Effect of LED Lighting on Physical Environment and Microenvironment on In Vitro Plant Growth and Morphogenesis: The Need to Standardize Lighting Conditions and Their Description

Abstract

In the last decades, lighting installations in plant tissue culture have generally been renewed or designed based on LED technology. Thanks to this, many different light quality advances are available but, with their massive implementation, the same issue is occurring as in the 1960s with the appearance of the Grolux (Sylvania) fluorescent tubes: there is a lack of a methodological standardization of lighting. This review analyzes the main parameters and variables that must be taken into account in the design of LED-based systems, and how these need to be described and quantified in order to homogenize and standardize the experimental conditions to obtain reproducible and comparable results and conclusions. We have designed an experimental system in which the values of the physical environment and microenvironment conditions and the behavior of plant tissue cultures maintained in cabins illuminated with two lighting designs can be compared. Grolux tubes are compared with a combination of monochromatic LED lamps calibrated to provide a spectral emission, and light irradiance values similar to those generated by the previous discharge lamps, achieving in both cases wide uniformity of radiation conditions on the shelves of the culture cabins. This study can help to understand whether it is possible to use LEDs as one standard lighting source in plant tissue culture without affecting the development of the cultures maintained with the previously regulated protocols in the different laboratories. Finally, the results presented from this caparison indicate how temperature is one of the main factors that is affected by the chosen light source.

UV-B Radiation as a Novel Tool to Modulate the Architecture of In Vitro Grown Mentha spicata (L.)

“…Light can affect a variety of physiological processes such as the development of photosynthetic competence, accumulation of secondary metabolites, cell wall development, and plant and leaf morphology [12]. While the importance of the light spectrum for in vitro culture is well established [12,13], knowledge is largely limited to visible wavelengths (380-700 nm). In contrast, very limited information is available on the influence of ultraviolet A (315-400 nm) and B (280-315 nm) wavelengths.…”

Characterizing the Spatial Uniformity of Light Intensity and Spectrum for Indoor Crop Production

“…Although lighting conditions are considered to be one of the key control parameters in CEA applications [24][25][26][27][28][29][30][31][32][33][34][35], there is still no standardized methodology to characterize the spatial variability of photon irradiance distributions. Quantification of photon irradiance distributions is important both from scientific and economic perspectives.…”

“…In cultivation facilities, light inhomogeneity can reduce crop yield and production efficiency. The lack of a universally accepted protocol is considered as a major issue while comparing results of plant photobiological research studies [31,34]. Pan et al have published methods to map intensity and spectral characteristics in 3D space which can provide a full characterization of the lighting environment relevant to plant growth [36], but the near-field goniometry proposed has been considered to be complicated and expensive for general use in horticultural lighting [34].…”

Secondary metabolites, hormonal homeostasis, and antioxidant enzymes of Moringa oleifera in response to white or violet Light Emitting Diodes (LEDs) combined with cytokinins under tissue culture conditions

“…This has led to several improvements in light quality. Still, the same problem that arose in the 1960s with the introduction of Grolux (Sylvania) fluorescent tubes continues to exist with their widespread implementation (Barceló-Muñoz et al, 2021). using LEDs as a primary illumination source in plant tissue culture without impairing the growth of the cultures kept up using the previously established methods in various labs.…”

“…using LEDs as a primary illumination source in plant tissue culture without impairing the growth of the cultures kept up using the previously established methods in various labs. Finally, the comparison's findings show that one of the key aspects that the light source of choice affects is the temperature (Barceló-Muñoz et al, 2021).…”