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Janes JK, van der Voort GE, Huber DPW. We know very little about pollination in the Platanthera Rich (Orchidaceae: Orchidoideae). Ecol Evol 2024; 14:e11223. [PMID: 38606342 PMCID: PMC11007262 DOI: 10.1002/ece3.11223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 03/06/2024] [Accepted: 03/15/2024] [Indexed: 04/13/2024] Open
Abstract
The Platanthera Rich. (Orchidoideae) comprise a speciose genus of orchids primarily in the northern hemisphere, with up to 200 known species worldwide. Individual species are known to self-pollinate, but many rely on insect pollinators with characteristics such as floral color, timing of floral odor emissions, nectar rewards, and spur length associated with particular pollination syndromes. As with many orchids, some orchid-pollinator associations are likely highly co-evolved, but we also know that some Platanthera spp. are the result of hybridization events, which implies a lack of pollinator fidelity in some cases. Some Platanthera spp. occur in large numbers which, coupled with the numerous Platanthera-pollinator systems, make them accessible as study species and useful for co-evolutionary studies. Due to the likely effects of climate change and ongoing development on Platanthera spp. habitats, these orchids and their associated pollinators should be a focus of conservation attention and management. However, while there is a fairly substantial literature coverage of Platanthera-pollinator occurrence and interactions, there are still wide gaps in our understanding of the species involved in these systems. In this systematic review, we outline what is current knowledge and provide guidance on further research that will increase our understanding of orchid-insect co-evolutionary relationships. Our review covers 157 orchid species and about 233 pollinator species interacting with 30 Platanthera spp. We provide analyses on aspects of these interactions such as flower morphology, known insect partners of Platanthera species, insect-Platanthera specificity, pollination visitor timing (diurnal vs. nocturnal), floral rewards, and insect behavior affecting pollination outcomes (e.g., pollinia placement). A substantial number of Platanthera spp. and at least a few of their known pollinators are of official (IUCN) conservation concern - and many of their pollinators remain unassessed or even currently unknown - which adds to the urgency of further research on these co-evolved relationships.
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Affiliation(s)
- Jasmine K Janes
- Biology Department Vancouver Island University Nanaimo British Columbia Canada
- Faculty of Environment University of Northern British Columbia Prince George British Columbia Canada
- IUCN, Species Survival Commission, Orchid Specialist Group
| | - Genevieve E van der Voort
- Faculty of Environment University of Northern British Columbia Prince George British Columbia Canada
| | - Dezene P W Huber
- Faculty of Environment University of Northern British Columbia Prince George British Columbia Canada
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Bateman RM, Stott KM, Pearce DF. Trait analysis in a population of the Greater Butterfly-orchid observed through a 16-year period. FRONTIERS IN PLANT SCIENCE 2023; 14:1213250. [PMID: 37615028 PMCID: PMC10442717 DOI: 10.3389/fpls.2023.1213250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 07/05/2023] [Indexed: 08/25/2023]
Abstract
A large English population of the temperate tuberous Greater Butterfly-orchid, Platanthera chlorantha, was monitored through a 16-year period. Each June the number of flowering plants was counted and 60 flowering plants were measured in situ for four morphological traits, selected for both ease of measurement and their contrasting contributions to the life history of the species. Trait data were tested annually in pairwise combinations for individual plants, before mean values throughout the study period were regressed and cross-correlated against each other and against local data for four meteorological parameters. Labellar spur length proved to be more constrained than either flower number or stem height, and rarely yielded statistically significant correlations with other traits, whereas the three remaining traits reliably showed modest but significant correlations. Mean values and coefficients of variation differed only modestly among years and showed few of any meaningful trends. Spring rainfall and insolation had no detectable effect on traits of plants flowering that June; instead, they impacted on trait expression during the following year, presumably as a result of differential resourcing of replacement tubers formed during the previous year. High spring rainfall in year t-1 increased leaf area and stem height in year t, whereas the widely fluctuating number of flowering plants was highest in years immediately following those characterised by relatively dry and/or sunny springs. The "decision" to flower is taken during the previous summer, though it may be modified through winter/spring abortion of above-ground organs. The proportion of the population electing to flower is the only measured parameter that impacts significantly on annual reproductive output, emphasising the under-rated difficulty of evolving through directional selection. Any attempt to predict the behaviour of plant species in response to climate change must integrate information on demography with that on life history, habitat preference and intimate symbioses.
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Lin DL, Ya JD, Schuiteman A, Ma CB, Liu C, Guo XL, Chen SS, Wang XL, Zhang ZR, Yu WB, Jin XH. Four new species and a new record of Orchidinae (Orchidaceae: Orchideae) from China. PLANT DIVERSITY 2021; 43:390-400. [PMID: 34816064 PMCID: PMC8591144 DOI: 10.1016/j.pld.2021.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 05/21/2021] [Accepted: 05/23/2021] [Indexed: 06/13/2023]
Abstract
Four new species of Orchidaceae from China, Heminium lijiangense, Peristylus fasciculatus, Platanthera milinensis, and Ponerorchis gongshanensis, together with a new country record, Peristylus tenuicallus, are described and illustrated based on morphological and/or phylogenetic analyses. Heminium lijiangense is closely related to H. elisabethae but differs from it by having the dorsal sepal ovate-orbicular and lip mid-lobe distinctly shorter than lateral lobes. P. fasciculatus is close to Peristylus tradescantifolius but is distinguished from it by having several fascicled and straight, root-like tubers (vs. one or two oblongoid tubers), old stems usually persistent, middle lobe of lip narrowly ligulate-lanceolate and half as long as the lateral lobes (vs. middle lobe deltoid, about a third as long as the lateral lobes or less), a raised callus at the base of each lateral lobe (vs. callus absent), spur gradually attenuate toward the apex (vs. spur clavate). Platanthera milinensis is similar to P. stenochila by sharing small green flowers and lip without a spur, but differs in having a creeping rhizome, a corymbose inflorescence, and a broadly ovate and slightly 3-lobed lip. Ponerochis gongshanensis is similar to P. faberi in its small flowers, but differs in having a linear leaf c. 3 mm wide (vs. leaf 5-13 mm wide), in the lip having collar-like raised margins on the sides of the spur entrance, and a mid-lobe which is notched at the apex but not divided into two divergent lobules that are nearly as large as the lateral lobes, as in P. faberi. All the proposed species obtained high support in phylogenetic analysis as new species. The recently described genus Apetalanthe is reduced to synonymy of Ponerorchis and a new combination is made.
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Affiliation(s)
- Dong-Liang Lin
- State Key Laboratory of Systematic and Evolutionary Botany and Herbarium, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ji-Dong Ya
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Lanhei Road 132, Heilongtan, Kunming, Yunnan, 650201, China
| | - André Schuiteman
- Herbarium, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK
| | - Chong-Bo Ma
- State Key Laboratory of Systematic and Evolutionary Botany and Herbarium, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing, 100093, China
| | - Cheng Liu
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Lanhei Road 132, Heilongtan, Kunming, Yunnan, 650201, China
| | - Xue-Lian Guo
- State Key Laboratory of Systematic and Evolutionary Botany and Herbarium, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing, 100093, China
| | - Shi-Si Chen
- State Key Laboratory of Systematic and Evolutionary Botany and Herbarium, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing, 100093, China
| | - Xi-Long Wang
- Tibet Plateau Institute of Biology, Lhasa, Xizang 850001, China
| | - Zhi-Rong Zhang
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Lanhei Road 132, Heilongtan, Kunming, Yunnan, 650201, China
| | - Wen-Bin Yu
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Mengla 666303, Yunnan, China
| | - Xiao-Hua Jin
- State Key Laboratory of Systematic and Evolutionary Botany and Herbarium, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing, 100093, China
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Hetherington-Rauth MC, Johnson MTJ. Floral Trait Evolution of Angiosperms on Pacific Islands. Am Nat 2020; 196:87-100. [DOI: 10.1086/709018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Abstract
Nectar feeding by mosquitoes is important for survival and reproduction, and hence disease transmission. However, we know little about the sensory mechanisms that mediate mosquito attraction to sources of nectar, like those of flowers, or how this information is processed in the mosquito brain. Using a unique mutualism between Aedes mosquitoes and Platanthera obtusata orchids, we reveal that the orchid’s scent mediates this mutualism. Furthermore, lateral inhibition in the mosquito’s antennal (olfactory) lobe—via the neurotransmitter GABA—is critical for the representation of the scent. These results have implications for understanding the olfactory basis of mosquito nectar-seeking behaviors. Mosquitoes are important vectors of disease and require sources of carbohydrates for reproduction and survival. Unlike host-related behaviors of mosquitoes, comparatively less is understood about the mechanisms involved in nectar-feeding decisions, or how this sensory information is processed in the mosquito brain. Here we show that Aedes spp. mosquitoes, including Aedes aegypti, are effective pollinators of the Platanthera obtusata orchid, and demonstrate this mutualism is mediated by the orchid’s scent and the balance of excitation and inhibition in the mosquito’s antennal lobe (AL). The P. obtusata orchid emits an attractive, nonanal-rich scent, whereas related Platanthera species—not visited by mosquitoes—emit scents dominated by lilac aldehyde. Calcium imaging experiments in the mosquito AL revealed that nonanal and lilac aldehyde each respectively activate the LC2 and AM2 glomerulus, and remarkably, the AM2 glomerulus is also sensitive to N,N-diethyl-meta-toluamide (DEET), a mosquito repellent. Lateral inhibition between these 2 glomeruli reflects the level of attraction to the orchid scents. Whereas the enriched nonanal scent of P. obtusata activates the LC2 and suppresses AM2, the high level of lilac aldehyde in the other orchid scents inverts this pattern of glomerular activity, and behavioral attraction is lost. These results demonstrate the ecological importance of mosquitoes beyond operating as disease vectors and open the door toward understanding the neural basis of mosquito nectar-seeking behaviors.
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Esposito F, Vereecken NJ, Gammella M, Rinaldi R, Laurent P, Tyteca D. Characterization of sympatric Platanthera bifolia and Platanthera chlorantha (Orchidaceae) populations with intermediate plants. PeerJ 2018; 6:e4256. [PMID: 29379684 PMCID: PMC5787349 DOI: 10.7717/peerj.4256] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/20/2017] [Indexed: 12/25/2022] Open
Abstract
Platanthera bifolia and P. chlorantha are terrestrial and rewarding orchids with a wide Eurasian distribution. Although genetically closely related, they exhibit significant morphological, phenological and ecological differences that maintain reproductive isolation between the species. However, where both species co-occur, individuals with intermediate phenotypic traits, often considered as hybrids, are frequently observed. Here, we combined neutral genetic markers (AFLPs), morphometrics and floral scent analysis (GC-MS) to investigate two mixed Platanthera populations where morphologically intermediate plants were found. Self-pollination experiments revealed a low level of autogamy and artificial crossings combined with assessments of fruit set and seed viability, showed compatibility between the two species. The results of the genetic analyses showed that morphologically intermediate plants had similar genetic patterns as the P. bifolia group. These results are corroborated also by floral scent analyses, which confirmed a strong similarity in floral scent composition between intermediate morphotypes and P. bifolia. Therefore, this study provided a much more detailed picture of the genetic structure of a sympatric zone between two closely allied species and supports the hypothesis that intermediate morphotypes in sympatry could reflect an adaptive evolution in response to local pollinator-mediated selection.
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Affiliation(s)
- Fabiana Esposito
- Earth and Life Institute—Biodiversity Research Centre, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Nicolas J. Vereecken
- Agroecology Lab, Brussels Bioengineering School, Université libre de Bruxelles (ULB), Brussels, Belgium
| | | | - Rosita Rinaldi
- Department of Biology, University of Naples Federico II, Napoli, Italy
| | - Pascal Laurent
- Unit of General Chemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Daniel Tyteca
- Earth and Life Institute—Biodiversity Research Centre, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
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Jin WT, Schuiteman A, Chase MW, Li JW, Chung SW, Hsu TC, Jin XH. Phylogenetics of subtribe Orchidinae s.l. (Orchidaceae; Orchidoideae) based on seven markers (plastid matK, psaB, rbcL, trnL-F, trnH-psba, and nuclear nrITS, Xdh): implications for generic delimitation. BMC PLANT BIOLOGY 2017; 17:222. [PMID: 29178835 PMCID: PMC5702240 DOI: 10.1186/s12870-017-1160-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 11/08/2017] [Indexed: 05/13/2023]
Abstract
BACKGROUND Subtribe Orchidinae (Orchidaceae, Orchidoideae) are a nearly cosmopolitan taxon of terrestrial orchids, comprising about 1800 species in 47 to 60 genera. Although much progress has been made in recent years of phylogenetics of Orchidinae, considerable problems remain to be addressed. Based on molecular phylogenetics, we attempt to illustrate the phylogenetic relationships and discuss generic delimitation within Orchidinae. Seven DNA markers (five plastid and two nuclear), a broad sampling of Orchidinae (400 species in 52 genera) and three methods of phylogenetic analysis (maximum likelihood, maximum parsimony and Bayesian inference) were used. RESULTS Orchidinae s.l. are monophyletic. Satyrium is sister to the rest of Orchidinae s.l. Brachycorythis and Schizochilus are successive sister to Asian-European Orchidinae s.s. Sirindhornia and Shizhenia are successive sister to clade formed by Tsaiorchis-Hemipilia-Ponerorchis alliance. Stenoglottis is sister to the Habenaria-Herminium-Peristylus alliance. Habenaria, currently the largest genus in Orchidinae, is polyphyletic and split into two distant clades: one Asian-Australian and the other African-American-Asian. Diplomeris is sister to Herminium s.l. plus Asian-Australian Habenaria. CONCLUSIONS We propose to recognize five genera in the Ponerorchis alliance: Hemipilia, Ponerorchis s.l., Sirindhornia, Shizhenia and Tsaiorchis. Splitting Habenaria into two genera based on morphological characters and geographical distribution may be the least disruptive approach, and it is reasonable to keep Satyrium in Orchidinae.
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Affiliation(s)
- Wei-Tao Jin
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 10093 China
| | - André Schuiteman
- Identification and Naming Department, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB UK
| | - Mark W. Chase
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS UK
- School of Plant Biology, University of Western Australia, Crawley, Perth, 6009 Australia
| | - Jian-Wu Li
- Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun Township, Mengla County, Yunnan 666303 China
| | - Shih-Wen Chung
- Botanical Garden Division, Taiwan Forestry Research Institute, 53 Nanhai Road, Taipei, Taiwan 10066 China
| | - Tian-Chuan Hsu
- Department of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan 30013 China
| | - Xiao-Hua Jin
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 10093 China
- Southeast Asia Biodiversity Research Institute, Chinese Academy of Science (CAS-SEABRI), Yezin, Nay Pyi Taw, Myanmar
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Saarela JM, Sokoloff PC, Bull RD. Vascular plant biodiversity of the lower Coppermine River valley and vicinity (Nunavut, Canada): an annotated checklist of an Arctic flora. PeerJ 2017; 5:e2835. [PMID: 28194307 PMCID: PMC5300018 DOI: 10.7717/peerj.2835] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/28/2016] [Indexed: 11/30/2022] Open
Abstract
The Coppermine River in western Nunavut is one of Canada's great Arctic rivers, yet its vascular plant flora is poorly known. Here, we report the results of a floristic inventory of the lower Coppermine River valley and vicinity, including Kugluk (Bloody Falls) Territorial Park and the hamlet of Kugluktuk. The study area is approximately 1,200 km2, extending from the forest-tundra south of the treeline to the Arctic coast. Vascular plant floristic data are based on a review of all previous collections from the area and more than 1,200 new collections made in 2014. Results are presented in an annotated checklist, including citation of all specimens examined, comments on taxonomy and distribution, and photographs for a subset of taxa. The vascular plant flora comprises 300 species (311 taxa), a 36.6% increase from the 190 species documented by previous collections made in the area over the last century, and is considerably more diverse than other local floras on mainland Nunavut. We document 207 taxa for Kugluk (Bloody Falls) Territorial Park, an important protected area for plants on mainland Nunavut. A total of 190 taxa are newly recorded for the study area. Of these, 14 taxa (13 species and one additional variety) are newly recorded for Nunavut (Allium schoenoprasum, Carex capitata, Draba lonchocarpa, Eremogone capillaris subsp. capillaris, Sabulina elegans, Eleocharis quinqueflora, Epilobium cf. anagallidifolium, Botrychium neolunaria, Botrychium tunux, Festuca altaica, Polygonum aviculare, Salix ovalifolia var. arctolitoralis, Salix ovalifolia var. ovalifolia and Stuckenia pectinata), seven species are newly recorded for mainland Nunavut (Carex gynocrates, Carex livida, Cryptogramma stelleri, Draba simmonsii, Festuca viviparoidea subsp. viviparoidea, Juncus alpinoarticulatus subsp. americanus and Salix pseudomyrsinites) and 56 range extensions are reported. The psbA-trnH and rbcL DNA sequence data were used to help identify the three Botrychium taxa recorded in the study area. Three new combinations are proposed: Petasites frigidus subsp. sagittatus (Banks ex Pursh) Saarela, Carex petricosa subsp. misandroides (Fernald) Saarela and Carex simpliciuscula subsp. subholarctica (T. V. Egorova) Saarela.
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Affiliation(s)
- Jeffery M. Saarela
- Botany Section and Centre for Arctic Knowledge & Exploration, Research and Collections, Canadian Museum of Nature, Ottawa, ON, Canada
| | - Paul C. Sokoloff
- Botany Section and Centre for Arctic Knowledge & Exploration, Research and Collections, Canadian Museum of Nature, Ottawa, ON, Canada
| | - Roger D. Bull
- Botany Section and Centre for Arctic Knowledge & Exploration, Research and Collections, Canadian Museum of Nature, Ottawa, ON, Canada
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Tang Y, Yukawa T, Bateman RM, Jiang H, Peng H. Phylogeny and classification of the East Asian Amitostigma alliance (Orchidaceae: Orchideae) based on six DNA markers. BMC Evol Biol 2015; 15:96. [PMID: 26006185 PMCID: PMC4479074 DOI: 10.1186/s12862-015-0376-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/08/2015] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Tribe Orchideae dominates the orchid flora of the temperate Northern Hemisphere but its representatives in East Asia had been subject to less intensive phylogenetic study than those in Eurasia and North America. Although this situation was improved recently by the molecular phylogenetic study of Jin et al., comparatively few species were analyzed from the species-rich and taxonomically controversial East Asian Amitostigma alliance. Here, we present a framework nrITS tree of 235 accessions of Orchideae plus an in-depth analysis of 110 representative accessions, encompassing most widely recognized species within the alliance, to elucidate their relationships. RESULTS We used parsimony, likelihood and Bayesian approaches to generate trees from data for two nuclear (nrITS, low-copy Xdh) and four chloroplast (matK, psbA-trnH, trnL-F, trnS-trnG) markers. Nuclear and plastid data were analyzed separately due to a few hard incongruences that most likely reflect chloroplast capture. Our results suggest key phylogenetic placements for Sirindhornia and Brachycorythis, and confirm previous assertions that the Amitostigma alliance is monophyletic and sister to the Eurasian plus European clades of subtribe Orchidinae. Seven robust clades are evident within the alliance, but none corresponds precisely with any of the traditional genera; the smaller and more morphologically distinct genera Tsaiorchis, Hemipilia, Neottianthe and Hemipiliopsis are monophyletic but each is nested within a polyphyletic plexus of species attributed to either Ponerorchis or the most plesiomorphic genus, Amitostigma. Two early-divergent clades that escaped analysis by Jin et al. undermine their attempt to circumscribe an expanded monophyletic genus Ponerorchis. CONCLUSIONS We provide a new framework on the complex phylogenetic relationships between Amitostigma and other genera traditionally included in its alliance; based on which, we combine the entire Amitostigma alliance into a morphologically and molecularly circumscribed Amitostigma sensu latissimo that also contains seven molecularly circumscribed sections. Our molecular trees imply unusually high levels of morphological homoplasy, but these will need to be quantified via a future group-wide review of the alliance based on living plants if morphology is to be fully integrated into our classification.
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Affiliation(s)
- Ying Tang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Tomohisa Yukawa
- Department of Botany, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, Ibaraki, 305-0005, Japan.
| | - Richard M Bateman
- Jodrell Laboratory, Royal Botanic Gardens Kew, Richmond, Surrey, TW9 3AB, UK.
| | - Hong Jiang
- Yunnan Academy of Forestry/Yunnan Laboratory for Conservation of Rare, Endangered and Endemic Forest Plants, State Forestry Administration, Kunming, 650204, Yunnan, China.
| | - Hua Peng
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China.
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Bateman RM, Sramkó G, Rudall PJ. Floral miniaturisation and autogamy in boreal-arctic plants are epitomised by Iceland's most frequent orchid, Platanthera hyperborea. PeerJ 2015; 3:e894. [PMID: 25893148 PMCID: PMC4400879 DOI: 10.7717/peerj.894] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 03/25/2015] [Indexed: 02/04/2023] Open
Abstract
Background and Aims. This paper concludes our series of publications comparing island and mainland speciation in European butterfly-orchids, by studying the morphology, phylogenetics and reproductive biology of the controversial circum-arctic species Platanthera (Limnorchis) hyperborea-the most frequent of seven Icelandic orchids. We draw particular attention to its phylogenetic placement, remarkable reproductive biology and morphological convergence on other Platanthera lineages through floral miniaturisation. Methods. Five populations of P. hyperborea in southwest Iceland were measured for 33 morphological characters and subjected to detailed multivariate and univariate analyses, supported by light and scanning electron microscopy of selected flowers. Representative samples from six populations were sequenced for nrITS and placed in a taxonomically broader phylogenetic matrix derived from previous studies. Key Results . Section Limnorchis consists of three distinct ITS-delimited clades based on P. stricta, P. sparsifolia-limosa-aquilonis and P. dilatata-hyperborea. Within the latter group, supposed species boundaries overlap; instead, the data indicate a crude stepwise series of ribotypic transitions extending eastward from North America to Iceland. Morphometric data failed to identify any taxonomically meaningful partitions among Icelandic P. hyperborea populations, despite the presence of a distinct and apparently plesiomorphic ribotype at the most glacially influenced habitat sampled. Microscopic study of the flowers revealed several distinguishing features (some not previously reported), including resupinate lateral sepals, toothed bract margins, club-shaped papillae shared by both the interior of the labellar spur and the stigmatic surface, and an exceptionally adhesive stigma that is reliably covered in disaggregated pollen masses prior to anthesis; auricles are absent. Conclusions. Ribotypes suggest that Icelandic P. hyperborea represents the terminus of a migration route that may have begun in East Asia before passing through North America and presumably Greenland. The incohesive pollinia, rapidly desiccating anther locules, weakly developed rostellum, exceptionally adhesive stigma and the close juxtaposition of compact male and female reproductive organs together conspire to cause routine autogamy and frequent cleistogamy, despite the continued production of substantial nectar reservoirs in the spur and consequent ongoing attraction to the flowers of insects, including mosquitoes. When considered in combination with independently derived lineages of Platanthera on the Azorean and Hawaiian archipelagos also bearing small green flowers, our observations show allometric and paedomorphic reductions in flower size as the primary evolutionary driver, but also indicate strong developmental and functional constraints.
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Affiliation(s)
| | - Gábor Sramkó
- Department of Botany, University of Debrecen , Debrecen , Hungary
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Molecular systematics of subtribe Orchidinae and Asian taxa of Habenariinae (Orchideae, Orchidaceae) based on plastid matK, rbcL and nuclear ITS. Mol Phylogenet Evol 2014; 77:41-53. [DOI: 10.1016/j.ympev.2014.04.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 03/30/2014] [Accepted: 04/03/2014] [Indexed: 11/19/2022]
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Bateman RM, Rudall PJ, Bidartondo MI, Cozzolino S, Tranchida-Lombardo V, Carine MA, Moura M. Speciation via floral heterochrony and presumed mycorrhizal host switching of endemic butterfly orchids on the Azorean archipelago. AMERICAN JOURNAL OF BOTANY 2014; 101:979-1001. [PMID: 24907253 DOI: 10.3732/ajb.1300430] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
• Premise of the study: Most orchid species native to the Macaronesian islands reflect immigration from western Europe or North Africa followed by anagenesis. The only putative exception is the butterfly orchids (Platanthera) of the Azores, where three species apparently reflect at least one cladogenetic speciation event. This multidisciplinary study explores the origin, speciation, phenotypic, and genotypic cohesion of these Azorean species and their mainland relatives.• Methods: Plants of Platanthera from 30 localities spanning all nine Azorean islands were compared with those of four continental European relatives for 38 morphometric characters; substantial subsets were also analyzed for plastid microsatellites, and for nrITS of both the orchids and their mycorrhizae.• Key results: Although the three Azorean and four mainland species are all readily distinguished morphometrically using several floral characters, and hybridization appears rare, divergence in ITS and especially plastid sequences is small. Despite occupying similar laurisilva habitats, the Azorean species differ radically in the identities and diversity of their mycorrhizal partners; specialism apparently increases rarity.• Conclusions: Although morphological evidence suggests two invasions of the islands from NW Africa and/or SW Europe, ITS data imply only one. As the molecular data are unable to distinguish among the potential mainland ancestors, two scenarios of relationship are explored that imply different ancestors. Both scenarios require both anagenetic and cladogenetic speciation events, involving homoplastic shifts in overall flower size and (often substantial) changes in the relative dimensions of individual floral organs. Limited genotypic divergence among the three species compared with greater phenotypic divergence suggests comparatively recent speciation. Mycorrhizae may be the most critical factor dictating the respective ecological tolerances, and thus the relative frequencies, of these species. The recent IUCN Red-List amalgamation of Azorean Platanthera taxa into a single species urgently requires reappraisal, as P. micrantha is an excellent indicator species of seminatural laurisilva forest and P. azorica is arguably Europe's rarest orchid.
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Affiliation(s)
| | - Paula J Rudall
- Royal Botanic Gardens Kew, Richmond, Surrey, TW9 3AB, UK
| | - Martin I Bidartondo
- Royal Botanic Gardens Kew, Richmond, Surrey, TW9 3AB, UK Imperial College London, London, SW7 2AZ, UK
| | - Salvatore Cozzolino
- Department of Biology, University Federico II of Naples, Naples, I-80126, Italy
| | | | - Mark A Carine
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Mónica Moura
- CIBIO Research Center in Biodiversity and Genetic Resources-Azores, Department of Biology, University of the Azores, Rua Mae de Deus 58, Apartado 1422, 9501-801 Ponta Delgada, Portugal
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Bateman RM, Rudall PJ, Moura M. Systematic revision of Platanthera in the Azorean archipelago: not one but three species, including arguably Europe's rarest orchid. PeerJ 2013; 1:e218. [PMID: 24392284 PMCID: PMC3869205 DOI: 10.7717/peerj.218] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/08/2013] [Indexed: 11/20/2022] Open
Abstract
Background and Aims. The Macaronesian islands represent an excellent crucible for exploring speciation. This dominantly phenotypic study complements a separate genotypic study, together designed to identify and circumscribe Platanthera species (butterfly-orchids) on the Azores, and to determine their geographic origin(s) and underlying speciation mechanism(s). Methods. 216 individuals of Platanthera from 30 Azorean localities spanning all nine Azorean islands were measured for 38 morphological characters, supported by light and scanning electron microscopy of selected flowers. They are compared through detailed multivariate and univariate analyses with four widespread continental European relatives in the P. bifolia-chlorantha aggregate, represented by 154 plants from 25 populations, and with the highly misleading original taxonomic descriptions. Physiographic and ecological data were also recorded for each study population. Key Results. Despite limited genetic divergence, detailed phenotypic survey reveals not one or two but three discrete endemic species of Platanthera that are readily distinguished using several characters, most floral: P. pollostantha (newly named, formerly P. micrantha) occupies the widest range of habitats and altitudes and occurs on all nine islands; P. micrantha (formerly P. azorica) occurs on eight islands but is restricted to small, scattered populations in laurisilva scrub; the true P. azorica appears confined to a single volcanigenic ridge on the central island of São Jorge. Conclusions. Although hybridity seems low, the excess of phenotypic over genotypic divergence suggests comparatively recent speciation. The most probable of several credible scenarios is that Azorean Platantheras represent a single migration to the archipelago of airborne seed from ancestral population(s) located in southwest Europe rather than North America, originating from within the P. bifolia-chlorantha aggregate. We hypothesise that an initial anagenetic speciation event, aided by the founder effect, was followed by the independent origins of at least one of the two rarer endemic species from within the first-formed endemic species, via a cladogenetic speciation process that involved radical shifts in floral development, considerable phenotypic convergence, and increased mycorrhizal specificity. The recent amalgamation by IUCN of Azorean Platantheras into a single putative species on their Red List urgently requires overruling, as (a) P. azorica is arguably Europe's rarest bona fide orchid species and (b) the almost equally rare P. micrantha is one of the best indicators of semi-natural laurisilva habitats remaining on the Azores. Both species are threatened by habitat destruction and invasive alien plants. These orchids constitute a model system that illustrates the general advantages of circumscribing species by prioritising field-based over herbarium-based morphological approaches.
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Affiliation(s)
| | | | - Mónica Moura
- CIBIO Research Center in Biodiversity and Genetic Resources – Azores, Department of Biology, University of the Azores, Ponta Delgada, Portugal
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Bateman RM, James KE, Rudall PJ. Contrast in levels of morphological versus molecular divergence between closely related Eurasian species ofPlatanthera(Orchidaceae) suggests recent evolution with a strong allometric component. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/2042349712y.0000000013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Inda LA, Pimentel M, Chase MW. Phylogenetics of tribe Orchideae (Orchidaceae: Orchidoideae) based on combined DNA matrices: inferences regarding timing of diversification and evolution of pollination syndromes. ANNALS OF BOTANY 2012; 110:71-90. [PMID: 22539542 PMCID: PMC3380586 DOI: 10.1093/aob/mcs083] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 03/01/2012] [Indexed: 05/03/2023]
Abstract
BACKGROUND AND AIMS Tribe Orchideae (Orchidaceae: Orchidoideae) comprises around 62 mostly terrestrial genera, which are well represented in the Northern Temperate Zone and less frequently in tropical areas of both the Old and New Worlds. Phylogenetic relationships within this tribe have been studied previously using only nuclear ribosomal DNA (nuclear ribosomal internal transcribed spacer, nrITS). However, different parts of the phylogenetic tree in these analyses were weakly supported, and integrating information from different plant genomes is clearly necessary in orchids, where reticulate evolution events are putatively common. The aims of this study were to: (1) obtain a well-supported and dated phylogenetic hypothesis for tribe Orchideae, (ii) assess appropriateness of recent nomenclatural changes in this tribe in the last decade, (3) detect possible examples of reticulate evolution and (4) analyse in a temporal context evolutionary trends for subtribe Orchidinae with special emphasis on pollination systems. METHODS The analyses included 118 samples, belonging to 103 species and 25 genera, for three DNA regions (nrITS, mitochondrial cox1 intron and plastid rpl16 intron). Bayesian and maximum-parsimony methods were used to construct a well-supported and dated tree. Evolutionary trends in the subtribe were analysed using Bayesian and maximum-likelihood methods of character evolution. KEY RESULTS The dated phylogenetic tree strongly supported the recently recircumscribed generic concepts of Bateman and collaborators. Moreover, it was found that Orchidinae have diversified in the Mediterranean basin during the last 15 million years, and one potential example of reticulate evolution in the subtribe was identified. In Orchidinae, pollination systems have shifted on numerous occasions during the last 23 million years. CONCLUSIONS The results indicate that ancestral Orchidinae were hymenopteran-pollinated, food-deceptive plants and that these traits have been dominant throughout the evolutionary history of the subtribe in the Mediterranean. Evidence was also obtained that the onset of sexual deception might be linked to an increase in labellum size, and the possibility is discussed that diversification in Orchidinae developed in parallel with diversification of bees and wasps from the Miocene onwards.
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Affiliation(s)
- Luis A Inda
- Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, carretera de Cuarte s/n., Huesca, Spain.
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Yagame T, Orihara T, Selosse MA, Yamato M, Iwase K. Mixotrophy of Platanthera minor, an orchid associated with ectomycorrhiza-forming Ceratobasidiaceae fungi. THE NEW PHYTOLOGIST 2012; 193:178-187. [PMID: 21995447 DOI: 10.1111/j.1469-8137.2011.03896.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
• We investigated the fungal symbionts and carbon nutrition of a Japanese forest photosynthetic orchid, Platanthera minor, whose ecology suggests a mixotrophic syndrome, that is, a mycorrhizal association with ectomycorrhiza (ECM)-forming fungi and partial exploitation of fungal carbon. • We performed molecular identification of symbionts by PCR amplifications of the fungal ribosomal DNA on hyphal coils extracted from P. minor roots. We tested for a (13)C and (15)N enrichment characteristic of mixotrophic plants. We also tested the ectomycorrhizal abilities of orchid symbionts using a new protocol of direct inoculation of hyphal coils onto roots of Pinus densiflora seedlings. • In phylogenetic analyses, most isolated fungi were close to ECM-forming Ceratobasidiaceae clades previously detected from a few fully heterotrophic orchids or environmental ectomycorrhiza surveys. The direct inoculation of fungal coils of these fungi resulted in ectomycorrhiza formation on P. densiflora seedlings. Stable isotope analyses indicated mixotrophic nutrition of P. minor, with fungal carbon contributing from 50% to 65%. • This is the first evidence of photosynthetic orchids associated with ectomycorrhizal Ceratobasidiaceae taxa, confirming the evolution of mixotrophy in the Orchideae orchid tribe, and of ectomycorrhizal abilities in the Ceratobasidiaceae. Our new ectomycorrhiza formation technique may enhance the study of unculturable orchid mycorrhizal fungi.
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Affiliation(s)
- Takahiro Yagame
- Fungus/Mushroom Resource and Research Center, Faculty of Agriculture, Tottori University 4-101 Koyama-Minami, Tottori, 680-8553, Japan
| | - Takamichi Orihara
- Kanagawa Prefectural Museum of Natural History 499 Iryuda, Odawara, Kanagawa 250-0031, Japan
- The United Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-cho-minami, Tottori 680-8553, Japan
| | - Marc-André Selosse
- Centre d' Ecologie Fonctionnelle et Evolutive, 1919 Route de Mende, F-34293 Montpellier Cedex 5, France
| | - Masahide Yamato
- Fungus/Mushroom Resource and Research Center, Faculty of Agriculture, Tottori University 4-101 Koyama-Minami, Tottori, 680-8553, Japan
| | - Koji Iwase
- Department of Natural and Environmental Science Teikyo University of Science 2525 Yatsusawa, Uenohara 409-0193, Japan
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Baldwin BG, Wagner WL. Hawaiian angiosperm radiations of North American origin. ANNALS OF BOTANY 2010; 105:849-79. [PMID: 20382966 PMCID: PMC2876002 DOI: 10.1093/aob/mcq052] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2009] [Revised: 12/10/2009] [Accepted: 02/01/2010] [Indexed: 05/12/2023]
Abstract
BACKGROUND Putative phytogeographical links between America (especially North America) and the Hawaiian Islands have figured prominently in disagreement and debate about the origin of Pacific floras and the efficacy of long-distance (oversea) plant dispersal, given the obstacles to explaining such major disjunctions by vicariance. SCOPE Review of past efforts, and of progress over the last 20 years, toward understanding relationships of Hawaiian angiosperms allows for a historically informed re-evaluation of the American (New World) contribution to Hawaiian diversity and evolutionary activity of American lineages in an insular setting. CONCLUSIONS Temperate and boreal North America is a much more important source of Hawaiian flora than suggested by most 20th century authorities on Pacific plant life, such as Fosberg and Skottsberg. Early views of evolution as too slow to account for divergence of highly distinctive endemics within the Hawaiian geological time frame evidently impeded biogeographical understanding, as did lack of appreciation for the importance of rare, often biotically mediated dispersal events and ecological opportunity in island ecosystems. Molecular phylogenetic evidence for North American ancestry of Hawaiian plant radiations, such as the silversword alliance, mints, sanicles, violets, schiedeas and spurges, underlines the potential of long-distance dispersal to shape floras, in accordance with hypotheses championed by Carlquist. Characteristics important to colonization of the islands, such as dispersibility by birds and ancestral hybridization or polyploidy, and ecological opportunities associated with 'sky islands' of temperate or boreal climate in the tropical Hawaiian archipelago may have been key to extensive diversification of endemic lineages of North American origin that are among the most species-rich clades of Hawaiian plants. Evident youth of flowering-plant lineages from North America is highly consistent with recent geological evidence for lack of high-elevation settings in the Hawaiian chain immediately prior to formation of the oldest, modern high-elevation island, Kaua'i.
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Affiliation(s)
- Bruce G. Baldwin
- Jepson Herbarium and Department of Integrative Biology, University of California, Berkeley, CA 94720-2465, USA
| | - Warren L. Wagner
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington 20013-7012, DC, USA
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Fay MF, Chase MW. Orchid biology: from Linnaeus via Darwin to the 21st century. Preface. ANNALS OF BOTANY 2009; 104:359-64. [PMID: 19654223 PMCID: PMC2720656 DOI: 10.1093/aob/mcp190] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Orchidaceae are the largest family of flowering plants, with at least 24,000 species, and perhaps better than any other family of flowering plants, orchids represent the extreme specializations that are possible. As a result, they have long fascinated luminaries of the botanical world including Linnaeus and Darwin, but the size of the family has historically been an impediment to their study. Specifically, the lack of detailed information about relationships within the family made it difficult to formulate explicit evolutionary hypotheses for such a large group, but the advent of molecular systematics has revolutionized our understanding of the orchids. Their complex life histories make orchids particularly vulnerable to environmental change, and as result many are now threatened with extinction. In this Special Issue we present a series of 20 papers on orchid biology ranging from phylogenetics, floral evolutionary development, taxonomy, mycorrhizal associations, pollination biology, population genetics and conservation.
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Affiliation(s)
- Michael F Fay
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, UK.
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