Mycorrhizal network

Mycorrhizal networks (also known as common mycorrhizal networks or CMN) are underground hyphal networks created by mycorrhizal fungi that connect individual plants together and transfer water, carbon, nitrogen, and other nutrients and minerals. The formation of these networks is context dependent, and can be influenced by factors such as soil fertility, resource availability, host or myco-symbiont genotype, disturbance and seasonal variation (due to enrichment of nitrogen in soil affect michozial communities or effect of human activities of human affecting nitrogen cycle). By analogy to the many roles intermediated by the World Wide Web in human communities, the many roles that mycorrhizal networks appear to play in woodland have earned them a colloquial nickname: the Wood Wide Web.. Mycorrhizal networks (also known as common mycorrhizal networks or CMN) are underground hyphal networks created by mycorrhizal fungi that connect individual plants together and transfer water, carbon, nitrogen, and other nutrients and minerals. The formation of these networks is context dependent, and can be influenced by factors such as soil fertility, resource availability, host or myco-symbiont genotype, disturbance and seasonal variation (due to enrichment of nitrogen in soil affect michozial communities or effect of human activities of human affecting nitrogen cycle). By analogy to the many roles intermediated by the World Wide Web in human communities, the many roles that mycorrhizal networks appear to play in woodland have earned them a colloquial nickname: the Wood Wide Web.. Several studies have demonstrated that mycorrhizal networks can transport carbon, phosphorus, nitrogen, water, defense compounds, and allelochemicals from plant to plant. The flux of nutrients and water through hyphal networks has been proposed to be driven by a source-sink model, where plants growing under conditions of relatively high resource availability (e.g., high-light or high-nitrogen environments) transfer carbon or nutrients to plants located in less favorable conditions. A common example is the transfer of carbon from plants with leaves located in high-light conditions in the forest canopy, to plants located in the shaded understory where light availability limits photosynthesis. There are two main types of mycorrhizal networks: arbuscular mycorrhizal networks and ectomycorrhizal networks. Several positive effects of mycorrhizal networks on plants have been reported. These include increased establishment success, higher growth rate and survivorship of seedlings; improved inoculum availability for mycorrhizal infection; transfer of water, carbon, nitrogen and other limiting resources increasing the probability for colonization in less favorable conditions. These benefits have also been identified as the primary drivers of positive interactions and feedbacks between plants and mycorrhizal fungi that influence plant species abundance Myco-heterotrophic plants are plants that are unable to photosynthesize and instead rely on carbon transfer from mycorrhizal networks as their main source of energy. This group of plants includes about 400 species. Some families that include mycotrophic species are: Ericaceae, Orchidaceae, Monotropaceae, and Gentianaceae. In addition, mixotrophic plants also benefit from energy transfer via hyphal networks. These plants have fully developed leaves but usually live in very nutrient and light limited environments that restrict their ability to photosynthesize. Connection to mycorrhizal networks creates positive feedbacks between adult trees and seedlings of the same species and can disproportionally increase the abundance of a single species, potentially resulting in monodominance. Monodominance occurs when a single tree species accounts for the majority of individuals in a forest stand. McGuire (2007), working with the monodominant tree Dicymbe corymbosa in Guyana demonstrated that seedlings with access to mycorrhizal networks had higher survival, number of leaves, and height than seedlings isolated from the ectomycorrhizal networks. The importance of mycorrhizal networks facilitation is no surprise. Mycorrhizal networks help regulate plant survival, growth, and defense. Understanding the network structure, function and performance levels are essential when studying plant ecosystems. Increasing knowledge on seed establishment, carbon transfer and the effects of climate change will drive new methods for conservation management practices for ecosystems. Seedling establishment research often is focused on forest level communities with similar fungal species. However mycorrhizal networks may shift intra- and interspecific interactions that may alter pre-established plants physiology. Shifting competition can alter the evenness and dominance of the plant community. Discovery of seedling establishment showed seedling preference is near existing plants of con-or heterospecific species and seedling amount is abundant. Many believe the process of new seedlings becoming infected with existing mycorrhizae expedite their establishment within the community. The seedling inherit tremendous benefits from their new formed symbiotic relation with the fungi. The new influx of nutrients and water availability, help the seedling with growth but more importantly help ensure survival when in a stressed state. Mycorrhizal networks aid in regeneration of seedlings when secondary succession occurs, seen in temperate and boreal forests. Several studies have focused on relationships between mycorrhizal networks and plants, specifically their performance and establishment rate. Douglas fir seedlings' growth expanded when planted with hardwood trees compared to unamended soils in the Oregon Mountains. Douglas firs had higher rates of ectomycorrhizal fungal diversity, richness, and photosynthetic rates when planted alongside root systems of mature Douglas firs and Betula papyrifera than compared to those seedlings who exhibited no or little growth when isolated from mature trees. . The Douglas fir was the focus of another study to understand its preference for establishing in an ecosystem. Two shrub species, Arctostaphylos and Adenostoma both had the opportunity to colonize the seedlings with their ectomycorrhizae fungi. Arctostaphylos shrubs colonized Douglas fir seedlings who also had higher survival rates. The mycorrhizae joining the pair had greater net carbon transfer toward the seedling. The researchers were able to minimize environmental factors they encountered in order to avoid swaying readers in opposite directions.