不同烃链长度咪唑类离子液体对玉米幼苗生长的影响

Effects of imidazolium-based ionic liquids with different hydrocarbon chain Length on growth of maize seedlings

为探讨离子液体(ILs)对农业生物的毒性,以典型农作物玉米为材料,采用水培法研究三种不同烃链长度离子液体1-丁基-3-甲基咪唑氯盐([C4mim]Cl)、1-己基-3-甲基咪唑氯盐([C6mim]Cl)和1-辛基-3-甲基咪唑氯盐([C8mim]Cl)在不同浓度下对幼苗的根、茎生长以及部分生理生化指标的影响。结果表明:三种离子液体对玉米幼苗根、茎干重均有显著抑制作用。由EC50值得出,抑制程度表现为[C4mim]Cl<[C6mim]Cl<[C8mim]Cl,且对根重的抑制大于茎重。随三种离子液体处理浓度增加,玉米幼苗根、茎抗氧化酶系(SOD、POD、CAT、APX)总体呈下降趋势,而丙二醛(MDA)含量显著升高,表明氧化胁迫可能是离子液体产生毒性的重要原因。

Ionic liquids（ILs）are considered as ideal solvents in various chemical processes including organic synthesis, catalytic reactions,and separation engineering. However, the hazardous nature and poor biodegradability property of many ILs increase the risk of becoming potential environmental pollutants. Studies of the toxicity of ILs on crop growth could help assess the potential risks of ILs to field ecosystems.Maize has the largest planting area in China. Herein, the effects of three imidazolium-based ionic liquids（[C4mim]Cl, [C6mim]Cl, and[C8mim]Cl）on the growth of maize seedlings, as well as some physiological and biochemical indexes, were analyzed. The results suggested that the three ionic liquids had significant inhibitory effects on the dry weight accumulation of maize seedling roots and shoots. According to the logistic regression equation, EC50 of ILs for inhibiting maize showed a tendency toward an inhibitory effect：[C4mim]Cl〈 [C6mim]Cl〈 [C8mim]Cl. In addition, shoots were inhibited more than roots. Antioxidant enzymes play central roles in plant defense against reactive oxygen species（ROS）. The activities of antioxidant enzymes（SOD, POD, CAT, and APX）in maize roots and shoots were analyzed. Generally,the specific activity of the four antioxidant enzymes declined with an increase in IL concentration when exposed to the three ionic liquids.The contents of malondialdehyde（MDA）were significantly increased. The results indicated that oxidative stress may explain the toxic effects of imidazolium-based ILs.