The Impact of Spectral Composition of White LEDs on Spinach (Spinacia oleracea) Growth and Development

Abstract

Light-emitting diodes (LED) are a promising light source for the cultivation of edible vegetables in greenhouses. The spectral radiation of the light sources has an impact on plants physiological parameters, as well as on morphological features. In this study the growth of spinach plants has been carried out in experimental boxes under two white LED treatments having different correlate color temperature (CCT): the cold lighting (CL) corresponded to 6500 K, while the warm lighting (WL) to 3000 K. The work was aimed to investigate the influence of the two light spectra on plant development and comparing the results. Results showed that the different lighting treatments impact differently on plant development and on growth parameters.

Variation in terpenoids in leaves of Artemisia annua grown under different LED spectra resulting in diverse antimalarial activities against Plasmodium falciparum

“…LED spectra in an environmentally controlled system have been proven to regulate plant productivity. Fresh weight and dry weight of lettuce significantly increased under red LED light [ 25 ], blue spectrum induced biomass of amaranth and turnip greens [ 26 ] and white light promoted leaf, stem, root growth and overall growth rate of spinach [ 27 ].…”

Associative learning in plants: light quality history may matter

“…A difference in the history of light quality during early growth may result in physiologically and/or morphologically different plant individuals. Indeed, spinach plants exhibit subtle but consistent developmental differences when grown under two types of white LED lights with slightly different spectral compositions (Buratini et al, 2017). In a well-characterized example, the ratio of far-red/red light, which is increased in light reflected from or filtered through leaves, initiates the "shade avoidance response"-A very complex set of structural, developmental and physiological reactions to ongoing or imminent shading.…”

Optimization of Artificial Light for Spinach Growth in Plant Factory Based on Orthogonal Test

“…Under our experimental environment, in the preliminary experiments, when the light intensity was higher than 150 µmol•m −2 •s −1 , the spinach plant appeared burnt and died; when the lighting time exceeded 14 h per day, the plant showed early bolting. According to the preliminary experiments and the relevant researches before [16,17], the intensity of planting light for spinach growth should be set lower than 150 µmol•m −2 •s −1 , and the lighting time should not exceed 14 h/day. Thus, the experiment used the L 4 (2 3 ) orthogonal table [28] regardless of interaction to analyze.…”

“…However, as a popular vegetable, the suitable LED light parameters for spinach have not been fully investigated. Only the LED lamps with continuous spectrum and several specific light intensity levels were applied for this plant [16,17]. The quality of the spinach has not been investigated in those studies.…”