Blue Radiation Interacts with Green Radiation to Influence Growth and Predominantly Controls Quality Attributes of Lettuce
Abstract Adding green [G (500–600 nm)] radiation to blue [B (400–500 nm)] and red [R (600–700 nm)] radiation creates white radiation and improves crop inspection at indoor farms. Although G radiation can drive photosynthesis and elicit the shade-avoidance response, its effects on plant growth and m...
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doaj-10d4d33273dc432787e3c661a3c548f82020-11-25T03:33:12ZengAmerican Society for Horticultural Science (ASHS)Journal of the American Society for Horticultural Science2327-97882020-01-0114527587https://doi.org/10.21273/JASHS04759-19Blue Radiation Interacts with Green Radiation to Influence Growth and Predominantly Controls Quality Attributes of LettuceQingwu MengJennifer BoldtErik S. RunkleAbstract Adding green [G (500–600 nm)] radiation to blue [B (400–500 nm)] and red [R (600–700 nm)] radiation creates white radiation and improves crop inspection at indoor farms. Although G radiation can drive photosynthesis and elicit the shade-avoidance response, its effects on plant growth and morphology have been inconsistent. We postulated G radiation would counter the suppression of crop growth and promotion of secondary metabolism by B radiation depending on the B photon flux density (PFD). Lettuce (Lactuca sativa ‘Rouxai’) was grown in a growth room under nine sole-source light-emitting diode (LED) treatments with a 20-hour photoperiod or in a greenhouse. At the same photosynthetic photon flux density [PPFD (400–700 nm)] of 180 μmol·m−2·s−1, plants were grown under warm-white LEDs or increasing B PFDs at 0, 20, 60, and 100 μmol·m−2·s−1 with or without substituting the remaining R radiation with 60 μmol·m−2·s−1 of G radiation. Biomass and leaf expansion were negatively correlated with the B PFD with or without G radiation. For example, increasing the B PFD decreased fresh and dry mass by up to 63% and 54%, respectively. The inclusion of G radiation did not affect shoot dry mass at 0 or 20 μmol·m−2·s−1 of B radiation, but it decreased it at 60 or 100 μmol·m−2·s−1 of B radiation. Results suggest that the shade-avoidance response is strongly elicited by low B radiation and repressed by high B radiation, rendering G radiation ineffective at controlling morphology. Moreover, substituting R radiation with G radiation likely reduced the quantum yield. Otherwise, G radiation barely influenced morphology, foliage coloration, essential nutrients, or sensory attributes regardless of the B PFD. Increasing the B PFD increased red foliage coloration and the concentrations of several macronutrients (e.g., nitrogen and magnesium) and micronutrients (e.g., zinc and copper). Consumers preferred plants grown under sole-source lighting over those grown in the greenhouse, which were more bitter and less acceptable, flavorful, and sweet. We concluded that lettuce phenotypes are primarily controlled by B radiation and that G radiation maintains or suppresses lettuce growth depending on the B PFD.https://journals.ashs.org/jashs/view/journals/jashs/145/2/article-p75.xmlessential nutrients; indoor farming; light-emitting diode; morphology; red radiation; sensory quality |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Qingwu Meng Jennifer Boldt Erik S. Runkle |
spellingShingle |
Qingwu Meng Jennifer Boldt Erik S. Runkle Blue Radiation Interacts with Green Radiation to Influence Growth and Predominantly Controls Quality Attributes of Lettuce Journal of the American Society for Horticultural Science essential nutrients; indoor farming; light-emitting diode; morphology; red radiation; sensory quality |
author_facet |
Qingwu Meng Jennifer Boldt Erik S. Runkle |
author_sort |
Qingwu Meng |
title |
Blue Radiation Interacts with Green Radiation to Influence Growth and Predominantly Controls Quality Attributes of Lettuce |
title_short |
Blue Radiation Interacts with Green Radiation to Influence Growth and Predominantly Controls Quality Attributes of Lettuce |
title_full |
Blue Radiation Interacts with Green Radiation to Influence Growth and Predominantly Controls Quality Attributes of Lettuce |
title_fullStr |
Blue Radiation Interacts with Green Radiation to Influence Growth and Predominantly Controls Quality Attributes of Lettuce |
title_full_unstemmed |
Blue Radiation Interacts with Green Radiation to Influence Growth and Predominantly Controls Quality Attributes of Lettuce |
title_sort |
blue radiation interacts with green radiation to influence growth and predominantly controls quality attributes of lettuce |
publisher |
American Society for Horticultural Science (ASHS) |
series |
Journal of the American Society for Horticultural Science |
issn |
2327-9788 |
publishDate |
2020-01-01 |
description |
Abstract
Adding green [G (500–600 nm)] radiation to blue [B (400–500 nm)] and red [R (600–700 nm)] radiation creates white radiation and improves crop inspection at indoor farms. Although G radiation can drive photosynthesis and elicit the shade-avoidance response, its effects on plant growth and morphology have been inconsistent. We postulated G radiation would counter the suppression of crop growth and promotion of secondary metabolism by B radiation depending on the B photon flux density (PFD). Lettuce (Lactuca sativa ‘Rouxai’) was grown in a growth room under nine sole-source light-emitting diode (LED) treatments with a 20-hour photoperiod or in a greenhouse. At the same photosynthetic photon flux density [PPFD (400–700 nm)] of 180 μmol·m−2·s−1, plants were grown under warm-white LEDs or increasing B PFDs at 0, 20, 60, and 100 μmol·m−2·s−1 with or without substituting the remaining R radiation with 60 μmol·m−2·s−1 of G radiation. Biomass and leaf expansion were negatively correlated with the B PFD with or without G radiation. For example, increasing the B PFD decreased fresh and dry mass by up to 63% and 54%, respectively. The inclusion of G radiation did not affect shoot dry mass at 0 or 20 μmol·m−2·s−1 of B radiation, but it decreased it at 60 or 100 μmol·m−2·s−1 of B radiation. Results suggest that the shade-avoidance response is strongly elicited by low B radiation and repressed by high B radiation, rendering G radiation ineffective at controlling morphology. Moreover, substituting R radiation with G radiation likely reduced the quantum yield. Otherwise, G radiation barely influenced morphology, foliage coloration, essential nutrients, or sensory attributes regardless of the B PFD. Increasing the B PFD increased red foliage coloration and the concentrations of several macronutrients (e.g., nitrogen and magnesium) and micronutrients (e.g., zinc and copper). Consumers preferred plants grown under sole-source lighting over those grown in the greenhouse, which were more bitter and less acceptable, flavorful, and sweet. We concluded that lettuce phenotypes are primarily controlled by B radiation and that G radiation maintains or suppresses lettuce growth depending on the B PFD. |
topic |
essential nutrients; indoor farming; light-emitting diode; morphology; red radiation; sensory quality |
url |
https://journals.ashs.org/jashs/view/journals/jashs/145/2/article-p75.xml |
work_keys_str_mv |
AT qingwumeng blueradiationinteractswithgreenradiationtoinfluencegrowthandpredominantlycontrolsqualityattributesoflettuce AT jenniferboldt blueradiationinteractswithgreenradiationtoinfluencegrowthandpredominantlycontrolsqualityattributesoflettuce AT eriksrunkle blueradiationinteractswithgreenradiationtoinfluencegrowthandpredominantlycontrolsqualityattributesoflettuce |
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