Max Planck Partner Group 1 article published in JoVE Environment A Flexible Low Cost Hydroponic System for Assessing Plant Responses to Small Molecules in Sterile Conditions Carolina C. Monte-Bello*1,2, Elias F. Araujo*1,3, Marina C.M. Martins1, Valeria Mafra4, Viviane C.H. da Silva1,2, Viviane Celente1, Camila Caldana1,5 1Brazilian Bioethanol Science and Technology Laboratory (CTBE), Brazilian Center for Research in energy and materials (CNPEM), 2University of Campinas (UNICAMP), 3University of Viçosa (UFV), 4CTBE, CNPEM, 5Brazilian Bioethanol Science and Technology Laboratory (CTBE/CNPEM), Max Planck Partner Group A simple, versatile, and low-cost in vitro hydroponic system was successfully optimized, enabling large-scale experiments under sterile conditions. This system facilitates the application of chemicals in a solution and their efficient absorption by roots for molecular, biochemical, and physiological studies.