Light & Engineering Vol. 23, No. 4, pp. 55-62, 2015 Svetotekhnika No. 4, 2015, pp. 47-52 SPECTRAL ASPECT WHEN USING LIGHT-EMITTING DIODE IRRADIATORS FOR SALAD PLANT CULTIVATION UNDER PHOTOCULTURE CONDITIONS Andrei A. Yemelin1,2, Leonid B. Prikupets1,2, and Ivan G. Tarakanov3 1VNISI of S.I.Vavilov Open Company 2BL TRADE Open Company 3Russian State Agrarian University – MAA of K.A.Timiryzev FSEE, Moscow E-mail: prikup@vnisi.ru ABSTRACT The authors state that there is currently no alternative to the experimental method of searching for an optimum spectrum of optical radiation to cultivate some plant types. <...> Photobiological research was performed for salad photoculture conditions in a phytothron at the Russian State Agrarian University (RSAU) – Moscow Agrarian Academy (MAA). <...> Irradiators with high pressure sodium lamps (HPSL), and with white and colour (red-dark blue) LEDs were used in the experiment. <...> The obtained results hold out a hope of a decreasing electric energy costs by up to 40–45% when using red-dark blue phyto-irradiators with light emitting diodes to cultivate salad in industrial greenhouses. <...> Keywords: light emitting diode, photoculture, irradiating installation, light curves, salad-greengrocers cultures, photobiological experiment, HPSL, photosynthesis photon fl ux 1. <...> INTRODUCTION The emergence of light-emitting diode radiation sources holds out a hope for the ambition of photobiologists, light engineers and greenhouse cultivation specialists, which seeks to create light sources with an optimal spectrum for the cultivation of some types of plants [1–3]. <...> The fi nal reaction of the plants for infl uence of optical radiation (OR) can be expressed, with some assumptions, as an integral function, more likely being a conditional mathematical illustration: Nq T Ev () () () , =⋅ эф Ч 400 700 ∫ ⋅ ⋅K d ф ⋅ (1) where Ev (λ) is irradiance spectral concentration on the cone surface from a radiation source of photosynthetic active radiation (PAR) area (400–700 nm), α(λ) is the spectral absorption factor of the leaves, Кф(λ) is the spectrum of photosynthetic infl uence, N is the dry weight of plants, Т is the duration of irradiation, ηef is the effi ciency of synthesis of dry <...>