LED Lighting to Produce High-Quality Ornamental Plants

Abstract

The flexibility of LED technology, in terms of energy efficiency, robustness, compactness, long lifetime, and low heat emission, as well as its applications as a sole source or supplemental lighting system, offers interesting potential, giving the ornamental industry an edge over traditional production practices. Light is a fundamental environmental factor that provides energy for plants through photosynthesis, but it also acts as a signal and coordinates multifaceted plant-growth and development processes. With manipulations of light quality affecting specific plant traits such as flowering, plant architecture, and pigmentation, the focus has been placed on the ability to precisely manage the light growing environment, proving to be an effective tool to produce tailored plants according to market request. Applying lighting technology grants growers several productive advantages, such as planned production (early flowering, continuous production, and predictable yield), improved plant habitus (rooting and height), regulated leaf and flower color, and overall improved quality attributes of commodities. Potential LED benefits to the floriculture industry are not limited to the aesthetic and economic value of the product obtained; LED technology also represents a solid, sustainable option for reducing agrochemical (plant-growth regulators and pesticides) and energy inputs (power energy).

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“…However, plants have five different photoreceptors that can detect light outside the PAR range. Research has shown that UV-A radiation can increase plant vigor and affect leaf pigments, while IR radiation can affect the flowering cycle [24][25]. In contrast, the Vlambda curve shows the different light sensitivities of humans, with our visual system being most sensitive to green-yellow light (Figure 2).…”

Diverse Flowering Response to Blue Light Manipulation: Application of Electric Lighting in Controlled-Environment Plant Production

“…Electric lighting has been increasingly used for controlled environment production of ornamental plants [5,6]. There are different ways to apply electric lighting in production such as night interruption lighting, day extension lighting, supplemental lighting, and sole-source lighting, for different production purposes.…”

“…Chrysanthemums are quantitative short-day plants that flower uniformly when the critical day-length photoperiod is ≈13.5 h or less but fail to flower under longer photoperiods than the critical day length [31]. The grading standards for cut chrysanthemum on the world market require an elongated and unbranched plant shape and large-sized flowers [5]. Due to the required stem length specification in cut chrysanthemum production, artificially long days are maintained routinely for 2-3 weeks before the onset of short days [31].…”

The Role of Blue and Red Light in the Orchestration of Secondary Metabolites, Nutrient Transport and Plant Quality

“…Blue light enhances the chl a/b ratio and photosynthesis rate [ 25 ] and controls stomatal opening and the biosynthesis of secondary metabolites [ 26 , 27 , 28 ], while inhibiting cell division and extension of growth [ 23 ]. Horticulture plant quality takes advantage of LED lighting to shape plant architecture, induce flowering, prevent postharvest loss, and enhance flower and leaves pigmentation [ 29 ].…”