Effects of artificial light sources on growth and phytochemicals content in green oak lettuce

Abstract

<jats:p>ABSTRACT The artificial light source is one of the most important factors in a controlled environment for vegetable production. It could provide new opportunities to improve growth and increase phytochemicals content in vegetables. Therefore, this study focused on the effects of artificial light sources on growth and phytochemicals in green oak lettuce (Lactuca sativa). The plants were grown under growth chamber with three artificial light sources, namely bar-LED (the 1:1:1 ratio of blue 460 nm : red 630 nm : red 660 nm), bulb-LED (the 2:1:1 ratio of blue 460 nm : red 630 nm : red 660 nm), and fluorescent lamp (FL) (the wavelength range 380-700 nm) for 4 weeks. The quality of bar-LED light was better than either bulb-LED or FL, when assessed by the parameters of photosynthetically active radiation (PAR), photosynthetic photon flux density (PPFD, 400-700 nm), PPFD-B (blue, 400-500 nm), PPFD-R (red, 600-700 nm), the yield photon flux density (YPFD), and the color of red. However, shoot and root (fresh and dry mass), leaf area, leaf number, and shoot/root ratio did not significantly differ between plants grown under bar-LED and bulb-LED, but they were significantly higher than plants grown under FL. Bulb-LED and bar-LED induced larger dry mass of the plants than FL. The dry mass per mole of artificial lighting was highest in plants grown under bar-LED. On the other hand, the fresh mass per mole of artificial lighting was highest in plants grown under bulb-LED. As regards power consumption, bar-LED provided the lowest consumption with 44.4% energy saving over the FL. Total phenolic content, 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and 2,2-diphenylpicrylhydrazyl (DPPH) activities were highest in plants grown under bar-LED. FL lighting gave the least contents of chlorophyll a and chlorophyll a + b. However, chlorophyll b and carotenoid contents did not significantly differ among the treatments. Thus, the results suggested that bar-LED has the potential to improve energy saving, and both growth and phytochemicals content of green oak lettuce grown in a controlled environment of vegetable production.</jats:p>

Effect of artificial light on alfalfa (Medicago sativa L.) production

“…Likewise, the low efficiency of the IL to produce mol m 2 s is related to the heat production it generates. According to Massa et al (2008) and Etae et al (2020) IL provides only 15% of illumination and 85% of the remaining energy is transformed into heat, which justifies the high temperature presented by the ILs when they are illuminating, this being a negative effect of this source because they reached temperatures above 60 °C, when the room temperature fluctuated at 21 °C, which can cause negative effects on the crop if the ILs are near, contrary to what happened with LED and FL, which increased 1 °C with respect to the room temperature.…”

Effect of Post-harvesting with Different Photoperiods under Artificial Light Sources on Nitrate and Vitamin C Contents in Hydroponic Green Oak Lettuce

“…Lettuce plants were moved and placed into a post-harvest chamber with three shelves. The shelf has three cells [80 length x 40 width x 30 height (cm)] (More information is available in the previous experiment [23]). This post-harvest chamber was set up with three different artificial light sources 1); Bulb-LED (1:1:1 ratio of blue 460 nm: red 630 nm: red 660 nm, PPFD 2005.05 ± 53.62 µmol/m 2 /s), 2); Bar-LED (2:1:1 ratio of blue 460 nm: red 630 nm: red 660 nm, PPFD 256.32 ± 11.56 µmol/m 2 /s) and 3); fluorescence light (FL) (spectral wavelength 400 -700 nm PPFD; 51.64 ± 11.20 µmol/m 2 /s).…”

Supplementary Light on the Development of Lettuce and Cauliflower Seedlings

“…Factors such as climate change and water scarcity, the requirement for more resistant species to diseases, and the variation in the incidence of light available for photosynthesis are current problems that demand solutions to support increased crop productivity and quality [4]. Among the Stresses 2024, 4 95 technological alternatives for situations with a lack of available photosynthetically active radiation (PAR), the use of artificial light using light-emitting diodes (LEDs) stands out, especially at times of the year that suffer from variations in lighting during the winter period or cloudy/rainy days [5]. Artificial lighting, mainly in closed environments, has been studied to evaluate the incidence and quality of light and the photoperiod, with the aim to optimize the development and increase the quality of plants grown in a controlled environment [6].…”

“…Within the ePAR, the spectral bands corresponding to blue (400-520 nm) and red (610-720 nm) light are those with the highest energy conversion efficiency by chlorophylls [9]. Therefore, when using artificial light, it is recommended to optimize the system so that most of the artificial light spectrum encompasses these two radiation bands [5].…”