金红石型纳米TiO2对镉胁迫下水稻光合特性及镉、钛富集的影响

Effects of Rutile Type Nano-TiO2 on Photosynthetic Characteristics and Cd and Ti Enrichment in Rice under Cd Stress

摘要: 本文采用种植箱试验，研究金红石型纳米二氧化钛(TiO2-NPs)对镉胁迫下水稻光合特性及镉、钛富集的影响。试验结果表明，金红石型TiO2-NPs单一处理下对水稻叶绿素含量影响较小，随着金红石型TiO2-NPs浓度升高，对水稻叶绿素影响增大；单一Cd处理，导致水稻叶绿素含量增加；高浓度、小粒径的Cd与金红石型TiO2-NPs共同作用毒性增强，对水稻叶绿素含量影响较大。金红石型TiO2-NPs单一处理、单一Cd处理和二者结合可使水稻蒸腾速率和气孔导度逐渐增加，而净光合速率和胞间CO2浓度则明显下降；蒸腾速率、胞间CO2浓度、气孔导度与对照组没有显著差异，但净光合速率在金红石型TiO2-NPs与Cd的作用下出现不同程度的变化。水稻中镉主要在根部富集，Cd与金红石型TiO2-NPs联合作用会降低Cd的迁移率。水稻中根部钛含量远大于叶部，Cd与金红石型TiO2-NPs联合处理可以增加Ti的迁移率。这些试验结果可为探寻金红石型TiO2-NPs与Cd对水稻的单一与联合效应提供一定帮助和参考。

Abstract: The planting box test was used to study the effect of rutile nano-titanium dioxide (TiO2-NPs) on the photosynthetic properties and its enrichment in rice under Cd stress. The experimental results showed that the single treatment of rutile TiO2-NPs had little influence on rice chlorophyll content with the concentration of rutile TiO2-NPs. Single Cd treatment resulted in an increase in chlorophyll content and the toxicity of high concentration and small size Cd and rutile TiO2-NPs had great influence on chlorophyll content in rice. Under rutile TiO2-NPs single treatment, single Cd treatment and both, rice transpiration rate and stomatal conductivity gradually increased, but net photosynthetic rate and intercellular CO2 concentration significantly decreased. The transpiration rate, intercellular CO2 concentration and stomatal conductivity were not significantly different from the control, but the net photosynthetic rate changed differently under the combined stress of rutile TiO2-NPs and Cd. The content of Cd and Ti in roots of rice were much greater than those in the leaves. The rutile TiO2-NPs could reduce the mobility of Cd, but increase the mobility of Ti. These experimental results can provide some help and reference for exploring the single and joint effect of TiO2-NPs and Cd on rice.