Armillaria sinapina rhizomorphs growing in the Soudan Iron Ore Mine in northern Minnesota. Rhizomorphs grow in the wet mine environment (top photo) colonizing wood timbers (bottom photo) and move from timber to timber throughout the mine.
extensive underground network of rhizomorphs produced by Armillaria but recently we have had the opportunity to view this fungus in an unusual subterranean environment. Te Soudan Iron Ore Mine located in northern Minnesota (now a State Park) has a main shaft that is 2,341 feet deep and 18 different levels extending out laterally long distances. Large numbers of wooden timbers were used throughout the mine as rail ties for carts to remove the ore and for other structural uses. Our team from the University of Minnesota which included Benjamin Held and Christine Salomon, investigated the fungi in this mine to
The mine provides a view of rhizomorph biology that usually remains unseen. Massive Armillaria sinapina rhizomorphs grow from colonized wood (top photo) and extend many meters in their search for new food sources (bottom photo). The mine has exceedingly high concentrations of heavy metals but Armillaria growth is unaffected by them.
better understand their association with very high levels of iron, copper, and other heavy metals that occur there (
https://doi.org/10.1371/journal. pone.0234208 ). We were surprised to find Armillaria sinapina rhizomorphs in huge numbers as they colonized the timbers. In wet areas, the rhizomorphs were many meters long and they could be seen extending long distances as they searched the mine passageways for more wood substrates. It is likely that the many miles of rhizomorphs in the mine are all from one introduced fungus and compose one big clone. Te heavy metals in the Soudan Mine are at concentrations high enough to
inhibit many microorganisms—but not Armillaria. Tis fungus has the capacity to tolerate metal ions and use them as a protective coating on the melanized rhizomorphs. Our studies at the Soudan Mine help illustrate what is taking place with Armillaria rhizomorphs underground and how spectacular their network must be as it grows through forest soils. Our understanding about
rhizomorphs expanded greatly after a trip deep within the Amazon rainforest. Most previous research has focused on forest fungi in temperate areas and seminal publications have been written on these fungi. We did not
Winter 2022 FUNGI Volume 15:1 29
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60
