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The Impact of Human Pressure and Climate Change on the Habitat Availability and Protection of Cypripedium (Orchidaceae) in Northeast China. PLANTS 2021; 10:plants10010084. [PMID: 33401774 PMCID: PMC7824597 DOI: 10.3390/plants10010084] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/23/2020] [Accepted: 12/30/2020] [Indexed: 11/16/2022]
Abstract
Human pressure on the environment and climate change are two important factors contributing to species decline and overall loss of biodiversity. Orchids may be particularly vulnerable to human-induced losses of habitat and the pervasive impact of global climate change. In this study, we simulated the extent of the suitable habitat of three species of the terrestrial orchid genus Cypripedium in northeast China and assessed the impact of human pressure and climate change on the future distribution of these species. Cypripedium represents a genus of long-lived terrestrial orchids that contains several species with great ornamental value. Severe habitat destruction and overcollection have led to major population declines in recent decades. Our results showed that at present the most suitable habitats of the three species can be found in Da Xing’an Ling, Xiao Xing’an Ling and in the Changbai Mountains. Human activity was predicted to have the largest impact on species distributions in the Changbai Mountains. In addition, climate change was predicted to lead to a shift in distribution towards higher elevations and to an increased fragmentation of suitable habitats of the three investigated Cypripedium species in the study area. These results will be valuable for decision makers to identify areas that are likely to maintain viable Cypripedium populations in the future and to develop conservation strategies to protect the remaining populations of these enigmatic orchid species.
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Kaur J, Phillips C, Sharma J. Host population size is linked to orchid mycorrhizal fungal communities in roots and soil, which are shaped by microenvironment. MYCORRHIZA 2021; 31:17-30. [PMID: 33113039 DOI: 10.1007/s00572-020-00993-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 10/12/2020] [Indexed: 05/04/2023]
Abstract
Interaction with orchid mycorrhizal fungi (OMF) is essential to all members of the Orchidaceae, yet we know little about whether or how OMF abundances in substrates shape orchid populations. While root-associated OMF diversity is catalogued frequently, technological constraints have impeded the assessments of OMF communities in substrates until recently, thereby limiting the ability to link OMF communities in a habitat to population responses. Furthermore, there is some evidence that edaphic and microclimatic conditions impact OMF in soil, yet we lack an understanding of the coupled influences of abiotic environment and OMF structure on orchid population dynamics. To discover the linkages between abiotic environment, OMF community structure, and population size, we characterized the microclimatic conditions, soil physicochemistry, and OMF communities hosted by roots and soil across large and small populations of a terrestrial orchid endemic to California Floristic Province in North America. By using high-throughput sequencing of the ITS2 region of nrDNA amplified from root and soil DNAs, we determined that both roots and soil of larger populations, which were high in phosphorus but low in zinc, organic matter, and silt, were dominated by Tulasnellaceae OTUs. In comparison, roots and soil from smaller populations of the orchid hosted higher relative abundances of the Ceratobasidiaceae. In this multiyear, range-wide study that simultaneously measured habitat environmental conditions, and soil and root OMF communities, our results suggest that soil chemistry is clearly linked to soil and root OMF communities, which then likely alter and shape orchid populations.
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Affiliation(s)
- Jaspreet Kaur
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, USA.
| | - Caleb Phillips
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Jyotsna Sharma
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, USA
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Alibrandi P, Schnell S, Perotto S, Cardinale M. Diversity and Structure of the Endophytic Bacterial Communities Associated With Three Terrestrial Orchid Species as Revealed by 16S rRNA Gene Metabarcoding. Front Microbiol 2020; 11:604964. [PMID: 33519751 PMCID: PMC7839077 DOI: 10.3389/fmicb.2020.604964] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/23/2020] [Indexed: 01/13/2023] Open
Abstract
The endophytic microbiota can establish mutualistic or commensalistic interactions within the host plant tissues. We investigated the bacterial endophytic microbiota in three species of Mediterranean orchids (Neottia ovata, Serapias vomeracea, and Spiranthes spiralis) by metabarcoding of the 16S rRNA gene. We examined whether the different orchid species and organs, both underground and aboveground, influenced the endophytic bacterial communities. A total of 1,930 operational taxonomic units (OTUs) were obtained, mainly Proteobacteria and Actinobacteria, whose distribution model indicated that the plant organ was the main determinant of the bacterial community structure. The co-occurrence network was not modular, suggesting a relative homogeneity of the microbiota between both plant species and organs. Moreover, the decrease in species richness and diversity in the aerial vegetative organs may indicate a filtering effect by the host plant. We identified four hub OTUs, three of them already reported as plant-associated taxa (Pseudoxanthomonas, Rhizobium, and Mitsuaria), whereas Thermus was an unusual member of the plant microbiota. Core microbiota analysis revealed a selective and systemic ascent of bacterial communities from the vegetative to the reproductive organs. The core microbiota was also maintained in the S. spiralis seeds, suggesting a potential vertical transfer of the microbiota. Surprisingly, some S. spiralis seed samples displayed a very rich endophytic microbiota, with a large number of OTUs shared with the roots, a situation that may lead to a putative restoring process of the root-associated microbiota in the progeny. Our results indicate that the bacterial community has adapted to colonize the orchid organs selectively and systemically, suggesting an active involvement in the orchid holobiont.
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Affiliation(s)
- Pasquale Alibrandi
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
- Institute of Applied Microbiology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Sylvia Schnell
- Institute of Applied Microbiology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Silvia Perotto
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Massimiliano Cardinale
- Institute of Applied Microbiology, Justus-Liebig-University Giessen, Giessen, Germany
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
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Shao SC, Luo Y, Jacquemyn H. Co-Cultures of Mycorrhizal Fungi Do Not Increase Germination and Seedling Development in the Epiphytic Orchid Dendrobium nobile. FRONTIERS IN PLANT SCIENCE 2020; 11:571426. [PMID: 33193505 PMCID: PMC7644947 DOI: 10.3389/fpls.2020.571426] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/29/2020] [Indexed: 05/27/2023]
Abstract
Orchids are highly dependent on mycorrhizal fungi for seed germination and subsequent growth to a seedling as they provide essential carbon, water, and mineral nutrients to developing seeds. Although there is mounting evidence that orchid seeds are often colonized by multiple fungi simultaneously, most in vitro germination experiments focus on mycorrhizal monocultures and little is known about how mycorrhizal assemblages affect seed germination and growth of seedlings. In this study, we compared the effects of mycorrhizal monocultures and co-cultures on seed germination and seedling growth of the epiphytic orchid Dendrobium nobile. In situ baiting was used to isolate mycorrhizal fungi from protocorms for germination experiments. Germination experiments were conducted under two light regimes for 90 days. In total, five fungal strains were isolated from protocorms of D. nobile, indicating that the species was not highly specific to its fungal partners. Four strains (JC-01, JC-02, JC-04, and JC-05) belonged to the Serendipitaceae and one (JC-03) to the Tulasnellaceae. In vitro germination experiments showed that germination percentages were higher under light-dark conditions than under complete dark conditions, supporting previous findings that light facilitates germination in epiphytic orchids. While all strains were able to induce protocorm formation and growth into the seedling stage, large differences between fungal strains were observed. Co-cultures did not result in significantly higher seed germination percentages and seedling development than monocultures. Taken together, these results demonstrate that effects of fungal assemblages are not predictable from those of component species, and that more work is needed to better understand the role of fungal assemblages determining seed germination and subsequent growth under natural conditions.
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Affiliation(s)
- Shi-Cheng Shao
- Gardening and Horticulture Department, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Yan Luo
- Gardening and Horticulture Department, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Hans Jacquemyn
- Department of Biology, Plant Conservation and Population Biology, KU Leuven, Leuven, Belgium
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Mujica MI, Cisternas M, Claro A, Simunovic M, Pérez F. Nutrients and fungal identity affect the outcome of symbiotic germination in Bipinnula fimbriata (Orchidaceae). Symbiosis 2020. [DOI: 10.1007/s13199-020-00737-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Phillips RD, Reiter N, Peakall R. Orchid conservation: from theory to practice. ANNALS OF BOTANY 2020; 126:345-362. [PMID: 32407498 PMCID: PMC7424752 DOI: 10.1093/aob/mcaa093] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/07/2020] [Indexed: 05/21/2023]
Abstract
BACKGROUND Given the exceptional diversity of orchids (26 000+ species), improving strategies for the conservation of orchids will benefit a vast number of taxa. Furthermore, with rapidly increasing numbers of endangered orchids and low success rates in orchid conservation translocation programmes worldwide, it is evident that our progress in understanding the biology of orchids is not yet translating into widespread effective conservation. SCOPE We highlight unusual aspects of the reproductive biology of orchids that can have important consequences for conservation programmes, such as specialization of pollination systems, low fruit set but high seed production, and the potential for long-distance seed dispersal. Further, we discuss the importance of their reliance on mycorrhizal fungi for germination, including quantifying the incidence of specialized versus generalized mycorrhizal associations in orchids. In light of leading conservation theory and the biology of orchids, we provide recommendations for improving population management and translocation programmes. CONCLUSIONS Major gains in orchid conservation can be achieved by incorporating knowledge of ecological interactions, for both generalist and specialist species. For example, habitat management can be tailored to maintain pollinator populations and conservation translocation sites selected based on confirmed availability of pollinators. Similarly, use of efficacious mycorrhizal fungi in propagation will increase the value of ex situ collections and likely increase the success of conservation translocations. Given the low genetic differentiation between populations of many orchids, experimental genetic mixing is an option to increase fitness of small populations, although caution is needed where cytotypes or floral ecotypes are present. Combining demographic data and field experiments will provide knowledge to enhance management and translocation success. Finally, high per-fruit fecundity means that orchids offer powerful but overlooked opportunities to propagate plants for experiments aimed at improving conservation outcomes. Given the predictions of ongoing environmental change, experimental approaches also offer effective ways to build more resilient populations.
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Affiliation(s)
- Ryan D Phillips
- Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria, Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park, WA, Australia
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Noushka Reiter
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Royal Botanic Gardens Victoria, Corner of Ballarto Road and Botanic Drive, Cranbourne, VIC, Australia
| | - Rod Peakall
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
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Herrera H, Sanhueza T, Martiarena R, Valadares R, Fuentes A, Arriagada C. Mycorrhizal Fungi Isolated from Native Terrestrial Orchids from Region of La Araucanía, Southern Chile. Microorganisms 2020; 8:microorganisms8081120. [PMID: 32722489 PMCID: PMC7465119 DOI: 10.3390/microorganisms8081120] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 12/05/2022] Open
Abstract
Mycorrhizal interactions of orchids are influenced by several environmental conditions. Hence, knowledge of mycorrhizal fungi associated with orchids inhabiting different ecosystems is essential to designing recovery strategies for threatened species. This study analyzes the mycorrhizal associations of terrestrial orchids colonizing grassland and understory in native ecosystems of the region of La Araucanía in southern Chile. Mycorrhizal fungi were isolated from peloton-containing roots and identified based on the sequence of the ITS region. Their capacities for seed germination were also investigated. We detected Tulasnella spp. and Ceratobasidium spp. in the pelotons of the analyzed orchids. Additionally, we showed that some Ceratobasidium isolates effectively induce seed germination to differing degrees, unlike Tulasnella spp., which, in most cases, fail to achieve protocorm growth. This process may underline a critical step in the life cycle of Tulasnella-associated orchids, whereas the Ceratobasidium-associated orchids were less specific for fungi and were effectively germinated with mycorrhizal fungi isolated from adult roots.
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Affiliation(s)
- Hector Herrera
- Laboratorio de Biorremediación, Departamento de Ciencias Forestales, Facultad de Ciencias Agropecuarias y Forestales, Universidad de La Frontera, 4811230 Temuco, Chile; (H.H.); (T.S.); (A.F.)
| | - Tedy Sanhueza
- Laboratorio de Biorremediación, Departamento de Ciencias Forestales, Facultad de Ciencias Agropecuarias y Forestales, Universidad de La Frontera, 4811230 Temuco, Chile; (H.H.); (T.S.); (A.F.)
| | - Rodolfo Martiarena
- Estación Experimental Agropecuaria Montecarlo, Instituto Nacional de Tecnología Agropecuaria, Av. el Libertador 2472, Montecarlo N3384, Misiones, Argentina;
| | - Rafael Valadares
- Instituto Tecnologico Vale, Rua Boaventura da Silva 955, Cep, 66050-090 Belém, PA, Brazil;
| | - Alejandra Fuentes
- Laboratorio de Biorremediación, Departamento de Ciencias Forestales, Facultad de Ciencias Agropecuarias y Forestales, Universidad de La Frontera, 4811230 Temuco, Chile; (H.H.); (T.S.); (A.F.)
| | - Cesar Arriagada
- Laboratorio de Biorremediación, Departamento de Ciencias Forestales, Facultad de Ciencias Agropecuarias y Forestales, Universidad de La Frontera, 4811230 Temuco, Chile; (H.H.); (T.S.); (A.F.)
- Correspondence: ; Tel.: +56-045-232-5635; Fax: +56-045-234-1467
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Shao SC, Wang QX, Beng KC, Zhao DK, Jacquemyn H. Fungi isolated from host protocorms accelerate symbiotic seed germination in an endangered orchid species (Dendrobium chrysotoxum) from southern China. MYCORRHIZA 2020; 30:529-539. [PMID: 32562087 DOI: 10.1007/s00572-020-00964-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/18/2020] [Indexed: 05/03/2023]
Abstract
To ensure long-term survival of epiphytic orchids through active reintroduction, more research on critical life cycle stages such as seed germination and seedling establishment are needed. In this study, we used in vitro germination experiments to investigate the role of mycorrhizal fungi in determining seed germination and growth in the endangered epiphytic orchid species, Dendrobium chrysotoxum. Symbiotic seed germination experiments were conducted for 90 days under different light conditions with fungal strains isolated from protocorms of D. chrysotoxum and three sister species. Molecular analyses showed that five strains belonged to the typical orchid mycorrhizal family Tulasnellaceae, whereas the other two strains belonged to the Sebacinaceae and the genus Coprinellus. Fungal inoculation, light conditions, and their interaction had a significant effect on protocorm formation and seedling development. Three fungal isolates, including two from D. chrysotoxum and one from D. catenatum, significantly stimulated protocorm formation and seedling development under light conditions. However, fungi isolated from host protocorms (GC-14 and GC-15) produced the highest number of seedlings after 50 days (49.5 ± 8.5%, 51.3 ± 9.0%, respectively), while the fungus isolated from D. catenatum protocorms produced the maximum number of seedlings only after 90 days (48.7 ± 16.1%). To conclude, this study has shown that light conditions and the identity of fungi had a strong effect on in vitro seed germination and seedling formation in an epiphytic orchid, with fungi isolated from host protocorms leading to accelerated germination and seedling formation. Therefore, fungal source should be taken into account when using seeds and compatible fungi for seedling propagation and in situ reintroduction.
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Affiliation(s)
- Shi-Cheng Shao
- Gardening and Horticulture Dep artment, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla county, Yunnan, 666 303, People's Republic of China
| | - Qiu-Xia Wang
- College of Agriculture and Life Sciences, Kunming University, Kunming, 650214, People's Republic of China
| | - Kingly C Beng
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, 666303, People's Republic of China
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587, Berlin, Germany
| | - Da-Ke Zhao
- School of Life Science, Yunnan University, Kunming, 650504, People's Republic of China.
| | - Hans Jacquemyn
- Department of Biology, Plant Conservation and Population Biology, KU Leuven, Leuven, Belgium.
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59
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Is the Distribution of Two Rare Orchis Sister Species Limited by Their Main Mycobiont? DIVERSITY 2020. [DOI: 10.3390/d12070262] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
As orchids rely on their mycorrhizal fungi for nutrient supply, their spatial range is dependent on the distribution of orchid mycorrhizal (OM) fungi. We addressed possible correlations between mycorrhizal specificity and the geographic distribution of orchids and OM fungi in three populations of the rare sister species Orchis patens and O. canariensis. Metabarcoding of the fungal ITS2 region indicated that, although adult plants of either species were colonized by several ceratobasidioid, tulasnelloid, sebacinoid and serendipitoid fungi, the mycobiont spectra were dominated by Tulasnella helicospora (which occurred in 100% of examined plants with high read numbers), which is a globally distributed fungus. In vitro assays with a T. helicospora isolate obtained from O. patens indicated the effectiveness of this OM fungus at germinating seeds of its native host. At a local scale, higher read numbers for T. helicospora were found in soil samples collected underneath O. patens roots than at locations unoccupied by the orchid. Although these findings suggest that the geographical pattern of the main fungal symbiont does not limit the distribution of O. patens and O. canariensis at this scale, the actual causal link between orchid and OM fungal occurrence/abundance still needs to be better understood.
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60
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Lin M, Xiong H, Xiang X, Zhou Z, Liang L, Mei Z. The Effect of Plant Geographical Location and Developmental Stage on Root-Associated Microbiomes of Gymnadenia conopsea. Front Microbiol 2020; 11:1257. [PMID: 32625183 PMCID: PMC7314937 DOI: 10.3389/fmicb.2020.01257] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/18/2020] [Indexed: 12/26/2022] Open
Abstract
Gymnadenia conopsea (L.) R. Br. is an important perennial terrestrial photosynthetic orchid species whose microbiomes are considered to play an important role in helping its germination and growth. However, the assemblage of G. conopsea root-associated microbial communities is poorly understood. The compositions of fungal and bacterial communities from the roots and corresponding soil samples in G. conopsea across distinct biogeographical regions from two significantly different altitudes were characterized at the vegetative and reproductive growth stages. The geographical location, developmental stage and compartment were factors contributing to microbiome variation in G. conopsea. Predominant fungal taxa include Ascomycota, Basidiomycota, Mortierellomycota and Chytridiomycota, whereas Proteobacteria, Bacteroidetes, Acidobacteria, Actinobacteria, Verrucomicrobia, Chloroflexi, TM7 and Planctomycetes were predominant bacterial taxa. Using G. conopsea as a model, the structural and functional composition in G. conopsea root-associated microbiomes were comprehensive analyzed. Contrary to previous studies, biogeography was the main factor influencing the microbial community in this study. Besides, compartment and developmental stage should also be considered to analyze the variation of microbiota composition. Although the microbial composition varied greatly by location, the symbiotic microorganisms of G. conopsea still have certain specificity. This study gives an abundant information of G. conopsea root-associated microbiomes and provides new clues to better understanding the factors affecting the composition and diversity of fungal/bacterial communities associated with orchids. Our results also laying a foundation for harnessing the microbiome for sustainable G. conopsea cultivation. Moreover, these results might be generally applicable to other orchidaceae plants.
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Affiliation(s)
- Min Lin
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Hui Xiong
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Xuechuan Xiang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Zelin Zhou
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
| | - Lifeng Liang
- Institute of Ethnomedicine, South-Central University for Nationalities, Wuhan, China
| | - Zhinan Mei
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, China
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61
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Xing X, Liu Q, Gao Y, Shao S, Guo L, Jacquemyn H, Zhao Z, Guo S. The Architecture of the Network of Orchid–Fungus Interactions in Nine Co-occurring Dendrobium Species. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00130] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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62
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Freitas EFS, da Silva M, Cruz EDS, Mangaravite E, Bocayuva MF, Veloso TGR, Selosse MA, Kasuya MCM. Diversity of mycorrhizal Tulasnella associated with epiphytic and rupicolous orchids from the Brazilian Atlantic Forest, including four new species. Sci Rep 2020; 10:7069. [PMID: 32341376 PMCID: PMC7184742 DOI: 10.1038/s41598-020-63885-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 04/07/2020] [Indexed: 11/29/2022] Open
Abstract
The genus Tulasnella often forms mycorrhizas with orchids and has worldwide distribution. Species of this genus are associated with a wide range of orchids, including endangered hosts. Initially, species identification relied mostly on morphological features and few cultures were preserved for later phylogenetic comparisons. In this study, a total of 50 Tulasnella isolates were collected from their natural sites in Minas Gerais, Brazil, cultured, and subjected to a phylogenetic analysis based on alignments of sequences of the internal transcribed spacer (ITS) of the nuclear ribosomal DNA. Our results, based on phylogeny, integrated with nucleotide divergence and morphology, revealed the diversity of isolated Tulasnella species, which included four new species, namely, Tulasnella brigadeiroensis, Tulasnella hadrolaeliae, Tulasnella orchidis and Tulasnella zygopetali. The conservation of these species is important due to their association with endangered orchid hosts and endemic features in the Brazilian Atlantic Forest.
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Affiliation(s)
| | - Meiriele da Silva
- Departamento de Microbiologia, Universidade Federal de Viçosa, 36570-900, Viçosa, Minas Gerais State, Brazil
| | - Everaldo da Silva Cruz
- Departamento de Microbiologia, Universidade Federal de Viçosa, 36570-900, Viçosa, Minas Gerais State, Brazil
| | - Erica Mangaravite
- Centro Universitário Unifaminas, 36888-233, Muriaé, Minas Gerais State, Brazil
| | - Melissa Faust Bocayuva
- Departamento de Microbiologia, Universidade Federal de Viçosa, 36570-900, Viçosa, Minas Gerais State, Brazil
| | - Tomás Gomes Reis Veloso
- Departamento de Microbiologia, Universidade Federal de Viçosa, 36570-900, Viçosa, Minas Gerais State, Brazil
| | - Marc-André Selosse
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, CP 39, 57 rue Cuvier, F-750055, Paris, France
- University of Gdańsk, Faculty of Biology, ul. Wita Stwosza 59, 80-308, Gdańsk, Poland
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Tedersoo L, Bahram M, Zobel M. How mycorrhizal associations drive plant population and community biology. Science 2020; 367:367/6480/eaba1223. [PMID: 32079744 DOI: 10.1126/science.aba1223] [Citation(s) in RCA: 290] [Impact Index Per Article: 72.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Mycorrhizal fungi provide plants with a range of benefits, including mineral nutrients and protection from stress and pathogens. Here we synthesize current information about how the presence and type of mycorrhizal association affect plant communities. We argue that mycorrhizal fungi regulate seedling establishment and species coexistence through stabilizing and equalizing mechanisms such as soil nutrient partitioning, feedback to soil antagonists, differential mycorrhizal benefits, and nutrient trade. Mycorrhizal fungi have strong effects on plant population and community biology, with mycorrhizal type-specific effects on seed dispersal, seedling establishment, and soil niche differentiation, as well as interspecific and intraspecific competition and hence plant diversity.
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Affiliation(s)
- Leho Tedersoo
- Natural History Museum of Estonia, Tallinn, Estonia.
| | - Mohammad Bahram
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Martin Zobel
- Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia
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64
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Isolation and Identification of Endophytic Bacteria from Mycorrhizal Tissues of Terrestrial Orchids from Southern Chile. DIVERSITY-BASEL 2020. [DOI: 10.3390/d12020055] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Endophytic bacteria are relevant symbionts that contribute to plant growth and development. However, the diversity of bacteria associated with the roots of terrestrial orchids colonizing Andean ecosystems is limited. This study identifies and examines the capabilities of endophytic bacteria associated with peloton-containing roots of six terrestrial orchid species from southern Chile. To achieve our goals, we placed superficially disinfected root fragments harboring pelotons on oatmeal agar (OMA) with no antibiotic addition and cultured them until the bacteria appeared. Subsequently, they were purified and identified using molecular tools and examined for plant growth metabolites production and antifungal activity. In total, 168 bacterial strains were isolated and assigned to 8 OTUs. The orders Pseudomonadales, Burkholderiales, and Xanthomonadales of phylum Proteobacteria were the most frequent. The orders Bacillales and Flavobacteriales of the phylla Firmicutes and Bacteroidetes were also obtained. Phosphate solubilization was detected in majority of isolates; however, it was significantly higher in Collimonas pratensis and Chryseobacterium sp. (PSI = 1.505 ± 0.09 and 1.405 ± 0.24, respectively). Siderophore production was recorded only for C. pratensis (0.657 ± 0.14 mm day−1), Dyella marensis (0.131 ± 0.02 mm day−1), and Luteibacter rhizovicinus (0.343 ± 0.12 mm day−1). Indole acetic acid production was highly influenced by the isolate identity; however, the significantly higher activity was recorded for Pseudomonas spp. (ranging from 5.507 ± 1.57 µg mL−1 to 7.437 ± 0.99 µg mL−1). Additionally, six bacterial isolates were able to inhibit the growth of some potential plant pathogenic fungi. Our findings demonstrate the potential for plant growth promoting capabilities and some antifungal activities of endophytic bacteria inhabiting the mycorrhizal tissue of terrestrial orchids, which may contribute especially at early developmental stages of orchid seedlings.
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Alghamdi SA. Biological role of mycorrhizal fungi on the assimilation and transportation of carbon and nitrogen to Anacamptis palustris and Anacamptis laxiflor. Saudi J Biol Sci 2020; 27:465-473. [PMID: 31889872 PMCID: PMC6933280 DOI: 10.1016/j.sjbs.2019.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/11/2019] [Accepted: 11/13/2019] [Indexed: 11/28/2022] Open
Abstract
Fungal is a physiological trail and its understanding in the assimilation with the transfer of carbon (C) cum nitrogen (N) or (C/N) to orchid-seedlings have not been determined. Labelled stable isotopes 13C and 15N were used to plan the flow of C and N between orchid plants and mycorrhizal connotations in-terms of bulk transfer for C/N. This study attends to comprehend the mechanism, supporting mycorrhizal fungi which influences on orchid-seedling growth. Determined integration and transfer of C/N from amino acids (AA), ammonium nitrate (NH4NO3) and sugar for orchid-plant may lead to understand these mechanisms. This current study tries to estimate the importance of organic compounds as a source for C/N over the inorganic-NH4NO3. Generally, after begging of germination and when it is found to be associated to the nutrient resource, organic compound enhance the biomass accumulation of two orchid species. AA significantly increase the mass of 13C assimilated by two species. With amino acids the concentration of 13C in two species was greater than with NH4NO3 and sugar. At another phase, amount of 15N content shoots was a higher value in Anacamptis laxiflora shoots assimilated substantially additional of 15N with NH4NO3 plus sugar compared with ammonium nitrate only. This study showed that two terrestrial orchids species are reliant on organic compounds as a source of carbon and nitrogen more than inorganic compounds.
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Affiliation(s)
- Sameera A. Alghamdi
- Address: Department of Biological Sciences, Faculty of Science, King Abdulaziz University, P.O. Box 8020, Jeddah 21589, Jeddah, Saudi Arabia.
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Favre-Godal Q, Gourguillon L, Lordel-Madeleine S, Gindro K, Choisy P. Orchids and their mycorrhizal fungi: an insufficiently explored relationship. MYCORRHIZA 2020; 30:5-22. [PMID: 31982950 DOI: 10.1007/s00572-020-00934-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 01/17/2020] [Indexed: 05/03/2023]
Abstract
Orchids are associated with diverse fungal taxa, including nonmycorrhizal endophytic fungi as well as mycorrhizal fungi. The orchid mycorrhizal (OM) symbiosis is an excellent model for investigating the biological interactions between plants and fungi due to their high dependency on these symbionts for growth and survival. To capture the complexity of OM interactions, significant genomic, numerous transcriptomic, and proteomic studies have been performed, unraveling partly the role of each partner. On the other hand, several papers studied the bioactive metabolites from each partner but rarely interpreted their significance in this symbiotic relationship. In this review, we focus from a biochemical viewpoint on the OM dynamics and its molecular interactions. The ecological functions of OM in plant development and stress resistance are described first, summarizing recent literature. Secondly, because only few studies have specifically looked on OM molecular interactions, the signaling pathways and compounds allowing the establishment/maintenance of mycorrhizal association involved in arbuscular mycorrhiza (AM) are discussed in parallel with OM. Based on mechanistic similarities between OM and AM, and recent findings on orchids' endophytes, a putative model representing the different molecular strategies that OM fungi might employ to establish this association is proposed. It is hypothesized here that (i) orchids would excrete plant molecule signals such as strigolactones and flavonoids but also other secondary metabolites; (ii) in response, OM fungi would secrete mycorrhizal factors (Myc factors) or similar compounds to activate the common symbiosis genes (CSGs); (iii) overcome the defense mechanism by evasion of the pathogen-associated molecular patterns (PAMPs)-triggered immunity and by secretion of effectors such as small inhibitor proteins; and (iv) finally, secrete phytohormones to help the colonization or disrupt the crosstalk of plant defense phytohormones. To challenge this putative model, targeted and untargeted metabolomics studies with special attention to each partner's contribution are finally encouraged and some technical approaches are proposed.
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Affiliation(s)
- Quentin Favre-Godal
- LVMH recherche, Innovation Matériaux Naturels et Développement Durable, 185 avenue de Verdun, 45800, St Jean de Braye, France.
- CNRS, IPHC UMR 7178, Chimie analytique des molécules bioactives et pharmacognosie, Université de Strasbourg, F-67000, Strasbourg, France.
| | - Lorène Gourguillon
- LVMH recherche, Innovation Matériaux Naturels et Développement Durable, 185 avenue de Verdun, 45800, St Jean de Braye, France
| | - Sonia Lordel-Madeleine
- CNRS, IPHC UMR 7178, Chimie analytique des molécules bioactives et pharmacognosie, Université de Strasbourg, F-67000, Strasbourg, France
| | - Katia Gindro
- Agroscope, Swiss Federal Research Station, Plant Protection, 60 Route de Duiller, PO Box, 1260, Nyon, Switzerland
| | - Patrick Choisy
- LVMH recherche, Innovation Matériaux Naturels et Développement Durable, 185 avenue de Verdun, 45800, St Jean de Braye, France
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Low mycorrhizal diversity in the endangered and rare orchids Bipinnula volckmannii and B. apinnula of Central Chile. Symbiosis 2019. [DOI: 10.1007/s13199-019-00648-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Miura C, Saisho M, Yagame T, Yamato M, Kaminaka H. Bletilla striata (Orchidaceae) Seed Coat Restricts the Invasion of Fungal Hyphae at the Initial Stage of Fungal Colonization. PLANTS (BASEL, SWITZERLAND) 2019; 8:E280. [PMID: 31405202 PMCID: PMC6724134 DOI: 10.3390/plants8080280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/05/2019] [Accepted: 08/08/2019] [Indexed: 12/02/2022]
Abstract
Orchids produce minute seeds that contain limited or no endosperm, and they must form an association with symbiotic fungi to obtain nutrients during germination and subsequent seedling growth under natural conditions. Orchids need to select an appropriate fungus among diverse soil fungi at the germination stage. However, there is limited understanding of the process by which orchids recruit fungal associates and initiate the symbiotic interaction. This study aimed to better understand this process by focusing on the seed coat, the first point of fungal attachment. Bletilla striata seeds, some with the seed coat removed, were prepared and sown with symbiotic fungi or with pathogenic fungi. The seed coat-stripped seeds inoculated with the symbiotic fungi showed a lower germination rate than the intact seeds, and proliferated fungal hyphae were observed inside and around the stripped seeds. Inoculation with the pathogenic fungi increased the infection rate in the seed coat-stripped seeds. The pathogenic fungal hyphae were arrested at the suspensor side of the intact seeds, whereas the seed coat-stripped seeds were subjected to severe infestation. These results suggest that the seed coat restricts the invasion of fungal hyphae and protects the embryo against the attack of non-symbiotic fungi.
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Affiliation(s)
- Chihiro Miura
- Faculty of Agriculture, Tottori University, 4-101 Koyama Minami, Tottori 680-8553, Japan
| | - Miharu Saisho
- Faculty of Agriculture, Tottori University, 4-101 Koyama Minami, Tottori 680-8553, Japan
| | - Takahiro Yagame
- Mizuho Kyo-do Museum, 316-5 Komagatafujiyama, Mizuho, Tokyo 190-1202, Japan
| | - Masahide Yamato
- Faculty of Education, Chiba University, 1-33 Yayoicho, Inage-ku, Chiba 263-8522, Japan
| | - Hironori Kaminaka
- Faculty of Agriculture, Tottori University, 4-101 Koyama Minami, Tottori 680-8553, Japan.
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Taylor A, Weigelt P, König C, Zotz G, Kreft H. Island disharmony revisited using orchids as a model group. THE NEW PHYTOLOGIST 2019; 223:597-606. [PMID: 30848492 DOI: 10.1111/nph.15776] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 02/18/2019] [Indexed: 05/28/2023]
Abstract
One central concept in island biology is that island assemblages form subsets of the mainland species pool, being disproportionately rich or poor in certain taxonomic groups. This unbalanced composition, termed 'disharmony', is generally explained using a taxon-centred approach, linking the over- or under-representation of taxa to their colonisation abilities. However, islands may also harbour 'functionally' disharmonic flora, being disproportionately rich or poor in species with certain traits, which may offer greater insights into the processes driving island colonisation. Here, we use orchids as a model to illustrate key processes involved in the formation of functionally disharmonic island floras, including filtering effects (for example biotic interactions), and speciation. Our synthesis is based on a comprehensive orchid dataset of 27 637 species and combines both a literature review and simple exploratory analyses to show that orchids are significantly under-represented on islands relative to mainland regions and that insular orchids display shifts in functional traits, from the shortening of nectar spurs to facilitate ornithophily to changes in colour associated with generalist insect pollinators. We highlight that taxa are simply coarse proxies and that we need to consider species traits and interactions to gain a full understanding of the processes constraining plant assembly on islands.
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Affiliation(s)
- Amanda Taylor
- Biodiversity, Macroecology & Biogeography, Faculty for Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 1, Göttingen, 37077, Germany
| | - Patrick Weigelt
- Biodiversity, Macroecology & Biogeography, Faculty for Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 1, Göttingen, 37077, Germany
| | - Christian König
- Biodiversity, Macroecology & Biogeography, Faculty for Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 1, Göttingen, 37077, Germany
| | - Gerhard Zotz
- Institute of Biology and Environmental Sciences, University of Oldenburg, Ammerländer Heerstrasse 114, Oldenburg, 26129, Germany
| | - Holger Kreft
- Biodiversity, Macroecology & Biogeography, Faculty for Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 1, Göttingen, 37077, Germany
- Centre of Biodiversity and Sustainable Land Use (CBL), University of Goettingen, Büsgenweg 1, Göttingen, 37077, Germany
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Sorensen PO, Bhatnagar JM, Christenson L, Duran J, Fahey T, Fisk MC, Finzi AC, Groffman PM, Morse JL, Templer PH. Roots Mediate the Effects of Snowpack Decline on Soil Bacteria, Fungi, and Nitrogen Cycling in a Northern Hardwood Forest. Front Microbiol 2019; 10:926. [PMID: 31114563 PMCID: PMC6503048 DOI: 10.3389/fmicb.2019.00926] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 04/11/2019] [Indexed: 11/16/2022] Open
Abstract
Rising winter air temperature will reduce snow depth and duration over the next century in northern hardwood forests. Reductions in snow depth may affect soil bacteria and fungi directly, but also affect soil microbes indirectly through effects of snowpack loss on plant roots. We incubated root exclusion and root ingrowth cores across a winter climate-elevation gradient in a northern hardwood forest for 29 months to identify direct (i.e., winter snow-mediated) and indirect (i.e., root-mediated) effects of winter snowpack decline on soil bacterial and fungal communities, as well as on potential nitrification and net N mineralization rates. Both winter snowpack decline and root exclusion increased bacterial richness and phylogenetic diversity. Variation in bacterial community composition was best explained by differences in winter snow depth or soil frost across elevation. Root ingrowth had a positive effect on the relative abundance of several bacterial taxonomic orders (e.g., Acidobacterales and Actinomycetales). Nominally saprotrophic (e.g., Saccharomycetales and Mucorales) or mycorrhizal (e.g., Helotiales, Russalales, Thelephorales) fungal taxonomic orders were also affected by both root ingrowth and snow depth variation. However, when grouped together, the relative abundance of saprotrophic fungi, arbuscular mycorrhizal fungi, and ectomycorrhizal fungi were not affected by root ingrowth or snow depth, suggesting that traits in addition to trophic mode will mediate fungal community responses to snowpack decline in northern hardwood forests. Potential soil nitrification rates were positively related to ammonia-oxidizing bacteria and archaea abundance (e.g., Nitrospirales, Nitrosomondales, Nitrosphaerales). Rates of N mineralization were positively and negatively correlated with ectomycorrhizal and saprotrophic fungi, respectively, and these relationships were mediated by root exclusion. The results from this study suggest that a declining winter snowpack and its effect on plant roots each have direct effects on the diversity and abundance of soil bacteria and fungal communities that interact to determine rates of soil N cycling in northern hardwood forests.
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Affiliation(s)
- Patrick O. Sorensen
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences Division, Berkeley, CA, United States
- Department of Biology, Boston University, Boston, MA, United States
| | | | - Lynn Christenson
- Biology Department, Vassar College, Poughkeepsie, NY, United States
| | - Jorge Duran
- Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal
| | - Timothy Fahey
- Department of Natural Resources, Cornell University, Ithaca, NY, United States
| | - Melany C. Fisk
- Department of Biology, Miami University, Oxford, OH, United States
| | - Adrien C. Finzi
- Department of Biology, Boston University, Boston, MA, United States
| | - Peter M. Groffman
- City University of New York Advanced Science Research Center at the Graduate Center, New York, NY, United States
- Cary Institute of Ecosystem Studies, Millbrook, NY, United States
| | - Jennifer L. Morse
- Department of Environmental Science and Management, Portland State University, Portland, OR, United States
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Host Tree Identity Influences Leaf Nutrient Relations of the Epiphyte Dendrobium guamense Ames. HORTICULTURAE 2018. [DOI: 10.3390/horticulturae4040043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Epiphytic orchid species grow in stressful conditions that include nutrient deficiency. A greater understanding of the factors that influence epiphytic orchid nutrition may benefit conservationists and horticulturists. Green and senesced leaf nutrient concentrations of the epiphytic Dendrobium guamense were quantified among six host tree species to more fully understand the role of contrasting host identity. Green leaves for D. guamense plants on species with vertical stems contained greater nitrogen, calcium, iron, manganese, zinc, and boron concentrations. Green leaves for D. guamense plants on species with horizontal stems contained greater phosphorus, magnesium, and copper concentrations. Senesced D. guamense leaves followed similar patterns among the host species for all elements except calcium, manganese, and boron. The stoichiometry among green leaf macronutrients indicated nitrogen was most limiting, and the limitation was more severe for plants on horizontal stems. Carbon:nitrogen of senesced leaves indicated D. guamense plants on vertical stems produced higher quality leaf litter, predicting slower decomposition of orchid leaf litter from plants growing on hosts with horizontal stems. The results may improve horticultural decisions to support conservation efforts and show that host identity is a variable that should be more fully studied to understand epiphyte biology.
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