Abstract:

To gain learners’ interest, it is important to provide a realistic experience. The author, a plant cell biologist, has used several approaches to observe the structure and function of organelles within cells without using raw cells; however, preparing and handling raw cells was difficult owing to their small size and frangibility. Therefore, microscopes are required to explore the microworld within cells. Recently, learning materials for immersive learning by adopting contents based on raw microscopic data are emerging (Babilonia-Rosa et al., 2018, Johnston et al., 2017). For a realistic experience, it is useful to combine virtual reality (VR) with raw data obtained through microscopic observation. Employing the VR technology ensures the possibility to offer a realistic experience in a virtual space while simultaneously providing efficacious approaches for learning cell biology. From this perspective, the author has developed learning materials to envision the subcellular plant cell structure through three-dimensional (3D) reconstruction using an advanced 3D printer and an immersive VR approach (Tanabashi, 2021).

Technological advancements in microscopy and learning materials are ongoing. Particularly, correlative light and electron microscopy (CLEM) is an approach that enables obtaining microscopic data from simultaneous observations by combining light or fluorescence microscopic observations with those of the transmission electron microscope and merging the correlation between the acquired images, i.e., unity of the two worlds between fluorescence microscopic images and electron microscopic images (Razi & Tooze, 2009, Jahn et al., 2012). It has been demonstrated that this method correspondingly unveils both the subcellular localization and ultrastructure of subcellular microstructures called organelles (Tanabashi & Tange, 2022). This study aimed to use the immersive VR approach to envision the structure relating to the function of organelles in plant cells based on more fine raw microscopic data as learning materials for learners.

This study focuses on the mitochondrial behavior of the pollen tube in Arabidopsis thaliana, an angiosperm model plant, as the internal structure of the pollen tube is easier to observe under light or fluorescent microscopes than that of the pollen due to the complex cell wall structure. Mitochondrial behavior changes with the increase or decrease in their number or size during pollen development, making it suitable for this study to develop the learning materials by combining microscopy with immersive VR technology. The material preparation for this study was performed based on the previous study (Tanabashi & Tange, 2022).

Fluorescent microscopic images showed mitochondrial localization, and transmission electron microscopic images showed the mitochondrial ultrastructure in detail. The fluorescent and transmission electron microscopic images were overlaid. These data confirmed alterations in mitochondrial behavior, including number, size, and internal structure during pollen development.

Mitochondrial images captured using the transmission electron microscope were analyzed using Adobe Photoshop CS6, an image processing software. The structure of the cristae was rugged intricately. The objective structure was identified so that these were aligned and segmented. Such 3D reconstruction data was developed as learning materials with immersive VR technology with Unity.

Keywords:

Plant cells, organelles, 3D reconstruction, microscopy, immersive VR technology.