 | 4.21 ± 0.71 | |
Total (all treatments’ mean) | 6.64 ± 0.78 | 0.08 ± 0.69 | 3.68 ± 1.21 | 32.29 ± 0.54 | 3.75 ± 1.16 | |
Variety | 0.182 ns | 0.539 ns | 0.365 ns | 0.100 ns | 0.9432 ns | |
Treatment | 0.044 * | 0.432 ns | 0.031 * | 0.001 ** | 0.2335 ns | |
Variety * Treatment | 0.374 ns | 0.813 ns | 0.048 * | 0.179 ns | 0.8558 ns |
(a) | ||||||||
Plant Varieties | Oxygen Treatments | Plant Height (cm) | Plant Mass (g) | Plant Diameter (cm) | Number of Leaves | Root Mass (g) | Root Volume (cm3) | Root Length (cm) |
Lugano | Natural oxygen concentration (NOC) | 13.50 ± 0.79 | 47.65 ± 3.01 | 22.50 ± 180 | 10 ± 1.00 | 1.82 ± 0.49 | 1.86 ± 0.11 | 19.50 ± 0.56 |
Elevated oxygen concentration (EOC) | 15.66 ± 0.3 | 58.33 ± 1.95 | 23.66 ± 2.51 | 13 ± 1.15 | 3.24 ± 0.43 | 3.43 ± 0.02 | 24.83 ± 1.24 | |
LED + elevated oxygen concentration (LED + EOC) | 15.80 ± 0.5 | 75.57 ± 2.66 | 26.66 ± 2.08 | 13 ± 1.73 | 4.36 ± 0.59 | 3.66 ± 1.15 | 35.93 ± 2.47 | |
Total (all treatments’ mean) | 14.98 ± 1.22 | 54.23 ± 20.48 | 22.27 ± 2.27 | 12 ± 1.39 | 3.14 ± 1.18 | 2.98 ± 1.07 | 26.76 ± 0.57 | |
Carmesi | Natural oxygen concentration (NOC) | 18.30 ± 1.15 | 50.44 ± 0.65 | 26.36 ± 1.41 | 11 ± 1.61 | 3.20 ± 0.87 | 3.46 ± 0.64 | 21.27 ± 1.71 |
Elevated oxygen concentration (EOC) | 19.33 ± 1.10 | 55.72 ± 2.84 | 26.50 ± 1.32 | 12 ± 0.01 | 3.86 ± 0.44 | 4.30 ± 0.86 | 29.17 ± 0.67 | |
LED + elevated oxygen concentration (LED + EOC) | 21.90 ± 1.20 | 67.74 ± 1.40 | 27.16 ± 2.75 | 13 ± 1.73 | 4.54 ± 2.05 | 4.07 ± 1.03 | 31.33 ± 0.17 | |
Total (all treatments’ mean) | 19.84 + 1.89 | 57.38 ± 2.13 | 26.67 ± 1.72 | 12 ± 1.39 | 3.87 ± 1.27 | 3.53 ± 1.16 | 27.26 ± 1.41 | |
Variety | *** | *** | ns | ns | * | * | ** | |
Treatment | *** | * | ** | ** | * | * | ** | |
Variety * Treatment | ns | *** | ns | ns | ns | ns | * | |
(b) | ||||||||
All Oxygen Treatment Groups | Applied Oxygen Treatments | Plant Mass (g) | Plant Height (cm) | Plant Diameter (cm) | Number of Leaves | Root Mass (g) | Root Volume (cm3) | Root Length (cm) |
Natural oxygen concentration (NOC) | × Elevated oxygen concentration (EOC) | * | *** | ns | ** | ns | ns | ns |
× LED + elevated oxygen concentration (LED + EOC) | *** | *** | ** | ** | ** | * | *** | |
Elevated oxygen concentration (EOC) | × Natural oxygen concentration (NOC) | * | *** | ns | ** | ns | ns | ns |
× LED + elevated oxygen concentration (LED + EOC) | ns | ** | ns | ns | ns | ns | ns | |
LED + elevated oxygen concentration (LED + EOC) | × Natural oxygen concentration (NOC) | *** | *** | ** | ** | ** | * | *** |
× Elevated oxygen concentration (EOC) | ns | ** | ns | ns | ns | ns | ns |
(a) | ||||||||
Plant Varieties | Oxygen Treatments | Chl. at Leaf Base (mg kg−1) | Chl. at Leaf Center (mg kg−1) | Chl. at Leaf Upper Part (mg kg−1) | Nitrate at Leaf Base (mg kg−1) | Nitrate at Leaf Center (mg kg−1) | Nitrate at Leaf Upper Part (mg kg−1) | Glucose Contents |
Lugano | Natural oxygen concentration (NOC) | 2.92 ± 0.27 | 2.51 ± 0.25 | 2.18 ± 0.40 | 1133.26 ± 45.32 | 1157.83 ± 42.49 | 654.40 ± 141.40 | 3.64 ± 0.07 |
Elevated oxygen concentration (EOC) | 3.20 ± 0.86 | 2.85 ± 1.19 | 1.71 ± 0.75 | 1838.86 ± 41.92 | 1463.30 ± 47.3 | 286.63 ± 153.19 | 3.31 ± 0.18 | |
LED + elevated oxygen concentration (LED + EOC) | 3.03 ± 0.48 | 2.14 ± 0.18 | 1.82 ± 0.72 | 2011.06 ± 49.87 | 1276.66 ± 41.72 | 531.10 ± 171.36 | 3.22 ± 0.01 | |
Total (all treatments’ mean) | 3.05 ± 0.53 | 2.50 ± 0.68 | 1.90 ± 0.21 | 1661.06 ± 40.39 | 1132.93 ± 142.35 | 490.71 ± 121.53 | 3.39 ± 0.21 | |
Carmesi | Natural oxygen concentration (NOC) | 4.1 ± 0.18 | 6.06 ± 1.14 | 4.86 ± 0.35 | 1916.63 ± 61.61 | 515.53 ± 183.41 | 437.73 ± 138.64 | 3.82 ± 0.17 |
Elevated oxygen concentration (EOC) | 4.50 ± 1.08 | 4.78 ± 0.69 | 4.01 ± 0.31 | 1903 ± 52.01 | 675.50 ± 125.86 | 484.40 ± 157.12 | 2.91 ± 0.67 | |
LED + elevated oxygen concentration (LED + EOC) | 4.31 ± 0.75 | 4.05 ± 1.78 | 3.59 ± 0.67 | 1165.53 ± 56.73 | 686.63 ± 165.34 | 677.73 ± 130.54 | 3.67 ± 0.23 | |
Total (all treatments’ mean) | 4.84 + 1.05 | 4.96 ± 1.42 | 4.15 ± 0.69 | 1661.82 ± 43.71 | 625.88 ± 129.51 | 533.28 ± 121.16 | 3.47 ± 0.59 | |
Variety | ** | *** | *** | ns | ** | ns | ns | |
Treatment | ns | ns | ** | * | ns | ns | * | |
Variety * Treatment | ns | ns | ns | *** | * | * | * | |
(b) | ||||||||
All Oxygen Treatment Groups | Applied Oxygen Treatments | Chl. at Leaf Base (mg kg−1) | Chl. at Leaf Center (mg kg−1) | Chl. at Leaf Upper Part (mg kg−1) | Nitrate at Leaf Base (mg kg−1) | Nitrate at Leaf Center (mg kg−1) | Nitrate at Leaf Upper Part (mg kg−1) | Glucose Contents |
Natural Oxygen Concentration (NOC) | × Elevated oxygen concentration (EOC) | ns | ns | * | Ns | * | ns | * |
× LED + elevated oxygen concentration (LED + EOC) | * | ** | ** | * | * | ns | ** | |
Elevated Oxygen Concentration (EOC) | × Natural oxygen concentration (NOC) | ns | ns | * | Ns | * | ns | ** |
× LED + elevated oxygen concentration (LED + EOC) | ns | * | ns | Ns | ns | ns | * | |
LED + Elevated Oxygen Concentration (LED + EOC) | × Natural oxygen concentration (NOC) | * | ** | ** | * | * | ns | ** |
× Elevated oxygen concentration (EOC) | ns | * | ns | Ns | ns | ns | * |
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Nitu, O.A.; Ivan, E.Ş.; Tronac, A.S.; Arshad, A. Optimizing Lettuce Growth in Nutrient Film Technique Hydroponics: Evaluating the Impact of Elevated Oxygen Concentrations in the Root Zone under LED Illumination. Agronomy 2024, 14, 1896. https://doi.org/10.3390/agronomy14091896
Nitu OA, Ivan EŞ, Tronac AS, Arshad A. Optimizing Lettuce Growth in Nutrient Film Technique Hydroponics: Evaluating the Impact of Elevated Oxygen Concentrations in the Root Zone under LED Illumination. Agronomy. 2024; 14(9):1896. https://doi.org/10.3390/agronomy14091896
Chicago/Turabian StyleNitu, Oana Alina, Elena Ştefania Ivan, Augustina Sandina Tronac, and Adnan Arshad. 2024. "Optimizing Lettuce Growth in Nutrient Film Technique Hydroponics: Evaluating the Impact of Elevated Oxygen Concentrations in the Root Zone under LED Illumination" Agronomy 14, no. 9: 1896. https://doi.org/10.3390/agronomy14091896