Cultivo de Sonchus oleraceus L. sob malhas coloridas e adubação verde em resposta às características agronômicas e acúmulo de ácido chicórico

Abstract

Sonchusoleraceus L. is a plant consumed as food in various regions of Brazil. It has medicinal properties, mainly due to the presence of chicoric acid. Light quality and green manure directly influence the growth and secondary metabolism of plants. This study aimed to evaluate the cultivation of Sonchusoleraceus under the effect of different doses of green manure and cultivation under colored nets on growth, photosynthetic pigments, and nutrient and secondary metabolite contents. The green manure experiment was conducted during two cultivation periods, in six-liter pots with the following treatments: no fertilization (control), and 30, 60, 90, and 120 t/ha of crotalaria. In the experiment with colored nets, plants were grown under black, red, and blue nets, and full sun (control), in autumn and spring. Fifty days after the experiments were set up, the number of leaves and branches, leaf area, stem diameter, shoot length, and dry matter of stem, leaf, and root were evaluated, along with the quantification of photosynthetic pigments, phenolic compounds, total flavones/flavonols, and chicoric acid. Green manure significantly increased biomass growth in Sonchusoleraceus, also promoting higher levels of photosynthetic pigments. However, the treatment without green manure resulted in higher accumulations of phenolic compounds, total flavones/flavonols, and chicoric acid, suggesting a differentiated influence on secondary metabolism. Furthermore, the use of colored shading nets played a key role in biomass and bioactive compound production. The red net was more effective in promoting dry matter in both autumn and spring, while the black net and full sun stood out in phenolic compound production. Flavones/flavonols production was optimized under the black net in autumn and full sun in spring, and chicoric acid levels were higher under the blue net in autumn and the black net in spring. These results highlight the importance of green manure and light management, using colored nets, to optimize growth, pigment production, and bioactive compound accumulation in Sonchusoleraceus, showcasing these practices as promising agronomic tools.