BIOINSUMOS E INTENSIDADE LUMINOSA NO CULTIVO DE ALFACE (lactuca sativa l.) EM AMBIENTE INDOOR

Abstract

The cultivation of lettuce (Lactuca sativa L.) in Controlled Environment Agriculture (CEA) systems has gained prominence due to its production efficiency, rational use of resources, and the possibility of precise management of environmental factors. Light intensity and the application of plant growth-promoting microorganisms stand out as strategies capable of modulating physiological, morphological, and metabolic responses in plants. The objective of this study was to evaluate the effect of inoculation with Bacillus subtilis UFV S1 and Priestia aryabhattai CCT 7986, applied individually or in consortium, combined with two light intensities (PPFD 700 μmol m⁻² s⁻¹ and 950 μmol m⁻² s⁻¹), on the development of crisp lettuce (Itapuã Super variety) grown indoors. Assays were conducted to quantify viable cells, assess germination, perform morphometric analyses, physiological evaluations, nutrient content determination in leaves and roots, and characterization of the metabolic profile by GC–MS (Gas Chromatography coupled to Mass Spectrometry), complemented by multivariate analyses (PCA and PLS-DA). The results indicated that inoculation significantly increased lettuce seed germination, while the interaction between light intensity and microorganisms positively influenced the bacterial population in the substrate. The use of bioinputs altered plant metabolism, promoting distinct clustering according to light intensity and type of inoculation, especially for P. aryabhattai and the consortium. Nutritional analyses revealed increases in P and Zn. Morphometric and physiological characteristics showed variable responses, suggesting that the association between beneficial microorganisms and light intensity can integratively modulate plant growth. The integration of bioinputs and light intensity proved to be a promising approach to optimizing lettuce production in indoors systems, demonstrating that inoculation with B. subtilis, combined with lower light intensity (PPFD 700 μmol m⁻² s⁻¹), enhances morphophysiological development and improves secondary metabolism in plants.