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Updated: May 8, 2026

Real-Time Detection of Reactive Oxygen Species Production in Immune Response in Rice with a Chemiluminescence Assay
Published on: November 25, 2022
Characterization of photosystem I in rice (Oryza sativa L.) seedlings upon exposure to random positioning machine
Boya Chen1, Aihong Zhang, Qingtao Lu
1Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Abstract:
To gain a better understanding of how photosynthesis is adapted under altered gravity forces, photosynthetic apparatus and its functioning were investigated in rice (Oryza sativa L.) seedlings grown in a random positioning machine (RPM). A decrease in fresh weight and dry weight was observed in rice seedlings grown under RPM condition. No significant changes were found in the chloroplast ultrastructure and total chlorophyll content between the RPM and control samples. Analyses of chlorophyll fluorescence and thermoluminescence demonstrate that PSII activity was unchanged under RPM condition. However, PSI activity decreased significantly under RPM condition. 77 K fluorescence emission spectra show a blue-shift and reduction of PSI fluorescence emission peak in the RPM seedlings. In addition, RPM caused a significant decrease in the amplitude of absorbance changes of P700 at 820 nm (A 820) induced by saturated far-red light. Moreover, the PSI efficiency (Φ I) decreased significantly under RPM condition. Immunoblot and blue native gel analyses further illustrate that accumulation of PSI proteins was greatly decreased in the RPM seedlings. Our results suggest that PSI, but not PSII, is down-regulated under RPM condition.
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