Photochemical & Photobiological Sciences ( IF 2.7 ) Pub Date : 2022-08-08 , DOI: 10.1007/s43630-022-00269-1 Rocio Torres 1, 2 , Virginia Emilse Diz 2 , María Gabriela Lagorio 1, 2
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Interaction between 11 nm-sized magnetite nanoparticles and Cichorium intybus plants was studied in this work. In particular, the effect of these nanoparticles on the photosynthesis electron chain was carefully analysed. Magnetite nanoparticles were synthesised and physically characterised by Transmission electron microscopy (TEM), Scanning electron microscopy (SEM)), Energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), Magnetic hysteresis cycles and UV–visible spectroscopy. Suspensions of the obtained magnetite nanoparticles with different concentrations (10–1000 ppm) were sprayed over chicory leaves and their photosynthetic activity was evaluated using chlorophyll fluorescence techniques. The study was complemented with the determination of pigment concentration and spectral reflectance indices. The whole set of results was compared to those obtained for control (non-treated) plants. Magnetite nanoparticles caused an increment in the content of Chlorophyll a (up to 36%) and Chlorophyll b (up to 41%). The ratio Chlorophyll/ Carotenoids significantly increased (up to 29%) and the quotient Chlorophyll a/b remained relatively constant, except for a sharp increase (19%) at 100 ppm. The reflectance index that best manifested the improvement in chlorophyll content was the modified Normalised Difference Vegetation Index (mNDI), with a maximum increase of about 35%. Electronic transport fluxes were favoured and the photosynthetic parameters derived from Kautsky’s kinetics were improved. An optimal concentration of nanoparticles (100 ppm) for the most beneficial effects on photosynthesis was identified. For this dose, the probability by which a trapped electron in PSII was transferred up to PSI acceptors (ΦRE0) was doubled and the parameter that quantifies the energy conservation of photons absorbed by PSII up to the reduction of PSI acceptors (\({\mathrm{PI}}_{\mathrm{total}}^{\mathrm{ABS}}\)), augmented five times. The fraction of absorbed energy used for photosynthesis increased to 86% and the energy lost as heat by the non-photochemical quenching mechanism was reduced to 31%. Beyond 100 ppm, photosynthetic parameters declined but remained above the values of the control.
Graphical abstract
中文翻译：
Fe3O4纳米粒子诱导的光合性能改善
11 nm 大小的磁铁矿纳米粒子与菊苣的相互作用在这项工作中研究了植物。特别是，仔细分析了这些纳米粒子对光合作用电子链的影响。磁铁矿纳米粒子通过透射电子显微镜 (TEM)、扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDS)、傅里叶变换红外光谱 (FTIR)、磁滞循环和紫外-可见光谱进行合成和物理表征. 将获得的具有不同浓度（10-1000 ppm）的磁铁矿纳米粒子悬浮液喷洒在菊苣叶上，并使用叶绿素荧光技术评估其光合活性。该研究补充了色素浓度和光谱反射指数的测定。将整组结果与对照（未处理）植物获得的结果进行比较。磁铁矿纳米颗粒导致叶绿素 a（高达 36%）和叶绿素 b（高达 41%）的含量增加。叶绿素/类胡萝卜素的比例显着增加（高达 29%），并且叶绿素 a/b 的商数保持相对恒定，除了在 100 ppm 时急剧增加（19%）。最能体现叶绿素含量改善的反射率指数是修正后的归一化植被指数（mNDI），最大增幅约为 35%。电子传输通量受到青睐，并改进了源自考茨基动力学的光合参数。确定了对光合作用最有益的纳米粒子的最佳浓度 (100 ppm)。对于这个剂量，PSII 中捕获的电子被转移到 PSI 受体的概率（ΦRE0 ) 加倍，量化 PSII 吸收的光子能量守恒的参数直到 PSI 受体的减少 ( \({\mathrm{PI}}_{\mathrm{total}}^{\mathrm{ABS}} \) )，增加了五次。用于光合作用的吸收能量比例增加到 86%，非光化学猝灭机制作为热量损失的能量减少到 31%。超过 100 ppm，光合参数下降但仍高于对照值。
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