TY - JOUR
T1 - Spectral effects of light-emitting diodes on plant growth, visual color quality, and photosynthetic photon efficacy
T2 - White versus blue plus red radiation
AU - Park, Yujin
AU - Runkle, Erik S.
N1 - Funding Information:
This work was supported by the USDA Floriculture and Nursery Research Initiative Project No. 0500-00059-001-00D to E.R. (https://www. ars.usda.gov/research/project/?accnNo=402626), Michigan State University’s Project GREEEN (http:// www.canr.msu.edu/research/plant-agriculture/ project_greeen) and AgBioResearch (http://www. canr.msu.edu/research/agbioresearch), and
Publisher Copyright:
© 2018 Park, Runkle. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2018/8
Y1 - 2018/8
N2 - Arrays of blue (B, 400−500 nm) and red (R, 600−700 nm) light-emitting diodes (LEDs) used for plant growth applications make visual assessment of plants difficult compared to a broad (white, W) spectrum. Although W LEDs are sometimes used in horticultural lighting fixtures, little research has been published using them for sole-source lighting. We grew seedlings of begonia (Begonia ×semperflorens), geranium (Pelargonium ×horturum), petunia (Petunia ×hybrida), and snapdragon (Antirrhinum majus) at 20C under six sole-source LED lighting treatments with a photosynthetic photon flux density (PPFD) of 160 μmolm–2s–1 using B (peak = 447 nm), green (G, peak = 531 nm), R (peak = 660 nm), and/or mint W (MW, peak = 558 nm) LEDs that emitted 15% B, 59% G, and 26% R plus 6 μmolm−2s−1 of far-red radiation. The lighting treatments (with percentage from each LED in subscript) were MW100, MW75R25, MW45R55, MW25R75, B15R85, and B20G40R40. At the transplant stage, total leaf area, and fresh and dry weight were similar among treatments in all species. Surprisingly, when petunia seedlings were grown longer (beyond the transplant stage) under sole-source lighting treatments, the primary stem elongated and had flower buds earlier under MW100 and MW75R25 compared to under B15R85. The color rendering index of MW75R25 and MW45R55 were 72, and 77, respectively, which was higher than those of other treatments, which were 64. While photosynthetic photon efficacy of B15R85 (2.25 μmolJ–1) was higher than the W light treatments (1.51−2.13 μmolJ–1), the dry weight gain per unit electric energy consumption (in gkWh–1) of B15R85 was similar to those of MW25R75, MW45R55, and MW75R25 in three species. We conclude that compared to B+R radiation, W radiation had generally similar effects on seedling growth at the same PPFD with similar electric energy consumption, and improved the visual color quality of sole-source lighting.
AB - Arrays of blue (B, 400−500 nm) and red (R, 600−700 nm) light-emitting diodes (LEDs) used for plant growth applications make visual assessment of plants difficult compared to a broad (white, W) spectrum. Although W LEDs are sometimes used in horticultural lighting fixtures, little research has been published using them for sole-source lighting. We grew seedlings of begonia (Begonia ×semperflorens), geranium (Pelargonium ×horturum), petunia (Petunia ×hybrida), and snapdragon (Antirrhinum majus) at 20C under six sole-source LED lighting treatments with a photosynthetic photon flux density (PPFD) of 160 μmolm–2s–1 using B (peak = 447 nm), green (G, peak = 531 nm), R (peak = 660 nm), and/or mint W (MW, peak = 558 nm) LEDs that emitted 15% B, 59% G, and 26% R plus 6 μmolm−2s−1 of far-red radiation. The lighting treatments (with percentage from each LED in subscript) were MW100, MW75R25, MW45R55, MW25R75, B15R85, and B20G40R40. At the transplant stage, total leaf area, and fresh and dry weight were similar among treatments in all species. Surprisingly, when petunia seedlings were grown longer (beyond the transplant stage) under sole-source lighting treatments, the primary stem elongated and had flower buds earlier under MW100 and MW75R25 compared to under B15R85. The color rendering index of MW75R25 and MW45R55 were 72, and 77, respectively, which was higher than those of other treatments, which were 64. While photosynthetic photon efficacy of B15R85 (2.25 μmolJ–1) was higher than the W light treatments (1.51−2.13 μmolJ–1), the dry weight gain per unit electric energy consumption (in gkWh–1) of B15R85 was similar to those of MW25R75, MW45R55, and MW75R25 in three species. We conclude that compared to B+R radiation, W radiation had generally similar effects on seedling growth at the same PPFD with similar electric energy consumption, and improved the visual color quality of sole-source lighting.
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U2 - 10.1371/journal.pone.0202386
DO - 10.1371/journal.pone.0202386
M3 - Article
C2 - 30114282
AN - SCOPUS:85053533304
SN - 1932-6203
VL - 13
JO - PloS one
JF - PloS one
IS - 8
M1 - e0202386
ER -