CONICET, Universidad de Buenos Aires, INQUIMAE, Facultad de Ciencias Exactas y Naturales, Buenos Aires, Argentina.
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Dpto. de Química Inorgánica, Analítica y Química Física, Ciudad Universitaria, Pabellón II, 1er piso, C1428EHA, Buenos Aires, Argentina.
Photochem Photobiol Sci. 2022 Nov;21(11):1931-1946. doi: 10.1007/s43630-022-00269-1. Epub 2022 Aug 8.
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 (Φ) was doubled and the parameter that quantifies the energy conservation of photons absorbed by PSII up to the reduction of PSI acceptors ([Formula: see text]), 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.
本工作研究了 11nm 尺寸的磁铁矿纳米粒子与菊苣植物之间的相互作用。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。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)、磁滞回线和紫外可见光谱对磁铁矿纳米粒子进行了合成和物理表征。用不同浓度 (10-1000ppm) 的获得的磁铁矿纳米粒子悬浮液喷洒在菊苣叶片上，并使用叶绿素荧光技术评估其光合作用活性。该研究还补充了色素浓度和光谱反射率指数的测定。将整套结果与对照 (未处理) 植物的结果进行了比较。磁铁矿纳米粒子导致叶绿素 a 的含量增加 (高达 36%) 和叶绿素 b 的含量增加 (高达 41%)。叶绿素/类胡萝卜素的比值显著增加 (高达 29%)，而叶绿素 a/b 的商保持相对稳定，除了在 100ppm 时急剧增加 (19%)。最好地体现叶绿素含量提高的反射率指数是改进的归一化差异植被指数 (mNDI)，最大增加约 35%。电子传递通量得到促进，并且从 Kautsky 动力学推导出的光合作用参数得到改善。确定了纳米粒子的最佳浓度 (100ppm)，以获得对光合作用最有益的效果。对于该剂量，PSII 中被捕获的电子被转移到 PSI 受体的概率 (Φ) 增加了一倍，并且量化 PSII 吸收的光子的能量守恒到 PSI 受体的还原的参数 ([Formula: see text])，增加了五倍。用于光合作用的吸收能量的分数增加到 86%，并且通过非光化学猝灭机制损失的热能减少到 31%。超过 100ppm 后，光合作用参数下降，但仍高于对照值。
