2016 年 37 巻 12 号 p. 604-609
The high sensitivity of secondary ion mass spectrometry (SIMS) allows isotope imaging and the high spatial precision has a potential for the localization of isotopes corresponding to the ultrastructure of cell components. This paper reviews a study in which transfers of carbon and nitrogen from the fungus in a symbiotic orchid protocorm were analyzed, combining an isotope tracer experiment, sample preparation for transmission electron microscopy, and SIMS cellular imaging. The results showed that, 13C and15N transferred from young and senescent hyphae, and in the plant cells, they were localized differently in individual cells and organelles, depending on the colonization status (the presence or absence of fungal structures and the early or late developmental stage of the fungal structure). Stable isotope imaging at the cellular level provides new insights into cellular functions of the endosymbiosis.