Light-emitting Diodes and the Modulation of Specialty Crops: Light Sensing and Signaling Networks in Plants

Abstract

<jats:p>The technology to drive the output of individual arrays of light-emitting diodes (LEDs) on timescales down to microseconds is enabling plant scientists and growers control over irradiance- and spectrum-induced plant responses. The two light sensing and signaling networks that regulate desired plant responses involve either photoreceptors (PR) and/or photosynthesis (PSN). These networks control morphological, physiological, and developmental processes (e.g., seed development and germination, seedling development, apical meristem formation, differentiation, flowering, etc.) as well as the energy distribution within the plant. Understanding the individual plant responses and the synergy between the PR and PSN networks will assist in the selection and timing of LED light programs for crop regulation and growth. Both networks sense and respond to irradiance and narrow-band spectra between 350 and 750 nm although their modes of action are different. Comparing the PR and PSN networks and their effect on plants shows that the PR network primarily regulates developmental processes in new tissues while the PSN network regulates routine operational processes. The two networks are required for healthy plant growth and are reliant on each other for biological fitness. A balance between these two networks will result in greater plant efficacy and can be achieved by light programs whose irradiance, spectra, duration, and timing can be regulated. Replacing high-intensity discharge (HID) lamps with LEDs is a catalyst for a fundamental change in plant lighting and we are on a steep learning curve to fully realize how to fully control LED technology in plant growth applications.</jats:p>

An Update on Plant Photobiology and Implications for Cannabis Production

“…Light is one of the most important environmental parameters that impacts plant growth and development. It exerts a vast range of effects on photosynthetic activity and photomorphogenic responses throughout the plant’s life (Pocock, 2015; Naznin et al., 2016; Ouzounis et al., 2016). Close to half of the sun’s total radiation emission reaching the Earth’s surface is visible light, ranging from 400 to 740 nm wavelengths (Both et al., 2015).…”

“…Photomorphogenesis is the light-mediated development of plants regulated by five different photoreceptors (Figure 2; Folta and Carvalho, 2015; Pocock, 2015). They mediate and modulate dozens of structural plant developments such as height, leaf size, and flowering.…”

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“…Understanding the mechanisms that underlie plant spectral light responses and tolerance is hence paramount to improve plant agriculture productivity and global food security. Within the photosynthetically active radiation (PAR) light spectrum (400-700 nm), plant photoreceptors perceive the major wavelengths corresponding to blue (400-500 nm) and red (600-700 nm) regions, and less within the green (500-600 nm) [4]. While only 10-50% of these regions are reflected by plant chloroplasts [5], there is a misconception that plants do not make use of the wavelengths regions (500-600 nm) [6].Within this region, there is a narrow wavelength with a peak at 595 nm that a growing body of evidence has highlighted for its physiological impact on plants growth and photosynthesis [7,8].…”

Usefulness of LED lightings in cereal breeding on example of wheat, barley and oat seedlings

“…"Replacing high-intensity discharge lamps with LEDs is a catalyst for a fundamental change in plant lighting and we are on a steep learning curve to fully realize how to fully control LED technology in plant growth applications" [10] .…”