The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Richard M. K. Saunders - One of the best experts on this subject based on the ideXlab platform.
-
Specificity of assemblage, not fungal partner species, explains mycorrhizal partnerships of mycoheterotrophic Burmannia plants.
The ISME journal, 2021Co-Authors: Zhongtao Zhao, Vincent S F T Merckx, Richard M. K. Saunders, Ming Fai Liu, Dianxiang ZhangAbstract:Mycoheterotrophic plants (MHPs) growing on arbuscular mycorrhizal fungi (AMF) usually maintain specialized mycorrhizal associations. The level of specificity varies between MHPs, although it remains largely unknown whether interactions with mycorrhizal fungi differ by plant lineage, species, and/or by population. Here, we investigate the mycorrhizal interactions among Burmannia species (Burmanniaceae) with different trophic modes using high-throughput DNA sequencing. We characterized the inter- and intraspecific dynamics of the fungal communities by assessing the composition and diversity of fungi among sites. We found that fully mycoheterotrophic species are more specialized in their fungal associations than chlorophyllous species, and that this specialization possibly results from the gradual loss of some fungal groups. In particular, although many fungal species were shared by different Burmannia species, fully MHP species typically host species-specific fungal assemblages, suggesting that they have a preference for the selected fungi. Although no apparent cophylogenetic relationship was detected between fungi and plants, we observe that evolutionarily closely related plants tend to have a greater proportion of shared or closely related fungal partners. Our findings suggest a host preference and specialization toward fungal assemblages in Burmannia, improving understanding of interactions between MHPs and fungi.
-
Thismia tentaculata (Burmanniaceae tribe Thismieae) from Hong Kong: first record of the genus and tribe from continental China
Journal of Systematics and Evolution, 2009Co-Authors: Shek Shing Mar, Richard M. K. SaundersAbstract:Thismia tentaculata (Burmanniaceae 部落 Thismieae ) 的人口在香港从傣族瞬间掸人被描述并且说明，南部的中国。这从大陆人中国代表类和部落的第一份报告。
-
Thismia taiwanensis sp. nov. (Burmanniaceae tribe Thismieae): First Record of the Tribe in China
Systematic Botany, 2002Co-Authors: Sheng-zehn Yang, Richard M. K. Saunders, Chung-jou HsuAbstract:A new holomycotrophic species, Thismia taiwanensis (Burmanniaceae), is described and illustrated from Kaohsiung County, south-central Taiwan. It most closely resembles the Japanese species T. abei and T. tuberculata, but is distinct as the flowers are subsessile, the outer surface of the perianth tube is smooth, the outer tepals bear very short solitary appendages, and the inner tepals bear longer solitary appendages. This represents the first record of both Thismia and Burmanniaceae tribe Thismieae in China. The genus Thismia Griff. (Burmanniaceae) consists of ca. 35 species of small holomycotrophic herbs, typ- ically growing amongst leaf litter on the forest floor. The only comprehensive taxonomic monograph of the genus was published by Jonker (1938), who recognized 23 species in Thismia itself, as well as several other genera that have been subsequently reduced to syn- onymy with it, viz. Glaziocharis Taub. ex Warm. (one species), Triscyphus Taub. ex Warm. (one species), Geomitra Becc. (one species), and Scaphiophora Schltr. (two species). Jonker (1938) proposed a supraspecific classification system for Thismia, with five sections. This classifica- tion was necessarily reassessed following the accep- tance of a broader generic concept for Thismia: Hatu- sima (1976), for example, established Thismia sect. Gla- ziocharis (Taub. ex Warm.) Hatusima following the re- duction of Glaziocharis into synonymy with Thismia. Maas et al. (1986) recently proposed a comprehensive subgeneric and sectional classification for the neotrop- ical members of the genus, with several new taxa that were previously recognized as distinct genera. Although Thismia has an essentially pantropical distribution, several species have been described from warm temperate regions. In Asia, the genus extends northwards into southern Japan: T. abei (Akasawa) Ha- tusima (syn. Glaziocharis abei Akasawa) has been re- corded from Honshu, Shikoku, and Kyushu (Akasawa 1950; Shin 1974, as ''Glaziocharis sp.''; Matsumoto and Yamada 1994), and T. tuberculata Hatusima has been recorded from Kyushu (Shin 1974; Hatusima 1976). A new species of Thismia was recently collected in Kaohsiung County in south-central Taiwan; this rep- resents the first record of the genus in China. The spe- cies is formally named and described here as T. tai- wanensis S.-Z. Yang, R. M. K. Saunders & C.-J. Hsu. T
-
Reproductive biology of a mycoheterotrophic species, Burmannia wallichii (Burmanniaceae)
Botanical Journal of the Linnean Society, 2000Co-Authors: Dianxiang Zhang, Richard M. K. SaundersAbstract:The breeding system of a mycoheterotrophic species, Burmannia wallichii (Miers) Hook. f. (Burmanniaceae), is assessed using field observations, floral anatomy, pollen histochemistry and isozyme electrophoresis. The structure of the flower effectively prevents pollinators from accessing the stamens, and no pollinators were observed visiting natural populations in Hong Kong. The pollen is starch-rich but lipid-poor. Analysis of isozyme variation revealed a small proportion of polymorphic loci, a low level of total heterozygosity (HT=0.1972), and a very high overall fixation index of populations (FIT=0.6602). These results strongly suggest that B. wallichii is predominantly self-pollinated. The coefficient of gene differentiation (GST) is low (0.05), although it is suggested that this is due to genetic homogenization of populations consonant with the formation of numerous tiny «diaspora» seeds that are wind dispersed.
-
Systematics of the Burmannia coelestis complex (Burmanniaceae)
Nordic Journal of Botany, 2000Co-Authors: Dianxiang Zhang, Richard M. K. SaundersAbstract:Patterns of morphological variation in the Burmannia coelestis species complex are investigated, and three distinct species recognized. Burmannia coelestis sensu stricto (widespread in Asia, extending from eastern Nepal and Assam to New Guinea and northern Australia) possesses outer perianth lobes with conspicuous double margins running the entire lengths of the lobes. The name B. chinensis is revived for specimens from north-eastern India, southern China, northern Indochina and northern Thailand which possess outer perianth lobes with single margins or short double margins. A new species, B. filamentosa, is described from Guangdong province, China; it is distinctive in possessing narrow triangular outer and inner perianth lobes, and stamens with prominent filaments.
Hirokazu Tsukaya - One of the best experts on this subject based on the ideXlab platform.
-
Phylogenetics of the mycoheterotrophic genus Thismia (Thismiaceae: Dioscoreales) with a focus on the Old World taxa: delineation of novel natural groups and insights into the evolution of morphological traits
Botanical Journal of the Linnean Society, 2020Co-Authors: Ekaterina A Shepeleva, Vincent S F T Merckx, Kenji Suetsugu, Sahut Chantanaorrapint, Mikhail I. Schelkunov, Michal Hroneš, Michal Sochor, Martin Dančák, Izai Abs Kikuchi, Hirokazu TsukayaAbstract:Abstract Thismia is a genus of > 80 mycoheterotrophic species characterized by a peculiar appearance and complex floral morphology. A significant proportion of the species and morphological diversity of Thismia has only been uncovered in the past two decades, and new discoveries continue to be made. Given that many new data have recently become available, and the most comprehensive taxonomic revision of the genus from 1938 addresses less than half of the currently known species, previous hypotheses for species relationships and infrageneric taxonomic classification in Thismia was in need of review. Extensive molecular phylogenetic studies of Thismia at the genus level have never been presented. We investigate the phylogenetic relationships of 41 species (and one variety) of Thismia from the Old World. Our study comprises 68 specimens (for 28 of which the data were newly generated), including outgroup taxa broadly representing Thismiaceae (= Burmanniaceae p.p. sensuAPG IV, 2016), and is based on two nuclear and one mitochondrial marker. We use maximum likelihood and Bayesian inference to infer relationships among the taxa. We also constructed a morphological dataset of 12 mostly floral characters, comparing these characters to hypotheses based on molecular evidence to identify putative synapomorphies for major clades and to discuss hypotheses regarding the evolution of structural traits in the genus. Our analyses indicate that the majority of currently accepted infrageneric taxa of Thismia are polyphyletic. We find support for the monophyly of the Old World group, in which we recognize five well-supported lineages (clades); the only New World species studied appears to be related to the Neotropical genus Tiputinia. Ancestral state reconstructions demonstrate that the evolution of most morphological characters was homoplastic, but we identify characters that provide each of the five clades of Old World Thismia with a unique morphological description. The geographical distribution of the species under study is also shown to be consistent with the major clades. Our investigation provides a phylogenetic basis for the development of a novel sectional classification of Thismia reflecting morphological and geographical traits.
-
Emended description and new localities of Oxygyne shinzatoi (Burmanniaceae/Thismiaceae), with discussion of phylogenetic relationships of Oxygyne from Japan and Africa
Phytotaxa, 2019Co-Authors: Kenji Suetsugu, Takaomi Sugimoto, Hirokazu TsukayaAbstract:During a recent survey, Oxygyne specimens were discovered in three lowland evergreen forests on Okinawa Island, Japan. After morphological investigation, we identified the specimens as O. shinzatoi. Intriguingly, the colour of the specimens from one of the localities was significantly different from that of specimens collected from both the type and two of the new localities. Furthermore, morphological analysis also revealed clear differences between specimens collected from the type locality, including the type specimen, and previous descriptions of O. shinzatoi. Therefore, an amended description of O. shinzatoi is provided, based on the type and newly collected specimens. Phylogenetic relationships of Oxygyne from Japan and western Central Africa are also discussed, with consideration of the characteristics of newly discovered colour variation.
-
Flora of Bokor National Park VII: Thismia bokorensis (Burmanniaceae), a new species representing a new generic record.
Phytotaxa, 2018Co-Authors: Kenji Suetsugu, Hirokazu Tsukaya, Tomohisa Yukawa, Shuichiro Tagane, Phourin Chhang, Tetsukazu YaharaAbstract:The genus Thismia Griffith (1844: 221) of the tribe Thismieae, Burmanniaceae sensu APG IV (2016) or Thismiaceae of other authors, represents one of the most species-rich mycoheterotrophic genera and consists of more than 60 species (Jonker 1948, Merckx 2008). Considering that the majority of these species were collected only once (Jonker 1948), and that many new species have recently been discovered, especially from various Southeast Asian countries (e.g., Tsukaya & Okada 2012, Dancak et al. 2013, Nuraliev et al. 2014, 2015, Truong et al. 2014, Chantanaorrapint & Sridith 2015, Li & Bi 2013, Hrones et al. 2015, Tsukaya et al. 2017, Suetsugu et al. 2017), many more undescribed species are probably still hidden in the tropical rain forests of Southeast Asia.
-
Thismia bryndonii (Thismiaceae) , a new species from Maliau Basin, Sabah, Borneo
Phytotaxa, 2017Co-Authors: Hirokazu Tsukaya, Kenji Suetsugu, Monica SuleimanAbstract:Thismia Griffith (1845: 341) in Thismiaceae or Burmanniaceae ( sensu APG 2016) consists of more than 60 species (Ridley 1924, Jonker 1948, Stone 1980, van Steenis 1982; Merckx 2008). Many new species in this genus have been discovered, and 12 have been described after 2010 ( e.g., Dancak et al. 2013, Nuraliev et al. 2014, 2015, Chantanaorrapint & Sridith 2015, Li & Bi 2013, Hrones et al. 2015). Considering that the majority of these species were collected only once (Jonker 1948), it is likely that many more undescribed species remain hidden in the forests, particularly in the tropical rain forests of Southeast Asia. Borneo is one of the most biodiverse areas for mycoheterotrophs, and our recent botanical exploration in Borneo revealed many previously undescribed mycoheterotrophic species ( e.g., Tsukaya et al. 2011, 2014a,b, 2016, Tsukaya & Okada 2005, 2012a,b,c, 2013a,b, Tsukaya & Hidayat 2016, Tsukaya & Suetsugu 2014). In 2016, we conducted a botanical survey in the Malaiu Basin, Sabah, Borneo, with the permission of the Maliau Basin Management Committee (YS/MBMC/2016/184) and the Sabah Biodiversity Council [access license JKM/MBS.1000-2/2JLD.5(23)]. The Maliau Basin Conservation Area (MBCA) is a huge basin surrounded by sandstone ridges and covers approximately 39,000 ha. Few botanical explorations have previously been conducted in this area. During the survey, we encountered a specimen from the MBCA that apparently belongs to Thismia section Euthismia Schltr. subsect. Odoardoa Schlechter (1921: 31) because it has a free inner perianth, spreading, creeping and vermiform roots, perianth lobes equal in length and size, but it differs from all known species. Here, we describe this new species with a revised key to the species of this genus in Malesia.
-
Burmannia bengkuluensis sp. nov. (Burmanniaceae) from Sumatra
Nordic Journal of Botany, 2012Co-Authors: Hirokazu Tsukaya, Dedy DarnaediAbstract:A new species of Burmannia (Burmanniaceae), Burmannia bengkuluensis Tsukaya et Daernadi, discovered in a swamp adjacent to Bengkulu Airport, Sumatra, Indonesia, is described. It has poorly developed photosynthetic leaves and resembles B. ledermannii Jonker, described from a specimen collected in Palau, in having poorly developed leaves, narrowly 3-winged erect flowers, and in particular, funnel-shaped anthers, but differs in having dark purple flowers, longer outer perianth lobes, well-developed, fan-shaped inner perianth lobes, and a thick and short style. Sequence data on genomic DNA regions covering ITS1 and ITS2 are also provided.
Vincent S F T Merckx - One of the best experts on this subject based on the ideXlab platform.
-
Specificity of assemblage, not fungal partner species, explains mycorrhizal partnerships of mycoheterotrophic Burmannia plants.
The ISME journal, 2021Co-Authors: Zhongtao Zhao, Vincent S F T Merckx, Richard M. K. Saunders, Ming Fai Liu, Dianxiang ZhangAbstract:Mycoheterotrophic plants (MHPs) growing on arbuscular mycorrhizal fungi (AMF) usually maintain specialized mycorrhizal associations. The level of specificity varies between MHPs, although it remains largely unknown whether interactions with mycorrhizal fungi differ by plant lineage, species, and/or by population. Here, we investigate the mycorrhizal interactions among Burmannia species (Burmanniaceae) with different trophic modes using high-throughput DNA sequencing. We characterized the inter- and intraspecific dynamics of the fungal communities by assessing the composition and diversity of fungi among sites. We found that fully mycoheterotrophic species are more specialized in their fungal associations than chlorophyllous species, and that this specialization possibly results from the gradual loss of some fungal groups. In particular, although many fungal species were shared by different Burmannia species, fully MHP species typically host species-specific fungal assemblages, suggesting that they have a preference for the selected fungi. Although no apparent cophylogenetic relationship was detected between fungi and plants, we observe that evolutionarily closely related plants tend to have a greater proportion of shared or closely related fungal partners. Our findings suggest a host preference and specialization toward fungal assemblages in Burmannia, improving understanding of interactions between MHPs and fungi.
-
Phylogenetics of the mycoheterotrophic genus Thismia (Thismiaceae: Dioscoreales) with a focus on the Old World taxa: delineation of novel natural groups and insights into the evolution of morphological traits
Botanical Journal of the Linnean Society, 2020Co-Authors: Ekaterina A Shepeleva, Vincent S F T Merckx, Kenji Suetsugu, Sahut Chantanaorrapint, Mikhail I. Schelkunov, Michal Hroneš, Michal Sochor, Martin Dančák, Izai Abs Kikuchi, Hirokazu TsukayaAbstract:Abstract Thismia is a genus of > 80 mycoheterotrophic species characterized by a peculiar appearance and complex floral morphology. A significant proportion of the species and morphological diversity of Thismia has only been uncovered in the past two decades, and new discoveries continue to be made. Given that many new data have recently become available, and the most comprehensive taxonomic revision of the genus from 1938 addresses less than half of the currently known species, previous hypotheses for species relationships and infrageneric taxonomic classification in Thismia was in need of review. Extensive molecular phylogenetic studies of Thismia at the genus level have never been presented. We investigate the phylogenetic relationships of 41 species (and one variety) of Thismia from the Old World. Our study comprises 68 specimens (for 28 of which the data were newly generated), including outgroup taxa broadly representing Thismiaceae (= Burmanniaceae p.p. sensuAPG IV, 2016), and is based on two nuclear and one mitochondrial marker. We use maximum likelihood and Bayesian inference to infer relationships among the taxa. We also constructed a morphological dataset of 12 mostly floral characters, comparing these characters to hypotheses based on molecular evidence to identify putative synapomorphies for major clades and to discuss hypotheses regarding the evolution of structural traits in the genus. Our analyses indicate that the majority of currently accepted infrageneric taxa of Thismia are polyphyletic. We find support for the monophyly of the Old World group, in which we recognize five well-supported lineages (clades); the only New World species studied appears to be related to the Neotropical genus Tiputinia. Ancestral state reconstructions demonstrate that the evolution of most morphological characters was homoplastic, but we identify characters that provide each of the five clades of Old World Thismia with a unique morphological description. The geographical distribution of the species under study is also shown to be consistent with the major clades. Our investigation provides a phylogenetic basis for the development of a novel sectional classification of Thismia reflecting morphological and geographical traits.
-
Phylogenomic inference in extremis: A case study with mycoheterotroph plastomes.
American journal of botany, 2018Co-Authors: Vivienne K. Y. Lam, Vincent S F T Merckx, Hayley Darby, Gwynne S. Lim, Tomohisa Yukawa, Kurt M. Neubig, J. Richard Abbott, Gemma E. Beatty, Jim Provan, Marybel Soto GomezAbstract:PREMISE OF THE STUDY Phylogenomic studies employing large numbers of genes, including those based on plastid genomes (plastomes), are becoming common. Nonphotosynthetic plants such as mycoheterotrophs (which rely on root-associated fungi for essential nutrients, including carbon) tend to have highly elevated rates of plastome evolution, substantial genome reduction, or both. Mycoheterotroph plastomes therefore provide excellent test cases for investigating how extreme conditions impact phylogenomic inference. METHODS We used parsimony and likelihood analysis of protein-coding gene sets from published and newly completed plastomes to infer the phylogenetic placement of taxa from the 10 angiosperm families in which mycoheterotrophy evolved. KEY RESULTS Despite multiple very long branches that reflect elevated substitution rates, and frequently patchy gene recovery due to genome reduction, inferred phylogenetic placements of most mycoheterotrophic lineages in DNA-based likelihood analyses are both well supported and congruent with other studies. Amino-acid-based likelihood placements are broadly consistent with DNA-based inferences, but extremely rate-elevated taxa can have unexpected placements-albeit with weak support. In contrast, parsimony analysis is strongly misled by long-branch attraction among many distantly related mycoheterotrophic monocots. CONCLUSIONS Mycoheterotrophic plastomes provide challenging cases for phylogenomic inference, as substitutional rates can be elevated and genome reduction can lead to sparse gene recovery. Nonetheless, diverse likelihood frameworks provide generally well-supported and mutually concordant phylogenetic placements of mycoheterotrophs, consistent with recent phylogenetic studies and angiosperm-wide classifications. Previous predictions of parallel photosynthesis loss within families are supported for Burmanniaceae, Ericaceae, Gentianaceae, and Orchidaceae. Burmanniaceae and Thismiaceae should not be combined as a single family in Dioscoreales.
-
A few-gene plastid phylogenetic framework for mycoheterotrophic monocots
American journal of botany, 2016Co-Authors: Vivienne K. Y. Lam, Vincent S F T Merckx, Sean W. GrahamAbstract:PREMISE OF THE STUDY Few-gene studies with broad taxon sampling have provided major insights into phylogeny and underpin plant classification. However, they have typically excluded heterotrophic plants because of loss, pseudogenization, or rapid evolution of plastid genes. Here we performed a phylogenetic survey of three commonly retained plastid genes to assess their utility in placing mycoheterotrophs. METHODS We surveyed accD, clpP, and matK for 34 taxa from seven monocot families that include full mycoheterotrophs and a broad sampling of photosynthetic taxa. After screening for weak contaminants, we conducted phylogenetic analyses and characterized among-lineage rate variation. KEY RESULTS Likelihood analyses strongly supported local placements of fully mycoheterotrophic taxa for Corsiaceae, Iridaceae, Orchidaceae, and Petrosaviaceae, in positions consistent with other studies. Depression of likelihood bootstrap support values near mycoheterotrophic clades was alleviated when each mycoheterotrophic family was considered separately. Triuridaceae (Sciaphila) monophyly was recovered in a partitioned likelihood analysis, and the family then placed as sister to Cyclanthaceae-Pandanaceae. Burmanniaceae placed in Dioscoreales with weak to strong support depending on analysis details, and we inferred a plastid-based phylogeny for the family. Thismiaceae species may retain a plastid genome, based on accD retention. The inferred position of Thismiaceae is unstable, but was close to Taccaceae (Dioscoreales) in some analyses. CONCLUSIONS Long branches/elevated substitution rates, missing genes, and occasional contaminants are challenges for plastid-based phylogenetic inference with full mycoheterotrophs. However, most mycoheterotrophs can be readily integrated into the broad picture of plant phylogeny using several plastid genes and broad taxonomic sampling.
-
taxonomy and classification
Mycoheterotrophy - The Biology of Plants living on Fungi, 2013Co-Authors: Vincent S F T Merckx, Jonathan Kissling, Raymond E Stotler, Barbara Crandallstotler, Hiltje Maasvan De Kamer, Norman J. Wickett, Paula J Rudall, John V Freudenstein, Maarten J. M. Christenhusz, Paul J M MaasAbstract:This chapter provides a description of all plant families and genera that include putative fully mycoheterotrophic species, excluding initial and partial mycoheterotrophs. The overview covers a total of 17 families, 101 genera, and ca. 880 species. For each family and genus (except for Orchidaceae) a short morphological description is provided followed by notes on taxonomy, distribution, evolution, and ecology. For most genera a line drawing of a representative species is provided. Included families are: Aneuraceae, Burmanniaceae, Corsiaceae, Ericaceae, Gentianaceae, Gleicheniaceae, Iridaceae, Lycopodiaceae, Ophioglossaceae, Orchidaceae, Petrosaviaceae, Podocarpaceae, Polygalaceae, Psilotaceae, Schizaeaceae, Thismiaceae, and Triuridaceae.
Dianxiang Zhang - One of the best experts on this subject based on the ideXlab platform.
-
Specificity of assemblage, not fungal partner species, explains mycorrhizal partnerships of mycoheterotrophic Burmannia plants.
The ISME journal, 2021Co-Authors: Zhongtao Zhao, Vincent S F T Merckx, Richard M. K. Saunders, Ming Fai Liu, Dianxiang ZhangAbstract:Mycoheterotrophic plants (MHPs) growing on arbuscular mycorrhizal fungi (AMF) usually maintain specialized mycorrhizal associations. The level of specificity varies between MHPs, although it remains largely unknown whether interactions with mycorrhizal fungi differ by plant lineage, species, and/or by population. Here, we investigate the mycorrhizal interactions among Burmannia species (Burmanniaceae) with different trophic modes using high-throughput DNA sequencing. We characterized the inter- and intraspecific dynamics of the fungal communities by assessing the composition and diversity of fungi among sites. We found that fully mycoheterotrophic species are more specialized in their fungal associations than chlorophyllous species, and that this specialization possibly results from the gradual loss of some fungal groups. In particular, although many fungal species were shared by different Burmannia species, fully MHP species typically host species-specific fungal assemblages, suggesting that they have a preference for the selected fungi. Although no apparent cophylogenetic relationship was detected between fungi and plants, we observe that evolutionarily closely related plants tend to have a greater proportion of shared or closely related fungal partners. Our findings suggest a host preference and specialization toward fungal assemblages in Burmannia, improving understanding of interactions between MHPs and fungi.
-
Plastome of mycoheterotrophic Burmannia itoana Mak. (Burmanniaceae) exhibits extensive degradation and distinct rearrangements.
PeerJ, 2019Co-Authors: Xin Qian, Gang Yao, Zhongtao Zhao, Dianxiang ZhangAbstract:Plastomes of heterotrophs went through varying degrees of degradation along with the transition from autotrophic to heterotrophic lifestyle. Here, we identified the plastome of mycoheterotrophic species Burmannia itoana and compared it with those of its reported relatives including three autotrophs and one heterotroph (Thismia tentaculata) in Dioscoreales. B. itoana yields a rampantly degraded plastome reduced in size and gene numbers at the advanced stages of degradation. Its length is 44,463 bp with a quadripartite structure. B. itoana plastome contains 33 tentatively functional genes and six tentative pseudogenes, including several unusually retained genes. These unusual retention suggest that the inverted repeats (IRs) regions and possibility of being compensated may prolong retention of genes in plastome at the advanced stage of degradation. Otherwise, six rearrangements including four inversions (Inv1/Inv2/Inv3/Inv4) and two translocations (Trans1/Trans2) were detected in B. itoana plastome vs. its autotrophic relative B. disticha. We speculate that Inv1 may be mediated by recombination of distinct tRNA genes, while Inv2 is likely consequence of extreme gene losses due to the shift to heterotrophic lifestyle. The other four rearrangements involved in IRs and small single copy region may attribute to multiple waves of IRs and overlapping inversions. Our study fills the gap of knowledge about plastomes of heterotroph in Burmannia and provides a new evidence for the convergent degradation patterns of plastomes en route to heterotrophic lifestyle.
-
Reproductive biology of a mycoheterotrophic species, Burmannia wallichii (Burmanniaceae)
Botanical Journal of the Linnean Society, 2000Co-Authors: Dianxiang Zhang, Richard M. K. SaundersAbstract:The breeding system of a mycoheterotrophic species, Burmannia wallichii (Miers) Hook. f. (Burmanniaceae), is assessed using field observations, floral anatomy, pollen histochemistry and isozyme electrophoresis. The structure of the flower effectively prevents pollinators from accessing the stamens, and no pollinators were observed visiting natural populations in Hong Kong. The pollen is starch-rich but lipid-poor. Analysis of isozyme variation revealed a small proportion of polymorphic loci, a low level of total heterozygosity (HT=0.1972), and a very high overall fixation index of populations (FIT=0.6602). These results strongly suggest that B. wallichii is predominantly self-pollinated. The coefficient of gene differentiation (GST) is low (0.05), although it is suggested that this is due to genetic homogenization of populations consonant with the formation of numerous tiny «diaspora» seeds that are wind dispersed.
-
Systematics of the Burmannia coelestis complex (Burmanniaceae)
Nordic Journal of Botany, 2000Co-Authors: Dianxiang Zhang, Richard M. K. SaundersAbstract:Patterns of morphological variation in the Burmannia coelestis species complex are investigated, and three distinct species recognized. Burmannia coelestis sensu stricto (widespread in Asia, extending from eastern Nepal and Assam to New Guinea and northern Australia) possesses outer perianth lobes with conspicuous double margins running the entire lengths of the lobes. The name B. chinensis is revived for specimens from north-eastern India, southern China, northern Indochina and northern Thailand which possess outer perianth lobes with single margins or short double margins. A new species, B. filamentosa, is described from Guangdong province, China; it is distinctive in possessing narrow triangular outer and inner perianth lobes, and stamens with prominent filaments.
-
Burmannia larseniana (Burmanniaceae): a new species from Thailand
Nordic Journal of Botany, 1999Co-Authors: Dianxiang Zhang, Richard M. K. SaundersAbstract:Zhang, D. X. & Saunders, R. M. K. 1999. Burmannia larsenianu (Burmanniaceae): a new species from Thailand. - Nord. J. Bot. 19: 241-244. Copenhagen. ISSN 0107055X. A new semi-mycotrophic species, Burmannia larseniana, is described from northern Thailand. The species is related to B. pusilla, a species widely distributed in Cambodia, Vietnam, Burma, India and Sri Lanka, but can be easily distinguished from the latter by its succulent stem, single-veined leaf, and the outer perianth lobes with double margins that encircle the inner perianth lobes. The ecological preferences of the species are also discussed.
Saunders Rmk - One of the best experts on this subject based on the ideXlab platform.
-
Thismia tentaculata (Burmanniaceae tribe Thismieae) from Hong Kong: First record of the genus and tribe from continental China
'Wiley', 2009Co-Authors: Ss Mar, Saunders Rmk, Ho GwcAbstract:Populations of Thismia tentaculata (Burmanniaceae tribe Thismieae) are described and illustrated from Tai Mo Shan in Hong Kong, southern China. This represents the first report of the genus and tribe from continental China. © 2009 Institute of Botany, Chinese Academy of Sciences.link_to_subscribed_fulltex
-
Thismia taiwanensis sp. nov. (Burmanniaceae tribe Thismieae): First record of the tribe in China
'United States Sports Academy', 2002Co-Authors: Sz Yang, Saunders Rmk, Cj HsuAbstract:A new holomycotrophic species, Thismia taiwanensis (Burmanniaceae), is described and illustrated from Kaohsiung County, south-central Taiwan. It most closely resembles the Japanese species T. abei and T. tuberculata, but is distinct as the flowers are subsessile, the outer surface of the perianth tube is smooth, the outer tepals bear very short solitary appendages, and the inner tepals bear longer solitary appendages. This represents the first record of both Thismia and Burmanniaceae tribe Thismieae in China.link_to_subscribed_fulltex
-
Reproductive biology of a mycoheterotrophic species, Burmannia wallichii (Burmanniaceae)
'Elsevier BV', 2000Co-Authors: Zhang D, Saunders RmkAbstract:The breeding system of a mycoheterotrophic species, Burmannia wallichii (Miers) Hook. f. (Burmanniaceae), is assessed using field observations, floral anatomy, pollen histochemistry and isozyme electrophoresis. The structure of the flower effectively prevents pollinators from accessing the stamens, and no pollinators were observed visiting natural populations in Hong Kong. The pollen is starch-rich but lipid-poor. Analysis of isozyme variation revealed a small proportion of polymorphic loci, a low level of total heterozygosity (H(T) = 0.1972), and a very high overall fixation index of populations (F(IT))= 0.6602). These results strongly suggest that B. wallichii is predominantly self-pollinated. The coefficient of gene differentiation (G(ST)) is low (0.05), although it is suggested that this is due to genetic homogenization of populations consonant with the formation of numerous tiny 'diaspora' seeds that are wind dispersed. (C) 2000 The Linnean Society of London.link_to_subscribed_fulltex
-
The occurrence and taxonomic relationships of Burmannia wallichii (Burmanniaceae) in Malesia
'NEN Netherlands Standardization Institute', 1996Co-Authors: Saunders RmkAbstract:Burmannia wallichii (Miers) Hook. f. (Burmanniaceae) is shown to occur in Malesia. The similarities between this species and related saprophytic Burmannia species from Southeast Asia are discussed, and the Flora Malesiana key published by Jonker (1948) is amended accordingly. A new taxonomic description of the species is provided.link_to_subscribed_fulltex
