Produção de mudas e teor de óleo essencial de Lippia alba (Mill.) N.e.br ex Britton & P. Wilson sob inoculação com Trichoderma asperellum

Abstract

Lippia alba is a medicinal plant that has economic importance due to the production of bioactive compounds, among which we can mention essential oils. Therefore, it is necessary to develop its production chain, aiming at plant quality and increasing the production of these special metabolites. Thus, associating Trichoderma with Lippia alba can favor its growth and development, producing plants of better quality and vigor. Therefore, the objective of this work was to evaluate the influence of Trichoderma and hydrogel on the production of seedlings and essential oil content of Lippia alba grown in a greenhouse and to analyze the influence of Trichoderma at different times after inoculation, on the production of biomass and special metabolites of these plants. The treatments significantly influenced the fresh mass, dry mass of the aerial part and dry mass of the root of the Lippia seedlings at 15 days and the height, fresh root mass, root length, number of stems and essential oil content of the seedlings at 30 days. The results indicate that separately the hydrogel and Trichoderma provide a positive effect on the increment of phytomass of Lippia seedlings, at 15 days. At 30 days, Trichoderma provided the highest values for height, root length, number of stems and root fresh mass. The essential oil content was higher in the control seedlings, differing from the other treatments. In field cultivation, at 30 days, all variables differed from each other, where plants cultivated with two applications of Trichoderma presented the highest averages, with the exception of height. At 45 days, all analyzed variables showed significant differences, the L. alba plants that were cultivated with the microorganism showed higher averages than the control plants, indicating that three applications of Trichoderma suspension is enough to increase growth and growth. accumulation of phytomass of these plants. Regarding the production of special metabolites, there was only a significant difference in the essential oil content at 45 days, that is, with three applications of Trichoderma, which provided the highest essential oil content. As for the total phenolics, there was only a significant difference at 15 days, where the cultivation with Trichoderma provided a greater biosynthesis of phenolic compounds. For total flavonoids, the only period in which there was no difference between plants grown with and without Trichoderma was at 45 days, with Trichoderma increasing the concentration 12 of this phytochemical. Therefore, Trichoderma in the production of Lippia alba plants favors the accumulation of biomass and increases the production of special metabolites, mainly the essential oil content, obtaining its highest yield at 45 days, which is the best period for harvesting the plants.