Articles
Red and green light-emitting diodes (LED) promote lettuce seed germination
Article number
1423_26
Pages
195 – 202
Language
English
Abstract
The effect of light quality is a crucial factor in the seed germination process.
Three experiments were conducted to determine the optimal R:G:B ratio for lettuce seed germination.
The first experiment focused on red and blue LED lights, testing six R:B ratios (0:100, 20:80, 40:60, 60:40, 80:20, and 100:0). Light intensity was 130 µmol m‑2 s‑1. The 100:0 R:B ratio showed the lowest mean germination time (MGT) (23.29 h), and highest mean daily germination (MDG) (30.76 seeds day‑1), germination rate (GR) (4.76 seeds h-1), and PI index, with over 80% germination by the 28 h compared to the 0:100 R:B ratio (blue light) that resulted in the highest MGT and lowest GR, MDG, and PI index, with only 64% germination until 28 h after sowing.
The second experiment used red light supplemented with green light, testing five R:G ratios (0:100, 50:50, 70:30, 80:20, 90:10) with a constant R:B 100:0 ratio.
Light intensity was 130 µmol m‑2 s‑1. The 80:20 R:G ratio proved optimal, surpassing 80% seed germination by 24 h after sowing, with the lowest MGT (20.96 h) and the highest MDG (30.69 seeds day‑1), GR (4.79 seeds h‑1), and PI index compared to the 50:50 R:G ratio that showed the lowest MDG, PI index, and GR. However, under green light only (R:G 0:100), results did not significantly differ from the R:G 50:50 ratio.
In the third experiment, red, green, and blue light were used based on the previous two experiments.
Light intensity was 350 µmol m‑2 s‑1. Among the three R:G:B ratios (60:20:20, 72:10:18, 80:10:10) and R:G 80:20, the highest GR (4.53 seeds h‑1) and PI index were recorded in R:G 80:20. However, GR, MDG, and PI index of 60:20:20, 72:10:18, and 80:10:10 were not significantly different.
In conclusion, supplementing green light with a high proportion of red light (R:G 80:20) effectively promotes lettuce seed germination.
Three experiments were conducted to determine the optimal R:G:B ratio for lettuce seed germination.
The first experiment focused on red and blue LED lights, testing six R:B ratios (0:100, 20:80, 40:60, 60:40, 80:20, and 100:0). Light intensity was 130 µmol m‑2 s‑1. The 100:0 R:B ratio showed the lowest mean germination time (MGT) (23.29 h), and highest mean daily germination (MDG) (30.76 seeds day‑1), germination rate (GR) (4.76 seeds h-1), and PI index, with over 80% germination by the 28 h compared to the 0:100 R:B ratio (blue light) that resulted in the highest MGT and lowest GR, MDG, and PI index, with only 64% germination until 28 h after sowing.
The second experiment used red light supplemented with green light, testing five R:G ratios (0:100, 50:50, 70:30, 80:20, 90:10) with a constant R:B 100:0 ratio.
Light intensity was 130 µmol m‑2 s‑1. The 80:20 R:G ratio proved optimal, surpassing 80% seed germination by 24 h after sowing, with the lowest MGT (20.96 h) and the highest MDG (30.69 seeds day‑1), GR (4.79 seeds h‑1), and PI index compared to the 50:50 R:G ratio that showed the lowest MDG, PI index, and GR. However, under green light only (R:G 0:100), results did not significantly differ from the R:G 50:50 ratio.
In the third experiment, red, green, and blue light were used based on the previous two experiments.
Light intensity was 350 µmol m‑2 s‑1. Among the three R:G:B ratios (60:20:20, 72:10:18, 80:10:10) and R:G 80:20, the highest GR (4.53 seeds h‑1) and PI index were recorded in R:G 80:20. However, GR, MDG, and PI index of 60:20:20, 72:10:18, and 80:10:10 were not significantly different.
In conclusion, supplementing green light with a high proportion of red light (R:G 80:20) effectively promotes lettuce seed germination.
Authors
K.P.S. Kumaratenna, B.H. Sung, N. Kwak, Y.-Y. Cho
Keywords
lettuce, plant factory, R:G:B ratio, seed germination
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