Fig 1.
Schematic diagram of experimental schedule and LED inter-lighting used.
LED inter-lighting was used when the shade cloth was applied.
Fig 2.
Effects of LED inter-lighting on photosynthetic photon flux density (PPFD) within the plant canopy.
PPFD was measured by a quantum sensor held at the same angle as nearby leaves. Data are means ± SEM (n = 10). Values marked with the same letter are not significantly different (Tukey’s HSD at P < 0.05).
Table 1.
Effects of shading and LED inter-lighting on daily light integral (mean ± SEM, n = 15).
Fig 3.
Total chlorophyll contents of single-truss tomato leaves measured in three canopy layers in plants grown under shading during 0%, 40% and 60% of days, with or without LED inter-lighting.
Data are means ± SEM (n = 15). Values marked with the same letter are not significantly different for the same leaf number in different treatments (Tukey’s HSD at P < 0.05).
Fig 4.
Effects of LED inter-lighting on leaf photosynthetic capacity of single-truss tomato plants.
Light-response curve was measured from 10:00 to 14:00 in representative leaves in three canopy layers in plants grown under shading during 0%, 40% and 60% of days with or without LED inter-lighting. Data are means ± SEM (n = 5).
Fig 5.
Shoot dry weights and fruit yield of single-truss tomato plants grown under shading during 0%, 40% and 60% of days with or without LED inter-lighting.
Data are means ± SEM (n = 5). Values marked with the same letter are not significantly different (Tukey’s HSD at P < 0.05).
Table 2.
Effect of shading and LED inter-lighting on growth of single-truss tomato plants (means ± SEM, n = 15).
Fig 6.
Ascorbic acid and total soluble solids contents of single-truss tomato plants grown under shading during 0%, 40% and 60% of days with or without LED inter-lighting.
Data are means ± SEM (n = 10). Bars with the same letter are not significantly different (Tukey’s HSD at P < 0.05). NS, no significant differences.
Fig 7.
Relation between yield and daily light integral (DLI).
Open circle: plants grown under shading during 0%, 40% and 60% of days, Filled triangle: plants grown under shading during 40% of days with supplemental LED inter-lighting, filled square: plants grown under shading during 60% of days with supplemental LED inter-lighting. The regression line among plants grown under shading during 0%, 40% and 60% of days is shown (y = 0.1869x + 1.0605, R2 = 0.97).