Development of safe solubilizing solution for use in germination testing

The development of a safe formulation that enables the solubilization of water-insoluble urease inhibitors is essential to convey these substances and to verify their phytotoxic effects. In this work a screening of solvent combinations was performed based on the mixtures' solubilization capacity over the most nonpolar urease inhibitor developed by the group and on the safety demonstrated in seed germination tests performed in lettuce seeds (Lactuca sativa). This study showed that combination of different solvents was an important strategy to solubilize the new urease inhibitors, enabling a safe formulation to be obtained. The developed formulation proved to be non-phytotoxic, showing similar results (p>0.05) to water (control) for all evaluated response factors (germination speed index², germination rate of 50% of total seed population³, germination percentage and root length).