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bioRxiv · 10.64898/2026.09.08.750243

Plant-adapted OTO staining improves ultrastructural imaging by transmission electron microscopy

Yao, H.·Jin, X.·Sun, M.·Cheng, H.·Liao, Y.·Jiang, Y.·Zhao, H.·Zhou, H.
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Abstract

Transmission electron microscopy (TEM) is widely used to examine plant cellular ultrastructure, but sample preparation remains challenging because polysaccharide-rich cell walls, large vacuoles and complex membrane systems compromise staining and structural preservation. Here, we developed a plant-adapted TEM preparation method based on a modified osmium-thiocarbohydrazide-osmium (OTO) staining workflow combined with optimized washing, dehydration and resin infiltration. Using tomato roots and leaves, we show that the optimized method produces cleaner backgrounds, better-defined cellular boundaries and improved preservation of cellular morphology compared with conventional preparation. Fine membrane-associated structures, including mitochondrial cristae, chloroplast grana and stroma lamellae, nuclear membranes and other endomembrane structures, were more clearly resolved, while staining-related precipitates and diffuse background artifacts were reduced. This method provides a practical approach for high-contrast TEM imaging of plant tissues and ultrastructural analysis of plant cells and organelles.

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Yao, H., Jin, X., Sun, M., Cheng, H., Liao, Y., Jiang, Y., Zhao, H., Zhou, H.. 2026-09-11. Plant-adapted OTO staining improves ultrastructural imaging by transmission electron microscopy. https://doi.org/10.64898/2026.09.08.750243

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