Arbuscule of Funneliformis mosseae under incident light and phase contrast.
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- Spores of F. mosseae concentrated in the vermiculite
- Does F. mosseae prefer proximity to roots to sporulate?
- 58-day survival in refrigeration
Spores of F. mosseae, Mostly in the Vermiculite
November 19, 2025: In a two-compartment dish containing vermiculite and Hortasorb polymer, with Plantago lanceolata, inoculated in June 2024 and examined in November 2025 (17 months in culture), a few spores were present in the polymer, which nonetheless showed marked degradation (yellowish discoloration). No spores were visually detected in the vermiculite. Sieving at 38 µm, however, isolated thousands of them, suggesting that this species sporulates preferentially in the vermiculite.
Does F. mosseae Prefer Proximity to Roots to Sporulate?
F. mosseae does not have a reputation for being an easy fungus to grow. In particular, it can produce an abundance of hyphae while forming few spores, or none at all, for reasons that remain unclear. The culture presented here suggests a hypothesis that would be worth validating through more formal experiments.
Experiment #388 is based on six two-compartment Petri dishes: one side contains a mixture of vermiculite and polymer, while the other contains pure polymer, the two compartments being separated by a Nitex membrane. The vermiculite side is heavily colonized by roots, some of which can even be seen through the polymer itself. The 100% polymer side, by contrast, contains little to no roots.
In two of the dishes, however, spore production was observed to have begun near the roots, while a high density of hyphae was visible on the polymer side, where no roots were present at all. The plants had been inoculated on July 16, 2026, and this observation was made on September 13, 2026, after two months of culture. The two images below come from the two compartments of the same dish, illustrating this contrast.
It is worth keeping in mind that such a small number of dishes in culture does not allow for robust statistics or conclusions. This culture was, moreover, only a routine maintenance replication, with no measurable objective at the outset. Nevertheless, this kind of observation, even if only anecdotal, can give rise to hypotheses that would be worth validating more formally.
Surprising 58-Day Survival in Refrigeration
Plantago lanceolata plants colonized by F. mosseae survived a 58-day stay in the dark in a refrigerator at 4 °C.
An extended absence from the lab, with no one to look after the cultures, led to placing four dishes of P. lanceolata well colonized by F. mosseae in a sealed freezer bag in the refrigerator. The intent was that the colonized roots could be used to restart the cultures upon return, even if the plants themselves did not survive. These plants had been in culture for roughly 4 to 6 months.
Against all expectations, all four plants survived and resumed growth as soon as they were placed back under LED lighting. The polymer was then replaced with fresh, uncolonized polymer to check whether the fungus was still active. An observation made 46 days after this replacement confirms that all four plants are healthy, with normal foliage. All four dishes show new hyphae in the fresh polymer; two of them display an intense resurgence of fungal activity, while the other two show only a few scattered hyphae.
As of July 22, 2026, restarting the fungus appears difficult. It no longer shows movement within the polymer, though the plants themselves remain vigorous. An attempt to revive it using root fragments was also tried, with similarly mixed results. It is possible that the fungus has “retreated” into the vermiculite; this point remains unresolved as of this writing.