A recent study has been carried out to determine the effects of four different illuminators with red, far-red, blue, and white light-emitting diodes (LEDs) on the growth, morphology, pigment composition, and chlorophyll fluorescence of spinach (Spinacia oleracea L.) of the ‘Zhirnolistny’ cultivar.
The researchers investigated these variants in two-photon flux densities, 400–800 nm (PFD) 120 µmol m−2 s−1 and 180 µmol m−2 s−1. The studies were carried out in a climate chamber. Plant measurements were carried out on the 30th and 45th days of cultivation.
The results showed that during the period of active growth, on the 30th day, spinach plants accumulated 2.6 and 2.4 times more fresh weight in the variant with a higher PFD (180 µmol m−2 s−1). At the end of the growing season, only a decrease in PFD had an effect on the fresh and dry weight of plants.
The highest concentration of chlorophyll on both the 30th and 45th days of vegetation was found when spinach plants were grown under red-blue (RB) LEDs in a spectrum proportion of R70:B30. It was found that the variants had a higher proportion of green radiation in the spectrum of illuminators with PFD 180 µmol m−2 s−1, and the nitrate content in spinach was slightly lower than in other variants.