More about Mycorrhizae

More about Mycorrhizae

A dense closter of small mushrooms with shiny yellow caps that look as though they were dipped in honey.

Have you ever seen an uprooted tree while walking in a forest? If so, you might have noticed strands of white thread-like structures attached to the tree roots and running through the soil. What you were seeing were mycorrhizal fungi. These fungi surround and bind almost all of the plants growing in an ecosystem together. Some of them, like the honey fungus (Armillaria mellea; pictured) are even luminous, glowing in the dark. The honey fungus is also the world’s largest organism (that we know of, at least); one specimen stretches for an astounding 2.4 miles (3.8 km) (Ferguson et al. 2003)! This fungus is attached to hundreds of trees, which are also attached to countless other mycorrhizal fungi and forest plants. Sugars, water, and nutrients are exchanged between the plants and the fungi. Trillions of insects and microorganisms live on, and interact with these fungi-root systems. Unfortunately, our understanding of this massive system is horrible, because we can’t actually see what is going on.

Image: Wikimedia Commons

 

It’s important to remember that the parts of a forest or a prairie that we can see above ground are probably less than a half of the ecosystem’s total biomass; almost all of the fungal biomass is beneath the ground.

Some mycorrhizal fungi appear to only associate with certain plant species while others are less discriminating. About 80% of all plant species (including all trees) associate with mycorrhizae; the plants that don’t are the rushes, sedges, nettles, mustards, goosefoots, and pinks. Some plants are so dependent on mycorrhizae that they can’t live without them: the orchids are one such group. While most mycorrhizal relationships appear to be mutualistic, with both partners benefiting from the interaction, many orchids appear to be parasitic on the fungi!

Close up on a cluster of four-petaled yellow flowers.

Plants in the mustard family like Western wallflower (Erysimum asperum) are some of the only species that do not associate with mycorrhiza. © MM

Two thick stalks growing up from the ground, with leaf-like petals on the top third.

Striped coralroot (Corallorrhiza striata) parasitize both trees and mycorrhizal fungi. © MM

The most parasitic orchids are the coralroots (Corallorrhiza spp.). These species are vascular plants that can no longer photosynthesize, as indicated by the fact that they are orange instead of green. Coralroot orchids parasitize mycorrhizal fungi, which form relationships with pine (Pinus spp.) trees. Thus all of the sugars the coralroot uses to fuel its growth come from the pine trees (via the mycorrhiza), and the water and minerals it needs come from the fungus (Zelmer and Smith 1995).

View over a clearing towards a group of Paper birch trees.

Mycorrhizae appear to help tree “parents” feed their offspring. In “The Hidden Life of Trees” the German forester Peter Wohlleben describes how sugars produced by large, adult trees in a forest are transferred through the mycorrhizae to the saplings, which are unable to access much light. In this way, young trees are provided with enough nourishment to stay alive until the adult tree dies and the young ones can obtain light for themselves. Resources are even transferred between trees of different species. Douglas firs (Pseudotsuga menziesii) were found to transfer nutrients to paper birch (Betula papyrifera) trees in the spring and fall when the birches had no leaves and the birches transferred nutrients to the firs in the summer when their leaves were shaded (Song et al. 2015). Wohllenben thinks that this happens because “a tree can be only as strong as the forest that surrounds it.”

This is just the tiniest shred of what scientists know about mycorrhizae and new studies are being conducted all the time using new tools and analytical techniques. Next time you’re out hiking in a forest remember this amazing invisible world under your feet!

 

Image: Paper birch (Betula papyrifera) trees exchange nutrients with other trees through mycorrhizal links. © MM

References

Ferguson, B.A., T.A. Dreisbach, C.G. Parks, G.M. Filip, and C.L. Schmitt. 2003. Coarse-scale population structure of pathogenic Armillaria species in a mixed-conifer forest in the Blue Mountains of northeast Oregon. Canadian Journal of Forest Research 33:612-623.

Song Y.Y., S.W. Simard, A. Carroll, W.W. Mohn and R.S. Zeng. 2015. Defoliation of interior Douglas-fir elicits carbon transfer and stress signalling to ponderosa pine neighbors through ectomycorrhizal networks. Scientific Reports, 5 8495. DOI: http://dx.doi.org/10.1038/srep08495

Wohlleben, P. 2016. The hidden life of trees: What they feel, how they communicate discoveries from a secret world. Greystone Books.

Zelmer, C.D. and R.S. Currah. 1995. Evidence for a fungal liaison between Corallorrhiza trifida (Orchidaceae) and Pinus contorta (Pinaceae). Canadian Journal of Botany 73:862-866.

Dr. Diana Bizecki Robson

Dr. Diana Bizecki Robson

Curator of Botany

Dr. Bizecki Robson obtained a Master’s Degree in Plant Ecology at the University of Saskatchewan studying rare plants of the mixed grass prairies. After working as an environmental consultant and sessional lecturer…
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Red Cross Quilt Returns Home

When the weather turns cold many of us pull out handcrafted quilts and afghans. The comfort they bring often goes beyond the mere physical and can make us feel as if the people that created them are enveloping us in a warm and loving hug. Recently, a very special quilt was donated to the Manitoba Museum. One of thousands sent overseas by the Canadian Red Cross during the Second World War to provide warmth and comfort, it has now returned home to Manitoba nearly 75 years later.

A quilt stitched of pastel pink, orange, and cream fabric with an accent portion in the middle in blues and greens.

Red Cross Quilt, H9-38-563. © The Manitoba Museum

A black and white photograph of a woman standing outdoors holding a baby, with a dog seated beside them.

Betty Craddock with son Anthony. © Anthony Craddock

The story of the quilt begins in Steep Rock, Manitoba where local women would have been part of a network of participants in the Red Cross “Women’s War Work” sewing and knitting program. It was likely sorted and packed at a Red Cross facility before being shipped overseas and on to the Dudley Road Hospital in Birmingham. There, a Matron passed the quilt on to Cynthia (Betty) Craddock sometime towards the end of the war. Betty worked as a lathe operator making tank parts in a factory in Coventry. Her husband Joe had completed apprenticeship as a painter and decorator and then was called up for the army in 1940. He worked as a cook for the Army Intelligence Corp, serving in England and Wales. Joe reached the continent just after D-Day and was among the first troops in Belgium. They had married in 1943 and were together for over 70 years. Their only son Anthony was born in 1945.

Following the war, the family moved to Kenilworth and the quilt went along with them. Britain was recovering from the war and rationing was still in place. Joe was working to start his own business. Anthony’s earliest memories are “of this quilt being on my bed and keeping me warm when times were hard.” He recalls that, “with no central heating, frost would often appear on the inside of the window.” The young Anthony was amazed by the colours and patterns and remembers reading the message on a tag on one corner of the quilt, “Gift Canadian Red Cross, Steep Rock Man. Can.”

 

Image: Close-up of label on quilt. © The Manitoba Museum

The Canadian Red Cross Society was founded in 1896. The purpose of the Society, as set out in its 1909 Act of Incorporation, was “to furnish volunteer aid to the sick and wounded of armies in time of war”. Following WWI, the Red Cross expanded its role into public health, especially in remote or newly settled areas of Canada. The two mandates merged in WWII as the Red Cross worked with military personnel and civilian victims of the war. On the home front, countless volunteers worked to high standards creating supplementary hospital and relief supplies.

The Canadian Red Cross Society distributed patterns and lapel pins to volunteers in the “Women’s War Work” program.

A Canadian Red Cross Knitting Instructions for War Work booklet, with two lapel pins beside it.

Lapel pins, H9-22-407 and H9-31-994, Knitting Pattern, H9-29-545. © Manitoba Museum

A grey-haired man holding a DSLR camera sitting on a blue bench with the quilt draped over the back of it.

Anthony Craddock has been a professional photographer since 1965 and is now a director of Images Etc Ltd”. Anthony Craddock with quilt, 2016. © Anthony Craddock

Now that the quilt has been received into the museum’s collection, Roland Sawatzky, Curator of History is looking forward to sharing it with the community and perhaps learning more about the “hands-on” humanitarians who sewed it. As the women of Steep Rock gathered to create this quilt, I’m sure they would not have imagined that it would be treasured by the receiving family into the next century.

 

Sources:

120 Years of the Canadian Red Cross at www.redcross.ca/history/home
Biographical and historical notes provided by Anthony Craddock

Nancy Anderson

Nancy Anderson

Collections Management Specialist – Human History

Nancy Anderson holds a B.A. (Hons) in History from the University of Winnipeg, and received her M.A. in Canadian Social History jointly from the University of Winnipeg and University of Manitoba. She has over 30 years experience…
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