Supplemental Far-Red Light Stimulates Lettuce Growth: Disentangling Morphological and Physiological Effects
Department of Horticulture, University of Georgia, Athens, GA 30602, USA
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Plants 2021, 10(1), 166; https://doi.org/10.3390/plants10010166
Received: 11 December 2020
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Revised: 12 January 2021
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Accepted: 14 January 2021
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Published: 16 January 2021
(This article belongs to the Special Issue Applications and Advances in Artificial Light for Horticulture and Crop Production)
Light-emitting diodes allow for the application of specific wavelengths of light to induce various morphological and physiological responses. In lettuce (Lactuca sativa), far-red light (700–800 nm) is integral to initiating shade responses which can increase plant growth. In the first of two studies, plants were grown with a similar photosynthetic photon flux density (PPFD) but different intensities of far-red light. The second study used perpendicular gradients of far-red light and PPFD, allowing for examination of interactive effects. The far-red gradient study revealed that increasing supplemental far-red light increased leaf length and width, which was associated with increased projected canopy size (PCS). The higher PCS was associated with increased cumulative incident light received by plants, which increased dry matter accumulation. In the perpendicular gradient study, far-red light was 57% and 183% more effective at increasing the amount of light received by the plant, as well as 92.5% and 162% more effective at increasing plant biomass at the early and late harvests, respectively, as compared to PPFD. Light use efficiency (LUE, biomass/mol incident light) was generally negatively correlated with specific leaf area (SLA). Far-red light provided by LEDs increases the canopy size to capture more light to drive photosynthesis and shows promise for inclusion in the growth light spectrum for lettuce under sole-source lighting.
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Keywords:
canopy size; incident light; leaf morphology; light-emitting diodes; light interception; light use efficiency; radiation use efficiency
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
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MDPI and ACS Style
Legendre, R.; van Iersel, M.W. Supplemental Far-Red Light Stimulates Lettuce Growth: Disentangling Morphological and Physiological Effects. Plants 2021, 10, 166. https://doi.org/10.3390/plants10010166
AMA Style
Legendre R, van Iersel MW. Supplemental Far-Red Light Stimulates Lettuce Growth: Disentangling Morphological and Physiological Effects. Plants. 2021; 10(1):166. https://doi.org/10.3390/plants10010166
Chicago/Turabian StyleLegendre, Reeve, and Marc W. van Iersel. 2021. "Supplemental Far-Red Light Stimulates Lettuce Growth: Disentangling Morphological and Physiological Effects" Plants 10, no. 1: 166. https://doi.org/10.3390/plants10010166
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