Preparation Of Cationic Zero-and One-dimensional Water-soluble Carbon Nanomaterials And Their Application On Promoting Root Growth Of Maize Seedling

In recent years,the research on the preparation of water-soluble derivatives of carbon nanomaterials and their application in agriculture has been attracting attention.Carbon nanomaterials are insoluble in water,so the bigger concern is how to obtain water-soluble carbon nanomaterials by means of covalent bond modification.In this study,zero-dimensional(C60,C70)and one-dimensional(SWCNTs,MWCNTs)carbon nanomaterials were modified by one-step nitrene reaction with solvent-free strategy.The prepared water-soluble carbon nanomaterials by nitrene reaction were also used to treat maize seedling roots.The studies are as follows:1.Zero-dimensional cationic water-soluble derivatives of fullerenes were prepared by one-step nitrene reaction with solvent-free strategy.C60/C70 azo iminofullerenes were prepared by the reaction of azoethylamine with C60/C70,and the resulted produce were labeled as C60-NH2 and C70-NH2,respectively.2.One-dimensional water-soluble derivatives of carbon nanotubes were prepared by one-step nitrene reaction with solvent-free strategy.Water-soluble polyethylenediamines of SWCNTs/MWCNTs were prepared by the reaction of azidethylamine with SWCNTs and various specifications MWCNTs,which were labeled as SWCNTs-NH2,MWCNTs-A-NH2,MWCNTs-B-NH2 and MWCNTs-C-NH2.3.The average molecular formulas of polyethylenediamine of SWCNTs/MWCNTs were calculated by thermogravimetric analysis and X-ray photoelectron spectroscopy.4.C60-NH2,C70-NH2,SWCNTs-NH2,MWCNTs-A-NH2,MWCNTs-B-NH2 and MWCNTs-C-NH2 were tested in vitro to scavenge ABTS+·free radicals,and the results showed that the scavenging ability to ABTS+·was as follows:SWCNTs-NH2>MWCNTs-C-NH2>MWCNTs-B-NH2>MWCNTs-A-NH2>C60-NH2>C70-NH2.5.The experiment on the effects of C60-NH2 and MWCNTS-A-NH2 on maize root system was studied.The results showed that both carbon materials can promote the maize root growth at lower concentrations;while inhibit the growth at higher concentrations.The scavenging ability of C60-NH2 and MWCNTs-A-NH2 to ABTS+· is positive correction to the results of promoting maize root growth.The stronger the in vitro free radical scavenging of ABTS+·was,the more obvious the effect of promoting maize root growth was.6.When C60-NH2 with positive charge was treated the roots of maize seedlings,the results showed that cationic C60-NH2 was easily adsorbed on the surface of roots,especially the root tips which showed a light yellow color,Therefore,it was verified that positive charge properties in surface of carbon nanomaterials would significantly affect its absorption into plant tissues.This study provides a method for large-scale preparation of cationic water-soluble carbon nanomaterials in agricultural research field,and also provides a reference for the application of different dimensions of carbon nanomaterials to regulate plant growth in the field of plant protection.