Download Free Molecular Systematics Biogeography And Mycorrhizal Associations In The Acianthinae Orchidaceae With A Focus On The Genus Corybas Book in PDF and EPUB Free Download. You can read online Molecular Systematics Biogeography And Mycorrhizal Associations In The Acianthinae Orchidaceae With A Focus On The Genus Corybas and write the review.

The orchid subtribe Acianthinae, containing roughly 170 species in five genera, consists of almost exclusively terrestrial, diminutive species, most of which seem to be pollinated by small flies. The group is poorly studied, and presents unique opportunities for evolutionary studies. While the vegetative features are fairly uniform within the group, floral diversity is quite substantial, especially in the large genus Corybas. Though part of the primarily Australian Diurideae, this particular subtribe has a remarkably wide range spanning much of Australasia and the Malay Archipelago, into mainland Asia and the Pacific. This is the first phylogenetic study to extensively sample the Acianthinae outside of Australia, New Zealand, and New Caledonia. By using multiple genes, we achieve good resolution and support, allowing us to propose a revised generic classification system than would both minimize taxonomic changes yet incorporate our new understanding of evolutionary relationships in the group. The phylogeny also reveals that some morphological traits that have been used to define taxonomic groups in the past are quite labile, and indicates a remarkable case of floral convergence. Biogeographical studies indicate a mid-Oligocene origin in Australia with extensive dispersal via West Wind Drift in the southern parts of its range. In the tropical parts of its range, dispersal appears more limited, mostly occurring on a smaller scale--with some dramatic exceptions. Much diversification appears to occur locally, especially within the rapidly uplifting New Guinea. We also employ Next Generation Sequencing genotyping techniques to address relationships within one very recently evolved clade endemic to Australia, the genus Corysanthes Jones et al. This results in unprecedented resolution within and among species, allowing us to evaluate phylogeographic structure and make recommendations on species delimitation. In addition, we present results of an extensive study of the mycorrhizal associations in the Corysanthes clade. All species appear to be strongly associated with one to several undescribed Tulasnella fungi, most of which have not been previously detected in other orchids. Species within the clade clearly differ in regards to their mycorrhizal preferences, though there is a strong environmental signal in their patterns of association.
This book offers a timely overview and synthesis of biogeographic patterns of plants and fungi and their mycorrhizal associations across geographic scales. Written by leading experts in the field, it provides an updated definition of mycorrhizal types and establishes the best practices of modern biogeographic analyses. Individual chapters address the basic processes and mechanisms driving community ecology, population biology and dispersal in mycorrhizal fungi, which differ greatly from these of prokaryotes, plants and animals. Other chapters review the state-of-the-art knowledge about the distribution, ecology and biogeography of all mycorrhizal types and the most important fungal groups involved in mycorrhizal symbiosis. The book argues that molecular methods have revolutionized our understanding of the ecology and biogeography of mycorrhizal symbiosis and that rapidly evolving high-throughput identification and genomics tools will provide unprecedented information about the structure and functioning of mycorrhizal symbiosis on a global scale. This volume appeals to scientists in the fields of plant and fungal ecology and biogeography.
Some plant species have abandoned an autotrophic life style and obtain their carbon and mineral nutrition exclusively from mycorrhizal fungi. Although myco-heterotrophic species have evolved in many plant families, they are most common in the Orchidaceae. Several myco-heterotrophic orchid species have been shown to associate with a very narrow range of ectomycorrhizal forming fungi, revealing a high degree of mycorrhizal specificity. However, these studies have often investigated single or few, often unrelated, species without support for their monophyly or knowledge of their phylogenetic relationships. Using primarily molecular methods and phylogenetic analyses, this dissertation investigates i) the monophyly and circumscription of Hexalectris species, ii) interspecific phylogenetic relationships within Hexalectris, iii) the identities of the mycorrhizal fungi that associate with each Hexalectris species, iv) the breadth of mycorrhizal associations within Hexalectris and within each of its species, and v) uses a Hexalectris phylogeny as a framework for investigating mycorrhizal specificity and patterns of associations. The monophyly of H. warnockii, H. grandiflora, H. brevicaulis, and H. nitida, plus the H. spicata species complex, are well supported. The remaining species are not monophyletic, prompting the recircumscription of H. spicata s.l. as H. spicata and H. arizonica, H. revoluta s.l. as H. revoluta and H. colemanii, and H. fallax as a synonym of H. parviflora. Extreme specificity with ectomycorrhizal agaricomycete fungi was identified in each Hexalectris species. Hexalectris warnockii associates exclusively with members of the Thelephoraceae; H. brevicaulis and H. grandiflora associate exclusively with members of Russulaceae and Sebacinaceae subgroup A; the remaining species, all members of the H. spicata complex, associate strictly with members of Sebacinaceae subgroup A. Optimizing these associations onto a Hexalectris phylogeny reveals that, with one exception, each Hexalectris species associates with a different clade or group of fungal clades, and that shifts in association from one group of fungi to another occurred during each speciation event in the evolutionary history of this genus.
The Neotropical orchid genus Mormolyca Fenzl, with at least 28 species, consists of epiphytic plants distributed from southern Mexico to Bolivia and Northern Brazil, including the Greater Antilles. For a relatively small genus, species exhibit considerable flower diversity, possibly correlated with different pollination systems, which include both sexual deception and mutualism (rewards). To study the mechanisms and evolution of pollination systems in the group, a phylogenetic inference based on multiple DNA markers is constructed for use as a framework. The phylogenetic tree, which had good resolution and support, reveals patterns of evolution that are likely related to pollination systems. At the same time, confirms classification of new species that were discovered during this study. To better understand the characters involved in the attraction of insect pollinators, floral micro-morphological traits were studied among species of Mormolyca. Labella of flowers were sectioned and examined for micro-morphological and anatomical characters, as well as for the presence of possible food rewards (e.g., starch, lipids, and proteins). Species were found to cluster into three morphological groups, the Hedwigiae, Ringens and Rufescens groups, based on a combination of labellar papillae, the presence/absence of secretions, nutrients, and scents. The presence of capillary papillae is restricted to the Ringens group, which includes the sexually deceptive species, whereas the Hedwigiae and Rufescens groups (the rewarding species) have papillae with distended apices that produce aromatic amino acids. Labellar papillae, in conjunction with osmophores (glandular tissue), provide the flowers the ability to attract, guide, feed, and/or deceive pollinators through a combination of visual, tactile, and/or olfactory cues. To further understand the possible olfactory cues, floral fragrance composition was investigated for six species of Mormolyca representing the three morphologically distinct groups. Volatile and nonvolatile constituents of flower extracts were identified with Gas Chromatograph-Mass Spectrometry. The species that are sexually deceptive contain alkanes and alkenes known to be involved with sexual mimicry in Orchidaceae. Species that are thought to offer rewards in the form of nutrient-rich labellar secretions or papillae were distinctively scented. These species release volatiles that are characteristic of euglossophilous flowers (flowers pollinated by euglossine bees).
Remarkably, subtribe Pleurothallidinae (Orchidaceae) accounts for 15-20% of total orchid diversity with>4,000 species in 29 genera. One of the most extraordinary genera of 'pleurothallids' is Porroglossum, which accounts for 54 described species that are distributed throughout Andean cloud forests in South America. In actuality, the flowers of Porroglossum set it apart from nearly all other 'pleurothallids' because the labellum, when physically stimulated, actively snaps inward thrusting pollinators against the column to ensure pollination. Porroglossum is also an exceedingly young plant lineage that arose between approximately 3 and 4 million years ago. Despite the evolution of an elaborate pollination trap, little is known about the biology of Porroglossum, which presents unique opportunities for evolutionary studies. As a result, we present the first phylogenetic study of the genus Porroglossum. By sequencing multiple genetic markers, we achieve good resolution and support, which allows us to propose a revised subgeneric classification system incertae sedis. Additionally, we found that individual gene trees vary in terms of resolution and statistical support. In particular, we note that species P. sergioi and P. teaguei switch clades when comparing the plastid and nuclear datasets, which suggests potential hybridization when coupled with geographic data that indicates sympatry among their proposed parents. Moreover, we employ Next-Generation Sequencing, in the form of genotyping-by-sequencing, to address phylogenetic uncertainty that stems from the Sanger sequencing study. The GBS study illustrates the importance of extensive parameter testing when reconstructing the evolutionary history of non-model organisms with de novo assembled loci. Specifically, parameter testing helps maximize the recovery of phylogenetically informative characters while reducing the amount of sequencing errors and paralogs in the final dataset. This results in unprecedented resolution thereby resolving deep internal nodes as well as interspecific relationships within Porroglossum. Furthermore, we present the first kinematics study in a phylogenetic context that addresses the active floral snap-trap. Continuous traits appear to be strongly correlated with the evolutionary history of Porroglossum. Within the genus, we note clades with delayed and undelayed snap-traps that take multiple minutes or only a few seconds to close respectively. Lastly, snap-trap traits appear to be correlated with elevation.
This action plan chronicles the threats faced by wild orchids, but more importantly to critical habitats that host extraordinarily high orchid diversity and endemicity. It explores and recommends specific ways that national and local government, legislators, scientists and orchid conservationists as well as growers can all help to reverse present trends. The facts and viewpoints presented in this comprehensive document update and supplement the information available to conservation organizations and agencies through the world so that they can lobby their appropriate government offices more effectively.
Pollen studies make important contributions nature, into three main themes: pollen struc to our knowledge in many interdisciplinary ture and constituents, pollen evolutionary arenas. Pollen identification is widely used in ecology and the pollen-pollinator interface. reconstruction of, e.g., vegetation, the climate Several papers overlap somewhat or are of the past, and plant biodiversity. Studies perhaps even somewhat contradictory and concerning pollen structure, size and form are reflect the author's own ideas and experience. key issues in basic sciences, as, e.g., plant Some could be understood more deeply by taxonomy and evolution, but are also of consulting other closely related articles. The importance in applied fields as, e.g., plant reader is strongly referred to the respective breeding. In pollination studies pollen is literature list of each article. generally used specifically to identify food ofanther ripening and pollen The last steps development (Pacini) and the mature pollen sources of visitors and to reconstruct their foraging routes. Fewer have been devoted to wall structure (Hesse) are key factors to pollen collection mechanisms and to the struc understand pollen dispersal mechanisms in ture and content of pollen in relation to its biotic pollination (Stroo) as well as abiotic pollination (Ackerman). Pollen size, shape, function.
This book contains a detailed survey of the biology of terrestrial orchids, from seed dispersal to establishment and life of the adult plant.