氧化石墨烯对拟南芥生长的促进作用

Promoting Effect of Graphene Oxide on the Root Growth of Arabidopsis thaliana

明确氧化石墨烯(graphene oxide,GO)对拟南芥生长的促进作用,为纳米材料应用于农业生产提供理论依据。采用不同浓度GO的1/2 MS培养基点拟南芥种子,测定其主根长、侧根数、根系活力、超氧阴离子自由基的产生、超氧化物歧化酶活性、根系生长相关基因的表达情况。经20-200 μg/mL GO处理后,拟南芥主根长度比对照(不加GO)提高了4.6%-43.0%,在50-200 μg/mL内,与对照相比,差异达显著水平。50 μg/mL处理显著促进了侧根形成,侧根数比对照增加了约27.1%,高于或低于50 μg/mL则不利于侧根的形成。表明50 μg/mL GO对拟南芥的主根长和侧根数均存在促进作用,同时还发现该浓度可以增加拟南芥根尖的分生区和伸长区的长度,而对根尖直径和根冠长度无影响。氯化三苯基四氮唑(TTC)和四硝基氮蓝四唑(NBT)组织染色法结果表明50 μg/mL GO浓度处理提高了根系活力和超氧化物歧化酶活性及降低了超氧阴离子的产生。基因表达分析显示ADC1和DAR2表达量下调和IQM3表达量上调,从而促进了主根的伸长;ARF7、ARF19、ERFII-1和IQM3表达量上调,从而促进了侧根数量的增加。50 μg/mL GO处理可促进拟南芥根系的生长。根系活力的增加、超氧阴离子的减少及根相关基因的表达上调是GO促进根系生长的主要原因。

This work aims to clarify the promoting effect of graphene oxide(GO)on the growth of Arabidopsis thaliana,so as to provide a theoretical basis for the application of nanomaterials in agricultural production.Seeds of A.thaliana were cultured in 1/2 MS with different concentrations of GO.The primary root length,lateral root number,root activity,production of superoxide anion free radical,superoxide dismutase activity and expression of root growth-related gene were measured.After 20-200μg/mL GO treatment,the taproot length of A.thaliana increased by 4.6%-43.0%.Compared with the control(without GO),and the difference was significant within 50-200μg/mL.Treatment with 50μg/mL GO significantly promoted the formation of lateral roots,and the number of lateral roots increased by 27.1%compared with the control,while treatment with higher or lower than 50μg/mL was not conducive to the formation of lateral roots.The results showed that 50μg/mL GO promoted the taproot length and lateral root number of A.thaliana.It was also found that the concentration of 50μg/mL GO increased the length of meristem and elongation zone of root tip,but had no effect on the root tip diameter and root cap length.The tissue staining of triphenyltetrazole chloride(TTC)and nitrio blue tetrazolium(NBT)indicated that 50μg/mL GO increased the root activity,superoxide dismutase activity and decreased the production of superoxide anion.Gene expression analysis demonstrated that ADC1 and DAR2 were down-regulated and IQM3 was up-regulated,which promoted the taproot elongation.The expressions of ARF7,ARF19,ERFII-1 and IQM3 were up-regulated,which promoted the increase of the lateral root number.Treatment with 50μg/mL GO could promote root growth of A.thaliana.The increase of root activity,the decrease of superoxide anion and the up-regulation of root-related gene expression are the main reasons that GO promotes the growth of root system.