Effect of 1-Butyl-3-Methylimidazolium Tetrafluoroborate on the Wheat (Triticum aestivum L.) Seedlings

Although many studies describe ionic liquids (ILs) as potentially greener solvents, few studies address their relationship with the environment. Recent researches suggest that some ILs have toxicity. 1-Butyl-3-methylimidazolium tetrafluoroborate ([C(4)mim][BF4]) was reported to have the lowest toxicity among ILs. In this work, we studied the toxicity of this IL on wheat seedlings. It was shown that wheat germination was reduced to 38.0% in the presence of 4.4 mmol/L [C(4)mim][BF4] compared with 100% germination for the control. Similarly, the root and shoot length of wheat seedlings decreased with increasing concentrations of [C(4)mim][BF4]. The activity of amylase increased in shoots and roots, but it decreased significantly in germinating seeds when the [C(4)mim][BF4] concentration exceeded 1.8 mmol/L. Peroxidase (POD) activity and soluble protein content in shoots treated with [C(4)mim][BF4] changed similarly, but chlorophyll content tended to decrease with increasing concentration of [C(4)mim][BF4], except for at 1.8 mmol/L. Thus, [C(4)mim][BF4] at the concentration of 0.9 mmol/L or more was toxic to wheat seedlings. Some remedial measures are suggested to deal with IL pollution in the environment. (C) 2008 Wiley Periodicals, Inc. Environ Toxicol 24: 296-303, 2009.