How Fungi Built a Social Safety Net Beneath Your Feet

The post How Fungi built a social safety net under your feet appeared first on AZ Animals.

Take it quickly

• Plants, including trees, can communicate through wall-like structures called mycelium.

• Mycelium are part of fungi, which form their own biological kingdom separate from plants.

• Mother trees act as centers and nurture the young ones.

• Communication is achieved by a number of methods, including advective mass flow, driven by a source-sink gradient.

A walk through a forest is a treat for the senses. Stop and look, listen and touch what is around you. The sunlight shines through the branches, the rustle of the leaves, and the rough texture of the bark under your fingertips. But this is only a very small part of a bigger picture. Forest life continues underground in complex networks that you cannot see or feel. Without these networks, forests and many other plants that we love so much could not exist.

The Essential Role of Fungus

Trees have an essential communication network that they use to share information with each other. The messages are carried through thread-like structures called mycelium, which are actually part of the fungi. The mycelium is the root-like structure of a fungus that is normally hidden from view beneath the soil. It is also the part that does all the work and forms vast networks.

Crucially for trees, the mycelium grows or descends into their roots. This allows the trees to use this network to share water and nutrients. It is called the mycorrhizal network.

Trees Take Care of Their Own

In a healthy forest, each tree is connected to the others through this network. However, trees prioritize some of their neighbors over others. Research has shown that seeds can struggle to establish themselves in shady areas because there is not enough light reaching them for sufficient photosynthesis. This is the mechanism that green plants use to convert sunlight into a form of energy they can use. So, older, taller trees that can access light use the mycorrhizal network to send nutrients and sugars to younger, struggling trees. There are some experts who believe that trees favor their relatives when sending carbon and nutrients.

Trees Make a Carbon Compromise

Rather than being exploited by trees as a free conduit system, fungi also gain an advantage from this relationship. By providing this service to the trees, the fungi obtain a regular and reliable supply of carbon. In fact, the fungi get to keep between 20 and 30 percent of the sugar it transports. Trees also benefit from phosphorus and other mineral nutrients, which are picked up by the mycelium and transported to the trees.

Mother Trees form a Hub

Not all trees connected to this network are equal. Some, called ‘mother trees,’ act as centers. They are older and typically have the most fungal connections. Because their roots reach deeper into the soil, they can access water sources that are not available to other trees. When they pass this on to the minors, they help nurture the next generation. However, communication is not only one-way. The mother trees use the fungal connections to sense when another tree is in trouble (sending distress signals) and help it by sending nutrients on its way.

The Science of Tree Communication

Scientists have made significant progress in understanding how trees communicate using mycorrhizal networks, although many details are still being uncovered. Currently, experts think it involves a combination of biochemical signaling, resource transfers, or electrical signals driven by an action potential.

In general, trees form relationships with a wide range of fungal species, and one fungal species can colonize many different plant species. Some, however, depend on a single host. That said, plants tend to remain loyal to a particular class of fungus. Often, arbuscular mycorrhizal fungi are involved. This type of fungus is found most often in temperate grasslands, tropical forests, and agricultural systems, but is also associated with some temperate forest trees. In contrast, ectomycorrhizal fungi are associated with coniferous trees as well as temperate and boreal forests. While mycorrhizal networks may be more common among related plants, they are also known to connect different species, allowing interspecies communication and resource sharing.

How do substances move along the mycelium?

It is likely that different substances move in different ways through mycorrhizal networks. For example, carbon is transported over long distances by what is called advective mass flow, driven by a source-sink gradient. Basically, this means that carbon moves from an area of ​​high concentration (the source tree) to an area of ​​low concentration (the sink tree). Consider the scenario of a struggling juvenile: due to its age and location, the juvenile will have high respiratory demands as it grows and will therefore inevitably have a lower concentration of carbon because it is using it up rapidly. Therefore, the gradient persists, and the flow is kept one way.

Fast Stress Signs

Perhaps the most remarkable feature of the mycorrhizal network is its ability to rapidly transfer stress signals from injured plants to healthy plants. It can take at least 6 hours for healthy neighbors to receive a stress signal generated by a herbivore or a pathogen.

Neighboring plants upregulate their own defense-related genes, essentially preparing themselves for the same danger that affected their neighbor. This early warning system allows other plants to produce defensive enzymes to protect themselves. This is only a small part of the story, and we have only just begun to discover the wonders of the forest’s social safety net!

The post How Fungi built a social safety net under your feet appeared first on AZ Animals.