Effects Of Imidazolium-based Ionic Liquids With Different Anionson Wheat Seedlings

Ionic liquids are salts that are completely made up of ions at room temperature and generally consist of two parts: large asymmetric organic cation part and small inorganic or organic anion part.Due to its unique physical and chemical properties such as low saturation vapor pressure,uninflammability,good thermal stability and electrochemical stability,it is widely used in organic synthesis,electrochemistry,biology and other areas,and is regarded as a type of environmental friendly alternatives to traditional organic solvents.Nevertheless,with the land of mass adoption of ILs,they eventually have to be lost to the environment as one kind of solvent.Chemical stability makes them possible to exist in the form of persistent organic pollutant,in biodegradation,chemical residues and biological system effects.The effects and other aspects have potential risks,and then it may cause water or soil pollution.Thus,it has a very important practical significance to evaluate the ecological safety of ionic liquids.In this experiment,the effects of imidazole-type ionic liquids with different anions(amino acids,lactic acids,tetrafluoroborates,halogens,and sulfonic acids)on the growth and physiological indexes of wheat seedlings under hydroponic culture at50-300 mg/L,and the ultrastructure of mesophyll and root tips of wheat were observed.The toxicity mechanism of ionic liquids and the toxicity of imidazole-based ionic liquids containing different anions are discussed in terms of plant growth,physiology,and cells.The main conclusions of the present study were as follows:1.In the experimental range of 50-300 mg/L,the shoot and root length of wheat seedlings became shorter as the concentration of ILs increased,and the aboveground and underground biomasses were reduced.And wheat seedlings treated with sulfonic acid ionic liquids,the growth index decreased sharply at the lowest concentration of50 mg/L.At the same concentration,there are significant differences in growth indexes between different ionic liquid treatment groups;anions can affect the toxicity of ionic liquids.2.The antioxidant enzyme activity of wheat seedling leaves decreased with the increase of the ILs concentration at 50-300 mg/L,and the malonaldehyde content increased.Oxidative stress and membrane lipid peroxidation were occured in wheat seedlings.At the same concentration,there are significant differences betweendifferent ionic liquid treatments.The degree of toxicity of imidazolium-based ionic liquids with different anions varies.The sulfonic acid ionic liquids are the most toxic,followed by halogens,tetrafluoroborates,lactic acids and amino acids.3.The contents of chlorophyll a,chlorophyll b,and carotenoid in leaves of wheat seedlings generally decreased with the increase of ionic liquid concentrations at50-300 mg/L.These imidazolium-based ionic liquids can reduce the content of photosynthetic pigments.At the same concentration,the change trend of photosynthetic pigment content was the same as that of other indexes measured in this experiment,sulfonate ionic liquids showed strong toxicity at lower concentrations of50 mg/L,and there were significant differences between different ionic liquid treatments.Anions can affect the toxicity of ionic liquids.4.Through the observation of the ultrastructure of wheat seedlings at 150 mg/L ILs concentration,the five ionic liquids have negative effects on leaf cell and root tip cells.Ionic liquids can Ionic liquids cause loose chloroplast particles,disordered thylakoids,abnormal chromatin nuclear chromatin,nuclear membrane dissolution,mitochondrial swelling,mitochondrial internal hemorrhoid ablation,rough endoplasmic reticulum enlargement and separation from ribosomes,but with little effect on the Golgi apparatus.In summary,the five ionic liquids have various effects on the growth index,antioxidant enzyme activity,malondialdehyde content,photosynthetic pigment content and cell structure of wheat seedlings.And the greater the concentration of ionic liquids,the more toxic effects obvious it is.Ionic liquids influence the growth and development of turbulent plants through their physiological metabolism and changes in cell structure.When the cations are partly the same,the anion part can affect the overall toxicity of the ionic liquid.The sulfonic acid anion has the highest toxicity,followed by the halogen anion,the fluorine anion,the lactic anion,and the amino acid anion is the least toxic.