Influência da radiação eletromagnética de diodos emissores de luz no cultivo da alface.

Abstract

Advances in light-emitting diode (LED) technology have become a viable alternative to current lighting systems for lighting requirements in plant growth greenhouses, regardless of environmental conditions. And understand how the specific LED illumination, at the wavelength of the spectral range between blue and red, could affect the development of plants is therefore of great interest to science. The objective of this research was to evaluate the influence of LED lamps with different combinations of blue and red light bands on the growth, production and physiology of lettuce (Lactuca sativa). A factorial scheme with 4 combinations of LED light (5: 1; 3: 1; R: B and 6: 3) and 2 lettuce cultivars (Smooth: Regina and Crispy: Veneranda) was used. The plants were transplanted 30 days after sowing (DAS), and grown in pots in a closed environment under these conditions for 21 days, with a controlled photoperiod of 12 h. At 11 and 21 days after transplant (DAT), the variables, number of leaves (NF) and leaf cover (CF), the variables related to gas exchange were determined (Pn: Liquid photosynthesis, E: Transpiration, Gs: Stomatal conductance; Ci: internal CO2 concentration; EIUA: instantaneous efficiency of water use) and chlorophyll content determined by the SPAD. At 21 DAT, the leaf area (DC), stem length (CC), fresh / dry leaf mass (MFF / MSF), fresh / dry stem mass (MFC) / MSC), fresh / dry mass of the roots (MFR / MSR), and the content of photosynthetic pigments, chlorophyll a, and carotenoids. The highest growth and yield of lettuce plants were observed in the source of 5: 1 combination LED light variation, as well as, a greater efficiency in photosynthesis by plants. The cultivar of crisp lettuce presented superior to smooth in all analyzed variables, suggesting adaptation to the treatments applied.