TABLE 1.
Effects of different supplementary lightings on plant development and yield of tomato plants.
| Weeks after sowing |
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| Plant parameter | Unit | Light treatment | 6 | 7 | 8 | 9 | 10 | 11 |
| Plant height | cm | LEDs | 24.1 ± 1.9a | 51.0 ± 4.1a | 82.1 ± 5.3b | 112.4 ± 9.1b | 143.4 ± 10.9b | 172.1 ± 9.2b |
| HPS | 24.2 ± 1.6a | 48.5 ± 4.1a | 75.6 ± 5.8a | 104.5 ± 8.5a | 131.9 ± 7.9a | 161.1 ± 6.3a | ||
| Internode distance | cm | LEDs | 3.5 ± 0.3a | 7.3 ± 0.7b | 8.7 ± 0.7b | 9.4 ± 0.9b | 9.5 ± 0.8b | 9.8 ± 0.6b |
| HPS | 3.2 ± 0.4a | 6.2 ± 0.7a | 7.7 ± 0.6a | 8.4 ± 0.7a | 8.5 ± 0.3a | 8.7 ± 0.4a | ||
| Stem diameter | cm | LEDs | 6.3 ± 0.4a | 7.4 ± 0.3a | 7.8 ± 0.5a | 8.5 ± 0.4a | 8.9 ± 0.6a | 9.5 ± 0.5a |
| HPS | 6.2 ± 0.5a | 7.2 ± 0.2a | 7.7 ± 0.3a | 8.4 ± 0.5a | 8.9 ± 0.3a | 9.3 ± 0.6a | ||
| Trusses | number plant–1 | LEDs | 0.0 ± 0.0a | 0.0 ± 0.0a | 0.0 ± 0.0a | 1.0 ± 0.0a | 2.0 ± 0.0a | 3.1 ± 0.3a |
| HPS | 0.0 ± 0.0a | 0.0 ± 0.0a | 0.0 ± 0.0a | 1.0 ± 0.0a | 2.0 ± 0.0a | 3.1 ± 0.3a | ||
| Leaves | number plant–1 | LEDs | 3.8 ± 0.4a | 5.1 ± 0.3a | 7.6 ± 0.5a | 9.9 ± 0.6a | 13.4 ± 0.5a | 15.4 ± 0.9a |
| HPS | 3.8 ± 0.3a | 5.1 ± 0.3a | 7.8 ± 0.4a | 10.2 ± 0.4a | 13.6 ± 0.5a | 16.0 ± 0.5a | ||
| Leafarea | cm2 plant–1 | LEDs | 489.3 ± 60.9a | 965.1 ± 99.9a | 1713.0 ± 132.7a | 2872.0 ± 186.0a | 4946.0 ± 351.3a | 6674.9 ± 431.5a |
| HPS | 509.6 ± 52.1a | 975.1 ± 90.6a | 1863.4 ± 124.5b | 3243.6 ± 228.4b | 5346.8 ± 482.9a | 7196.3 ± 589.2a | ||
| End of the experiments | ||||||||
| Yield | g plant–1 | LEDs | 2102.1 ± 159.0b | |||||
| HPS | 1844.3 ± 91.8a | |||||||
| Fruit weight | g fruit–1 | LEDs | 96.7 ± 5.2a | |||||
| HPS | 92.4 ± 5.4a | |||||||
Values represent means of three plots per light treatment (n = 3) ± standard deviation. Values followed by the same letter do not differ significantly according to student’s t-tests (p < 0.05).