Hudsonia ericoides and Hudsonia tomentosa: Anatomy of mycorrhizas of two members in the Cistaceae from Eastern Canada

Botany ◽  
2010 ◽  
Vol 88 (6) ◽  
pp. 607-616 ◽  
Author(s):  
Hugues B. Massicotte ◽  
R. Larry Peterson ◽  
Lewis H. Melville ◽  
Linda E. Tackaberry
Keyword(s):  
Mycorrhizal Fungi ◽  
Soil Stabilization ◽  
Cortical Cell ◽  
Root Systems ◽  
Structural Features ◽  
Eastern Canada ◽  
Root Cortex ◽  
Hartig Net ◽  
Disturbed Areas ◽  
Pioneer Plants

Most species in the family Cistaceae are found in the Mediterranean basin. Several hosts are of special interest, owing to their associations with truffle species, while many are important as pioneer plants in disturbed areas and in soil stabilization. For these reasons, understanding their root systems and their associated fungal symbionts is important. Most studies of the structure of mycorrhizas in this family involve two genera, Cistus and Helianthemum . The present study examines structural features of mycorrhizas in two North American species, Hudsonia ericoides L. and Hudsonia tomentosa Nutt. Root systems of both species are highly branched with most fine roots colonized by mycorrhizal fungi. Based on morphological features, several mycorrhizal fungi were identified; structural details also provided evidence of more than one fungal symbiont for each host species. All mycorrhizas had a multi-layered fungal mantle and Hartig net hyphae confined to radially elongated epidermal cells; no intracellular hyphae were observed. Although the Hartig net was confined to the epidermis, the outer row of cortical cell walls lacked suberin, a known barrier to fungal penetration. Mycorrhizas in H. ericoides and H. tomentosa differed from those of Cistus and Helianthemum species that have a Hartig net that extends into the root cortex, as well as frequently present intracellular hyphae.

Comparative anatomy of roots and mycorrhizae of common Ontario trees

1990 ◽  
Vol 68 (3) ◽  
pp. 551-578 ◽  
Author(s):  
Mark Brundrett ◽  
Gracia Murase ◽  
Bryce Kendrick
Keyword(s):  
Comparative Anatomy ◽  
Lateral Roots ◽  
Arbuscular Mycorrhizal ◽  
Structural Diversity ◽  
Root Systems ◽  
Structural Features ◽  
Root Anatomy ◽  
Tree Roots ◽  
Hartig Net ◽  
Vesicular Arbuscular

The structure of roots and mycorrhizae of trees belonging to 20 important Ontario tree genera were examined. During this study efficient methods for examining root anatomy were developed, and tree root information was compiled. The ultimate lateral roots of most species examined were consistently mycorrhizal, and many species had heterorhizic root systems with separate long and short lateral roots. Tree roots displayed enough structural diversity in features such as thickened, lignified, or suberized walls, and secondary metabolite-containing cells to allow identification of genera. The roots of trees belonged to four major anatomical groups as a result of the major differences between angiosperm and gymnosperm roots, and between those with ectomycorrhizal (ECM) or vesicular–arbuscular mycorrhizal (VAM) associations, (i) Members of the Pinaceae had structurally similar heterorhizic roots that had ECM with a cortical Hartig net. (ii) Thuja (Cupressaceae) had distinctive nonheterorhizic roots with phi thickenings and VAM. (iii) Angiosperms with ECM belonged to diverse families, but all had similar heterorhizic root systems with ECM short roots that had an epidermal Hartig net and a narrow cortex of thick-walled cells, (iv) Most angiosperms with VAM had nonheterorhizic roots, and this group had the greatest diversity of root structural features. Possible structural and defensive roles of root features and potential influences of these features on mycorrhizal formation are considered.

The mycoheterotroph Arachnitis uniflora has a unique association with arbuscular mycorrhizal fungi

Botany ◽  
2009 ◽  
Vol 87 (12) ◽  
pp. 1198-1208 ◽  
Author(s):  
Laura S. Domínguez ◽  
Lewis Melville ◽  
Alicia Sérsic ◽  
Antonella Faccio ◽  
R. Larry Peterson
Keyword(s):  
Host Cell ◽  
Mycorrhizal Fungi ◽  
Cortical Cell ◽  
Arbuscular Mycorrhizal ◽  
Structural Features ◽  
Wall Layer ◽  
Wall Material ◽  
Nutrient Exchange ◽  
Host Cell Wall ◽  
Hyphal Coils

Achlorophyllous plants that are dependent on an association with fungi linked to photosynthetic plants for their carbon source are known as mycoheterotrophs. Arachnitis uniflora Phil., a monotypic member of the monocotyledonous family Corsiaceae, fits this category, as it relies on a glomalean fungus belonging to Glomus Group A for carbon acquisition. Although basic structural features of root colonization have been reported for A. uniflora, the nutrient exchange interface has not been studied. This is the first study to use confocal microscopy, transmission electron microscopy, and cytochemical procedures to study the interface between a glomalean fungus and the roots of a mycoheterotrophic species. Results showed that arbuscules are never formed, and that the “vesicles in bundles” reported earlier are unlike typical glomalean vesicles, in that they form in clusters by the enlargement of hyphal branches and have a complex multilayered wall. The thick inner wall layer consists primarily of β-1,3-glucans (callose) and is surrounded by a thin outer layer of chitin. Each structure is surrounded by host cell wall material and a perifungal membrane, suggesting an involvement in nutrient exchange. The cytoplasm contains a complex of small β-1,3-glucan-containing vacuoles, lipid bodies, endobacteria, and many nuclei. These structures enlarge to occupy most of the cortical cell volume and then degrade, releasing lipids and other materials into the host cell. We suggest that these structures should not be equated with typical glomalean vesicles but are unique structures that may be involved, along with the hyphal coils, in nutrient acquisition by the host.

Response of Taxus times media var. densiformis to inoculation with arbuscular mycorrhizal fungi

1998 ◽  
Vol 28 (1) ◽  
pp. 150-153
Author(s):  
J N Gemma ◽  
R E Koske ◽  
E M Roberts ◽  
S Hester
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Arbuscular Mycorrhizal ◽  
Dry Weight ◽  
Root Systems ◽  
Stem Diameter ◽  
Rooted Cuttings ◽  
Shoot Dry Weight ◽  
Mycorrhizal Plants

Rooted cuttings of Taxus times media var. densiformis Rehd. were inoculated with the arbuscular mycorrhizal fungi Gigaspora gigantea (Nicol. & Gerd.) Gerd. & Trappe or Glomus intraradices Schenck and Smith and grown for 9-15 months in a greenhouse. At the completion of the experiments, leaves of inoculated plants contained significantly more chlorophyll (1.3-4.1 times as much) than did noninoculated plants. In addition, mycorrhizal plants had root systems that were significantly larger (1.3-1.4 times) and longer (1.7-2.1 times) than nonmycorrhizal plants, and they possessed significantly more branch roots (1.3-2.9 times). No differences in stem diameter and height or shoot dry weight were evident at the end of the experiments, although the number of buds was significantly greater in the cuttings inoculated with G. intraradices after 15 months.

Mycorrhizal fungi as drivers of ecosystem processes in heathland and boreal forest biomes

2004 ◽  
Vol 82 (8) ◽  
pp. 1243-1263 ◽  
Author(s):  
David J Read ◽  
Jonathan R Leake ◽  
Jesus Perez-Moreno
Keyword(s):  
Boreal Forest ◽  
Mycorrhizal Fungi ◽  
Global Climate ◽  
Structural Features ◽  
Plant Litter ◽  
Organic Soils ◽  
Organic Substrates ◽  
Nutrient Cycles ◽  
Mycorrhizal Associations ◽  
Anthropogenic Pollutant

The importance of mycorrhizas in heathland and boreal forest biomes, which together cover much of the landmass of the Northern Hemisphere and store most of the global stocks of carbon, is reviewed. The taxonomic affinities of the organisms forming these symbiotic partnerships are assessed, and the distinctive structural features of the ericoid mycorrhizas of heathland dwarf shrubs and the ectomycorrhizas of boreal forest trees are described. It is stressed that neither in terms of the geographical distribution of the plants nor in terms of the occurrence of their characteristic mycorrhizas in the soil profile should these biomes be considered to be mutually exclusive. What unites them is their apparent affinity for acidic organic soils of inherently low accessibility of the major nutrients nitrogen (N) and phosphorus (P). These properties relate directly to the nature of the nutrient-poor recalcitrant litter produced by their host plants and through positive-feedback mechanisms that are reinforced by selective removal of labile nutrients by the mycorrhizas. We suggest that coevolution of these plant litter traits with mycorrhizal associations that are adapted to them has been one of the defining features of these ecosystems. Ericoid and ectomycorrhizal fungi have biochemical and physiological attributes that make them highly efficient at scavenging for organic sources of N and P in surface soil horizons. In so doing, they restrict supplies of these elements to the decomposer communities. Case studies involving exploitation of N and P in defined organic substrates are described. In both biomes the dominant plants depend upon the abilities of their fungal partners to recover nutrients, so the symbioses control nutrient cycles, productivity, species composition, and functioning of these ecosystems. It is in this context that the fungal symbionts are here considered to be drivers of nutritional processes in their respective biomes. Through their influences upon the quality of carbon residues mycorrhizal fungi must also affect the sink-source balance for this key element in soil. There is an urgent need for the evaluation of the relative contributions of symbiotic and saprotrophic components of the microflora to the processes of carbon storage and cycling in these biomes, particularly in the context of global climate change and impacts of anthropogenic pollutant N deposition.Key words: carbon sequestration, peatlands, C/N ratios, carbon and nutrient cycles.

scholarly journals Morphological-cultural and molecular genetic features of collection strains of mycoris mushrooms Phialocephala fortinii and Pezicula sp.

2020 ◽  
Vol 64 (5) ◽  
pp. 567-573
Author(s):  
Ya. S. Kamelchuk ◽  
O. Yu. Baranov ◽  
P. S. Kiryanov ◽  
V. E. Padutov
Keyword(s):  
Mycorrhizal Fungi ◽  
Dominant Species ◽  
Molecular Genetic ◽  
Root Systems ◽  
Vaccinium Corymbosum ◽  
Phialocephala Fortinii ◽  
Taxonomic Analysis ◽  
Genetic Features ◽  
Pure Cultures ◽  
Genetic Assay

A metagenomic analysis of the endophytic microflora of Vaccinium corymbosum L. and Vaccinium myrtillus L. root systems was carried out. Two dominant species of micromycetes forming ericoid mycorrhiza were identified - Phialocephala fortinii C. J. K. Wang & H. E. Wilcox and Pezicula sp. Tul. & C. Tul. Pure cultures of mycorrhizal fungi were prepared, a comprehensive morphological and genetic assay of the strains was carried out. Based on the results of genetic-taxonomic analysis, the assumption of the polyphyletic origin of species belonging to Phialocephala and Pezicula is confirmed.

scholarly journals Chandelier cell anatomy and function reveal a variably distributed but common signal

2020 ◽  
Author(s):  
Casey M. Schneider-Mizell ◽  
Agnes L. Bodor ◽  
Forrest Collman ◽  
Derrick Brittain ◽  
Adam A. Bleckert ◽  
...  
Keyword(s):  
Large Scale ◽  
Pyramidal Neurons ◽  
Cell Activity ◽  
Cortical Cell ◽  
Cell Types ◽  
Structural Features ◽  
Target Neuron ◽  
Chandelier Cell ◽  
Chandelier Cells

AbstractThe activity and connectivity of inhibitory cells has a profound impact on the operation of neuronal networks. While the average connectivity of many inhibitory cell types has been characterized, we still lack an understanding of how individual interneurons distribute their synapses onto their targets and how heterogeneous the inhibition is onto different individual excitatory neurons. Here, we use large-scale volumetric electron microscopy (EM) and functional imaging to address this question for chandelier cells in layer 2/3 of mouse visual cortex. Using dense morphological reconstructions from EM, we mapped the complete chandelier input onto 153 pyramidal neurons. We find that the number of input synapses is highly variable across the population, but the variability is correlated with structural features of the target neuron: soma depth, soma size, and the number of perisomatic synapses received. Functionally, we found that chandelier cell activity in vivo was highly correlated and tracks pupil diameter, a proxy for arousal state. We propose that chandelier cells provide a global signal whose strength is individually adjusted for each target neuron. This approach, combining comprehensive structural analysis with functional recordings of identified cell types, will be a powerful tool to uncover the wiring rules across the diversity of cortical cell types.

Biological weathering by the Devonian trees

2020 ◽  
Author(s):  
Lukasz Pawlik ◽  
Brian Buma ◽  
Pavel Samonil ◽  
Jiri Kvacek ◽  
Anna Galazka ◽  
...  
Keyword(s):  
Vascular Plants ◽  
Soil Stabilization ◽  
Environmental Changes ◽  
Global Climate ◽  
Root Systems ◽  
Weathering Processes ◽  
Form And Function ◽  
Tree Uprooting ◽  
Biological Weathering

<p class="western" lang="en-US"><span>We applied the biogeomorphic ecosystem engineers concept to the Devonian Plant Hypotheses. By linking these two ideas we want to explore how recent discoveries on the role of trees in weathering processes could support the explanation of global environmental changes in the Devonian period. The occurrence of first land plants, vascular plants, trees, and complex forest ecosystems likely changed the nature and pace of many geomorphic and pedogenic processes. For instance, intensification of biological weathering driven by vascular plants might have influenced the global climate through consumption and accumulation of a large volume of atmospheric CO2. Innovation in the form and function of trees likely strongly influenced these processes, including soil stabilization via deep root systems. Mycorrhizal relationships further influenced weathering via chemical processes. While the lack of solid evidence in the fossil record still pose a problem, the progress in our understanding of soil-weathering processes induced by trees and root systems has expanded greatly in recent years, especially in terms of their biogeomorphic functions (e.g. tree uprooting, pedoturbations, biomechanical weathering, etc.), and can provide insights and testable hypotheses regarding the role of trees in the Late Devonian.</span></p>

Sign in / Sign up

Export Citation Format

Share Document