Photoregulation of Bioprotectant Content of Red Leaf Lettuce with Light-emitting Diodes

Abstract

<jats:p><jats:italic>Lactuca sativa</jats:italic> cv. Outredgeous was grown under either fluorescent lamps or light-emitting diodes (LEDs) to test the hypothesis that antioxidant potential could be regulated by light quality. Red leaf lettuce was grown at 300 μmol·m<jats:sup>−2</jats:sup>·s<jats:sup>−1</jats:sup> of photosynthetically active radiation, 1200 μmol·mol<jats:sup>−1</jats:sup> CO<jats:sub>2</jats:sub>, 23 °C, and an 18 h-light /6-h dark photoperiod in controlled-environment chambers. The LED treatments were selected to provide different amounts of red (640 nm), blue (440 nm), green (530 nm), and far-red (730 nm) light in the spectra. Total anthocyanin content and the oxygen radical absorbance capacity of the tissue were measured at harvest. The source of light had a dramatic effect on both plant growth and production of radioprotective compounds. LEDs resulted in 50% greater bioprotectant content per plant at the same light level over triphosphor fluorescent lamps. Blue LEDs (440 nm) appeared to regulate the metabolic pathways leading to increased concentration of bioprotective compounds in leaf tissue. LED lighting induced a number of effects on morphology that increased both accumulation of bioprotective compounds and total yield.</jats:p>

Plant Growth and Photosynthetic Characteristics of Mesembryanthemum crystallinum Grown Aeroponically under Different Blue- and Red-LEDs

“…They reported that shoot DW increased with increasing red/blue light ratio, which was mainly due to increased leaf number and leaf area under the higher red/blue light ratio. It was also reported that the optimal red/blue light ratios for FW and DW accumulation were 7/3 in strawberry plantlet (Nhut et al, 2003) and 1/3 in rapeseed plantlets in vitro (Li et al, 2013), respectively, but 9 in cucumber seedlings (Hernández and Kubota, 2016), spinach (Yorio et al, 2001), lettuce (Bula et al, 1991; Yorio et al, 2001; Stutte et al, 2009), and Arabidopsis (Ooi et al, 2016). Based on the above discussion, blue light promote growth by stimulating morphological response.…”

Plant lighting system with five wavelength-band light-emitting diodes providing photon flux density and mixing ratio control

“…The blue-type LED emits light with 460 nm λ p , which activates photosynthesis [22,29,30,32] and which induces phototropin-mediated and cryptochrome-mediated plant responses [33-38]. Blue light also enhances the accumulation of pigments such as chlorophylls in cucumber leaves [22], carotenoids in citrus juice sacs cultured in vitro [39], and anthocyanins in lettuce leaves [21]. Orange-red light with 630 nm λ p enhances photosynthesis [29,30].…”

The effects of LED illumination spectra and intensity on carotenoid content in Brassicaceae microgreens

“…One of the main advantages of LEDs is the possibility of using specific light wavelengths for influencing plant morphology and phytochemical contents (Morrow, 2008;Tamulaitis et al, 2005). Data in the literature have mostly reported about successful cultivation of various plants under different lighting combinations of blue, red, and far-red LEDs (Kopsell & Sams, 2013;Olle & Viršilė , 2013;Stutte, Edney, & Skerritt, 2009;Tarakanov, Yakovleva, Konovalova, Paliutina, & Anisimov, 2012). However, there is insufficient information regarding effects of irradiance levels and other wavelengths in LED lighting systems, mostly designed to replace HPS lamps, which main spectral composition is in yellow-orange-red region (Morrow, 2008;Spaargaren, 2001) on plant metabolic composition, including carotenoids.…”