SUBSTANTIATION OF OPTIMAL LIGHTING REGIMES FOR PLANTS IN SPACE GREENHOUSE <>

A 3-factor experiment with 24-d vegetation of Brassica chinensis L. crops demonstrated the dependence of dry mass yield on lighting regimes provided by a lamp composed of white (color temperature 4000 K) and red (660 nm) LEDs (light-emitting diodes). Experimental data were used to build regressive dependences of plant dry mass and optimal light criterion (product of dry mass and photosynthesis efficiency) on 3 LEDs lamp parameters: photosynthetic photon flux density (PPFD), red and white PPFD ratio, and pulse period. The following LEDs light parameters were found to be optimal for the Chinese cabbage: time-averaged PFD - 500.μmol/(m².s), red and white PPFD ratio - 1.5 and pulse period - 501 ps. Considering the wattage rating for projectible vitamin greenhouse Vitacycle-To, continuous light should have PPFD = 430 pmol/(m²-s), rPPFD/wPPFD ratio - 1.5 and continuous light.