Effects of ionic liquid [N₄₄₄₄] AOT on rice seedling growth cytomembrane damage and rhizobacteria resistance

Ionic liquids (ILs) are solvents composed of ions, containing a large asymmetric cation with an anion. With increasing and widespread applications, the toxic effects of ILs have been considerable in recent years. This study explained the effects of the new functional ionic liquids [N₄₄₄₄] bis(2-ethylhexyl) sulfonyl succinate (AOT) on rice seedling and the growth of rhizobacteria. The rice seeds pretreated by [N₄₄₄₄] AOT revealed that it exhibited a significant negative impact on rice seedlings. The inhibition of rice growth increased with increasing concentration. When the concentration of [N₄₄₄₄] AOT increased to 0.25 and 0.5 mL L^-1, the germination potential decreased by 40.0% and 86.3%, respectively, compared with the control. The germination potential and germination rate of rice were reduced, and the stress effect of ionic liquid on the root parts was higher than the aerial parts. The biomass of rice seedlings was decreased by 34.8 to 91.2%. Iodinic propane staining showed that by increasing concentration, the root cell cytomembrane damage level was increased and also changed the cell shapes, especially under 0.25 mg L^-1 concentration stress. However, rhizobacteria of rice showed strong [N₄₄₄₄] AOT-resistant characteristics when the concentration was reached to 120 mg L^-1. The ILs even more promoted the growth of Enterobacter sp. NP1142 and Pantoea sp. BR23. It was indicated that IL [N₄₄₄₄] AOT can be degraded easily by rhizobacteria to eliminate the eco-risk of ILs.