The Influence of LED Lights of Different Spectrum on the Development of <i>Lactuca sativa</i>

Abstract

The effect of light-emitting diode (LED) lamps with 5 different spectra on L. sativa plants (variety ‘Aficion’) grown in protected soil conditions was studied. Warm white light (WW) was used as a control (the ratio of blue, green and red portions in the spectrum was 14% : 48% : 38%). The maximum values of leaf size and fresh weight of the aerial parts were found in the RGB group (blue-green-red ratio 32% : 19% : 49%), highest values of dry weight and ash content – in the FS group (blue-green-red ratio 27% : 11% : 62%). Stomatal size and density on the abaxial leaf’s side was the highest in SB plants (blue-green-red ratio 33% : 41% : 38%). This was the most effective combination of parameters in terms of leaf architectonics. An increase in the portion of red light in the spectrum with a decrease in the portion of green light had a positive effect on the development of L. sativa plants, while an increase in the portion of green light in the spectrum positively affected-the stomatal apparatus formation.