不同浓度纳米铈和离子铈对小油菜生理指标的影响

Effects of different concentrations of nano cerium and ionic cerium on physiological properties of bok choy(Brassica chinensis L.)

[目的]纳米铈的广泛生产与应用不可避免地导致了纳米铈进入环境并发生积累。但铈在环境中的不同形态和浓度对植物的影响还不完全清楚。[方法]本研究以小油菜为例,通过盆栽试验,研究分析了施加不同浓度(0、1、10、100、500 mg·kg^(-1))纳米铈(纳米CeO_(2))和离子铈(Ce(NO_(3))_(3))后,对小油菜的叶片抗性指标(丙二醛和脯氨酸含量以及过氧化氢酶活性)、光合作用相关指标(胞间CO2、蒸腾速率、气孔导度、净光合速率和叶绿素含量)和植株品质指标(全氮、全钾、还原糖和维生素C)的影响,并采用双因素方差分析研究了铈的形态和浓度对小油菜生理特性的交互作用。[结果]铈形态和浓度对小油菜生理指标的影响具有显著的交互作用(P<0.05),且两者在低浓度时对小油菜叶片抗氧化性起促进作用,而在高浓度逐渐向抑制作用转变。铈的两种形态的不同施加浓度对净光合速率和叶绿素含量均表现为抑制作用。纳米CeO_(2)的施加提高了小油菜植株的还原糖和维生素C的含量。RDA分析揭示土壤中的速效磷、速效钾和铈含量是驱动不同铈处理下小油菜综合生理特征产生分异的重要环境因素。[结论]本研究表明,由于交互作用的存在,纳米CeO_(2)和离子Ce^(3+)对小油菜生理性状的影响总体上没有显著区别,铈对小油菜生长和品质的影响过程中,钾元素可能发挥着重要作用。

[Objective]Wide production and application of engineered nanomaterial(nano-CeO_(2))inevitably lead to the accumulation of nano-cerium into the environment. However,the effects of different forms and concentrations of cerium in the environment on plants are not fully understood. [Methods]In this study,potting experiments were performed to investigate the effects of soil application of nano CeO_(2) and ionic cerium Ce(NO_(3))_(3) on the leaf resistance properties,photosynthesis related properties and the quality of bok choy(Brassica chinensis L.). The average diameter of CeO_(2) was 25 nm,and five treatments including the concentration of 0,1,10,100,500 mg·kg^(-1) in DW soil for both CeO_(2) and Ce(NO_(3))_(3) were setup. Leaf resistance properties such as malonaldehyde content(MDA),proline(PRO)and catalase activity(CAT),photosynthetic related properties such as intercellular carbon dioxide(Ci),transpiration rate(E),stomatal conductance(Gs),net photosynthetic rate(Pn)and chlorophyll content(Chl)and bok choy quality properties such as plant total nitrogen(PTN),plant total potassium(PTK),reducing sugar(RS)and vitamin C(VC)were measured. Two-way ANOVA were used to test the interaction effect of Cerium form and concentration on the physiological properties of bok choy. [Results]Results showed that the significant interaction effects(P<0.05)were observed between different Cerium forms and different concentrations on all the physiological properties of bok choy,except Ciand Chl. Both cerium forms promoted the antioxidation at lower concentrations and gradually changed to inhibitory activity as the concentrations were increased. Compared to CK,both Chl and Pnwere inhibited in all cerium treatments,while the application of nano-CeO_(2) increased the content of RS and VC. RDA analysis revealed that AP,AK and soil cerium content were important environmental factors that drove the differentiation of the comprehensive physiological properties of bok choy under different cerium treatments.[Conclusion]This study revealed that the effects of nano-CeO_(2) and ionic-Ce on physiological properties of bok choy were not significantly different due to the interaction of these two forms. Potassium migh play an important role in the influence of ceriu on the growth and quality of bok choy.