Challenges and Opportunities of Light-Emitting Diode (LED) as Key to Modulate Antioxidant Compounds in Plants. A Review

Abstract

Plant antioxidants are important compounds involved in plant defense, signaling, growth, and development. The quantity and quality of such compounds is genetically driven; nonetheless, light is one of the factors that strongly influence their synthesis and accumulation in plant tissues. Indeed, light quality affects the fitness of the plant, modulating its antioxidative profile, a key element to counteract the biotic and abiotic stresses. With this regard, light-emitting diodes (LEDs) are emerging as a powerful technology which allows the selection of specific wavelengths and intensities, and therefore the targeted accumulation of plant antioxidant compounds. Despite the unique advantages of such technology, LED application in the horticultural field is still at its early days and several aspects still need to be investigated. This review focused on the most recent outcomes of LED application to modulate the antioxidant compounds of plants, with particular regard to vitamin C, phenols, chlorophyll, carotenoids, and glucosinolates. Additionally, future challenges and opportunities in the use of LED technology in the growth and postharvest storage of fruits and vegetables were also addressed to give a comprehensive overview of the future applications and trends of research.

Combined Effect of Salinity and LED Lights on the Yield and Quality of Purslane (Portulaca oleracea L.) Microgreens

“…In fact, in a review concerning LED lighting as a key to modulate antioxidant compounds in plants, Loi et al [59] stated that B, R and FR lights had shown to be able to increase the TPC and TFC in different plant commodities, and that the regulation of TPC and TFC by LEDs can be performed directly by inducing the expression of the key enzyme and indirectly by increasing the shikimic acid as precursor molecule [60]. Nevertheless, besides light intensity, their contents also depend upon plant species, cultivars and timing of LED exposure [59]. It is well established that salinity can enhance the synthesis of secondary metabolites in plants [61], producing reactive oxygen species, which are harmful to plant cells.…”

Supplementary Light Differently Influences Physico-Chemical Parameters and Antioxidant Compounds of Tomato Fruits Hybrids

“…YP showed the lowest vitamin C content, while RP and RC showed similar values ( Table 3 ). Moreover, Loi et al [ 39 ] reported that vitamin C synthesis is light dependent and its synthesis depends on light intensity, quality, and penetration into the canopy. During this study, the vitamin C content was influenced by the interaction of SL treatment with genotypes ( Figure 2 ).…”

Applications and Development of LEDs as Supplementary Lighting for Tomato at Different Latitudes

“…The spectral output of the source should, therefore, match the plant's photosynthesis and photomorphogenesis requirement [10]. Fluorescent, metal-halide, high-pressure sodium, and incandescent lamps were developed for human lighting requirements and are, therefore, not ideal light sources for plants, whereas LEDs emit specific wavelengths and can be matched to plant needs [11]. The first LEDs used in plant research were based on a gallium-aluminium-arsenide substrate (GaAIAs) with an emission peak range from 630 to 680 nm (Table 3) [10].…”

“…Summary of photoreceptors involved in physiological responses of plants to different light spectra. Semiconductors in LEDs and their emission spectra[11].…”