Download or read book Mycorrhizal Associations Shape Complex Plant soil Interactions in the Early Seedling Recruitment of Bornean Rainforest Trees written by Richard Maxfield Segnitz and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Biotic feedbacks between plants and soil fungi have been shown to influence seedling recruitment and plant community structure. This dissertation is principally concerned with how mycorrhizal associations influence such feedbacks as experienced by tropical tree seedlings, how soil fertility might change these interactions, and how the fungal communities that drive feedbacks assemble on seedling roots. While work in temperate forests suggests that there are consistent differences in plant-soil feedback between plants with arbuscular and ectomycorrhizal associations, it is unclear whether these differences exist in diverse tropical rainforests or how they may be impacted by heterogeneity in soil nutrients. In this dissertation, I address several current knowledge gaps by examining how plant-soil feedbacks operate in a diverse but ectomycorrhizal dominated rainforest in Northern Borneo. I conducted a shadehouse experiment (Chapters 1 & 2) using a design that allowed me to test whether the direction and strength of plant-soil feedback depends on a tree species' mycorrhizal association type, phylogenetically driven variation in the soil microbiota, and the fertility of the soil. I established a large scale multispecies shadehouse experiment in which the edaphic and biotic origins of soils were manipulated. I found that phylogenetically structured plant-soil feedbacks could influence seedling performance, but did so differently for ectomycorrhizal and arbuscular mycorrhizal seedlings (Chapter 1). Further, I found that soil resource availability changed the strength and direction of feedbacks for arbuscular mycorrhizal hosts but not ectomycorrhizal hosts. Using environmental DNA sequencing to characterize root-associated fungi in this experiment (Chapter 2), I showed that root-associated fungal communities differed at broad taxonomic scales across host mycorrhizal types but were similarly structured by host identity and soil type at finer scales. Further, I show that evolutionary relationships between seedlings and the overstory species that condition the soil can predictably affect root community structure, but that this effect differed depending on seedling mycorrhizal type, providing a possible mechanism by which plant-soil feedbacks is mediated. In my final chapter, I examine plant-soil feedbacks in a field experiment that focused on a single ectomycorrhizal seedling species. I explored how plant-soil feedbacks interact with density-dependent seedling mortality across the landscape in the field (Chapter 3). I found that seedlings of this species might weakly benefit from recruitment near conspecific adults and were likely not subject to conspecific negative density dependence typically thought to limit recruitment in tropical forests. I found that local scale density-dependence in seedling mortality did not vary with proximity to conspecific adults, suggesting that for this species the predominant effects on growth and mortality might be driven more by variation in the presence of beneficial soil biota than natural enemies. The results of this thesis collectively suggest that mycorrhizal associations of tropical trees play an important role in shaping how complex plant-soil interactions affect early seedling recruitment and, ultimately, tropical tree diversity. I found that species' mycorrhizal type shaped the feedbacks they experienced in a diverse Bornean rainforest, and also that mycorrhizal type could affect how the overstory canopy shapes root fungal communities. Further, the impact of overstory canopy composition on seedling growth can be dependent on both mycorrhizal type and edaphic heterogeneity. Keywords: tropical, seedling, mycorrhizal, ectomycorrhizal, arbuscular, fungal, plant-soil feedback, plant community, recruitment, diversity.
Download or read book Friends in High Places written by Katie M. Becklin Atkinson and published by . This book was released on 2010 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mutualisms are ubiquitous in nature, yet these interactions often vary in strength and persistence. This variation raises the questions of what determines whether mutualisms persist or vanish, and how does variation in the strength of mutualisms affect populations, communities, and ecosystems. I addressed these questions by evaluating mycorrhizal associations, symbiotic interactions between plants and root-colonizing fungi, in co-occurring alpine plant species along an environmental gradient. First, I examined the distribution, diversity, and composition of mycorrhizal fungi across the willow-meadow ecotone at treeline on Pennsylvania Mountain (Park County, CO, USA). Results highlight the context-dependent nature of mutualisms and indicate that both biotic and abiotic factors determine the strength of these associations. Next, I identified environmental factors that contribute to variation in mycorrhizal associations across the willow-meadow ecotone. Field and greenhouse studies indicate that biotic and abiotic factors alter partner benefits, thereby generating variation in these mutualisms. Finally, I evaluated implications of variation in mycorrhizal associations for plant populations and communities. Results of two studies demonstrate the potential for mycorrhizae to impact plant invasions, aboveground interaction webs, and the evolution of plant traits. Overall, this research advances our understanding of mutualism, highlighting the inherent complexity of these interactions and their importance to ecological and evolutionary processes.
Download or read book Mycorrhizosphere and Pedogenesis written by Ajit Varma and published by Springer. This book was released on 2019-07-13 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present book highlights importance of mycorrhiza in soil genesis wherein it reflects mycorrhizal occurrence and diversity, various tools to characterize them and its impact on soil formation/health together with crop productivity. The edited compendium provides glimpses on the mycorrhizal fungi and their prominent role in nutrient transfer into host plants, and presenting view on application of mycorrhiza for crop biofortification. It focuses on the mechanisms involve in weathering process employed by mycorrhiza with highlighting the current and advanced molecular approaches for studying mycorrhizal diversity. Further, book emphasizes following aspects in details: significance of AMF in phytoremediation of hydrocarbon contaminated sites, the role of mycorrhiza in soil genesis using scientometric approach, the concept of mycorrhizosphere, xenobiotic metabolism, molecular approaches for detoxifying the organic xenobiotics and the role of mycorrhizosphere in stabilizing the environment in an eco-friendly way. In addition, the book will be benign to researchers that involved in mycorrhiza characterization especially by deploying metagenomics/PCR based and non PCR based molecular techniques that may be utilized to study the microbial diversity and structure within the mycorrhizosphere.
Download or read book Workshop written by and published by . This book was released on 1999 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Mechanisms Regulating Mycorrhizal Associations in Woody Plants written by Kevin Richard Cope and published by . This book was released on 2018 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: The application of fertilizers in agronomic systems is necessary to meet the nutrient demands of crop production. However, this practice often results in the pollution of the environment. More sustainable practices are needed to prevent the continued degradation of natural systems. In nature, the roots of plants have forged alliances with beneficial microbes in the soil to help alleviate nutrient deficiencies. Understanding how symbiotic plant-microbe interactions form is crucial for developing more sustainable agronomic practices that limit our dependence on fertilizers and minimize negative impacts of crop production on the environment. Mycorrhizal fungi are one class of filamentous microorganisms that form a mutualistic association with the roots of most land plant species. They provide the roots of their host plants with increased access to limited mineral nutrients in the soil in exchange for carbon derived from photosynthesis. Two major types of mycorrhizal associations include arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM). The molecular mechanisms regulating how both types of mycorrhizal associations form has been a major research topic for decades, although more attention has been given to AM fungi. As a result, an entire molecular signaling pathway has been identified that is necessary for the development of the AM symbiosis. It is known as the "common symbiosis pathway" (CSP) because it is also required for both the rhizobia-legume and actinorhizal symbioses. The CSP is activated by lipochitooligosaccharides (LCOs), which are symbiotic signaling molecules that are also produced by rhizobia. At the core of the CSP are three genes: CASTOR, POLLUX, and CCaMK. CASTOR and POLLUX regulate a cellular phenomenon known as nuclear calcium spiking which is then decoded by CCaMK leading to changes in gene expression necessary for the development of both the AM and rhizobia-legume symbioses. Ectomycorrhizal symbioses are one of the most widespread associations between roots of woody plants and soil fungi in forest ecosystems. These associations contribute significantly to the sustainability and sustainagility of these ecosystems through nutrient cycling and carbon sequestration. Unfortunately, the molecular mechanisms controlling the mutual recognition between both partners are still poorly understood. Given the role of the CSP in diverse symbiotic associations, we hypothesized that the CSP might also play a role in ECM associations. Genomic data suggests that ECM fungi possess all of the genetic components necessary for the biosynthesis of LCOs. Furthermore, the genomes of some ECM-host plants possess all of the genes associated with the CSP (e.g., Populus). Using mass spectrometry, we showed that multiple ECM fungi produce an array of LCOs and demonstrated that they can trigger both root hair branching in legumes and, most importantly, calcium spiking in the ECM-host plant Populus. For one ECM fungal species, Laccaria bicolor, we demonstrated that calcium spiking in Populus occurred in a CASTOR/POLLUX-dependent manner. Purified non-sulfated LCOs enhanced lateral root development in Populus in a CCaMK-dependent manner and sulfated LCOs enhanced the colonization of Populus by L. bicolor. The colonization of Populus roots by L. bicolor was reduced in both CASTOR/POLLUX and CCaMK RNA interference lines and the expression of a mycorrhiza-induced phosphate transporter, PT12, was reduced in the CCaMK-RNA interference line compared to wild-type. Altogether, our work demonstrates that L. bicolor uses the CSP for full establishment of its mutualistic association with Populus. Future work should focus on determining if the CSP is required for the establishment of other ECM associations using stable gene knock-outs. Furthermore, the role of nutrient transporters in the maintenance of ECM associations should be evaluated. Investigating these areas of research will allow for better utilization of ECM associations in the sustainable production of woody plants and/or management of forest ecosystems.
Download or read book Mycorrhizal Mediation of Soil written by Nancy Collins Johnson and published by Elsevier. This book was released on 2016-11-22 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mycorrhizal Mediation of Soil: Fertility, Structure, and Carbon Storage offers a better understanding of mycorrhizal mediation that will help inform earth system models and subsequently improve the accuracy of global carbon model predictions. Mycorrhizas transport tremendous quantities of plant-derived carbon below ground and are increasingly recognized for their importance in the creation, structure, and function of soils. Different global carbon models vary widely in their predictions of the dynamics of the terrestrial carbon pool, ranging from a large sink to a large source. This edited book presents a unique synthesis of the influence of environmental change on mycorrhizas across a wide range of ecosystems, as well as a clear examination of new discoveries and challenges for the future, to inform land management practices that preserve or increase below ground carbon storage.
Download or read book Methods in Root soil Interactions Research Protocols written by María P. Martín and published by . This book was released on 2000 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Mycorrhizal Associations of Tree Seedlings in an Irish Bare root Nursery written by John J. M. O'Neill and published by . This book was released on 1997 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of the Mycorrhizal Type on Root rhizosphere Interactions in AM and ECM Tree Species Field Studies and Mesocosm Experiments written by Rebecca Liese and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on the two main types of mycorrhizal associations in temperate forests, which are arbuscular (AM) and ectomycorrhiza (ECM), the idea of a mycorrhizal-associated nutrient economy framework developed (Phillips et al., 2013). This framework predicts that AM dominated forests, with fast decomposition of high chemical quality litter, have an inorganic nutrient economy. In contrast, forests dominated by ECM trees have low chemical quality litter and slow decomposition rates, resulting in a dominantly organic nutrient economy. The acquisition of nutrients from soil and as a result also tree ...
Download or read book Seedling Ecology and Evolution written by Mary Allessio Leck and published by Cambridge University Press. This book was released on 2008-09-18 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seedlings are highly sensitive to their environment. After seeds, they typically suffer the highest mortality of any life history stage. This book provides a comprehensive exploration of the seedling stage of the plant life cycle. It considers the importance of seedlings in plant communities; environmental factors with special impact on seedlings; the morphological and physiological diversity of seedlings including mycorrhizae; the relationship of the seedling with other life stages; seedling evolution; and seedlings in human altered ecosystems, including deserts, tropical rainforests, and habitat restoration projects. The diversity of seedlings is portrayed by including specialised groups like orchids, bromeliads, and parasitic and carnivorous plants. Discussions of physiology, morphology, evolution and ecology are brought together to focus on how and why seedlings are successful. This important text sets the stage for future research and is valuable to graduate students and researchers in plant ecology, botany, agriculture and conservation.
Download or read book Early Seral Plant Species Interactions with an Arbuscular Mycorrhizal Fungi Community are Highly Variable written by Ryan Busby and published by . This book was released on 2011 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plant microbe Interactions Influence Ecosystem Processes written by Jessica Andrea Moore and published by . This book was released on 2016 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plant-microbe interactions shape ecosystem processes such as productivity and decomposition of organic matter. Plants interact with mycorrhizal fungal hyphae to acquire nutrients from soil in exchange for plant-assimilated carbon. The mycorrhizal interaction is therefore a key influence on ecosystem carbon dynamics. Mycorrhizal fungi are key players in soil carbon cycling as they stimulate plants to allocate carbon belowground, and mycorrhizal fungal hyphae interact with microbial decomposers of soil carbon. However, there are few studies on mycorrhizal fungal hyphal interactions with roots and soil organisms in light of soil carbon accrual and release, important ecosystem processes. In my doctoral research, I examined interactions among plants, mycorrhizal fungal hyphae, and soil microbes in order to better understand the role of mycorrhizal fungal hyphae in soil C dynamics through combining models with experiments. In my first chapter, I discussed the direct role of mycorrhizal fungi on organic matter decomposition and subsequent shifts in soil carbon. I compared the effect of mycorrhizal hyphal decomposition to decomposition by free-living microbes using a carbon simulation model. In my second chapter, I tested how roots and mycorrhizal fungal hyphae indirectly affect decomposition of organic matter through interactions with free-living microbes. I found non-additive effects of roots and mycorrhizal fungal hyphae on soil microbial activity and hypothesized the effects were driven by nutrient demand. Thus, in my third chapter, I examined microbial decomposition of carbon and nutrient substrates across a range of root and mycorrhizal hyphal influence. My dissertation advances the field of ecosystem ecology by evaluating the role of plant-microbe interactions in soil carbon dynamics.
Download or read book The Roles of Arbuscular Mycorrhizal Fungi AMF in Phytoremediation and Tree herb Interactions in Pb Contaminated Soil written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the roles of arbuscular mycorrhizal fungi (AMF) in plant interaction is essential for optimizing plant distribution to restore degraded ecosystems. Here, our study investigated the effects of AMF and the presence of legume or grass herbs on phytoremediation with a legume tree, Robinia pseudoacacia, in Pb polluted soil. In monoculture, mycorrhizal dependency of legumes was higher than that of grass, and AMF benefited the plant biomass of legumes but had no effect on grass. Mycorrhizal colonization of plant was enhanced by legume neighbors but inhibited by grass neighbor in co-culture system. N, P, S and Mg concentrations of mycorrhizal legumes were larger than these of non-mycorrhizal legumes. Legume herbs decreased soil pH and thereby increased the Pb concentrations of plants. The neighbor effects of legumes shifted from negative to positive with increasing Pb stress levels, whereas grass provided a negative effect on the growth of legume tree. AMF enhanced the competition but equalized growth of legume-legume under unpolluted and Pb stress conditions, respectively. In conclusion, (1) AMF mediate plant interaction through directly influencing plant biomass, and/or indirectly influencing plant photosynthesis, macronutrient acquisition, (2) legume tree inoculated with AMF and co-planted with legume herbs provides an effective way for Pb phytoremediation.
Download or read book Ant Plant Interactions written by Paulo S. Oliveira and published by Cambridge University Press. This book was released on 2017-08-17 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first volume devoted to anthropogenic effects on interactions between ants and flowering plants, considered major parts of terrestrial ecosystems.
Download or read book The Rhizosphere written by Zoe G. Cardon and published by Elsevier. This book was released on 2011-04-28 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: Below the soil surface, the rhizosphere is the dynamic interface among plant roots, soil microbes and fauna, and the soil itself, where biological as well as physico-chemical properties differ radically from those of bulk soil. The Rhizosphere is the first ecologically-focused book that explicitly establishes the links from extraordinarily small-scale processes in the rhizosphere to larger-scale belowground patterns and processes. This book includes chapters that emphasize the effects of rhizosphere biology on long-term soil development, agro-ecosystem management and responses of ecosystems to global change. Overall, the volume seeks to spur development of cross-scale links for understanding belowground function in varied natural and managed ecosystems. - First cross-scale ecologically-focused integration of information at the frontier of root, microbial, and soil faunal biology - Establishes the links from extraordinarily small-scale processes in the rhizosphere to larger-scale belowground patterns and processes - Includes valuable information on ecosystem response to increased atmospheric carbon dioxide and enhanced global nitrogen deposition - Chapters written by a variety of experts, including soil scientists, microbial and soil faunal ecologists, and plant biologists
Download or read book Structured Population Models in Marine Terrestrial and Freshwater Systems written by Shripad Tuljapurkar and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the summer of 1993, twenty-six graduate and postdoctoral stu dents and fourteen lecturers converged on Cornell University for a summer school devoted to structured-population models. This school was one of a series to address concepts cutting across the traditional boundaries separating terrestrial, marine, and freshwa ter ecology. Earlier schools resulted in the books Patch Dynamics (S. A. Levin, T. M. Powell & J. H. Steele, eds., Springer-Verlag, Berlin, 1993) and Ecological Time Series (T. M. Powell & J. H. Steele, eds., Chapman and Hall, New York, 1995); a book on food webs is in preparation. Models of population structure (differences among individuals due to age, size, developmental stage, spatial location, or genotype) have an important place in studies of all three kinds of ecosystem. In choosing the participants and lecturers for the school, we se lected for diversity-biologists who knew some mathematics and mathematicians who knew some biology, field biologists sobered by encounters with messy data and theoreticians intoxicated by the elegance of the underlying mathematics, people concerned with long-term evolutionary problems and people concerned with the acute crises of conservation biology. For four weeks, these perspec tives swirled in discussions that started in the lecture hall and carried on into the sweltering Ithaca night. Diversity mayor may not increase stability, but it surely makes things interesting.
Download or read book A Review of Dipterocarps written by Simmathiri Appanah and published by CIFOR. This book was released on 1998-01-01 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt:
