Non-destructive real-time analysis of plant metabolite accumulation in radish microgreens under different LED light recipes

Marco Garegnani; Carla Sandri; Claudia Pacelli; Francesca Ferranti; Elisabetta Bennici; Angiola Desiderio; Luca Nardi; Maria Elena Villani

doi:10.3389/fpls.2023.1289208

Non-destructive real-time analysis of plant metabolite accumulation in radish microgreens under different LED light recipes

Front Plant Sci. 2024 Jan 11:14:1289208. doi: 10.3389/fpls.2023.1289208. eCollection 2023.

Authors

Marco Garegnani^{1

2}, Carla Sandri¹, Claudia Pacelli³, Francesca Ferranti³, Elisabetta Bennici¹, Angiola Desiderio¹, Luca Nardi¹, Maria Elena Villani¹

Affiliations

¹ ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Department for Sustainability Casaccia Research Center, Rome, Italy.
² Department of Aerospace Science and Technology, Politecnico of Milano, Milan, Italy.
³ Human Spaceflight and Scientific Research Unit, Italian Space Agency, Rome, Italy.

Abstract

Introduction: The future of human space missions relies on the ability to provide adequate food resources for astronauts and also to reduce stress due to the environment (microgravity and cosmic radiation). In this context, microgreens have been proposed for the astronaut diet because of their fast-growing time and their high levels of bioactive compounds and nutrients (vitamins, antioxidants, minerals, etc.), which are even higher than mature plants, and are usually consumed as ready-to-eat vegetables.

Methods: Our study aimed to identify the best light recipe for the soilless cultivation of two cultivars of radish microgreens (Raphanus sativus, green daikon, and rioja improved) harvested eight days after sowing that could be used for space farming. The effects on plant metabolism of three different light emitting diodes (LED) light recipes (L1-20% red, 20% green, 60% blue; L2-40% red, 20% green, 40% blue; L3-60% red, 20% green, 20% blue) were tested on radish microgreens hydroponically grown. A fluorimetric-based technique was used for a real-time non-destructive screening to characterize plant methabolism. The adopted sensors allowed us to quantitatively estimate the fluorescence of flavonols, anthocyanins, and chlorophyll via specific indices verified by standardized spectrophotometric methods. To assess plant growth, morphometric parameters (fresh and dry weight, cotyledon area and weight, hypocotyl length) were analyzed.

Results: We observed a statistically significant positive effect on biomass accumulation and productivity for both cultivars grown under the same light recipe (40% blue, 20% green, 40% red). We further investigated how the addition of UV and/or far-red LED lights could have a positive effect on plant metabolite accumulation (anthocyanins and flavonols).

Discussion: These results can help design plant-based bioregenerative life-support systems for long-duration human space exploration, by integrating fluorescence-based non-destructive techniques to monitor the accumulation of metabolites with nutraceutical properties in soilless cultivated microgreens.

Keywords: LED lights; fluorescence-based non-destructive techniques; hydroponic; microgreen; space environment.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by LAerospaZIO project POR FESR, SOLE (www.laerospazio.enea.it/i-progetti/sole.html). [CUP I82F20000010002] and by the Italian Space Agency – ASI -, MICROx2 project [Implementation Agreement ASI n. 2021-2-HH.0; CUP F79C20000300005].