The impact of supplemental blue and green LED and HPS lamps lighting effects on the photosynthesis parameters of sweet pepper transplants

Abstract

The objective of studies was to compare photosynthesis parameters of sweet pepper transplants ‘Reda’ under emission of short-wavelength single-monochromatic solid-state lamps developed for supplementation of high-pressure sodium (HPS) lamps used winter time in greenhouses. Four types of solid-state lamps were made using advanced light-emitting diodes (LEDs) with peak emissions at blue 455, 470, cyan 505, and green 530 nm, and were installed in a greenhouse. The generated photosynthetic photon flux density (PPFD) of each type of solid-state lamps was 15 μmol m-2 s-1 and of HPS lamps PPFD was 100 μmol m-2 s-1. Transplants were grown in greenhouse of phytotron complex under illumination of HPS lamps and with supplementation LED lamps. The reference transplants were grown under illumination of HPS lamps (PPFD 110 μmol m-2 s-1). Our investigations revealed that the effect of supplemental green 530 nm LED illumination with HPS lamps increased photosynthetic pigments content. Meanwhile, supplemental 530 nm light had negative effect on photosynthetic rates (Pn), intercellular CO2 concentration (Ci), transpiration rate (Tn) and stomatal conductance (gs). Supplemental cyan 505 nm and blue 470 nm LED light had great positive effect on the photosynthesis parameters of sweet pepper transplants.