Continuous LED Lighting Enhances Yield and Nutritional Value of Four Genotypes of Brassicaceae Microgreens.

Tatjana G Shibaeva,Elena G Sherudilo,Alexandra A Rubaeva,Alexander F Titov

doi:10.3390/plants11020176

Tatjana G Shibaeva, Elena G Sherudilo + Show 2 more

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https://doi.org/10.3390/plants11020176

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Abstract

The effect of continuous lighting (CL, 24 h) and light spectrum on growth and nutritional quality of arugula (Eruca sativa), broccoli (Brassica oleracea var. italic), mizuna (Brassica rapa. var. nipposinica), and radish (Raphanus sativus var. radicula) were investigated in growth chambers under light-emitting diode (LED) and fluorescent lighting. Microgreens were grown under four combinations of two photoperiods (16 h and 24 h) providing daily light integral (DLI) of 15.6 and 23.3 mol m−2 day−1, correspondingly) with two light spectra: LED lamps and fluorescent lamps (FLU). The results show that fresh and dry weights as well as leaf mass per area and robust index of harvested arugula, broccoli, mizuna, and radish seedlings were significantly higher under CL compared to 16 h photoperiod regardless of light quality. There were no visible signs of leaf photodamage. In all CL-treated plants higher chlorophyll a/b and carotenoid-to-chlorophyll ratios were observed in all plants except mizuna. CL treatment was beneficial for anthocyanin, flavonoid, and proline accumulation. Higher activities of antioxidant enzymes (catalase, superoxide dismutase, ascorbate peroxidase, and guaiacol peroxidase) were also observed in CL-treated plants. In most cases, the effects were more pronounced under LED lighting. These results indicate that plants under mild oxidative stress induced by CL accumulated more non-enzymatic antioxidants and increased the activities of antioxidant enzymes. This added nutritional value to microgreens that are used as functional foods providing health benefits. We suggest that for arugula, broccoli, mizuna, and radish, an LED CL production strategy is possible and can have economic and nutritional benefits.

Highlights

CLgrown plants outperformed plants grown under 16 h photoperiod in terms of production of fresh weight (FW) and dry weight (DW), except for mizuna in FLU-CL treatment
This study investigated the responses of four microgreen genotypes to CL provided by florescent lights and red and blue (RB) light-emitting diodes (LED) with photosynthetic photon flux density (PPFD) of 270 μmol m−2 s−1
Yield, and nutritional quality of arugula, broccoli, mizuna, and radish microgreens, we suggest that CL had a significant impact on microgreen growth and nutritional quality

Summary

Introduction

Microgreens are a relatively new specialty crop and emerging commodity in worldwide markets They are defined as tender immature greens produced from seeds of vegetables, herbs, or gains, including local varieties and wild species having fully developed cotyledons with or without the emergence of a rudimentary pair of first true leaves [1,2]. Several species of microgreens are known for their health beneficial effects as they contain high concentrations of health-promoting phytochemicals [1,5]. Their bioactives include higher levels of antioxidant compounds such as polyphenols, carotenoids, and ascorbic acid, than their mature plants, qualifying microgreens as functional food [1,6]

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