《植物生理学报》 2015, 51(10): 1633-1639

纳米氧化钛颗粒对镉胁迫下玉米生长受抑的缓解效应

陈建伟, 余海娟, 李亮, 秦梦洁, 江淼, 谭明谱^*

南京农业大学生命科学学院, 南京210095

通信作者：谭明谱；E-mail: tempo@njau.edu.cn；Tel: 025-84396372

摘　要：

镉(cadmium, Cd)被认为是最具毒性的重金属污染物之一, 很容易被农作物通过根部吸收进入植物体, 进而在食物链中迁移, 不仅会影响作物的质量和产量, 还会对人类健康造成巨大的威胁。本研究采用营养液水培的方法, 以玉米‘农大108’为供试材料, 通过检测玉米体内超氧化物歧化酶(SOD)活性、重金属Cd含量、株高和根长的变化以及根尖染色, 研究纳米氧化钛颗粒(TiO₂-NPs)对Cd胁迫下玉米的缓解效应及机制。结果表明, 与Cd胁迫处理相比, 添加TiO₂-NPs后能明显提高玉米株高、根长以及最大光能转化效率(F_v/F_m), 同时缓解玉米根尖细胞损伤。Cd胁迫能显著诱导叶片SOD, 而TiO₂+Cd减缓了SOD的增长幅度; 通过测定各种处理下Cd的含量, 发现TiO₂+Cd和ZnO+Cd均使植物根系对Cd的吸收降低, 但并不降低Cd向叶片的迁移, 而且ZnO+Cd还使叶片的Cd含量增加, 可能加剧了Cd由根向叶的转移, 表明TiO₂-NPs可以降低Cd的生物毒性, 减缓过多的Cd对玉米生长的抑制作用。

关键词：玉米; 镉; 胁迫; 纳米氧化钛颗粒

收稿：2015-07-30   修定：2015-10-09

资助：国家自然科学基金(31271421)。

Titanium Oxide Nanoparticles Alleviate Growth Inhibition of Maize under Cadmium Stress

CHEN Jian-Wei, YU Hai-Juan, LI Liang, QIN Meng-Jie, JIANG Miao, TAN Ming-Pu^*

College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China

Corresponding author: TAN Ming-Pu; E-mail: tempo@njau.edu.cn; Tel: 025-84396372

Abstract:

Cadmium (Cd) is considered one of the most toxic heavy metal pollutants, and can be easily absorbed through the roots into the plant, and then migrates in the food chain. Consequently, Cd can not only affect the quality and yield of crops, but also cause a great threat to human health. In this study, the plant height and root length of maize ‘Nongda108’ in the hydroponic solution containing titanium oxide nanoparticles (TiO₂-NPs) supplied with Cd were measured. The changes in the activity of superoxide dismutase (SOD), plant heights, root lengths and apical staining were detected to study the effects and the mechanism of TiO₂ nanoparticles (TiO₂-NPs) on the alleviation of cadmium stress on maize seedlings. The results show that plant heights, root lengths and F_v/F_m were significantly improved, whereas the damage of maize root tip was significantly decreased using the TiO₂-NPs pretreatment, compared to Cd stress. Furthermore, Cd stress can significantly induce the activity of SOD in leaves, but the magnitude of changes of SOD is decreased in the TiO₂-NPs pretreated sample. The Cd content measured at various treatments indicated that the Cd absorption in roots was decreased under TiO₂+Cd and ZnO+Cd treatments, but the Cd migration to leaves did not reduce by TiO₂+Cd or ZnO+Cd treatmen, whereas the Cd content in leaves was increased by ZnO+Cd treatment, which may exacerbate the Cd transfer from roots to leaves. These results suggest that TiO₂-NPs could reduce the biological toxicity of Cd, thus alleviate the inhibitory effect of Cd on maize.

Key words: maize (Zea mays); cadmium; stress; titanium oxide nanoparticles