نبذة مختصرة : In 2014, experiments were carried out in the phytotron chambers of the Plant Physiology Laboratory and the greenhouse of the seed¬plot of the Lithuanian Research Centre for Agriculture and Forestry. The aim of this study was to select the optimal photosynthetic photon flux density (PPFD) of new solid¬state lighting lamps for growing of cucumber and tomato transplants and salad vegetable and to estimate their productivity and photosynthetic rates. Solid¬state lighting lamps containing 420–430 nm (violet), 460–470 nm (blue), 610–615 nm (orange), 620–630 and 660–670 nm (red) and blue 400–500 nm + green 500–600 nm + red 600–700 nm (white) light¬emitting diodes (LEDs) were used in the experiments. The generated photosynthetic photon flux density (PPFD) of each type of solid¬state modules was ~150 and ~ 250 μmol m–2 s–1. Salad and vegetable transplants were grown in the greenhouse with a combination of natural light and LED light lamps. In the phytotron chambers plants used only LED light lamps. As a reference group, transplants were grown under high¬pressure sodium lamps (SON¬T Agro) PPFD ~150 μmol m–2 s–1. Our investigations revealed that because of the effect of the light emitting diode (LED) lamps and different photosynthetic photon flux density (PPFD) on the greenhouse cultivation of salad and vegetable transplants, lighted with LED and natural day-light, they had a better net assimilation rate (NAR), relative growth rate (RGR) and maintained a good shoot–root ratio (SRR), compared with that of plants grown under SON¬T Agro with natural daylight. In the phytotron chambers cultivation of cucumber and tomato transplants and salad, illuminated by LED light, had a very high net assimilation rate (NAR), relative growth rate (RGR) and maintained the shoot–root ratio (SRR). PPFD ~250 μmol m–2 s–1 significantly reduced the leaf area ratio (LAR), specific leaf area (SLA) and leaf weight ratio (LWR).
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