人工合成纳米TiO_2和MWCNTs对玉米生长及其抗氧化系统的影响

Effect of Nano-rutile TiO_2 and Multiwalled Carbon Nanotubes on the Growth of Maize(Zea mays L.) Seedlings and the Relevant Antioxidant Response

通过营养液培养试验,研究了纳米金红石相TiO2和多壁碳纳米管(multiwalled carbon nanotubes,MWCNTs)2种人工合成纳米材料悬浮液对玉米幼苗生物量、根系形态、抗氧化酶活性和脂质过氧化的影响.结果表明,在纳米材料悬浮液培养9d后,纳米金红石相TiO2对玉米生长有显著抑制作用(p<0.05),50、100、200 mg/L浓度处理的植株根系干物质量分别比对照低40.31%、48.06%、62.02%;而MWCNTs对植物生长的抑制不明显.在2种纳米材料处理下,植物组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和过氧化物酶(POD)活性均显著升高(p<0.05).纳米金红石相TiO2处理使玉米植株体内脂质过氧化产物MDA含量增多,而MWCNTs处理下MDA含量减少但无显著性变化.说明纳米金红石相TiO2的植物毒性比MWCNTs大,2种纳米材料都能引起植株产生氧化应激,仅纳米TiO2造成氧化损伤,这可能与2种纳米材料的化学组成和形状不同有关.

The effects of nano-rutile TiO2and multiwalled carbon nanotubes on the growth and antioxidant enzymes of maize （Zea mays L. ） seedlings were investigated under hydroponic conditions. Nano-rutile TiO2 （ ≥ 50 mg/L） significantly decreased root and shoot growth （p 〈 0. 05 ） after 9 days, while MWCNTs did not influence the biomass obviously. Under two stress conditions, the antioxidant system was activated respectively. Compared to the control, superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） were up-regulated （p 〈 0. 05）. Lipid peroxidation in terms of malondialdehyde （MDA） content was enhanced by TiO2 exposure, whereas, MWCNTs did not cause oxidative damages in maize seedlings. The results indicated that the phytotoxicity of nano-rutile TiO2 was much higher than that of MWCNTs, and oxidative stress induced by nanoparticles （NPs） exposure might play a role in the phytotoxicity of NPs. The remarkable effect of nano-rutile TiO2 is probably attributed to particle composition and shape.