Evaluation of the Effectiveness of Different LED Irradiators When Growing Red Mustard (Brassica juncea L.) in Indoor Farming

Abstract

Investigation is devoted to the optimization of light spectrum and intensity used for red mustard growing. Notably, most of the studies devoted to red mustard growing were conducted on micro-greens, which is not enough for the development of methods and recommendations for making the right choices about the irradiation parameters for full-cycle cultivation. In this study, we tested four models of LED with different ratios of blue, green red and far red radiation intensity: 12:20:63:5; 15:30:49:6; 30:1:68:1, in two values of photon flux density (PFD)—120 and 180 µmol m−2 s−1—to determine the most effective combination for red mustard growing. The study was conducted in a container-type climate chamber, where the red leaf mustard was cultivated in hydroponics. On the 30th day of cultivation, the plant’s morphological, biochemical and chlorophyll fluorescence parameters, and reflection coefficients were recorded. The results indicated that the PFD 120 µmol m−2 s−1 had a worse effect on both mustard leaf biomass accumulation and nitrate concentration (13–30% higher) in the plants. The best lighting option for growing red mustard was the blue–red spectrum, as the most efficient in terms of converting electricity into biomass (77 Wth/g). This light spectrum contributes to plant development with a larger leaf area (60%) and a fresh mass (54%) compared with the control, which has a maximum similarity in spectrum percentage to the sunlight spectrum. The presence of green and far red radiation with the blue–red light spectrum in various proportions at the same level of PFD had a negative effect on plant fresh mass, leaf surface area and photosynthetic activity. The obtained results could be useful for lighting parameters’ optimization when growing red mustard in urban farms.

Effect of Far-Red Light on Biomass Accumulation, Plant Morphology, and Phytonutrient Composition of Ruby Streaks Mustard at Microgreen, Baby Leaf, and Flowering Stages

“…However, whether and to what extent FR accelerates flowering is species-dependent. , Within the brassica family, Chinese kale (Brassica alboglabra Bailey) and rapeseed (Brassica napus) showed increased flower buds and racemes, respectively, upon FR supplementation, while bok choi (Brassica chinensis) stopped flowering under FR treatments . In this study, the control did not show any flowers after 30 d, in line with previous reports on a similar red mustard species . In comparison, FR-including treatments shortened the time to flower by up to 46% and advanced the emergence of seedpods to a similar extent (Table ).…”

“…32 In this study, the control did not show any flowers after 30 d, in line with previous reports on a similar red mustard species. 5 In comparison, FR-including treatments shortened the time to flower by up to 46% and advanced the emergence of seedpods to a similar extent (Table 4). This finding demonstrated the possibility of producing mustard flowers and seeds within a relatively short period.…”

“…13 Related, mature red leaf mustard (B. juncea L.) was recently found to show larger leaves and higher fresh yield with 1% FR in the spectrum compared to 11% FR. 5 However, it remains unknown (1) whether the RS cultivar responds significantly to FR in terms of yield, morphology, and phytonutrient composition, (2) whether such responses persist or vary at different growth stages, and (3) whether RS responds differently to FR applied singularly versus FR supplemented with white light treatment. This study seeks a holistic understanding of how FR affects the morphology, development, and phytonutrient composition of RS.…”

“…Far-red (FR, wavelength between 700 and 780 nm) is an essential composition of the solar spectrum but has been traditionally disregarded in grow light design since monochromatic FR has been considered minimally photosynthetically active. Nonetheless, FR supplementation has been shown to affect plant development, yield, and nutrition profoundly in CEA, − which can be ascribed to several mechanisms. First, FR photons, especially those at a wavelength of 700–750 nm, have been recently demonstrated to enhance photosynthetic activity as effectively as shorter wavelength photons .…”

The Influence of Composite Luminescent Materials Based on Graphene Oxide on the Growth and Development of Solanum lycopersicum in Greenhouses

“…At the same time, the high cost of additional lighting reduces the profitability of production. Therefore, approaches aimed at changing the spectrum of sunlight are gaining great popularity [11][12][13][14]. Photoselective [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] or photoconversion [30][31][32][33] coatings are used for these purposes.…”