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Mycorrhizal Networks Facilitate Tree Communication, Learning, and Memory
Abstract
Mycorrhizal fungal networks linking the roots of trees in forests are increasingly recognized to facilitate inter-tree communication via resource, defense, and kin recognition signaling and thereby influence the sophisticated behavior of neighbors. These tree behaviors have cognitive qualities, including capabilities in perception, learning, and memory, and they influence plant traits indicative of fitness. Here, I present evidence that the topology of mycorrhizal networks is similar to neural networks, with scale-free patterns and small-world properties that are correlated with local and global efficiencies important in intelligence. Moreover, the multiple exploration strategies of interconnecting fungal species have parallels with crystallized and fluid intelligence that are important in memory-based learning. The biochemical signals that transmit between trees through the fungal linkages are thought to provide resource subsidies to receivers, particularly among regenerating seedlings, and some of these signals appear to have similarities with neurotransmitters. I provide examples of neighboring tree behavioral, learning, and memory responses facilitated by communication through mycorrhizal networks, including, respectively, (1) enhanced understory seedling survival, growth, nutrition, and mycorrhization, (2) increased defense chemistry and kin selection, and (3) collective memory-based interactions among trees, fungi, salmon, bears, and people that enhance the health of the whole forest ecosystem. Viewing this evidence through the lens of tree cognition, microbiome collaborations, and forest intelligence may contribute to a more holistic approach to studying ecosystems and a greater human empathy and caring for the health of our forests.
... Elementos y compuestos como nitrógeno, carbono, agua, fósforo, material genético, fitohormonas y aminoácidos conforman una multitud de señales químicas que son compartidas por una gran cantidad de plantas y árboles. Estas sustancias, al ser liberadas por las plantas, viajan por el aire para encontrar a otras y advertirlas, por ejemplo, sobre la presencia de plagas o depredadores, e inducir diferentes respuestas conductuales que incrementen sus defensas o resistencia (Simard, 2019;Gagliano, 2015). La comunicación química se concentra en las raíces y micorrizas 2 que forman extensas redes subterráneas que interconectan a los individuos de una localidad. ...
... Las sustancias y los compuestos viajan por medio de estas redes y se transforman en mensajes que las plantas intercambian. A través de las redes de micorrizas, las plantas pueden reconocer su grado de parentesco con sus vecinas y distribuir diferencialmente sus recursos y alertas para colaborar a su subsistencia (Simard, 2019). ...
... No obstante, si entendemos la inteligencia como la capacidad de procesar información, tomar decisiones y resolver problemas, las plantas podrían portar esta cualidad (Mancuso y Viola, 2019;Ananthaswamy, 2014;Head et al., 2014). Las redes que conectan micorrizas y raíces son muy diferentes de las redes neuronales que componen el sistema nervioso de los animales, pero cumplen una función semejante y permiten a las plantas obtener información sobre su entorno, compartirla, interpretarla y encauzar sus acciones hacia fines determinados, conductas asociadas a la inteligencia (Simard, 2019). ...
The main goal of this paper is to describe vegetal ethnography, an area of study interested in observing plants as beings with agency. Based on a literature review, the theoretical proposal, the main concepts, and some relevant works and authors are presented. Among the results, it is found that the reworking of the notion of agency offers anthropology new opportunities to explore how plants are embedded in social life entanglements. Although vegetal ethnography’s methods are still being developed and there is debate about the limits and possibilities of the tools employed, these new perspectives make it feasible to access other ways of understanding the world, different from those that modernity has established. It is concluded that recognizing the capabilities of plants is a way of questioning human exceptionalism and imagining futures based on collaboration and interdependence.
... As far as inter-plant communication through hyphal networks is concerned, the most studied and widely publicized aspect in society is the ability of mycorrhizal fungi, through what are known as common mycorrhizal networks (CMNs), to communicate to the forest trees with each other, as if it were "internet" (Simard, 2018). These connections between plants by CMNs can also occur between species that are very distant taxonomically, such as herbaceous and trees (Gilbert and Johnson, 2017). ...
... These connections between plants by CMNs can also occur between species that are very distant taxonomically, such as herbaceous and trees (Gilbert and Johnson, 2017). Both signaling molecules and electrical signals may be involved in this inter-plant communication, favoring the increase of chemical defenses against biotic and abiotic stresses, and even the creation of a collective memory-based interactions among plants (Johnson and Gilbert, 2015;Simard, 2018). However, the ability of filamentous endophytic fungi to act as vehicles of inter-plant communication, by simultaneously colonizing the rhizosphere and plant roots, has been scarcely studied (Oelmüller, 2019). ...
... The ability of mycorrhizal fungi to act as inter-plant communicators has been widely studied and reviewed by numerous authors, raising their clear similarities between the transmission of information through the fungal mycelium and the transmission of the nerve impulse by neurons (Johnson and Gilbert, 2015;Gilbert and Johnson, 2017;Simard, 2018;Oelmüller, 2019). However, there is little evidence of these processes in other root colonizing fungi that behave as endophytes and rhizospheric microorganisms. ...
Trichoderma is a genus of filamentous fungi widely studied and used as a biological control agent in agriculture. However, its ability to form fungal networks for inter-plant communication by means of the so-called inter-plant "wired communication" has not yet been addressed. In our study we used the model plant Arabidopsis thaliana, the fungus Trichoderma hamatum (isolated from Brassicaceae plants) and the pathogens Sclerotinia sclerotiorum and Xanthomnas campestris (necrotrophic fungus and hemibiotrophic bacteria, respectively). We performed different combinations of isolated/neighboring plants and root colonization/non-colonization by T. hamatum, as well as foliar infections with the pathogens. In this way, we were able to determine how, in the absence of T. hamatum, there is an inter-plant communication that induces systemic resistance in neighboring plants of plants infected by the pathogens. On the other hand, the plants colonized by T. hamatum roots show a greater systemic resistance against the pathogens. Regarding the role of T. hamatum as an inter-plant communicator, it is the result of an increase in foliar signaling by jasmonic acid (increased expression of LOX1 and VSP2 genes and decreased expression of ICS1 and PR-1 genes), antagonistically increasing root signaling by salicylic acid (increased expression of ICS1 and PR-1 genes and decreased expression of LOX1 and VSP2). This situation prevents root colonization by T. hamatum of the foliarly infected plant and leads to massive colonization of the neighboring plant, where jasmonic acid-mediated systemic defenses are induced.
... Elementos y compuestos como nitrógeno, carbono, agua, fósforo, material genético, fitohormonas y aminoácidos conforman una multitud de señales químicas que son compartidas por una gran cantidad de plantas y árboles. Estas sustancias, al ser liberadas por las plantas, viajan por el aire para encontrar a otras y advertirlas, por ejemplo, sobre la presencia de plagas o depredadores, e inducir diferentes respuestas conductuales que incrementen sus defensas o resistencia (Simard, 2019;Gagliano, 2015). La comunicación química se concentra en las raíces y micorrizas 2 que forman extensas redes subterráneas que interconectan a los individuos de una localidad. ...
... Las sustancias y los compuestos viajan por medio de estas redes y se transforman en mensajes que las plantas intercambian. A través de las redes de micorrizas, las plantas pueden reconocer su grado de parentesco con sus vecinas y distribuir diferencialmente sus recursos y alertas para colaborar a su subsistencia (Simard, 2019). ...
... No obstante, si entendemos la inteligencia como la capacidad de procesar información, tomar decisiones y resolver problemas, las plantas podrían portar esta cualidad (Mancuso y Viola, 2019;Ananthaswamy, 2014;Head et al., 2014). Las redes que conectan micorrizas y raíces son muy diferentes de las redes neuronales que componen el sistema nervioso de los animales, pero cumplen una función semejante y permiten a las plantas obtener información sobre su entorno, compartirla, interpretarla y encauzar sus acciones hacia fines determinados, conductas asociadas a la inteligencia (Simard, 2019). ...
... This communication, on the other hand, is thought to happen more swiftly and efficiently between plants via speech transmission across networks, or "wired communication" (Gagliano 2013). Although the exact manner of communication is unknown (Simard 2018), these communication signals are sent between fungal synapses and trees and/or plants by diffusion or active transport processes (mass flow) along source-sink gradients (Twieg et al. 2007;Simard et al. 2015). For example, leaf photosynthetic activity in donor plants causes N and C source-sink gradients that allow amino acids to be transported to mycorrhizal roots, which are subsequently transferred by mass flow from the connecting mycelium to the xylem of the connected recipient sink plants. ...
... This is insufficient to account for the complex plant activity observed in roots. It is hypothesized, however, that when plants have a symbiotic relationship with mycorrhizal fungus, this supplies them with the topology and energy required for advanced thinking (Simard 2018). The "topology" of a communication network refers to the organization of various elements (nodes and connections). ...
... The finest examples are neurons and axons, which are nodes and links in the human's brain. Mycorrhizal fungal micelles, which connection plants and plants, are an example of this in nature (Simard 2018). ...
Plants, animals, and even microbes well communicate with each other if we look at nature in cartoon terms. However, in the real world, there is little evidence on how this communication is established. In this context, we have focused on how plants communicate with mycorrhizal fungi and how they communicate with each other using mycorrhizal networks. We divide this communication in the rhizosphere into three categories: (i) communication of the plant with the fungus (plantish), (ii) communication of the fungus with the plant (fungish), and (iii) communication among plants through mycorrhizal networks (wired communication). We propose that molecules involved in inter-kingdom symbiotic communication, such as strigolactones, chitin-related compoundsand cutin monomers in plant-fungal communication, are initially unrelated to symbiosis, but they play important roles in its development. It’s not, however, known exactly whether the dialogue between plant-fungi is fungish or plantish; Despite this, since it is a language on which they agree, we consider it appropriate to call this language “symbioticish”. Moreover, mycorrhizal networks offer inter-plant communication by transferring nutrients, stress signalsand allelochemicals. We present evidence showing that these mycorrhizal networks impart sophisticated intelligence to plants and that their topology is similar to that of the human’s brain, with some features including scale-free and small-world network topology. The evidence presented in this review can contribute to the study of plant-mycorrhizal fungus communication and mycorrhizal networks in the inter-plant communication by establishing a better human empathy, taking a more holistic approach to examining ecosystems and caring about the health of our plants.
... With the availability of many sequence datasets from environmental samples, the focus now is to go beyond alpha and beta diversity and look more at the interactions between microbial taxa and their host [9,10]. Studying interactions between taxa across intricate and different inhabitants like plant microbiomes will aid in establishing useful roles or ecological niches engaged by beneficial microorganisms in promoting plant health [11][12][13]. Plants harbor diverse groups of microorganisms that live inside and outside their roots. The root microbiome is the active community of microbes connected with plant roots, be it inside or around the root, which is extensively involved in plant wellbeing and serves as a receptacle of extra genes that plants can acquire when required [14]. ...
... Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 7 July 2023 doi:10.20944/preprints202307.0451.v111 ...
Plant roots host various microorganisms around and inside their roots, known as the root microbiome. To become healthy and productive, plants should keep under surveillance niches around the roots to recognize disease-causing microbes and similarly exploit the services of beneficial microorganisms in nutrient acquisition, stress mitigation and growth promotion. Here we presented the communication strategies between plant roots and root-associated microbes in improving plant growth and yield. Understanding how plant root and root-associated microbes communicate is vital in designing ecofriendly strategies for targeted disease suppression and improved plant growth that will help in sustainable agriculture.
... It was noted by Simard et al. (2012) that C transfer between plants could make evolutionary sense if transport between plants connected through a CMN occurred in the form of amino acids such as glycine and glutamine so that these compounds would not only be occurring within hyphae and rhizomorphs but also be transferred to the receiver plant. This argument is further elaborated by Simard (2018). Uptake of amino acids from soil by mycorrhizal and non-mycorrhizal plants is well documented (N€ asholm et al., 2009). ...
... Uptake of amino acids from soil by mycorrhizal and non-mycorrhizal plants is well documented (N€ asholm et al., 2009). In the current context, however, a pathway involving a donor plant exporting organic N compounds to the CMN followed by the uptake of this organic N by the receiver plant is implied (Simard, 2018). An alternative scenario would be that inorganic N is acquired by a mycorrhizal fungus from soil and this N is subsequently assimilated by the fungus using C from a donor plant and the synthesized amino acid is subsequently exchanged for C from a receiver plant. ...
Seminal scientific papers positing that mycorrhizal fungal networks can distribute carbon (C) among plants have stimulated a popular narrative that overstory trees, or 'mother trees', support the growth of seedlings in this way. This narrative has far-reaching implications for our understanding of forest ecology and has been controversial in the scientific community. We review the current understanding of ectomycorrhizal C metabolism and observations on forest regeneration that make the mother tree narrative debatable. We then re-examine data and conclusions from publications that underlie the mother tree hypothesis. Isotopic labeling methods are uniquely suited for studying element fluxes through ecosystems, but the complexity of mycorrhizal symbiosis, low detection limits, and small carbon discrimination in biological processes can cause researchers to make important inferences based on miniscule shifts in isotopic abundance, which can be misleading. We conclude that evidence of a significant net C transfer via common mycorrhizal networks that benefits the recipients is still lacking. Furthermore, a role for fungi as a C pipeline between trees is difficult to reconcile with any adaptive advantages for the fungi. Finally, the hypothesis is neither supported by boreal forest regeneration patterns nor consistent with the understanding of physiological mechanisms controlling mycorrhizal symbiosis.
... Following in this epistemological vein, we must also recognize the sites of plant knowledge production outside of Western science, as created by Indigenous Peoples, enslaved and colonized people, and in popular botanical, medicinal, and pharmaceutical knowledge (Riddle, 1997;Kimmerer, 2013;Foster, 2017). From yet Marianna Szczygielska & Olga Cielemęcka, 2019 6 another perspective, contemporary research in plant science that concerns vegetal cognition, sentience, and communication (see, e.g., Mancuso & Viola, 2015;Simard, 2018) invites critical perspectives that challenge the historically inherited Western hierarchy of the human, the animal, and the vegetal life (Marder, 2013). ...
... Drawing on history of science (Merchant, 1990;Shteir, 1996;Carney, 2001;Schiebinger, 2017), feminist science and technology studies (Hustak & Myers, 2012;Subramaniam, 2014), and plant science (Gagliano, 2018;Simard, 2018), critical theories of plants problematize plant-human relationships in the context of power relations running along the lines of race, ethnicity, class, gender, sexuality, nationality, and more. Emerging fields of research such as plant philosophy (Marder, 2013), queer ecologies (Sandilands, 2016;Mortimer-Sandilands & Erickson, 2010), phytopoetics (Jacobs, this volume), multispecies ethnographies (Haraway, 2007;Tsing, 2012), environmental humanities (Rose et al., 2012), food studies (Shiva, 2000), studies on the Anthropocene (or the "Planthropocene" [Myers, 2016]), among others, look into plant life to further explore constellations of knowledge, matter, and power in which both plants and humans are entangled. ...
This is the introduction to the special section.
... For instance, a mycelium network is constructed by mushrooms and allows for the sharing of resources such as carbon or phosphorus to improve the use of nutrients coming from nonliving resources such as water or sunlight. Furthermore, some kinds of trees share carbon with smaller plants that do not receive sufficient sunlight (Simard, 2018). ...
... If trees cooperate with each other to survive and evolve (Simard, 2018), perhaps we as human beings are missing the opportunity to evolve by emphatically driving competition in the economy. ...
In the context of discussions regarding the relevance of innovation to the task of building new economic models that foster sustainable development, this paper focuses on clarifying and specifying the term “ecosystem”, which is typically used as a metaphor. Taking into account research concerning biological ecosystems, the article describes the components, structures and dynamics that biological ecosystems share in common with business, entrepreneurial, and innovation ecosystems, which together form one aspect of economic ecosystems as a whole. The paper utilizes primary data that were collected through a mixed methodology involving participatory workshops and an online survey instrument that involved members of innovation-oriented entrepreneurial ecosystems in eight cities throughout Europe and Latin America from June 2019 through February 2020.
Drawing on complex system theory as a unifying approach to describe and explain the components and structural conditions of any ecosystem, whether biological or economic, this paper proposes a theoretical approach and metrics that can be used to attain a better understanding of the social dynamics of ecosystems. Based on observations from the field of biology, it is proposed that such structural conditions tend toward equilibrium when they are constructed mainly through collaborative mechanisms. The results are shown graphically based on the data collected, utilizing metrics taken from complex network analysis and mathematical modeling from the perspective of complex system theory. This paper finds that the ecosystemic approach is more than a metaphor and can functionally describe how an ecosystem is structured and how it works by opening a wider path toward comprehending the dynamics underlying the interactions among components of economic ecosystems and their environment. The paper concludes by proposing that collaboration relationships among actors provide the required characteristics to increase balance and resilience in economic ecosystems.
... Simard et al. [39] have raised the possibility that organic forms of N could represent C transferred among plants. However, even if C from a donor plant is used to synthesize organic N compounds in a CMN (mainly glutamine and arginine), any receiver plant would still spend C for the uptake of this organic N, either for direct C-N trading [40] or, at least, for energy production, which is necessary to drive the uptake of amino acids across the plasma membrane [41]. ...
There are growing doubts about the true role of the common mycorrhizal networks (CMN or wood wide web) connecting the roots of trees in forests. We question the claims of a substantial carbon transfer from ‘mother trees’ to their offspring and nearby seedlings through the CMN. Recent reviews show that evidence for the ‘mother tree concept’ is inconclusive or absent. The origin of this concept seems to stem from a desire to humanize plant life but can lead to misunderstandings and false interpretations and may eventually harm rather than help the commendable cause of preserving forests. Two recent books serve as examples: The Hidden Life of Trees and Finding the Mother Tree.
... The nutrient exchange mutualism between arbuscular mycorrhizal fungi (AMFs) and their host plants qualifies as a biological market [62,41,74,73]. ...
Fungal organisms can perceive the outer world in a way similar to what animals sense. Does that mean that they have full awareness of their environment and themselves? Is a fungus a conscious entity? In laboratory experiments we found that fungi produce patterns of electrical activity, similar to neurons. There are low and high frequency oscillations and convoys of spike trains. The neural-like electrical activity is yet another manifestation of the fungal intelligence. We discuss fungal cognitive capabilities and intelligence in evolutionary perspective, and question whether fungi are conscious and what does fungal consciousness mean, considering their exhibiting of complex behaviours, a wide spectrum of sensory abilities, learning, memory and decision making. We overview experimental evidences of consciousness found in fungi. Our conclusions allow us to give a positive answer to the important research questions of fungal cognition, intelligence and forms of consciousness.
... This network integration is ancient reaching back some 400 million years ago (Redecker 2000;Selosse et al. 2015;Remy et al. 1994;Field et al. 2015;Hoysted et al. 2018). In intact forests that are always under environmental stresses, there are huge supra-organismal root-fungal networks, which together are characterized as the root-wide-web (Simard 2018(Simard , 2021Baluška and Mancuso 2020;Sheldrake 2020). We argue that this further networked integration of individual supra-organismal root-fungal networks represents another prominent iteration of multicellular consciousness as supracellular supraorganismal consciousness. ...
A unique exploration of teleonomy—also known as “evolved purposiveness”—as a major influence in evolution by a broad range of specialists in biology and the philosophy of science.
The evolved purposiveness of living systems, termed “teleonomy” by chronobiologist Colin Pittendrigh, has been both a major outcome and causal factor in the history of life on Earth. Many theorists have appreciated this over the years, going back to Lamarck and even Darwin in the nineteenth century. In the mid-twentieth century, however, the complex, dynamic process of evolution was simplified into the one-way, bottom-up, single gene-centered paradigm widely known as the modern synthesis. In Evolution “On Purpose,” edited by Peter A. Corning, Stuart A. Kauffman, Denis Noble, James A. Shapiro, Richard I. Vane-Wright, and Addy Pross, some twenty theorists attempt to modify this reductive approach by exploring in depth the different ways in which living systems have themselves shaped the course of evolution.
Evolution “On Purpose” puts forward a more inclusive theoretical synthesis that goes far beyond the underlying principles and assumptions of the modern synthesis to accommodate work since the 1950s in molecular genetics, developmental biology, epigenetic inheritance, genomics, multilevel selection, niche construction, physiology, behavior, biosemiotics, chemical reaction theory, and other fields. In the view of the authors, active biological processes are responsible for the direction and the rate of evolution. Essays in this collection grapple with topics from the two-way “read-write” genome to cognition and decision-making in plants to the niche-construction activities of many organisms to the self-making evolution of humankind. As this collection compellingly shows, and as bacterial geneticist James Shapiro emphasizes, “The capacity of living organisms to alter their own heredity is undeniable.”
... Theory trees, each representing a unique strand of evaluative thinking, could be a part of a larger evaluation ecosystem that is characterized by interaction, interdependence, and integration. Theory trees could speak with and learn from each other just as real trees do in the forest ecosystem (Simard, 2018). Ultimately, a theory "tree" serves as an organizational framework for evaluation theories; such frameworks could be represented by many different symbols. ...
Scholars, practitioners, and activists have all contributed to the discussion of decolonization of evaluation practice in recent years as attention has increasingly focused on the persistent harms of colonization. While these discussions have led to the development of evaluation frameworks rooted in Indigenous and locally-situated understandings, values, and methods, little attention has been paid to the colonial origins of Western-based evaluation practices that continue to pervade the field. This article seeks to contribute to the conversation about decolonization by focusing on the ways in which Western social theory, born of colonizing nations, has been influenced by the processes of colonization. Drawing on scholars and theorists from the Global South, this article highlights specific apparatuses for dismantling imperial ways of thinking and ways of knowing, and proposes a path forward for evaluators who wish to grapple with the deeply imperial epistemological roots of our field of practice.
... Basidiomycetes, specifically, form extensive mycelial networks commonly covering several square meters (Dowson et al., 1988;Nara 2015) and over hundreds of hectares in some cases (Ferguson et al., 2003). Field and laboratory studies have suggested that mycelial networks have the potential to transport various materials between plants (Simard 2018). Understanding whether there is potential for ecological interactions through a fungal mycelial network is crucial for better comprehension and prediction of forest ecosystem's response to environmental change. ...
... The research results have also shown that the BFBF practice can increase soil fungi significantly over chemical fertilizers (CF) alone application practice in paddy cultivation . Simard (2018) has reported that the mycorrhizal networks facilitate forest tree communication, learning, and memory. Therefore, it is hypothesized that the increased soil fungi in the paddy ecosystem too could contribute to develop an in-soil mega mycorrhizal network, which may act as a mega-organism with intelligence that establishes an "ecosystem brain". ...
... The integrity of forests depends on a rich tapestry of biodiversity (Müller 2000;Watson et al. 2018), and the strength and complexity of the relationships between organisms confer resilience to forest ecosystems. Microscopic organisms or "microbiota" provide forest trees with nutrients and the ability to communicate via mycorrhizae (Simard 2018;Robinson et al. 2021aRobinson et al. , 2021b, and soil mesoand macrofauna contribute to soil formation and energy flows (Le Bayon et al. 2021). ...
Forest restoration requires monitoring to assess above-and belowground communities, which is challenging due to practical and resource limitations. Ecological acoustic survey methods-also known as "ecoacoustics"-are increasingly available and provide a rapid, effective, and non-intrusive means of monitoring biodiversity. Aboveground ecoacoustics is widespread, but soil ecoacoustics has yet to be utilized in restoration despite its demonstrable effectiveness at detecting soniferous soil meso-and macrofauna. This study applied ecoacoustic tools and indices (Acoustic Complexity Index, Normalized Difference Soundscape Index, and Bioacoustic Index) to measure belowground (and aboveground as secondary) biodiversity in a forest restoration site spanning two age classes. We collected n = 198 belowground acoustic samples and n = 180 aboveground samples from three recently deforested (felled <3 years ago) and three deciduous forest plots undergoing restoration (for the last 30-51 years) across three monthly visits in South Yorkshire, U.K. We used a belowground sampling device and sound-attenuation chamber to record soil communities and passive acoustic monitoring to record aboveground sounds. We found that restored plot acoustic complexity and diversity were significantly higher than deforested plots in the sound-attenuation chamber, but there were no inter-plot differences in in-situ soil or aboveground samples. We also found that restored plots had a significantly greater high-frequency to low-frequency ratio (suggesting higher biophony to anthrophony ratios) for in-situ and sound chamber soil but no association for aboveground samples. Our results suggest that ecoacoustics has immense potential to monitor belowground biodiversity, adding to the restoration ecologist's toolkit and supporting global ecosystem recovery.
... Communication also takes place underground, thanks to the interactions of roots with the mycelial networks of mycorrhizal fungi (Johnson & Gilbert, 2015;Simard, 2018;Simard et al., 2012). The symbiotic exchange of information between fungi and plant roots results in flexible and adaptive changes on the plant's side, including rapid changes in physiology, gene regulation, and defense responses (Gorzelak et al., 2015;Song et al., 2015). ...
... We have learned recently that trees literally communicate with one another, in a manner not entirely unlike that imagined by Tolkein (1954) in his descriptions of the slow-talking ents. Trees share information (Simard, 2018). I couldn't help but wonder what this fallen ash might be telling others in the woods about me. ...
The author explores the liberatory experience of improvised, woodland drumming as DIY music-making music and DIY learning in nature. A drummer and music education professor, he presents descriptive vignettes on the transformative possibilities of making music amongst trees and by water. The method is autoethnographic, itself a DIY type of doing and recording research. Using Tim Ingold's lens of correspondence, the author suggests that, more than making music merely on trees and on ice, we channel music together with non-human co-musicians. The author draws on research in eco-psychology and eco-literacy to suggest, more than indulgence, being and making music in nature might be foundational to humanity recovering respect for our world and taking seriously how we might continue to live in it. Moreover, this article explores music making as a DIY pedagogical practice, grounded in the depth of listening and engagement with nature.
... If Aulozoon were not a separate organism, eating or parasitizing Dickinsonia, perhaps it was an underground part of Dickinsonia like a fungal cord, rhizome or rhizomorph. Comparable mycelial rhizomorphs include modern bootlace fungi (Armillaria spp: Basidiomycota: Mihail & Bruhn, 2005;Lamour et al., 2007), cord-forming fungi (Pisolithus, Rhizopogon, Hypholoma: Basidiomycota; Dowson et al., 1986;Allen, 2007;Simard, 2018), mycorrhizal threads (Rhizophagus irregularis, Glomeromycota: Olsson et al., 2014), and lichen rhizines (Xanthoparmelia, Ascomycota; Paradise, 1997;Anzia, Ascomycota, Liang et al., 2012). Rhizomorphs can be up to 5 mm wide and formed of thickwalled hyphae, densely packed into an exterior sheath, but loosely packed in the interior (Motta, 1969;Ott et al., 1993;Sanders & Ascaso, 1997;Ascaso & Wierchos, 1995;Yafetto, 2018). ...
Aulozoon scoliorum is best known from a single large slab from the Nilpena Member of the Rawnsley Quartzite of South Australia, representing an Ediacaran paleocommunity, including Phyllozoon hanseni, Dickinsonia costata, Aspidella terranovica, Pseudorhizostomites howchini, and Somatohelix sinuosus. The source of this slab in Bathtub Gorge is the surface of a thick red sandstone with pseudomorphs of gypsum desert roses, which is interpreted as a Gypsid paleosol of the Muru pedotype. On this “snakes and ladders slab” (nicknamed for snake–like Aulozoon and ladder–like Phyllozoon), four specimens of Dickinsonia are poorly preserved above rounded terminations of Aulozoon. Aulozoon also has been discovered in five other thin sections cut below Dickinsonia basal surfaces, and in one case it is attached to Dickinsonia. Aulozoon has a high width to thickness ratio (14 ± 0.7), even after accounting for burial compaction. Burrows this much wider than high are unknown and would be mechanically difficult for a burrower. Stronger objections to a burrow interpretation come from taper of Aulozoon to half its width and local lateral crimping. Unlike deep sea tube worms, animal or algal stolons, Aulozoon is not cylindrical and lacks a finished inside wall outline. Outer finished wall grading inwards to sandstone fill of Aulozoon scoliorum is most like a fungal rhizomorph with loose internal hyphae, and this biological interpretation is supported by growth within a paleosol with desert roses. सारांश औलोज़ून स्कोलियोरम दक्षिण ऑस्ट्रेलिया के रॉन्सले क्वार्टजाइट के नीलपेना सदस्य से एक बड़े स्लैब से भलीभांति जाना जाता है और एक एडियाकरन पुरासमुदाय का प्रतिनिधित्व करता है, जिसमें फ़िलोज़ून हैंसेनी, डिकिन्सोनिया कोस्टाटा, एस्पिडेला टेरानोविका, स्यूडोरहिज़ोस्टोमाइट्स हाउचिनी और सोमाटोहेलिक्स सिनुओसस शामिल हैं। बाथटब गॉर्ज में इस स्लैब का स्रोत जिप्सम डिज़र्ट रोजेस के स्यूडोमोर्फ्स के साथ एक मोटे लाल बलुआ पत्थर की सतह है, जिसकी मुरु पेडोटाइप के जिप्सिड पेलियोसोल के रूप में व्याख्या की गई है। इस "साँप और सीढ़ी स्लैब" पर (साँप-जैसे औलोज़ून और सीढ़ी-जैसे फ़िलोज़ून के लिए उपनाम), डिकिन्सोनिया के चार नमूने औलोज़ून के गोल सिरे के ऊपर खराब रूप से संरक्षित हैं। औलोज़ून को पाँच अन्य थिन सेक्शन में भी खोजा गया है, डिकिन्सोनिया बेसल सतहों के नीचे, और एक मामले में यह डिकिन्सोनिया से जुड़ा हुआ है। संरक्षण संघनन के लिए लेखांकन के बाद भी औलोज़ून में मोटाई चौड़ाई का अनुपात (14± 0.7) अधिक है। ऊंचाई की तुलना में इतनी चौड़ी बर्रो अज्ञात हैं और बर्रो बनाने वाले के लिए यंत्रात्मक रूप से कठिन है। औलोज़ून के टेपर से इसकी आधी चौड़ाई और स्थानीय पार्श्व ऐंठन से एक बर्रो की व्याख्या के लिए प्रबल आपत्तियां हैं। गहरे समुद्र ट्यूब वर्म, जन्तु या शैवालीय स्टोलन के विपरीत, औलोज़ून बेलनाकार नहीं है, और आंतरिक भित्ति की पूर्ण रूपरेखा की कमी को दर्शाता है। औलोज़ून स्कोलियोरम के बलुआ पत्थर के अंदर की ओर बाहरी तैयार दीवार की ग्रेडिंग ढीले आंतरिक हायफी के साथ एक कवक राइज़ोमॉर्फ की तरह है, और यह जैविक व्याख्या एक पेलियोसोल के भीतर डिज़र्ट रोजेस के साथ वृद्धि द्वारा समर्थित है।
... In mycorrhizal symbioses, the fungi not only colonize plant roots but also maintain an extensive hyphal network which extend far beyond the roots and can further colonize the roots of neighboring plants of the same or different species to form common mycorrhizal networks (CMNs) (Simard, 2018). The fungal networks influence plant community and co-existence via mediation of nutrient transfer, transmission of plant allelochemicals, and thereby affect interactions between plant individuals and species (Cardini et al., 2021). ...
Cadmium (Cd) is one of the most perilous nonessential heavy metal for plants, owing to its high water solubility and obstruction with various physiological and biochemical processes. It enters food chain via plant uptake from contaminated soil, posing a grave menace to ecosystem and mankind. Green remediation comprises approaches intended at prudent use of natural resources for increasing profits to humans and environment. Arbuscular mycorrhizal (AM) fungi are considered a promising green technological tool for remedial of Cd-polluted soils. They are naturally associated with root system of plants in Cd-contaminated soils, evidencing their tolerance to Cd. AM can decrease Cd uptake by plants broadly through two strategies: (1) extracellular mechanisms involving Cd chelation by root exudates, binding to fungal cell wall/structures or to the glycoprotein glomalin; (2) intracellular means involving transfer via hyphal network, detoxification and vacuolar sequestration mediated by complexation of Cd with glutathione (GSH), phytochelatins (PCs), metallothioneins (MTs) and polyphosphate granules. Additionally, mycorrhizal symbiosis facilitates reconditioning of plants' metabolism primarily through dilution effect, increased water and mineral uptake. Recently, AM-induced remodelling of root cell wall synthesis has been reported to improve plant vigor and survival under Cd stressed environments. The present article highlights Cd impacts on AM growth, its diversity in Cd contaminated soils, and variations among diverse AM fungal species for imparting plant Cd tolerance. The most recent perspectives on AM-mediated Cd tolerance mechanisms in plants, including cellular and molecular studies have also been reviewed for successful utilization of these beneficial microbes in sustainable agriculture.
... The prioritization of certain nonhumans' rights over others (e.g., cattle over trees) has also created immense tensions between human stakeholders as ecosystems are frequently denied welfare, rights, and agency in the U.S., especially under the Trump Administration. Trees have demonstrated mycelium networks which contribute to learning and memory (Simard, 2018;Piñuela et al., 2021). Nimble policy frameworks must account for flora such as trees to be understood as living individuals with extensive movement and communication that extends throughout nearby habitat and greater ecosystems. ...
... Sin embargo, la asociación no es tan simple como parece, ya que el sistema suelo es un ambiente complejo. Por ejemplo, una planta puede formar AM con varios tipos de hongos y un hongo puede hacer simbiosis con muchas plantas, lo que vuelve muy complejas las posibles combinaciones (Simard, 2018). Además, se forman redes micorrízicas comunes (Common Mycorrhizal Networks), que son uniones del micelio con distintas plantas (Simard Figura 2: Los hongos ectomicorrízicos y su papel en la nutrición de las plantas. ...
Antecedentes y Objetivos:
Las micorrizas son asociaciones simbióticas entre los hongos micorrízicos y las raíces de las plantas. La planta intercambia fotosintetatos por nutrientes, que el hongo obtiene del suelo, como nitrógeno y fósforo. Las plantas micorrizadas son más resistentes a la infección por patógenos, toleran mejor el estrés, y además promueven la conservación del suelo. El objetivo de este trabajo fue revisar aspectos generales del manejo de la simbiosis micorrízica de especies nativas de México, con el fin de usarlas como una herramienta potencial para la recuperación de suelos.
Métodos:
Se realizó una revisión exhaustiva de 140 artículos publicados entre los años 1984 y 2019. Se seleccionaron trabajos realizados en México con especies nativas y con información sobre los diferentes métodos de inoculación, y aquellos con conceptos ecológicos importantes. Las bases de datos bibliográficos consultadas fueron Scopus, Web of Science, Crop Protection Compendium Database, Forest Science Database, PubMed y SciELO. Para la búsqueda se utilizaron las siguientes palabras clave: “mycorrhizae”, “endo and ectomycorrhizae”, “ectomycorrhizae and Pinus”, “ectomycorrhizae and Quercus”, “mycorrhizae inoculation”, “ectomycorrhiza and ecological restoration” y “ectomycorrhiza and Mexico”. También se revisaron protocolos de investigación, tesis o patentes relacionadas.
Resultados clave:
Los resultados del análisis de la literatura revisada se estructuraron y se discutieron en seis apartados, incluyendo características generales de la asociación micorrizica, métodos generales de inoculación, complejidad simbiótica, impactos de la micorrización en la restauración de bosques templados, aspectos importantes para el establecimiento de la simbiosis, ejemplos de la utilización de hongos ectomicorrizicos y micorrizas arbusculares en bosques templados.
Conclusiones:
La presente revisión subraya la importancia de ahondar en el conocimiento y el potencial que tienen las asociaciones micorrízicas para ser utilizadas en programas de rehabilitación, y/o recuperación ecológica de zonas templadas afectadas o deforestadas.
... Similar to bacteria and viruses for mammals, fungi are the most important plant pathogens worldwide [17,18] and represent an increasing threat to certain groups of animals, including amphibians [19][20][21]. Fungi are also invaluable components of soils and forests [22][23][24], and are currently emerging as important members of the human microbiome (i.e., mycobiome) [25][26][27]. Currently, our protocol for DNA extraction for high-throughput microbiome sequencing focuses on describing bacterial/ archaeal taxa, and has not yet been tested to additionally describe Fungi. ...
Microbial communities contain a broad phylogenetic diversity of organisms; however, the majority of methods center on describing bacteria and archaea. Fungi are important symbionts in many ecosystems and are potentially important members of the human microbiome, beyond those that can cause disease. To expand our analysis of microbial communities to include data from the fungal internal transcribed spacer (ITS) region, five candidate DNA extraction kits were compared against our standardized protocol for describing bacteria and archaea using 16S rRNA gene amplicon- and shotgun metagenomics sequencing. The results are presented considering a diverse panel of host-associated and environmental sample types and comparing the cost, processing time, well-to-well contamination, DNA yield, limit of detection and microbial community composition among protocols. Across all criteria, the MagMAX Microbiome kit was found to perform best. The PowerSoil Pro kit performed comparably but with increased cost per sample and overall processing time. The Zymo MagBead, NucleoMag Food and Norgen Stool kits were included.
... The prioritization of certain nonhumans' rights over others (e.g., cattle over trees) has also created immense tensions between human stakeholders as ecosystems are frequently denied welfare, rights, and agency in the U.S., especially under the Trump Administration. Trees have demonstrated mycelium networks which contribute to learning and memory (Simard, 2018;Piñuela et al., 2021). Nimble policy frameworks must account for flora such as trees to be understood as living individuals with extensive movement and communication that extends throughout nearby habitat and greater ecosystems. ...
Ecosystem governance is a highly contested issue where competing human stakeholder groups wield unequal power over nonhuman species. Pluralistic approaches to ecosystem governance consider a diversity of voices and disciplines to apply translational ecological knowledge to policy. However, the rights, agency, and welfare of nonhuman species – at the abstract (macro) and individual (micro) levels – are rarely considered, distancing nonhumans from human interests. This ‘othering’, results in nonhumans being treated as subservient to humans in power relations, which can result in poor welfare and even death. This study draws on multispecies ethnography, posthumanism, multispecies livelihoods, decolonial ecology, and translational ecology literature to critically review current paradigms in ecosystem governance and questions how to represent nonhumans equitably in ecosystem governance. This essay also considers qualitative data collected during 15 months of a multi-sited, multispecies ethnographic study that explored wolf-human (Canis lupus) relations in the western United States during the Trump Administration. A pluralistic posthumanist wildlife-human coexistence framework for translational ecology is presented that emphasizes nonhumans’ rights, welfare, and agency in ecosystem governance.
... Chemical cues can be conveyed through the mycorrhizal network, as can allelopathic substances ( mycorrhizal fungi may convey allelopathic compounds, whose negative effect may undo the benefit of the N supply (Barto et al., 2011;Gorzelak et al., 2015). The mycorrhizal network can be used by plants to transfer N compounds to a neighbour (He et al., 2019;Simard, 2018), which may be beneficial at least for one plant partner in the network (Figure 1, circle 3). Teste et al. (2015) showed that a plant can transfer up to 4% of its N to another plant through the mycorrhizal network. ...
The nitrogen (N) economics of plants are generally described in terms of functional traits and how these affect N availability in a given environment. However, recent studies have shown that plant symbionts play a crucial role in plant N economics. A plant together with its symbiont can be considered as a meta‐organism, the holobiont. Plant‐associated symbionts are shaped by the plant, thereby extending the plant's phenotype. Decomposers also play an important role in plant N economics, yet are usually not included in the plant holobiont.
In this review, we show the important roles that both symbionts and decomposers play in plant N economics. We focus on how plants respond to fluctuating N availability in a complex interaction network, which includes the plant's strategies and its interactions and feedback loops with the soil biota and with neighbouring plants, through competition for N by exploitation and interference.
Synthesis . Plant N economics and the outcome of plant–plant interactions in a community cannot be fully described solely through the functional traits of plant individuals. Properties emerging from the interaction network bring new insights into plant N economics. Further research is now needed to gain a deeper understanding of plant N economics and resource economics in plant communities by integrating a broader extended plant phenotype.
... Basidiomycetes, specifically, form extensive mycelial networks commonly covering several square meters (Dowson et al., 1988;Nara 2015) and over hundreds of hectares in some cases (Ferguson et al., 2003). Field and laboratory studies have suggested that mycelial networks have the potential to transport various materials between plants (Simard 2018). Understanding whether there is potential for ecological interactions through a fungal mycelial network is crucial for better comprehension and prediction of forest ecosystem's response to environmental change. ...
... Instead, what the designation 'that tree' may make possible is itself influenced by the deeper knowledge of the differences that make the apparent individuality of the tree possible. Simard (2016Simard ( , 2018 has shown how, for example, mycorrhizal networks are fundamental to the thriving of trees, to such an extent that making a stark distinction between roots and fungi is itself problematic and only useful inasmuch as it makes further probing possible (also see Sheldrake 2000). As Margulis and Sagan argue, "independence is a political, not a scientific, term" (2000, on mutualism, but it should be understood that it is only one part of symbiotic relations. ...
Available Open Access: https://www.openbookpublishers.com/product/1522
... Instead, what the designation 'that tree' may make possible is itself influenced by the deeper knowledge of the differences that make the apparent individuality of the tree possible. Simard (2016Simard ( , 2018 has shown how, for example, mycorrhizal networks are fundamental to the thriving of trees, to such an extent that making a stark distinction between roots and fungi is itself problematic and only useful inasmuch as it makes further probing possible (also see Sheldrake 2000). As Margulis and Sagan argue, "independence is a political, not a scientific, term" (2000, on mutualism, but it should be understood that it is only one part of symbiotic relations. ...
... The nutrient exchange mutualism between arbuscular mycorrhizal fungi (AMFs) and their host plants qualifies as a biological market [62,41,74,73]. ...
Fungal organisms can perceive the outer world in a way similar to what animals sense. Does that mean that they have full awareness of their environment and themselves? Is a fungus a conscious entity? In laboratory experiments we found that fungi produce patterns of electrical activity, similar to neurons. There are low and high frequency oscillations and convoys of spike trains. The neural-like electrical activity is yet another manifestation of the fungal intelligence. In this paper we discuss fungal cognitive capabilities and intelligence in evolutionary perspective, and question whether fungi are conscious and what does fungal consciousness mean, considering their exhibiting of complex behaviours, a wide spectrum of sensory abilities, learning, memory and decision making. We overview experimental evidences of consciousness found in fungi. Our conclusions allow us to give a positive answer to the important research questions of fungal cognition, intelligence and forms of consciousness.
... In return, fungi behave as skilled root extensions that explore and interact formidably with soil, nurturing and protecting their host. Furthermore, the exploring mycelium of the fungi can associate with several other trees simultaneously, enabling forest trees to physically link together and establish complex below-ground communication networks (Molina and Horton 2015;Simard 2018). In Pewen trees, studies have shown a high degree of mycorrhizal fungal colonization on their roots (Diehl and Despite that mycorrhizal networks in Pewen forests have not been explored in detail, the formation of a common mycelium that links trees within and between species has been reported for temperate forests elsewhere (Smith and Read 2010). ...
In this paper we present a new algorithm Continuous Mycorrhiza Optimization Algorithm (CMOA) inspired by the symbiosis of plant roots and the Mycorrhiza Network (MN). Mycorrhiza Networks are fungal hyphae (Ectomycorrhizae) that connect the roots of at least two plants, this type of networks is very important ecologically because they facilitate the transfer of resources between plants and improve the growth, survival, regeneration and colonization of forests. The transfer of resources between plants that may or may not be of the same species are carbon, nitrogen and other minerals, and the transfer from the plants to the MN would basically be carbon, and water from the MN to the plants. In addition, this equipment created by the plants and the MN has a defense system of biochemical signals that travel through the network to warn of possible disturbances such as wind, fire, logging, flooding, predators, pests, etc. To model this ecological environment, we used the Lotka-Volterra (LV) system of continuous equations: LV Predator–Prey Model, LV Cooperative Model and LV Competitive Model, certainly these LV models are represented in this ecosystem, we performed experiments with mathematical functions and checked their effectiveness comparing with other similar researches.KeywordsOptimizationMetaheuristicsLotka-Volterra
Cultural evolution is the theory of evolution by means of natural selection in the realm of culture. The development of cultural evolution over the last few decades has gained great importance. In this chapter, I analyze Jean Gayon’s critical analysis of what he calls the “modes” of cultural evolution (Gayon, 23:139–150, 2005). These “modes”, for Gayon, are sets of research programs inspired by the same paradigm; they take for granted the existence of a close relationship between biological and human social phenomena. In addition, each of these modes seeks to connect the biological, the social, and even the physical sciences. One of the main differences between these modes is the importance they give to biology in anthropology. Since cultural evolution has grown into a field of great importance today, reflecting on Gayon’s critical appraisal regarding the strengths and weaknesses of these modes takes on a particular relevance. In conclusion I put forward some of my own criticisms of the work of Gayon regarding his assessment of the modes of cultural evolution; I suggest that a new study carried out in the spirit of the one undertaken by Gayon in 2005 could make a major contribution to the development of CE theory.KeywordsCultural evolutionDarwinismEpidemiology of representationSociobiologyNaturalismEthologyAnthropology
The resource distribution strategies of trees and plants in the forest are applied here as inspiration for the development of a blueprint for transactive, hybrid solar and storage microgrids. We used the Biomimicry Institute’s Biomimicry Spiral and their toolbox as a design methodology to inform the structural and functional characteristics of this peer-to-peer microgrid energy market and propose its utility in addressing some of the challenges associated with grid integration of distributed energy resources (DERs). We reviewed literature from the ecological domain on mycorrhizal networks and biological market theory to extract key insights into the possible structure and function of a transactive energy market modeled after the mutualism between trees and mycorrhizae. Our process revealed insights into how overlapping, virtual energy markets might grow, contract, adapt, and evolve through a dynamic network-based protocol to compete and survive in rapidly changing environments. We conclude with a discussion of the promise and limitations involved in translating the derived conceptual blueprints into a cyber-physical system and its potential for deployment in the real world as a novel energy market infrastructure.
This report provides the first detailed assessment of old growth at New River Gorge National Park & Preserve and in southern West Virginia in general. Large-diameter (> 50 cm DBH) tree density and CWD volume were within the range of values reported for eastern old-growth forests (McGee, 2018), while tree age surpassed 300 years in some cases. The forest, however, is not characterized by the “pristine” conditions often ascribed to old growth. Fire and then fire exclusion, invasive pests and pathogens, and climate change have and will continue to collectively shape the future of this pre-industrial legacy forest. The results of this report can be used to inform resource management objectives as well as interpretive programming at New River Gorge National Park & Preserve.
Detey, S. (2023). Savons-nous vraiment parler ? Du contrat linguistique comme contrat social. Paris : Armand Colin. ISBN : 978-2-200-63634-0, 416 p.
Cet ouvrage explique pourquoi, à l’heure où chacun revendique le droit de dire publiquement tout et n’importe quoi, il nous faut ouvrir nos programmes scolaires et nos débats médiatiques à la question du langage, en lien avec l'éducation civique et scientifique, afin de rationaliser les effets des réseaux sociaux et de la rhétorique mondialisée.
https://www.dunod.com/lettres-et-arts/savons-nous-vraiment-parler-du-contrat-linguistique-comme-contrat-social
Voici en outre ci-dessous 13 questions, parmi d’autres, auxquelles vous chercherez des réponses dans cet ouvrage : merci d’inviter vos amis, vos réseaux ou vos étudiants à en prendre connaissance, et, pour ceux qui en ont les moyens, de les poser sur la table des personnes et des institutions concernées.
1. Pourquoi la distinction entre « bien parler » et « mal parler » peut-elle avoir du sens ou n’en avoir aucun ?
2. Pourquoi l’absence de distinction entre parole publique et parole privée peut-elle nous conduire au désastre ?
3. Pourquoi une vie médiatique sans violence verbale ni cyberharcèlement devrait-elle être possible ?
4. Pourquoi la langue peut-elle constituer un ultime outil d’égalité sociale et devrait par conséquent être préservée des luttes socio-idéologiques ?
5. Pourquoi le pouvoir des journalistes et des éditeurs devrait-il être politiquement réévalué ?
6. Pourquoi des cours de phonétique devraient-ils aider à combattre le racisme et favoriser l’intégration ?
7. Pourquoi les cours de langue maternelle et de langue étrangère devraient-ils être menés en partie conjointement, en particulier dans le traitement de la liberté d’expression ?
8. Pourquoi faut-il des cours obligatoires de linguistique du primaire au supérieur, en lien avec l’éducation civique, scientifique, historique et sexuelle ?
9. Pourquoi l’éducation à la parole concerne-t-elle tout aussi bien les ministères de l’Education nationale et du Numérique que ceux de l’Intérieur, de la Justice, des Affaires étrangères et des Affaires Sociales ?
10. Pourquoi faut-il repenser un Ministère de l’information et de la communication respectueux de la démocratie du XXIe siècle, dont une des missions serait de mettre sur pied un séjour à l’étranger obligatoire pour tous les jeunes de 18 ans ?
11. Pourquoi les outils de traduction automatique risquent-ils de perpétuer l’illusion de la communication internationale ?
12. Pourquoi nos enfants devraient-ils mieux parler que nous ?
13. Pourquoi cet ouvrage s’adresse-t-il aussi bien aux enseignants, aux étudiants, aux stars des médias, aux journalistes et aux grands acteurs de la vie sociale et économique qu’aux citoyens lambdas qui aspirent à un monde meilleur ?
Et sur la base de ces 13 « Pourquoi » se dessinent des « Comment » …
L’ouvrage peut servir de manuel d’introduction à la communication pour tous les cursus, en lettres, en sciences, en SHS et en formation professionnelle.
Sommaire
Parler, une évidence ?
1. La communication : un handicap pour tous.
2. Être reconnu dans le monde : parler bien, parler fort ou parler peu ?
3. La norme : devons-nous tous parler de la même manière ?
4. La variation : pouvons-nous échapper à notre manière de parler ?
5. Du monolingue au polyglotte : apprendre au moins deux langues étrangères
6. Locuteur natif ou locuteur expert ? Devenir professeur de sa propre langue
7. Plurilinguisme et gestion de l’incertitude communicative : mondialisation de l’information et liberté d’expression
8. Du contrat linguistique comme il en est du contrat social : quelles perspectives éducatives ?
9. La communication de l’avenir passera-t-elle encore par la parole ?
Handicap communicatif, contrat linguistique et communication empathique
Annexes : Les dix-huit commandements linguistiques moralisateurs. Pourquoi légiférer sur la parole n’est pas tâche aisée. Vous, comment parlez-vous ?
Références
Présentation éditeur
Nous perdons un temps fou à ne pas être d’accord. Contrairement à ce que l’on imagine, nous ne nous comprenons pas – ou du moins pas suffisamment.
« Parlons plus pour mieux nous comprendre ! », entonnera-t-on. Et pourtant, il suffit de pratiquer une langue étrangère pour que la difficulté de comprendre et d’être compris nous assaille et nous éveille. Par effet retour, on prend la mesure de l’illusion dans laquelle nous bercent les langues que nous pensons maîtriser, à commencer par notre langue maternelle.
Plutôt que de parler plus, n’est-il pas temps de parler moins et de parler mieux, ou différemment ? Mais il en est du contrat linguistique comme du contrat social, du « savoir-parler » comme du savoir-vivre. Et pour savoir parler, les mots et les règles de grammaire ne suffisent pas. Tout particulièrement à l’heure d’internet et de la communication mondialisée, dans laquelle les frontières entre communication privée et publique d’une part, et nationale et internationale d’autre part, sont devenues dangereusement poreuses. Il est donc temps de reprendre le contrôle de nos comportements communicatifs, comme nous l’avons fait à chaque fois que l’innovation technologique nous a permis d’accroitre nos libertés et nos pouvoirs individuels, aujourd’hui internet et réseaux sociaux.
The continuity of life and its evolution, we proposed, emerge from an interactive group process manifested in networks of interaction. We term this process survival of the fitted. Here, we reason that survival of the fitted results from a natural computational process we term natural autoencoding. Natural autoencoding works by retaining repeating biological interactions while non-repeatable interactions disappear. (i) We define a species by its species interaction code, which consists of a compact description of the repeating interactions of species organisms with their external and internal environments. Species interaction codes are descriptions recorded in the biological infrastructure that enables repeating interactions. Encoding and decoding are interwoven. (ii) Evolution proceeds by natural autoencoding of sustained changes in species interaction codes. DNA is only one element in natural autoencoding. (iii) Natural autoencoding accounts for the paradox of genome randomization in sexual reproduction-recombined genomes are analogous to the diversified inputs required for artificial autoencoding. The increase in entropy generated by genome randomization compensates for the decrease in entropy generated by organized life. (iv) Natural autoencoding and artificial autoencoding algorithms manifest defined similarities and differences. Recognition of the importance of fittedness could well serve the future of a humanly livable biosphere.
A common mycorrhizal network (CMN) is formed when mycorrhizal fungal hyphae connect the roots of multiple plants of the same or different species belowground. Recently, CMNs have captured the interest of broad audiences, especially with respect to forest function and management. We are concerned, however, that recent claims in the popular media about CMNs in forests are disconnected from evidence, and that bias towards citing positive effects of CMNs has developed in the scientific literature. We first evaluated the evidence supporting three common claims. The claims that CMNs are widespread in forests and that resources are transferred through CMNs to increase seedling performance are insufficiently supported because results from field studies vary too widely, have alternative explanations or are too limited to support generalizations. The claim that mature trees preferentially send resources and defence signals to offspring through CMNs has no peer-reviewed, published evidence. We next examined how the results from CMN research are cited and found that unsupported claims have doubled in the past 25 years; a bias towards citing positive effects may obscure our understanding of the structure and function of CMNs in forests. We conclude that knowledge on CMNs is presently too sparse and unsettled to inform forest management. In this Perspective, Karst et al. discuss how both the popular media and scientific literature have inflated the extent of evidence for various roles of mycorrhizal fungal networks in forests.
Microbiome-Inspired Green Infrastructure (MIGI) was recently proposed as an integrative system to promote healthy urban ecosystems through multidisciplinary design. Specifically, MIGI is defined as nature-centric infrastructure restored, designed, and managed to enhance health-promoting interactions between humans and environmental microbiomes while sustaining microbially mediated ecosystem functionality and resilience. MIGI also aims to stimulate a research agenda that focuses on considerations for the importance of urban environmental microbiomes.
In this article, we provide details of what MIGI entails from a bioscience and biodesign perspective, highlighting the potential dual benefits for human and ecosystem health. We present ‘what is known’ about the relationship between urban microbiomes, green infrastructure, and environmental factors that may affect urban ecosystem health - taken here to mean ecosystem functionality and resilience, as well as human health. We discuss how to start operationalising the MIGI concept based on current available knowledge and present a horizon-scan of emerging and future considerations in research and practice.
We conclude by highlighting challenges to implementing MIGI and propose a series of workshops to discuss multi-stakeholder needs and opportunities. This research will enable urban landscape managers to incorporate initial considerations for the microbiome in their development projects to promote human and ecosystem health. However, overcoming the challenges to operationalising MIGI will be essential to furthering its practical development. Although the research is in its infancy, there is considerable potential for MIGI to help deliver sustainable urban development driven by considerations for reciprocal relations between humans and the foundations of our ecosystems – the microorganisms.
This article charts the contiguity of farming and film, blending permaculture and cinema to advance a modality of sustainable film theory and practice we call “permacinema.” As an alternative approach to looking and labour, permaculture exhibits a suite of cinematic concerns, and offers a model for cinematic creativity that is environmentally accountable and sensitive to multispecies entanglements. Through the peaceable gestures of cultivation and restraint, permacinema proposes an ecologically attentive philosophy of moving images in accordance with permaculture’s three ethics: care of earth, care of people, and fair share. We focus on work by Indigenous artists in which plants are encountered not only as raw material or as aesthetic resource but as ingenious agents and insightful teachers whose pedagogical and creative inputs are welcomed into the filmmaking process. By integrating Indigenous epistemologies and cosmologies we hope to situate permacinema in the wider project of cinema’s decolonization and rewilding.
Microorganisms associated with plants provide essential functions to their hosts, and therefore affect ecosystem productivity. Agricultural intensification has modified microbial diversity in the soil reservoir and may affect plant microbial recruitment. Weeds develop spontaneously in crop fields, and could influence microorganisms associated with crop plants through a neighbourhood effect. We explore the effect of weed species on crop plant microbiota as potentially auxiliary plants that affect agricultural productivity. We combined field and controlled laboratory studies to analyse the neighbourhood effect of weeds on wheat root endospheric mycobiota (i.e. fungi within roots) and growth. First, we analysed the effect of weed species diversity and identity recorded in the neighbourhood of individual wheat plants on soil and wheat root mycobiota in the field. Second, we used a plant‐matrix design in laboratory conditions to test the effect of weed identity (9 weed treatments) and their ability to transmit root mycobiota to wheat roots, and the resulting impact on wheat growth. In contrast to soil mycobiota, we demonstrated that wheat root endospheric mycobiota was influenced by the diversity and identity of weeds developing in their 1 m2 neighbourhood. Wheat root endospheric microbiota strongly differs in terms of richness and composition depending on the neighbouring weed plant species. Weed species transmitted from 13% to 74% of their root microbiota to wheat roots depending on weed identity in controlled conditions. Synthesis. Weed neighbours modified wheat plant performance, possibly as a result of competitive interactions and changes in microbiota. Our findings suggest that crop root mycobiota was variable and was modulated by their weed neighbourhood. Synergistic effects between mycobiota of crops and weeds could therefore contribute to soil biodiversity and sustainable agriculture.
This white paper lays out a vision of research and development in the field of artificial intelligence for the next decade (and beyond). Its denouement is a cyber-physical ecosystem of natural and synthetic sense-making, in which humans are integral participants$\unicode{x2014}$what we call ''shared intelligence''. This vision is premised on active inference, a formulation of adaptive behavior that can be read as a physics of intelligence, and which inherits from the physics of self-organization. In this context, we understand intelligence as the capacity to accumulate evidence for a generative model of one's sensed world$\unicode{x2014}$also known as self-evidencing. Formally, this corresponds to maximizing (Bayesian) model evidence, via belief updating over several scales: i.e., inference, learning, and model selection. Operationally, this self-evidencing can be realized via (variational) message passing or belief propagation on a factor graph. Crucially, active inference foregrounds an existential imperative of intelligent systems; namely, curiosity or the resolution of uncertainty. This same imperative underwrites belief sharing in ensembles of agents, in which certain aspects (i.e., factors) of each agent's generative world model provide a common ground or frame of reference. Active inference plays a foundational role in this ecology of belief sharing$\unicode{x2014}$leading to a formal account of collective intelligence that rests on shared narratives and goals. We also consider the kinds of communication protocols that must be developed to enable such an ecosystem of intelligences and motivate the development of a shared hyper-spatial modeling language and transaction protocol, as a first$\unicode{x2014}$and key$\unicode{x2014}$step towards such an ecology.
Recent decades have seen an intensification of scholarship on wellbeing. Looking ahead, the next frontier may be engaging with the possibility of non-human forms of wellbeing. This paper reviews the main candidates for what these forms may be, limiting its considerations to entities that are living and capable of conscious experience. However, what makes this topic so complex and fascinating is that what exactly constitutes life or conscious experience is not self-evident. Thus, this paper considers various potential life forms, which vary in the extent to which they challenge standard conceptions of life, including organic life forms on earth, matter, AI, and extra-terrestrial life. Some possibilities are unlikelier and more speculative than others, but all have at least a non-zero probability, so merit at least some consideration and attention. Moreover, the paper articulates why these possibilities have considerable relevance for human wellbeing, and so warrant the attention of wellbeing scholars.
As humans, we use the power of thinking to make scientific discoveries, develop technologies, manage social interactions, and transmit knowledge to the next generations. With the ability to think, we can trace back and discover the origin of the universe, the natural world, and ourselves. The content of this book, Mindsponge Theory, is part of that discovery process.This document is an excerpt from the book titled Mindsponge Theory, offering a sneak peek into this emerging theoretical development of the humanities and social sciences research realm.
© 2022 by Quan-Hoang Vuong
All Rights Reserved
Title: Mindsponge Theory
Book manuscript version 13
Date of this version: September 2, 2022
This Element follows the development of humans in constantly changing climates and environments from Homo erectus 1.9 million years ago, to fully modern humans who moved out of Africa to Europe and Asia 70,000 years ago. Biosemiotics reveals meaningful communication among coevolving members of the intricately connected life forms on this dynamic planet. Within this web hominins developed culture from bipedalism and meat-eating to the use of fire, stone tools, and clothing, allowing wide migrations and adaptations. Archaeology and ancient DNA analysis show how fully modern humans overlapped with Neanderthals and Denisovans before emerging as the sole survivors of the genus Homo 35,000 years ago. Their visions of the world appear in magnificent cave paintings and bone sculptures of animals, then more recently in written narratives like the Gilgamesh epic and Euripides' Bacchae whose images still haunt us with anxieties about human efforts to control the natural world.
Science fiction (SF), through its various generic conventions, provides a stage for exploring many dimensions of the Anthropocene: It enables challenges to time, to species, to causalities, to space-time coherences, and also to singularity. Tade Thompson’s- Wormwood trilogy engages several non-linear metaphors in engendering a nonhuman other, most specifically internet networks and fungi becoming. The alien sentience rendered in the trilogy offers an – amorphous and yet simultaneously very concrete – other against which humans must rally, themselves at the brink of the threat of extinction. Wormwood’s xenosphere – an atmosphere permeated with ›xenoforms‹, a kind of alien fungi which can interact with humans – constitutes only one of the many ways in which this SF world challenges the modes with which we organise our knowledges of our world.
Background: Microbiome-Inspired Green Infrastructure (MIGI) was recently proposed as an integrative system to promote healthy urban ecosystems, through multidisciplinary design. Specifically, MIGI is defined as nature-centric infrastructure restored and/or designed and managed to enhance health-promoting interactions between humans and environmental microbiomes, whilst sustaining microbially-mediated ecosystem functionality and resilience. MIGI also aims to stimulate a research agenda that focuses on considerations for the importance of urban environmental microbiomes. Objectives: In this paper we provide details of what MIGI entails from a bioscience and biodesign perspective, highlighting the potential dual benefits for human and ecosystem health. We present ‘what is known’ about the relationship between urban microbiomes, green infrastructure and environmental factors that may affect urban ecosystem health (ecosystem functionality and resilience as well as human health). We discuss how to start operationalising the MIGI concept based on current available knowledge, and present a horizon scan of emerging and future considerations in research and practice. We conclude by highlighting challenges to the implementation of MIGI and propose a series of workshops to discuss multi-stakeholder needs and opportunities. Discussion: This article will enable urban landscape managers to incorporate initial considerations for the microbiome in their development projects to promote human and ecosystem health. However, overcoming the challenges to operationalising MIGI will be essential to furthering its practical development. Although the research is in its infancy, there is considerable potential for MIGI to help deliver sustainable urban development driven by considerations for reciprocal relations between humans and the foundations of our ecosystems –– the microorganisms.
An enduring aim of research in the psychological and brain sciences is to understand the nature of individual differences in human intelligence, examining the stunning breadth and diversity of intellectual abilities and the remarkable neurobiological mechanisms from which they arise. In this Opinion article, we survey recent neuroscience evidence to elucidate how general intelligence (g) emerges from individual differences in the network architecture of the human brain. The reviewed findings motivate new insights about how network topology and dynamics account for individual differences in g, represented by the Network Neuroscience Theory. According to this framework, g emerges from the small-world topology of brain networks and the dynamic reorganization of its community structure in the service of system-wide flexibility and adaptation.
Sound and its use in communication have significantly contributed to shaping the ecology, evolution, behavior, and ultimately
the success of many animal species. Yet, the ability to use sound is not a prerogative of animals. Plants may also use sound,
but we have been unable to effectively research what the ecological and evolutionary implications might be in a plant’s life.
Why should plants emit and receive sound and is there information contained in those sounds? I hypothesize that it would be
particularly advantageous for plants to learn about the surrounding environment using sound, as acoustic signals propagate
rapidly and with minimal energetic or fitness costs. In fact, both emission and detection of sound may have adaptive value
in plants by affecting responses in other organisms, plants, and animals alike. The systematic exploration of the functional,
ecological, and evolutionary significance of sound in the life of plants is expected to prompt a reinterpretation of our understanding
of these organisms and galvanize the emergence of novel concepts and perspectives on their communicative complexity.
Processes governing the fixation, partitioning, and mineralization of carbon in soils are under increasing scrutiny as we develop a more comprehensive understanding of global carbon cycling. Here we examined fixation by Douglas‐fir seedlings and transfer to associated ectomycorrhizal fungi, soil microbes, and full‐sibling or nonsibling neighbouring seedlings.
Stable isotope probing with 99% ¹³ C‐ CO 2 was applied to trace ¹³ C‐labelled photosynthate throughout plants, fungi, and soil microbes in an experiment designed to assess the effect of relatedness on ¹³ C transfer between plant pairs. The fixation and transfer of the ¹³ C label to plant, fungal, and soil microbial tissue was examined in biomass and phospholipid fatty acids.
After a 6 d chase period, c . 26.8% of the ¹³ C remaining in the system was translocated below ground. Enrichment was proportionally greatest in ectomycorrhizal biomass. The presence of mesh barriers (0.5 or 35 μm) between seedlings did not restrict ¹³ C transfer.
Fungi were the primary recipients of ¹³ C‐labelled photosynthate throughout the system, representing 60–70% of total ¹³ C‐enriched phospholipids. Full‐sibling pairs exhibited significantly greater ¹³ C transfer to recipient roots in two of four Douglas‐fir families, representing three‐ and fourfold increases (+ c . 4 μg excess ¹³ C) compared with nonsibling pairs. The existence of a root/mycorrhizal exudation–hyphal uptake pathway was supported.
The establishment of common mycelial networks by mycorrhizal fungi shared between host plants depends on the ability of neighboring plants to enter into mycorrhizal associations with compatible fungal species. Such compatibility is governed by the potential mycorrhiza specificities of the symbionts. Mycorrhiza specificities exist along a continuum from low specificity (association with multiple partners) to high specificity (association with one or few partners). Although the ability of symbionts to form mycorrhizas may be largely governed by host-fungus gene interactions as influenced by co-evolutionary events, mycorrhizal associations in natural ecosystems can also be influenced by environmental factors (e.g. soil) and biological factors (e.g. different neighboring host species), phenomena referred to as “ecological specificity.” For example, in natural settings, mycorrhizal fungi often express “host preference” wherein fungi may be more common on a particular host in mixed-host settings than would be expected by random species assemblage within the fungal and plant communities. Mycorrhiza specificity phenomena significantly influence plant community dynamics, particularly plant succession. Early seral plants can positively affect the establishment of later-seral plants by maintaining commonly shared mycorrhizal fungi, and thus affecting the function of common mycelial networks over time. Such knowledge provides guidance for ecosystem managers to maintain “legacy” early -seral plants that benefit later-seral plants via shared mycorrhizal fungus species. Understanding specificity phenomena is also crucial for predicting the successful migration of plants and compatible mycorrhizal fungi during climate change. We review mycorrhiza specificity terminology and types of specificity phenomena, and suggest use of common terms to provide consistency in addressing this research topic. We also provide extensive examples from diverse ecosystems on the ability (or inability) of neighboring plants to develop common mycelial networks.
Almost all higher organisms, including plants, insects, and mammals, are colonized by complex microbial communities and harbor a microbiome. Emerging studies with plants reveal that these microbiomes are structured and form complex, interconnected microbial networks. Within these networks, different taxa have different roles, and keystone species have been identified that could be crucial for plant health and ecosystem functioning. A new paper in this issue of PLOS Biology by Agler et al. highlights the presence of microbial hubs in these networks that may act as mediators between the plant and its microbiome. A next major frontier is now to link microbiome composition to function. In order to do this, we present a number of hypothetical examples of how microbiome diversity and function potentially influence host performance.
Language is often considered a key feature of being human, and human linguistic behavior has been adopted as the universal template for studying the nature of language and its evolution. Yet it is not always clear what ''language'' actually is, and the lack of definition calls into question the notion that human language is unique because it has no equivalent in any nonhuman species. We ask whether the use of language is truly an activity, a form of behavior, which makes us so unique and unlike other species. We tackle this question by examining language from an ecological perspective and then considering language from a wider biological viewpoint, one that enables us to explore language as a meaning-making activity at the core of every form of life, including plants. We examine how innovative philosophical thinking and scientific research similarly call into question the current limits of language in describing the botanical world and human-plant dynamics. By providing an overview of the most recent empirically grounded advances in our understanding of the ''language'' of others, and particularly plants, we propose that the nonhuman world is not lacking in language the way we think it is. Ultimately, the overall aim is to invite the emergence of a new truly interdisciplinary dialogue to inspire novel approaches in further philosophical and scientific investigations, where language and its power are re-focused toward conceptualizing a more integrated perception of the world.
Adaptive behavior of plants, including rapid changes in physiology, gene regulation and defense response can be altered when linked to neighbouring plants by a mycorrhizal network. Mechanisms underlying the behavioral changes include mycorrhizal fungal colonization by the mycorrhizal network or interplant communication via transfer of nutrients, defense signals or allelochemicals. We focus this review on our new findings in ectomycorrhizal ecosystems, but also review recent advances in arbuscular mycorrhizal systems. We have found that the behavioral changes in ectomycorrhizal plants can depend on environmental cues, the identity of the plant neighbor and the characteristics of the mycorrhizal network. The hierarchical integration of this phenomenon with other biological networks at broader scales in forest ecosystems, and the consequences we have observed when it is interrupted, indicates that underground 'tree talk' is a foundational process in the complex adaptive nature of forest ecosystems.
Published by Oxford University Press on behalf of the Annals of Botany Company.
Arbuscular mycorrhizal (AM) fungi are mutualistic symbionts living in the roots of 80% of land plant species, and developing extensive, belowground extraradical hyphae fundamental for the uptake of soil nutrients and their transfer to host plants. Since AM fungi have a wide host range, they are able to colonize and interconnect contiguous plants by means of hyphae extending from one root system to another. Such hyphae may fuse due to the widespread occurrence of anastomoses, whose formation depends on a highly regulated mechanism of self recognition. Here, we examine evidences of self recognition and nonself incompatibility in hyphal networks formed by AM fungi and discuss recent results showing that the root systems of plants belonging to different species, genera and families may be connected by means of anastomosis formation between extraradical mycorrhizal networks, which can create indefinitely large numbers of belowground fungal linkages within plant communities.
Extensive regions of interior Douglas-fir (Pseudotsuga menziesii var. glauca, IDF) forests in North America are being damaged by drought and western spruce budworm (Choristoneura occidentalis). This damage is resulting from warmer and drier summers associated with climate change. To test whether defoliated IDF can directly transfer resources to ponderosa pine (Pinus ponderosae) regenerating nearby, thus aiding in forest recovery, we examined photosynthetic carbon transfer and defense enzyme response. We grew pairs of ectomycorrhizal IDF 'donor' and ponderosa pine 'receiver' seedlings in pots and isolated transfer pathways by comparing 35 μm, 0.5 μm and no mesh treatments; we then stressed IDF donors either through manual defoliation or infestation by the budworm. We found that manual defoliation of IDF donors led to transfer of photosynthetic carbon to neighboring receivers through mycorrhizal networks, but not through soil or root pathways. Both manual and insect defoliation of donors led to increased activity of peroxidase, polyphenol oxidase and superoxide dismutase in the ponderosa pine receivers, via a mechanism primarily dependent on the mycorrhizal network. These findings indicate that IDF can transfer resources and stress signals to interspecific neighbors, suggesting ectomycorrhizal networks can serve as agents of interspecific communication facilitating recovery and succession of forests after disturbance.
From the phytocentric perspective, a mycorrhizal network ( MN ) is formed when the roots of two or more plants are colonized by the same fungal genet. MN s can be modelled as interaction networks with plants as nodes and fungal genets as links. The potential effects of MN s on facilitation or competition between plants are increasingly recognized, but their network topologies remain largely unknown. This information is needed to understand the ecological significance of MN functional traits.
The objectives of this study were to describe the interaction network topologies of MN s formed between two ectomycorrhizal fungal species, Rhizopogon vesiculosus and R. vinicolor , and interior Douglas‐fir trees at the forest stand scale, identify factors leading to this structure and to contrast MN structures between forest plots with xeric versus mesic soil moisture regimes.
Tuberculate mycorrhizas were sampled in six 10 × 10 m plots with either xeric or mesic soil moisture regimes. Microsatellite DNA markers were used to identify tree and fungal genotypes isolated from mycorrhizas and for comparison with reference tree boles above‐ground.
In all six plots, trees and fungal genets were highly interconnected. Size asymmetries between different tree cohorts led to non‐random MN topologies, while differences in size and connectivity between Rhizopogon species‐specific subnetwork components contributed towards MN nestedness. Large mature trees acted as network hubs with a significantly higher node degree compared to smaller trees. MN s representing trees linked by R. vinicolor genets were mostly nested within larger, more highly connected R. vesiculosus ‐linked MN s.
Attributes of network nodes showed that hub trees were more important to MN topology on xeric than mesic sites, but the emergent structures of MN s were similar in the two soil moisture regimes.
Synthesis . This study suggests MN s formed between interior Douglas‐fir trees and R. vesiculosus and R. vinicolor genets are resilient to the random loss of participants, and to soil water stress, but may be susceptible to the loss of large trees or fungal genets. Our results regarding the topology of MN s contribute to the understanding of forest stand dynamics and the resilience of forests to stress or disturbance.
The most common system responses attributed to microfloral grazers (protozoa, nematodes, microarthropods) in the literature are increased plant growth, increased N uptake by plants, decreased or increased bacterial populations, increased CO"2 evolution, increased N and P mineralization, and increased substrate utilization. Based on this evidence in the literature, a conceptual model was proposed in which microfloral grazers were considered as separate state variables. To help evaluate the model, the effects of microbivorous nematodes on microbial growth, nutrient cycling, plant growth, and nutrient uptake were examined with reference to activities within and outside of the rhizosphere. Blue grama grass (Bouteloua gracilis) was grown in gnotobiotic microcosms containing sandy loam soil low in inorganic N, with or without chitin amendments as a source of organic N. The soil was inoculated with bacteria (Pseudomonas paucimobilis or P. stutzeri) or fungus (Fusarium oxysporum), with half the bacterial microcosms inoculated with bacterial-feeding nematodes (Pelodera sp. or Acrobeloides sp.) and half the fungal microcosms inoculated with fungal-feeding nematodes (Aphelenchus avenae). Similar results were obtained from both the unamended and the chitin-amended experiments. Bacteria, fungi, and both trophic groups of nematodes were more abundant in the rhizosphere than in nonrhizosphere soil. All treatments containing nematodes and bacteria had higher bacterial densities than similar treatments without nematodes. Plants growing in soil with bacteria and bacterial-feeding nematodes grew faster and initially took up more N than plants in soil with only bacteria, because of increased N mineralization by bacteria, NH"4^+-N excretion by nematodes, and greater initial exploitation of soil by plant roots. Addition of fungal-feeding nematodes did not increase plant growth or N uptake because these nematodes excreted less NH"4^+-N than did bacterial-feeding nematode populations and because the N mineralized by the fungus alone was sufficient for plant growth. Total shoot P was significantly greater in treatments with fungus or Pelodera sp. than in the sterile plant control or treatments with plants plus Pseudomonas stutzeri until the end of the experiment. The additional mineralization that occurs due to the activities of microbial grazers may be significant for increasing plant growth only when mineralization by microflora alone is insufficient to meet the plants' requirements. However, while the advantage of increased N mineralization by microbial grazers may be short-term, it may occur in many ecosystems in those short periods of ideal conditions when plant growth can occur. Thus, these results support other claims in the literature that microbial grazers may perform important regulatory functions at critical times in the growth of plants.
I. II. III. IV. V. VI. References SUMMARY: For survival, plants have to efficiently adjust their phenotype to environmental challenges, finely coordinating their responses to balance growth and defence. Such phenotypic plasticity can be modulated by their associated microbiota. The widespread mycorrhizal symbioses modify plant responses to external stimuli, generally improving the resilience of the symbiotic system to environmental stresses. Phytohormones, central regulators of plant development and immunity, are instrumental in orchestrating plant responses to the fluctuating environment, but also in the regulation of mycorrhizal symbioses. Exciting advances in the molecular regulation of phytohormone signalling are providing mechanistic insights into how plants coordinate their responses to environmental cues and mycorrhizal functioning. Here, we summarize how these mechanisms permit the fine-tuning of the symbiosis according to the ever-changing environment.
© 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
It is increasingly recognised that plants are highly sensitive organisms that perceive, assess, learn, remember, resolve problems, make decisions and communicate with each other by actively acquiring information from their environment. However, the fact that many of the sophisticated behaviours plants exhibit reveal cognitive competences, which are generally attributed to humans and some non-human animals has remained unappreciated. Here, I will outline the theoretical barriers that have precluded the opportunity to experimentally test such behavioural/cognitive phenomena in plants. I will then suggest concrete alternative approaches to cognition by highlighting how (1) the environment offers a multitude of opportunities for decision-making and action and makes behaviours possible, rather than causing them; (2) perception in itself is action in the form of a continuous flow of information; (3) all living organisms viewed within this context become agents endowed with autonomy rather than objects in a mechanistically conceived world. These viewpoints, combined with recent evidence, may contribute to move the entire field towards an integrated study of cognitive biology.
Published by Oxford University Press on behalf of the Annals of Botany Company.
Plant-mycorrhizal fungal interactions are ubiquitous in forest ecosystems. While ectomycorrhizal plants and their fungi generally dominate temperate forests, arbuscular mycorrhizal symbiosis is common in the tropics. In subtropical regions, however, ectomycorrhizal and arbuscular mycorrhizal plants co-occur at comparable abundances in single forests, presumably generating complex community structures of root-associated fungi. To reveal root-associated fungal community structure in a mixed forest of ectomycorrhizal and arbuscular mycorrhizal plants, we conducted a massively-parallel pyrosequencing analysis, targeting fungi in the roots of 36 plant species that co-occur in a subtropical forest. In total, 580 fungal operational taxonomic units were detected, of which 132 and 58 were probably ectomycorrhizal and arbuscular mycorrhizal, respectively. As expected, the composition of fungal symbionts differed between fagaceous (ectomycorrhizal) and non-fagaceous (possibly arbuscular mycorrhizal) plants. However, non-fagaceous plants were associated with not only arbuscular mycorrhizal fungi but also several clades of ectomycorrhizal (e.g., Russula) and root-endophytic ascomycete fungi. Many of the ectomycorrhizal and root-endophytic fungi were detected from both fagaceous and non-fagaceous plants in the community. Interestingly, ectomycorrhizal and arbuscular mycorrhizal fungi were concurrently detected from tiny root fragments of non-fagaceous plants. The plant-fungal associations in the forest were spatially structured, and non-fagaceous plant roots hosted ectomycorrhizal fungi more often in the proximity of ectomycorrhizal plant roots. Overall, this study suggests that belowground plant-fungal symbiosis in subtropical forests is complex in that it includes "non-typical" plant-fungal combinations (e.g., ectomycorrhizal fungi on possibly arbuscular mycorrhizal plants) that do not fall within the conventional classification of mycorrhizal symbioses, and in that associations with multiple functional (or phylogenetic) groups of fungi are ubiquitous among plants. Moreover, ectomycorrhizal fungal symbionts of fagaceous plants may "invade" the roots of neighboring non-fagaceous plants, potentially influencing the interactions between non-fagaceous plants and their arbuscular-mycorrhizal fungal symbionts at a fine spatial scale.
Mycelial fungi grow as indeterminate adaptive networks that have to forage for scarce resources in a patchy and unpredictable environment under constant onslaught from mycophagous animals. Development of contrast-independent network extraction algorithms has dramatically improved our ability to characterise these dynamic macroscopic networks and promises to bridge the gap between experiments in realistic experimental microcosms and graph-theoretic network analysis, greatly facilitating quantitative description of their complex behaviour. Furthermore, using digitised networks as inputs, empirically-based minimal biophysical mass-flow models already provide a high degree of explanation for patterns of long-distance radiolabel movement, and hint at global control mechanisms emerging naturally as a consequence of the intrinsic hydraulic connectivity. Network resilience is also critical to survival and can be explored both in silico by removing links in the digitised networks according to particular rules, or in vivo by allowing different mycophagous invertebrates to graze on the networks. Survival depends on both the intrinsic architecture adopted by each species and the ability to reconnect following damage. It is hoped that a comparative approach may yield useful insights into not just fungal ecology, but also biologically inspired rules governing the combinatorial trade-off between cost, transport efficiency, resilience and control complexity for self-organised adaptive networks in other domains.
Ectomycorrhizal (EM) networks are hypothesized to facilitate regeneration under abiotic stress. We tested the role of networks in interactions between P. menziesii var. glauca trees and conspecific seedlings along a climatic moisture gradient to: (1) determine the effects of climatic factors on network facilitation of Pseudotsuga menziesii (Mirb.) Franco var. glauca (Mayr) seedling establishment, (2) infer the changing importance of P. menziesii var. glauca parent trees in conspecific regeneration with climate, and (3) parse the competitive from facilitative effects of P. menziesii var. glauca trees on seedlings. When drought conditions were greatest, seedling growth increased when seedlings could form a network with trees in the absence of root competition, but was reduced when unable to form a network. Survival was maximized when seedlings were able to form a network in the absence of root competition. Seedling stem natural abundance δ13C increased with drought due to increasing water use efficiency, but was unaffected by distance from tree or network potential. We conclude that P. menziesii seedlings may benefit from the presence of established P. menziesii trees when growing under climatic drought, but that this benefit is contingent upon the establishment of an EM network prior to the onset of summer drought. These results suggest that networks are an important mechanism for EM plants establishing in a pattern consistent with the stress-gradient hypothesis, and therefore the importance of EM networks to facilitation in regeneration of EM trees is expected to increase with drought.
In the course of plant evolution, there is an obvious trend toward an increased complexity of plant bodies, as well as an increased sophistication of plant behavior and communication. Phenotypic plasticity of plants is based on the polar auxin transport machinery that is directly linked with plant sensory systems impinging on plant behavior and adaptive responses. Similar to the emergence and evolution of eukaryotic cells, evolution of land plants was also shaped and driven by infective and symbiotic microorganisms. These microorganisms are the driving force behind the evolution of plant synapses and other neuronal aspects of higher plants; this is especially pronounced in the root apices. Plant synapses allow synaptic cell-cell communication and coordination in plants, as well as sensory-motor integration in root apices searching for water and mineral nutrition. These neuronal aspects of higher plants are closely linked with their unique ability to adapt to environmental changes.
Mycorrhizal networks, defined as a common mycorrhizal mycelium linking the roots of at least two plants, occur in all major terrestrial ecosystems. This review discusses the recent progress and challenges in our understanding of the characteristics, functions, ecology and models of mycorrhizal networks, with the goal of encouraging future research to improve our understanding of their ecology, adaptability and evolution. We focus on four themes in the recent literature: (1) the physical, physiological and molecular evidence for the existence of mycorrhizal networks, as well as the genetic characteristics and topology of networks in natural ecosystems; (2) the types, amounts and mechanisms of interplant material transfer (including carbon, nutrients, water, defence signals and allelochemicals) in autotrophic, mycoheterotrophic or partial mycoheterotrophic plants, with particular focus on carbon transfer; (3) the influence of mycorrhizal networks on plant establishment, survival and growth, and the implications for community diversity or stability in response to environmental stress; and (4) insights into emerging methods for modelling the spatial configuration and temporal dynamics of mycorrhizal networks, including the inclusion of mycorrhizal networks in conceptual models of complex adaptive systems. We suggest that mycorrhizal networks are fundamental agents of complex adaptive systems (ecosystems) because they provide avenues for feedbacks and cross-scale interactions that lead to self-organization and emergent properties in ecosystems. We have found that research in the genetics of mycorrhizal networks has accelerated rapidly in the past 5 y with increasing resolution and throughput of molecular tools, but there still remains a large gap between understanding genes and understanding the physiology, ecology and evolution of mycorrhizal networks in our changing environment. There is now enormous and exciting potential for mycorrhizal researchers to address these higher level questions and thus inform ecosystem and evolutionary research more broadly.
Extraradical mycelia of mycorrhizal fungi are normally the "hidden half" of the symbiosis, but they are powerful underground influences upon biogeochemical cycling, the composition of plant communities, and agroecosystem functioning. Mycorrhizal mycelial networks are the most dynamic and functionally diverse components of the symbiosis, and recent estimates suggest they are empowered by receiving as much as 10% or more of the net photosynthate of their host plants. They often constitute 20%-30% of total soil microbial biomass yet are undetected by standard measures of biomass used by soil scientists and agromomists. Mycorrhizal mycelia provide extensive path- ways for carbon and nutrient fluxes through soil, often exceeding tens of metres per gram of soil. We consider the amounts of photosynthate "power" allocated to these mycelial networks and how this is used in fungal respiration, bio- mass, and growth and in influencing soil, plant, and ecosystem processes. The costs and functional "benefits" to plants linking to these networks are fungal specific and, because of variations in physiology and host specificity, are not shared equally; some plants even depend exclusively on these networks for carbon. We briefly assess the potential con- tribution of extraradical mycorrhizal mycelium to sustainable agriculture and maintenance of biodiversity and highlight technologies that promise new vistas and improved fine-scale resolution of the dynamic spatial and temporal function- ing of these networks in soil.
Understanding ectomycorrhizal fungal (EMF) community structure is limited by a lack of taxonomic resolution and autecological information. Rhizopogon vesiculosus and Rhizopogon vinicolor (Basidiomycota) are morphologically and genetically related species. They are dominant members of interior Douglas-fir (Pseudotsuga menziesii var. glauca) EMF communities, but mechanisms leading to their coexistence are unknown. We investigated the microsite associations and foraging strategy of individual R. vesiculosus and R. vinicolor genets. Mycelia spatial patterns, pervasiveness and root colonization patterns of fungal genets were compared between Rhizopogon species and between xeric and mesic soil moisture regimes. Rhizopogon spp. mycelia were systematically excavated from the soil and identified using microsatellite DNA markers. Rhizopogon vesiculosus mycelia occurred at greater depth, were more spatially pervasive, and colonized more tree roots than R. vinicolor mycelia. Both species were frequently encountered in organic layers and between the interface of organic and mineral horizons. They were particularly abundant within microsites associated with soil moisture retention. The occurrence of R. vesiculosus shifted in the presence of R. vinicolor towards mineral soil horizons, where R. vinicolor was mostly absent. This suggests that competition and foraging strategy may contribute towards the vertical partitioning observed between these species. Rhizopogon vesiculosus and R. vinicolor mycelia systems occurred at greater mean depths and were more pervasive in mesic plots compared with xeric plots. The spatial continuity and number of trees colonized by genets of each species did not significantly differ between soil moisture regimes.
The arbuscular mycorrhizal (AM) symbiosis is responsible for huge fluxes of photosynthetically fixed carbon from plants to the soil. Carbon is transferred from the plant to the fungus as hexose, but the main form of carbon stored by the mycobiont at all stages of its life cycle is triacylglycerol. Previous isotopic labeling experiments showed that the fungus exports this storage lipid from the intraradical mycelium (IRM) to the extraradical mycelium (ERM). Here, in vivo multiphoton microscopy was used to observe the movement of lipid bodies through the fungal colony and to determine their sizes, distribution, and velocities. The distribution of lipid bodies along fungal hyphae suggests that they are progressively consumed as they move toward growing tips. We report the isolation and measurements of expression of an AM fungal expressed sequence tag that encodes a putative acyl-coenzyme A dehydrogenase; its deduced amino acid sequence suggests that it may function in the anabolic flux of carbon from lipid to carbohydrate. Time-lapse image sequences show lipid bodies moving in both directions along hyphae and nuclear magnetic resonance analysis of labeling patterns after supplying ¹³C-labeled glycerol to either extraradical hyphae or colonized roots shows that there is indeed significant bidirectional translocation between IRM and ERM. We conclude that large amounts of lipid are translocated within the AM fungal colony and that, whereas net movement is from the IRM to the ERM, there is also substantial recirculation throughout the fungus.
The roots of most plants are colonized by symbiotic fungi to form mycorrhiza, which play a critical role in the capture of nutrients from the soil and therefore in plant nutrition. Mycorrhizal Symbiosis is recognized as the definitive work in this area. Since the last edition was published there have been major advances in the field, particularly in the area of molecular biology, and the new edition has been fully revised and updated to incorporate these exciting new developments. . Over 50% new material . Includes expanded color plate section . Covers all aspects of mycorrhiza . Presents new taxonomy . Discusses the impact of proteomics and genomics on research in this area.
We are re-addressing species concepts in the Rhizopogon vinicolor species complex (Boletales, Basidiomycota) using sequence data from the internal-transcribed spacer (ITS) region of the nuclear ribosomal repeat, as well as genotypic data from five microsatellite loci. The R. vinicolor species complex by our definition includes, but is not limited to, collections referred to as R. vinicolor Smith, R. diabolicus Smith, R. ochraceisporus Smith, R. parvulus Smith or R. vesiculosus Smith. Holo- and/or paratype material for the named species is included. Analyses of both ITS sequences and microsatellite loci separate collections of the R. vinicolor species complex into two distinct clades or clusters, suggestive of two biological species that subsequently are referred to as R. vinicolor sensu Kretzer et al and R. vesiculosus sensu Kretzer et al. Choice of the latter names, as well as morphological characters, are discussed.
Terrestrial fungi are commonly studied in the laboratory, growing on artificial media in which nutrients are typically homogeneously distributed and supplied in superabundance, the environment is sterile and microclimate (temperature, moisture, gaseous regime) usually relatively constant. This contrasts with the natural environment, in which: nutrients are often patchily and sparsely distributed or not readily available, because they are locked in recalcitrant material (e.g. lignin); many other organisms are encountered, including other fungi, bacteria and invertebrates; and microclimate is constantly changing, both temporally and spatially. This chapter explores the ways in which fungi cope with environmental heterogeneity. Similar situations are faced by macroorganisms and analogies are drawn. Emphasis is placed on basidiomycetes, not only because they have been studied in most detail, but because of their dominant role as decomposers and mutualistic symbionts (Boddy & Watkinson, 1995; Smith & Read, 1997) and because they are better adapted to respond to environmental heterogeneity over scales ranging from micrometres to many metres than are other fungi. Both saprotrophic and ectomycorrhizal Basidiomycota form extensive mycelial systems in woodland soil and litter, but it is the former that are the focus of this review. Saprotrophic, cord-forming Basidiomycota that ramify at the soil–litter interface, interconnecting disparate litter components, provide most examples. The key feature of these fungi that fits them for growth in environments where resources are heterogeneously distributed is that they are non-resource-unit restricted, i.e. they can grow out of one resource in search of others. © Cambridge University Press 2007 and Cambridge University Press, 2009.
Systems as diverse as genetic networks or the World Wide Web are best described as networks with complex topology. A common property of many large networks is that the vertex connectivities follow a scale-free power-law distribution. This feature was found to be a consequence of two generic mech-anisms: (i) networks expand continuously by the addition of new vertices, and (ii) new vertices attach preferentially to sites that are already well connected. A model based on these two ingredients reproduces the observed stationary scale-free distributions, which indicates that the development of large networks is governed by robust self-organizing phenomena that go beyond the particulars of the individual systems.
Rhizopogon is the largest genus of hypogeous Basidiomycota, with worldwide distribution among Pinaceae. Several Rhizopogon species are important members of ectomycorrhizal (ECM) fungal communities, contributing significantly to sporocarp productivity and ECM dominance. They occur in young and old forest stands alike and in diverse habitats. This ecological amplitude was recognized early in the twentieth century when Rhizopogon species were observed as dominant ECM fungi on Pinus in exotic plantations. Consequently, Rhizopogon has been the focus of considerable application research in forestry. The ease of culturing from sporocarps, manipulation of pure cultures of Rhizopogon and practical use of spore inoculation has made Rhizopogon a model genus to explore morphological, physiological, ecological, and symbiotic mutualisms of ECM. Nearly 200 papers have been published on Rhizopogon taxonomy, host range and specificity, ECM morphology, distribution, ecology, physiology, and applications in forestry.
Dendroctonus ponderosae has killed millions of Pinus contorta in western North America with subsequent effects on stand conditions, including changes in light intensity, needle deposition, and the composition of fungal community mutualists, namely ectomycorrhizal fungi. It is unknown whether these changes in stand conditions will have cascading consequences for the next generation of pine seedlings. To test for transgenerational cascades on pine seedlings, we tested the effects of fungal inoculum origin (beetle-killed or undisturbed stands), light intensity and litter (origin and presence) on seedling secondary chemistry and growth in a glasshouse. We also tracked survival of seedlings over two growing seasons in the same stands from which fungi and litter were collected. Fungal communities differed by inoculum origin. Seedlings grown with fungi collected from beetle-killed stands had lower monoterpene concentrations and fewer monoterpene compounds present compared with seedlings grown with fungi collected from undisturbed stands. Litter affected neither monoterpenes nor seedling growth. Seedling survival in the field was lower in beetle-killed than in undisturbed stands. We demonstrate that stand mortality caused by prior beetle attacks of mature pines have cascading effects on seedling secondary chemistry, growth and survival, probably mediated through effects on below-ground mutualisms.
© 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
Summary
1. Carbon (C), nutrients and water (H2O) have been known for five decades to flow between plants through ectomycorrhizal (EM) networks. This flux has the potential to affect plant and fungal performance and resource distribution within communities.
2. We asked two questions: 1) What are the pathways and mechanisms for C, nutrient and H2O fluxes between plants through EM networks? 2) What are the magnitude, fate and importance of C, nutrient and H2O transfer among EM plants?
3. Mycorrhizal networks provide a distinct pathway for resource fluxes among plants and mycorrhizal fungi, partitioning them away from other competing soil microbes and plant roots in the soil matrix, and potentially providing a competitive advantage (or disadvantage) for some individuals involved in the network. Carbon and nutrients flow symplastically and apoplastically through mycorrhizal symbionts, hyphae and rhizomorphs along source-sink gradients across the networking mycelia and plant community. Hydraulic redistribution from wetter to drier soil or plant pools can also be facilitated by mycorrhizal networks following water potential gradients.
4. Carbon fluxes through EM networks have been shown to supply 0-10% of autotrophic, up to 85% of partial myco-heterotrophic (MH), and 100% of fully MH plant C. This C supply has been loosely associated with increased survival and growth of autotrophic plants, but shown to be essential for survival of MH plants. Network-mediated nitrogen (N) fluxes between N2-fixing and non-N2-fixing plants have supplied up to 40% of receiver N, and this has been associated with increased plant productivity. Fluxes between non-N2-fixing plants have supplied <5% of receiver N. Hydraulic redistribution involving EM fungi has supplied up to 50% of plant water, and in some cases this has been shown as essential for plant survival, but how much of this water transfers through EM networks remains uncertain. Phosphorus transfer through EM networks has not been adequately demonstrated.
5. Overall, this review chapter shows that resource fluxes though EM networks are sufficiently large in some cases to facilitate plant establishment and growth. Resource fluxes through EM networks may thus serve as a method for interactions and cross-scale feedbacks for development of communities, consistent with complex adaptive system theory. How this may affect ecosystem stability depends on the environment.
Plants recognize their kin and respond to growing with relatives with changes in functional traits. Here, we integrate competition and evolutionary theory to evaluate these changes.
We draw parallels between the definitions and empirical measurement of competitive effect and competitive response from competition theory, and the costs and benefits of altruistic and selfish behaviours from kin selection theory.
Do plants compete less with relatives, as these parallels suggest? While functional traits respond to the presence of relatives or strangers, no study has directly demonstrated that plants are less competitive with siblings.
However, there are empirical challenges in identifying the competitive value of traits that are measured destructively, such as root allocation.
If these challenges can be addressed, kin recognition responses can offer new insights into plant competition.
Common mycorrhizal networks (CMNs) link multiple plants together. We hypothesized that CMNs can serve as an underground conduit for transferring herbivore-induced defence signals. We established CMN between two tomato plants in pots with mycorrhizal fungus Funneliformis mosseae, challenged a 'donor' plant with caterpillar Spodoptera litura, and investigated defence responses and insect resistance in neighbouring CMN-connected 'receiver' plants. After CMN establishment caterpillar infestation on 'donor' plant led to increased insect resistance and activities of putative defensive enzymes, induction of defence-related genes and activation of jasmonate (JA) pathway in the 'receiver' plant. However, use of a JA biosynthesis defective mutant spr2 as 'donor' plants resulted in no induction of defence responses and no change in insect resistance in 'receiver' plants, suggesting that JA signalling is required for CMN-mediated interplant communication. These results indicate that plants are able to hijack CMNs for herbivore-induced defence signal transfer and interplant defence communication.
Forest die-off caused by mountain pine beetle (MPB) is rapidly transforming western North American landscapes. The rapid and widespread death of lodgepole pine will likely have cascading effects on biodiversity. One group particularly prone to such declines associated with MPB are ectomycorrhizal fungi, symbiotic organisms that can depend on pine for their survival, and are critical for stand regeneration. We evaluated the indirect effects of MPB on above- (community composition of epigeous sporocarps) and belowground (hyphal abundance) occurrences of ectomycorrhizal fungi across 11 forest stands. Along a gradient of mortality (0-82% pine killed), macromycete community composition changed; this shift was driven by a decrease in the species richness of ectomycorrhizal fungi. Both the proportion of species that were ectomycorrhizal and hyphal length in the soil declined with increased MPB-caused pine mortality; less than 10% of sporocarp species were ectomycorrhizal in stands with high pine mortality compared with greater than 70% in stands without MPB attacks. The rapid range expansion of a native insect results not only in the widespread mortality of an ecologically and economically important pine species, but the effect of MPB may also be exacerbated by the concomitant decline of fungi crucial for recovery of these forests.
Volatile communication between plants causing enhanced defence has been controversial. Early studies were not replicated, and influential reviews questioned the validity of the phenomenon. We collected 48 well-replicated studies and found overall support for the hypothesis that resistance increased for individuals with damaged neighbours. Laboratory or greenhouse studies and those conducted on agricultural crops showed stronger induced resistance than field studies on undomesticated species, presumably because other variation had been reduced. A cumulative analysis revealed that early, non-replicated studies were more variable and showed less evidence for communication. Effects of habitat and plant growth form were undetectable. In most cases, the mechanisms of resistance and alternative hypotheses were not considered. There was no indication that some response variables were more likely to produce large effects. These results indicate that plants of diverse taxonomic affinities and ecological conditions become more resistant to herbivores when exposed to volatiles from damaged neighbours.
The year 1970 saw the publication of Origin of Eukaryotic Cells by Lynn Margulis. This influential book brought the exciting and weighty problems of cellular evolution to the scientific mainstream, simultaneously breaking new ground and ‘re-discovering’ the decades-old ideas of German and Russian biologists. In this commemorative review, I discuss the 40 years that have elapsed since this landmark publication, with a focus on the ‘molecular era’: how DNA sequencing and comparative genomics have proven beyond all doubt the central tenets of the endosymbiont hypothesis for the origin of mitochondria and plastids, and, at the same time, revealed a genetic and genomic complexity in modern-day eukaryotes that could not have been imagined in decades past.
Anthropogenic nitrogen (N) deposition alters ectomycorrhizal fungal communities, but the effect on functional diversity is not clear. In this review we explore whether fungi that respond differently to N deposition also differ in functional traits, including organic N use, hydrophobicity and exploration type (extent and pattern of extraradical hyphae). Cortinarius, Tricholoma, Piloderma, and Suillus had the strongest evidence of consistent negative effects of N deposition. Cortinarius, Tricholoma and Piloderma display consistent protein use and produce medium-distance fringe exploration types with hydrophobic mycorrhizas and rhizomorphs. Genera that produce long-distance exploration types (mostly Boletales) and contact short-distance exploration types (e.g., Russulaceae, Thelephoraceae, some athelioid genera) vary in sensitivity to N deposition. Members of Bankeraceae have declined in Europe but their enzymatic activity and belowground occurrence are largely unknown. Bankeraceae produce a distinct hydrophobic mat exploration type that may also be important in N acquisition under conditions of low N availability.