ed on the manuscript. Conflict of interest The authors declare no conflict of interest. Funding This study was supported by the National Science Centre Poland within the MINIATURA 4 project to P.H., number 2020/04/X/NZ4/01256. Data availability The data that support the findings of this study are openly available in FigShare at https://doi.org/10.6084/m9.figshare.21082654 (reflectance and transmittance recordings for Arabidopsis WT and mutants) and https://doi.org/10.6084/m9.figshare.24424843 (wild plants). Java source code for the software is publicly available via GitHub at https://github.com/pawelHerm/beamJ/tree/master/BeamJ. Wolfram Mathematica package for ray tracing is available at htt
Open resource ↗FigShare · 10.6084/m9.figshare.21082654 · pdf-raw-page:14 lines:1-47Unverified paper record
Sensitive detection of chloroplast movements through changes in leaf cross-polarized reflectance
bioRxiv · 27 Oct 2023 · 10.1101/2023.10.24.563792
Abstract
We present a sensitive method for non-contact detection of chloroplast movements in leaves and other photosynthetic tissues, based on changes in the magnitude of cross-polarized reflectance. We examined changes in bidirectional red light reflectance during irradiation with blue light, known to trigger chloroplast relocations. Experiments on the model plant Arabidopsis thaliana , wild-type, and several mutants with disrupted chloroplast movements showed that the chloroplast avoidance response, induced by high blue light, led to a substantial increase in diffuse reflectance of unpolarized red light. The effects of the accumulation response in low blue light were the opposite. The specular reflectance of the leaf was unaffected by the chloroplast positioning. To further improve the specificity of the detection, we examined the effects of chloroplast relocations on the leaf reflectance of a linearly polarized incident beam. The greatest relative change associated with chloroplast movements was observed when the planes of polarization of the incident and detected beams were perpendicular. Further experiments revealed that the chloroplast positioning affected the magnitude of depolarization of light by the leaf. We applied the developed approach to examine chloroplast relocations in four angiosperm species collected in the field. The method allowed us to detect the chloroplast avoidance response in the green stems of bilberry, a sample not amenable to transmittance-based detection. Despite the importance of chloroplast movements for the optimization of photosynthetic efficiency and biomass production, high throughput reflectance-based methods are not routinely used for their detection. This method opens the possibility of non-invasive, non-contact detection of chloroplast relocations in a manner insensitive to the orientation of the leaf.
Plant phenotyping relevance
葉のクロロプラスト移動という植物状態を、偏光反射によって非接触・非侵襲的に検出する手法を開発し、複数種で適用しているため、植物フェノタイピング手法が研究の中心である。
abstractWe present a sensitive method for non-contact detection of chloroplast movements in leaves and other photosynthetic tissues, based on changes in the magnitude of cross-polarized reflectance.
abstractThis method opens the possibility of non-invasive, non-contact detection of chloroplast relocations in a manner insensitive to the orientation of the leaf.
Code and data availability
The paper's Data availability statement openly deposits the paper's own reflectance/transmittance phenotype recordings (Arabidopsis WT/mutants and wild plants) on FigShare, and provides authors' public code: BeamJ (Java control software for the phenotyping setup) and openRayTracer (Mathematica ray-tracing package used,
the National Science Centre Poland within the MINIATURA 4 project to P.H., number 2020/04/X/NZ4/01256. Data availability The data that support the findings of this study are openly available in FigShare at https://doi.org/10.6084/m9.figshare.21082654 (reflectance and transmittance recordings for Arabidopsis WT and mutants) and https://doi.org/10.6084/m9.figshare.24424843 (wild plants). Java source code for the software is publicly available via GitHub at https://github.com/pawelHerm/beamJ/tree/master/BeamJ. Wolfram Mathematica package for ray tracing is available at https://github.com/plantPhotobiologyLab/openRayTracer.References Banaś, A. K., Aggarwal, C., Łabuz, J., Sztatelman, O., Gabryś,
Open resource ↗FigShare · 10.6084/m9.figshare.24424843 · pdf-raw-page:14 lines:1-47that support the findings of this study are openly available in FigShare at https://doi.org/10.6084/m9.figshare.21082654 (reflectance and transmittance recordings for Arabidopsis WT and mutants) and https://doi.org/10.6084/m9.figshare.24424843 (wild plants). Java source code for the software is publicly available via GitHub at https://github.com/pawelHerm/beamJ/tree/master/BeamJ. Wolfram Mathematica package for ray tracing is available at https://github.com/plantPhotobiologyLab/openRayTracer.References Banaś, A. K., Aggarwal, C., Łabuz, J., Sztatelman, O., Gabryś, H. (2012). Blue light signalling in chloroplast movements. Journal of Experimental Botany, 63(4), 1559– 1574. Baránková, B., Lazá
Open resource ↗GitHub · pawelHerm/beamJ · pdf-raw-page:14 lines:1-47uorescence. The filtered light was focused on a photodetector (amplified silicon photodiode, PDA100A2, Thorlabs) with a plano-convex lens (LA1074-A, Thorlabs). The angular size of the clear aperture of the collecting lens with respect to the sample center was 0.019 steradian (calculated using our ray-tracing Mathematica package https://github.com/plantPhotobiologyLab/openRayTracer). To control the observation angle, the detector was mounted at the RBB300A/M rotation board (Thorlabs). The experiments were performed with two angular positions of the polarizer: its transmission axis was either parallel (transmits P) or perpendicular (transmits S component) to the plane of incidence. The LEDs su
Open resource ↗GitHub · plantPhotobiologyLab/openRayTracer · pdf-raw-page:6 lines:1-45This is an automatically classified, unverified record. Curator approval is required before any resource enters the Catalog.