Phalaenopsis orchids are economically important ornamental crops;however,their commercial micropropagation is often limited by poor rooting efficiency and inconsistent growth.In this study,we investigated the effects ...Phalaenopsis orchids are economically important ornamental crops;however,their commercial micropropagation is often limited by poor rooting efficiency and inconsistent growth.In this study,we investigated the effects of silver nanoparticles(Ag-NPs)on the in vitro regeneration and growth of Phalaenopsis cultivar 611B to determine the optimal concentration of Ag-NPs for improved micropropagation outcomes.Shoot tip explants(2–3 mm)—derived from protocorm-like bodies were cultured on a regeneration medium containing Hyponex(20:20:20 and 6.5:6.5:19),18 g/L sugar,2 g/L peptone,0.8 g/L activated charcoal,12.5 g/L potato extract,50 mL/L apple juice,and 10 mg/L 6-benzylaminopurine(6-BA),with varying concentrations of Ag-NPs(0,0.5,1.0,2.0,and 2.5 mg/L).After 10–12 weeks,shoot and root formation,plant height,fresh weight,leaf number,and chlorophyll contents were evaluated.At 1.0 mg/L Ag-NPs,shoot regeneration(5.4 vs.2.9 shoots per explant),root induction(2.1 vs.1.4 roots per explant),and shoot formation frequency(100%vs.55%)were significantly higher than the control(0 mg/L).Fresh weight(592.4 mg)and leaf number(9.7)also showed notable increases at this concentration.Although chlorophyll a and b levels peaked at 2.0 mg/L,the difference from 1.0 mg/L was not statistically significant.These results suggest that 1.0mg/LAg-NPs is the optimal concentration for enhancing shoot and root development and improving overall plantlet quality in Phalaenopsis.The findings highlight the potential of nanomaterials to improve the efficiency of orchid tissue culture systems.展开更多
The Annapurna Conservation Area (ACA), the first conservation area and the largest protected area (PA) in Nepal, is incredibly rich in biodiversity. Notwithstanding this, orchids in the ACA have not been explored enou...The Annapurna Conservation Area (ACA), the first conservation area and the largest protected area (PA) in Nepal, is incredibly rich in biodiversity. Notwithstanding this, orchids in the ACA have not been explored enough yet thus making the need for ambitious research to be carried out. Previous study only included 81 species of orchids within ACA. This study aims to update the record of species and genera richness in the ACA. In total 198 species of orchids, belonging to 67 genera (40% and 62% of the total recorded orchid species and genera in Nepal) has been recorded in ACA. This represents an increase of 144% in species and 56% in genera over the previous data. Out of the 198 species, 99 were epiphytes, 6 were holomycotrophic and 93 were terrestrial. Among the 67 genera, Bulbophyllum (17) species were dominant, followed by Dendrobium (16), Herminium (10), Coelogyne, Plantanthera (9 each), Eria, Habenaria, Oberonia (8 each), Calanthe (7), and Liparis (6). Fifty-six species were found to be ornamentally significant and 85 species medicinally significant.展开更多
Orchidaceae is a large family of 1,260 species in Mexico, of which 433 grow in the state of Veracruz, Mexico. Although economically important in horticulture because of the beauty of their flowers, researches have don...Orchidaceae is a large family of 1,260 species in Mexico, of which 433 grow in the state of Veracruz, Mexico. Although economically important in horticulture because of the beauty of their flowers, researches have done little work regarding their medicinal properties. This paper aimed to present the results of ethnobotanical, pharmacological and active compounds research on Veracruz medicinal orchids. The ethnobotanical information was obtained by consulting the Atlas of the Mexican Traditional Medicine Plants, Veracruz Medicinal Flora Database （CITRO-UV project） and through field work in the Nahuatl community of Cuautlajapa, Veracruz. To obtain pharmacological and active compounds information of registered species, a search was carded out through MEDLINE （USA National Library of Medicine Journal Citation database）. Twelve medicinal orchids were recorded for Veracruz, i.e., Epidendrum chlorocorymbos Schltr., Habenaria floribunda Lindl., Isochillus latibracteatus A. Rich. ＆ Galeotti, lsochillus major Schltdl. ＆ Cham., Mormodes maculata var. unicolor （Hook.） L. O. Williams, Oestlundia luteorosea （A. Rich. ＆ Galeotti） W. E. Higgins, Oncidium ascendens Lindl., Scaphyglottis fasciculata Hook., Sobralia macrantha Lindl., Spiranthes eriophora （Rob. ＆ Greenm.）, Stanhopea oculata （G. Lodd.） Lindl. and Vanilla planifolia Andrews. Only two species have been investigated in terms of their pharmacology and active compounds. Also, information for another five species closely related to already identified ones was obtained. Given the relative poverty of current information on the topic, this paper demonstrates the need to further study the ethnobotanical, pharmacological and chemical aspects of the region＇s medicinal orchids.展开更多
The survival chance of epiphytie orchids today not only depends on the natural site conditions required by the orchids but also on anthropogenic changes in site conditions. This study answers two questions： （1） Wha...The survival chance of epiphytie orchids today not only depends on the natural site conditions required by the orchids but also on anthropogenic changes in site conditions. This study answers two questions： （1） What is the ecological niche of the different epiphytic orchid species？ （2） What are the ecological factors that threaten epiphytic orchid＇s population under anthropogenic disturbances？ Our study area was the Kathmandu valley, Nepal, with its subtropical forest. We established 156 systematically selected sampling points in the Kathmandu area covering different types of ecosystems under human impacts such as densely populated area, agricultural land, mixed agricultural and settled area, old tree patches, and a natural forest in a national park. The ecological niche of the orchid species was analyzed with a principal component analysis （PCA）. The correlations between the different site factors were statistically significant. Spearman＇s rank correlation matrices showed that the variables land-use intensities with altitude, and height with diameter in breast height （dbh） of host had the highest significant positive correlation coefficient （0.67 and 0.64 respectively）. On the other hand, host bark pH and altitude as well as land use had a significantly strong negative correlation coefficient （-0.80 and -0.61, respectively）. Different epiphytic orchid species interact differently with the given set of environmental factors： for occurrence of Vanda cristata there is no single environmental factor of special influence, while for Rhynehostylis retusa high bark pH and high light availability are important. First two axis of the PCA explained more than 50% of the total variance. Most orchid species occupy a specific, narrow niche in this ecological space. The main causes of anthropogenie influence of orchid population in the Kathmandu Valley are loss of adequate host trees （species and size） and increasing air pollution, resulting in increasing host bark pH.展开更多
We studied distribution and site conditions of epiphytic orchids in a gradient of human interference in Kathmandu valley, central Nepal. The aim was to understand the recent distribution pattern of epiphytic orchids, ...We studied distribution and site conditions of epiphytic orchids in a gradient of human interference in Kathmandu valley, central Nepal. The aim was to understand the recent distribution pattern of epiphytic orchids, with respect to (i) the micro-site conditions and (ii) the type and intensity of land use. The occurrence of epiphytic orchids was recorded for a grid with 1.5 km cell size. The cells represent different types and intensities of human impact. Site factors such as bark rugosity, bark pH, diameter at breast height (dbh; 1.3 m) of host trees, exposure to wind and sunlight intensity were recorded. With regard to the species richness and abundance of epiphytic orchids, we compared different human impact categories from very strong human impact (settlement area) to very low human impact (national park). Remote sensing was used for a supervised classification of land cover. Ficus religiosa turned out to be the most important host species for orchids in urban areas, while Schima wallichii and Alnus nepalensis significantly host orchids in the other categories. Both species richness and abundance of epiphytic orchids were significantly higher under very low human impact (forest in national park) and also some remaining patches of primary forest than the other regions. Micro-climate is crucial for orchid populations. Host bark pH, bark rugosity, sunlight intensity and host exposure were significantly different for all human impact categories in order to harbour epiphytic orchid species. Habitats with a mixture of mature trees are suitable and essential for the conservation of viable populations of epiphytic orchids in settled areas. The study reveals that to improve the population size of orchids it is essential for future urban forestry to: (i) Protect old trees as carriers of existing epiphytic orchid diversity, (ii) protect medium old trees to ensure that they may become old trees, (iii) plant new host trees for the future, (iv) plant in groups instead of single isolate trees. Trees should especially be planted in areas where orchids still exist to provide more trees for orchid population enlargement (e.g. along riparian system). Native species should be favoured; the pool of such native host species is wide.展开更多
We used standard isolation protocols to explore the endophytic fungal communities in three tissue types of two dominant orchids （Bulbophyllum neilgherrense and Vanda testacea） of the Kaiga forest of the Western Ghat...We used standard isolation protocols to explore the endophytic fungal communities in three tissue types of two dominant orchids （Bulbophyllum neilgherrense and Vanda testacea） of the Kaiga forest of the Western Ghats. We surface sterilized and assessed 90 segments of each orchid for the occurrence and diversity of endophytic fungal taxa. The 118 fungal isolates were obtained from root, bulb and leaves of B. neilgherrense, consisting of 17 anamorphic taxa （range, 10-15 taxa） with 1.3 fungal taxa per segment （range, 1.2-1.4 taxa）. Four taxa （Aspergillus flavus, A. niger, Penicillium sp. and morpho sp. 1） belonged to the core group （11.1%--32.2%）. The relative abundance of A. flavus and morpho sp. 1 was more than 10%. A total of 130 fungal isolates from roots, stems and leaves of V. testacea yielded 20 anamorphic taxa （range, 11-15 taxa） with 1.4 fungal taxa per segment （range, 1.4-1.5 taxa）. Aspergillusflavus, A. niger, A. ochraceus, Gliocladium viride, Penicillium sp. and morpho sp. 1 belonged to the core group. Relative abundance exceeded 10% for A. flavus, A. niger, and morpho sp. 1. The Simpson and Shannon diversity indices were higher in leaf than root or bulb/stem of both orchids. Jaccard＇s similarity coefficient was higher between root and leaf in both orchids （56.3%-60%） than between other pairs. Our study revealed that the endophytic fungal assemblage and diversity orB. neilgherrense and E testacea of Kaiga forest of the Western Ghats were relatively similar between orchids and their tissues.展开更多
Orchid diversity provides a unique opportunity to further our understanding of biotic and abiotic factors linked to patterns of richness,endemism,and phylogenetic endemism in many regions.However,orchid diversity is c...Orchid diversity provides a unique opportunity to further our understanding of biotic and abiotic factors linked to patterns of richness,endemism,and phylogenetic endemism in many regions.However,orchid diversity is consistently threatened by illegal trade and habitat transformation.Here,we identified areas critical for orchid conservation in the biogeographic province of Megamexico.For this purpose,we evaluated orchid endemism,phylogenetic diversity,and phylogenetic endemism within Megamexico and characterized orchid life forms.Our results indicate that the majority of the regions with the highest estimates of endemism and phylogenetic endemism are in southern Mexico and northern Central America,mostly located on the Pacific side of Megamexico.Among the most important orchid lineages,several belong to epiphytic lineages such as Pleurothallidinae,Laeliinae and Oncidiinae.We also found that species from diverse and distantly related lineages converge in montane forests where suitable substrates for epiphytes abound.Furthermore,the southernmost areas of phylogenetic diversity and endemism of Megamexico are in unprotected areas.Thus,we conclude that the most critical areas for orchid conservation in Megamexico are located in southern Mexico and northern Central America.We recommend that these areas should be given priority by the Mexican system of natural protected areas as complementary conservation areas.展开更多
Explants,namely the seeds (Cymbidium faberi) and buds (Cymbidium goeringii) of local Hunan orchids were disinfected with 75% ethanol, 0.1% mercuric chloride,and 10% sodium hypochlorite in six different disinfection tr...Explants,namely the seeds (Cymbidium faberi) and buds (Cymbidium goeringii) of local Hunan orchids were disinfected with 75% ethanol, 0.1% mercuric chloride,and 10% sodium hypochlorite in six different disinfection treatments. Results showed that The treatment with 75% ethanol (contact time: 45 s) and 0.1% mercuric chloride (contact time: 8 min) proved to be the most effective one in disinfecting the explants of Cymbidium faberi seeds.The combination of 75% ethanol (contact time: 45 s) and 0.1% mercuric chloride (contact time: 5 min) provided the optimal disinfection effects when disinfecting Cymbidium goeringii buds.In general, the disinfection effect of mercuric chloride was found to be superior to that of sodium hypochlorite,but care should be taken with the disinfection time to avoid damage to the explants.展开更多
Microsatellites, or simple sequence repeats (SSRs), are highly polymorphic, co-dominant genetic markers commonly used for population genetics analyses although de novo development of species specific microsatellites i...Microsatellites, or simple sequence repeats (SSRs), are highly polymorphic, co-dominant genetic markers commonly used for population genetics analyses although de novo development of species specific microsatellites is cost-and time-intensive. Orchidaceae is one of the most species-rich families of angiosperms with more than 30,000 species estimated. Despite its high species-diversity, microsatellites are available only for a few species and all were developed by only using Sanger sequencing methods. For the first time in orchids, we used 454 GS-FLX sequencing to isolate microsatellites in two species (Cypripedium kentuckiense and Pogonia ophioglossoides), and report preliminary results of the study. From 1/16th plate that was subjected to sequencing, 32,665 reads were generated, from which 15,473 fragments contained at least one SSR. We selected 20,697 SSRs representing di-, tri-, and tetra-nucleotides. While 3,674 microsatellites had flanking regions on both sides, useable primer pairs could be designed for 255 SSRs. The mean numbers of reads, SSRs, and SSR-containing reads useful for primer design estimated for other 15 orchid species using Sanger sequencing method were 166, 78 and 31, respectively. Results demonstrate that the efficiency of microsatellite isolation in orchids is substantially higher with 454 GS-FLX sequencing technique in comparison to the Sanger sequencing methods.展开更多
The Orchidaceae is a diverse and wide spread family of flowering plants that are of great value in ornamental, medical, conservation, and evolutionary research. The broad diversity in morphology,growth form, life hist...The Orchidaceae is a diverse and wide spread family of flowering plants that are of great value in ornamental, medical, conservation, and evolutionary research. The broad diversity in morphology,growth form, life history, and habitat mean that the members of Orchidaceae exhibit various physiological properties. Epiphytic orchids are often characterized by succulent leaves with thick cell walls,cuticles, and sunken stomata, whereas terrestrial orchids possess rhizomes, corms, or tubers. Most orchids have a long juvenile period, slow growth rate, and low photosynthetic capacity. This reduced photosynthetic potential can be largely explained by CO_2 diffusional conductance and leaf internal structure. The amount of light required for plant survival depends upon nutritional mode, growth form,and habitat. Most orchids can adapt to their light environments through morphological and physiological adjustments but are sensitive to sudden changes in irradiance. Orchids that originate from warm regions are susceptible to chilling temperatures, whereas alpine members are vulnerable to high temperatures.For epiphytic orchids, rapid water uptake by the velamen radicum, water storage in their pseudobulbs and leaves, slow water loss, and Crassulacean Acid Metabolism contribute to plant-water balance and tolerance to drought stress. The presence of the velamen radicum and mycorrhizal fungi may compensate for the lack of root hairs, helping with quick absorbance of nutrients from the atmosphere.Under cultivation conditions, the form and concentration of nitrogen affect orchid growth and flowering.However, the limitations of nitrogen and phosphorous on epiphytic orchids in the wild, which require these plants to depend on mycorrhizal fungi for nutrients throughout the entire life cycle, are not clearly understood. Because they lack endosperm, seed germination depends upon obtaining nutrients via mycorrhizal fungi. Adult plants of some autotrophic orchids also gain carbon, nitrogen, phosphorus, and other elements from their mycorrhizal partners. Future studies should examine the mechanisms that determine slow growth and flower induction, the physiological causes of variations in flowering behavior and floral lifespan, the effects of nutrients and atmospheric-nitrogen deposition, and practical applications of mycorrhizal fungi in orchid cultivation.展开更多
Mycorrhizal fungi are essential for the growth and development of both epiphytic(growing on trees)and lithophytic(growing on rocks)orchids.Previous studies indicate that in lowland tropical areas,orchid mycorrhizal fu...Mycorrhizal fungi are essential for the growth and development of both epiphytic(growing on trees)and lithophytic(growing on rocks)orchids.Previous studies indicate that in lowland tropical areas,orchid mycorrhizal fungal compositions are correlated with the life form(i.e.,epiphytic,lithophytic,or terrestrial)of their host plants.We therefore tested if a similar correlation exists in an orchid distributed at higher elevations.Coelogyne corymbosa is an endangered ornamental orchid species that can be found as a lithophyte and epiphyte in subtropical to subalpine areas.Based on high-throughput sequencing of the fungal internal transcribed spacer 2(ITS2)-rDNA region of mycorrhizae of C.corymbosa,we detected 73 putative mycorrhizal fungal Operational Taxonomic Units(OTUs).The OTUs of two dominant lineages(Cantharellales and Sebacinales)detected from C.corymbosa are phylogenetically different from those of other species within the genus Coelogyne,indicating that different orchid species prefer specific mycorrhizal fungi.We also found that the Non-metric multidimensional scaling(NMDS)plots of orchid mycorrhizal fungi were not clustered with life form,the variations among orchid mycorrhizal fungal communities of different life forms were not significant,and most of the OTUs detected from epiphytic individuals were shared by the lithophytic plants,suggesting that orchid mycorrhizal associations of C.corymbosa were not affected by life form.These findings provide novel insights into mycorrhizal associations with endangered ornamental orchids.展开更多
Native orchid species of Singapore in their natural conditions experience stress from high irradiance, high temperatures and periods of extended low rainfall, which impact orchid plant physiology and lead to reduced g...Native orchid species of Singapore in their natural conditions experience stress from high irradiance, high temperatures and periods of extended low rainfall, which impact orchid plant physiology and lead to reduced growth and productivity. In this study, it was found that there was a reduction in photochemical efficiency of photosystem II (PSII) in 6 native orchid species under high light (HL) and Bulbophyllum membranaceum under low light (LL). There was chronic photoinhibition in these 6 orchid species over a period of 3 months after transplanting onto the tree trunks without watering and fertilization, especially in Coelogynes mayeriana and Bulbophyllum membranaceum under both HL and LL. This chronic photoinhibition caused by sustained period of water deficit in their natural conditions was later reversed by natural re-watering conditions from higher rainfall. These results indicate that water deficit has a greater impact on photosynthetic light utilization efficiency than excess light. The present study also showed that after natural rewatering, relative water content (RWC) of leaves and pseudobulbs generally increased. During the natural re-watering, total leaf area also gradually increased and reached maximum expansion after 7 weeks under both HL and LL, with some exceptions due to leaf abscission or decline in total leaf area, possibly a strategy for water conservation.展开更多
Objective:To assess the antioxidant activity as well as the total polyphenolics and flavonoids content of thirteen extracts from nine wild orchids of Nepal.Methods:First,a preliminary phytochemical screening of thirte...Objective:To assess the antioxidant activity as well as the total polyphenolics and flavonoids content of thirteen extracts from nine wild orchids of Nepal.Methods:First,a preliminary phytochemical screening of thirteen extracts of nine orchids was carried out using established protocols.Then,the total polyphenolic and flavonoid contents of each extract were evaluated using the Folin-Ciocalteu's phenol reagent and aluminium chloride methods respectively.Finally,antioxidant activity was determined by 2,2-diphenyl-1-picryl hydrazyl free radical scavenging assay and expressed in terms of half inhibition concentrations(IC50 values).Results:All the tested parameters showed significant variation at P=0.05.The total flavonoids varied with the greatest amounts found in the leaves of Rhynchostylis retusa and the smallest amounts found in the roots of Gastrochilus acutifolius(G.acutifolius).The amount of total polyphenolics was highest in the stems of Vanda cristata and lowest in the leaves of G.acutifolius.Antioxidant activity was highest in the stems of Vanda cristata and lowest in the leaves of G.acutifolius.Conclusions:Some of the orchid extracts studied exhibited levels of antioxidant activity which were comparable to or even higher than those found for extracts of medicinal plants and orchids studied previously.It is suggested that drugs and natural food additives can be extracted from those wild orchids with high levels of antioxidant activity.展开更多
Nigeria’s first female train driver honoured for promoting understanding between China and Africa In mid-July,vips gathered at the Beijing Hotel in China’s capital to witness the presentation of Orchid Awards to 1...Nigeria’s first female train driver honoured for promoting understanding between China and Africa In mid-July,vips gathered at the Beijing Hotel in China’s capital to witness the presentation of Orchid Awards to 10 ambassadors of culture from di!erent continents.They were chosen from over 300 candidates from around 80 countries.展开更多
Orchid origin and evolution are common topics in evolutionary biology. Orchidaceae have approximately 30 000 orchid species distributed in diverse habitats and account for approximately 10% of the flowering plant spec...Orchid origin and evolution are common topics in evolutionary biology. Orchidaceae have approximately 30 000 orchid species distributed in diverse habitats and account for approximately 10% of the flowering plant species worldwide. Orchids provide us with materials to explore coevolution and organic evolution. In this review, we highlighted the genome study progress of orchids. In addition, we revealed the role of MADS-box gene families in the floral morphology and evolution of orchids. Genomics studies confirmed that all five subfamilies of existing orchids evolved from a common ancestor. Loss of Mβ MADS-box genes resulted in the endosperm from the seed of all existing orchids being absent. Perianth reversion to the ancestral state occurred because Apostasia and Apostasioideae lost B-AP3 and E class paralogous genes. Loss of P-subclade members of MIKC*-Type in Phalaenopsis equestris, Dendrobium catenatum, and Epidendroideae caused the formation of pollinium.In addition, the combined loss of AGL12 and contraction of ANR1 gave orchids the ability to be successfully epiphytic on trees or rocks and to develop a unique root system. Both pollinium and epiphytic production on trees are beneficial for orchid adaptations, and Epidendroideae evolved more species(~ 20 000) than Apostasioideae(16 species). Genome studies shed new light on determining the evolutionary history of orchids and understanding the genetic mechanisms of orchid morphological evolution.展开更多
Orchidaceae are one of the largest families of angiosperms in terms of species richness.In the last decade,numerous studies have delved into reconstructing the phylogenetic framework of Orchidaceae,leveraging data fro...Orchidaceae are one of the largest families of angiosperms in terms of species richness.In the last decade,numerous studies have delved into reconstructing the phylogenetic framework of Orchidaceae,leveraging data from plastid,mitochondrial and nuclear sources.These studies have provided new insights into the systematics,diversification and biogeography of Orchidaceae,establishing a robust foundation for future research.Nevertheless,pronounced controversies persist regarding the precise placement of certain lineages within these phylogenetic frameworks.To address these discrepancies and deepen our understanding of the phylogenetic structure of Orchidaceae,we provide a comprehensive overview and analysis of phylogenetic studies focusing on contentious groups within Orchidaceae since 2015,delving into discussions on the underlying reasons for observed topological conflicts.We also provide a novel phylogenetic framework at the subtribal level.Furthermore,we examine the tempo and mode underlying orchid species diversity from the perspective of historical biogeography,highlighting factors contributing to extensive speciation.Ultimately,we delineate avenues for future research aimed at enhancing our understanding of Orchidaceae phylogeny and diversity.展开更多
With nylon mesh bags, the decomposition and nutrients release characteristics of two kinds of green manure crops, February orchid （Orychophragmus violaceus） and Hair Vetch （Vicia villosa Roth）, were investigated i...With nylon mesh bags, the decomposition and nutrients release characteristics of two kinds of green manure crops, February orchid （Orychophragmus violaceus） and Hair Vetch （Vicia villosa Roth）, were investigated in this study. The results showed that these two kinds of green manure crops were decomposed rapidly in the first 14 days, and then decomposed slowly. After 80 days of incubation, the decomposition rates of February orchid and Hair Vetch were 66.92% and 63.12%, respectively. Different nutrients had different release rates from the green manures. Nitrogen （N） and potassium （K） were released rapidly in the initial 7 days, and phosphorus （P） was released steadily in the 80 days of incubation. In the two kinds of green manures, the release rates all ranked as K＇s〉N＇s〉P＇s. The release rates of nutrients, especially P （P〈0.05）, of February orchid were higher than those of Hair Vetch.展开更多
Approximately one fifth of the world's plants are at risk of extinction.Of these,a significant number exist as populations of few individuals,with limited distribution ranges and under enormous pressure due to hab...Approximately one fifth of the world's plants are at risk of extinction.Of these,a significant number exist as populations of few individuals,with limited distribution ranges and under enormous pressure due to habitat destruction.In China,these most-at-risk species are described as 'plant species with extremely small populations'(PSESP).Implementing conservation action for such listed species is urgent.Storing seeds is one of the main means of ex situ conservation for flowering plants.Spore storage could provide a simple and economical method for fern ex situ conservation.Seed and spore germination in nature is a critical step in species regeneration and thus in situ conservation.But what is known about the seed and spore biology(storage and germination) of at-risk species? We have used China's PSESP(the first group listing) as a case study to understand the gaps in knowledge on propagule biology of threatened plant species.We found that whilst germination information is available for 28 species(23%of PSESP),storage characteristics are only known for 8%of PSESP(10 species).Moreover,we estimate that 60%of the listed species may require cryopreservation for long-term storage.We conclude that comparative biology studies are urgently needed on the world's most threatened taxa so that conservation action can progress beyond species listing.展开更多
文摘Phalaenopsis orchids are economically important ornamental crops;however,their commercial micropropagation is often limited by poor rooting efficiency and inconsistent growth.In this study,we investigated the effects of silver nanoparticles(Ag-NPs)on the in vitro regeneration and growth of Phalaenopsis cultivar 611B to determine the optimal concentration of Ag-NPs for improved micropropagation outcomes.Shoot tip explants(2–3 mm)—derived from protocorm-like bodies were cultured on a regeneration medium containing Hyponex(20:20:20 and 6.5:6.5:19),18 g/L sugar,2 g/L peptone,0.8 g/L activated charcoal,12.5 g/L potato extract,50 mL/L apple juice,and 10 mg/L 6-benzylaminopurine(6-BA),with varying concentrations of Ag-NPs(0,0.5,1.0,2.0,and 2.5 mg/L).After 10–12 weeks,shoot and root formation,plant height,fresh weight,leaf number,and chlorophyll contents were evaluated.At 1.0 mg/L Ag-NPs,shoot regeneration(5.4 vs.2.9 shoots per explant),root induction(2.1 vs.1.4 roots per explant),and shoot formation frequency(100%vs.55%)were significantly higher than the control(0 mg/L).Fresh weight(592.4 mg)and leaf number(9.7)also showed notable increases at this concentration.Although chlorophyll a and b levels peaked at 2.0 mg/L,the difference from 1.0 mg/L was not statistically significant.These results suggest that 1.0mg/LAg-NPs is the optimal concentration for enhancing shoot and root development and improving overall plantlet quality in Phalaenopsis.The findings highlight the potential of nanomaterials to improve the efficiency of orchid tissue culture systems.
文摘The Annapurna Conservation Area (ACA), the first conservation area and the largest protected area (PA) in Nepal, is incredibly rich in biodiversity. Notwithstanding this, orchids in the ACA have not been explored enough yet thus making the need for ambitious research to be carried out. Previous study only included 81 species of orchids within ACA. This study aims to update the record of species and genera richness in the ACA. In total 198 species of orchids, belonging to 67 genera (40% and 62% of the total recorded orchid species and genera in Nepal) has been recorded in ACA. This represents an increase of 144% in species and 56% in genera over the previous data. Out of the 198 species, 99 were epiphytes, 6 were holomycotrophic and 93 were terrestrial. Among the 67 genera, Bulbophyllum (17) species were dominant, followed by Dendrobium (16), Herminium (10), Coelogyne, Plantanthera (9 each), Eria, Habenaria, Oberonia (8 each), Calanthe (7), and Liparis (6). Fifty-six species were found to be ornamentally significant and 85 species medicinally significant.
文摘Orchidaceae is a large family of 1,260 species in Mexico, of which 433 grow in the state of Veracruz, Mexico. Although economically important in horticulture because of the beauty of their flowers, researches have done little work regarding their medicinal properties. This paper aimed to present the results of ethnobotanical, pharmacological and active compounds research on Veracruz medicinal orchids. The ethnobotanical information was obtained by consulting the Atlas of the Mexican Traditional Medicine Plants, Veracruz Medicinal Flora Database （CITRO-UV project） and through field work in the Nahuatl community of Cuautlajapa, Veracruz. To obtain pharmacological and active compounds information of registered species, a search was carded out through MEDLINE （USA National Library of Medicine Journal Citation database）. Twelve medicinal orchids were recorded for Veracruz, i.e., Epidendrum chlorocorymbos Schltr., Habenaria floribunda Lindl., Isochillus latibracteatus A. Rich. ＆ Galeotti, lsochillus major Schltdl. ＆ Cham., Mormodes maculata var. unicolor （Hook.） L. O. Williams, Oestlundia luteorosea （A. Rich. ＆ Galeotti） W. E. Higgins, Oncidium ascendens Lindl., Scaphyglottis fasciculata Hook., Sobralia macrantha Lindl., Spiranthes eriophora （Rob. ＆ Greenm.）, Stanhopea oculata （G. Lodd.） Lindl. and Vanilla planifolia Andrews. Only two species have been investigated in terms of their pharmacology and active compounds. Also, information for another five species closely related to already identified ones was obtained. Given the relative poverty of current information on the topic, this paper demonstrates the need to further study the ethnobotanical, pharmacological and chemical aspects of the region＇s medicinal orchids.
文摘The survival chance of epiphytie orchids today not only depends on the natural site conditions required by the orchids but also on anthropogenic changes in site conditions. This study answers two questions： （1） What is the ecological niche of the different epiphytic orchid species？ （2） What are the ecological factors that threaten epiphytic orchid＇s population under anthropogenic disturbances？ Our study area was the Kathmandu valley, Nepal, with its subtropical forest. We established 156 systematically selected sampling points in the Kathmandu area covering different types of ecosystems under human impacts such as densely populated area, agricultural land, mixed agricultural and settled area, old tree patches, and a natural forest in a national park. The ecological niche of the orchid species was analyzed with a principal component analysis （PCA）. The correlations between the different site factors were statistically significant. Spearman＇s rank correlation matrices showed that the variables land-use intensities with altitude, and height with diameter in breast height （dbh） of host had the highest significant positive correlation coefficient （0.67 and 0.64 respectively）. On the other hand, host bark pH and altitude as well as land use had a significantly strong negative correlation coefficient （-0.80 and -0.61, respectively）. Different epiphytic orchid species interact differently with the given set of environmental factors： for occurrence of Vanda cristata there is no single environmental factor of special influence, while for Rhynehostylis retusa high bark pH and high light availability are important. First two axis of the PCA explained more than 50% of the total variance. Most orchid species occupy a specific, narrow niche in this ecological space. The main causes of anthropogenie influence of orchid population in the Kathmandu Valley are loss of adequate host trees （species and size） and increasing air pollution, resulting in increasing host bark pH.
文摘We studied distribution and site conditions of epiphytic orchids in a gradient of human interference in Kathmandu valley, central Nepal. The aim was to understand the recent distribution pattern of epiphytic orchids, with respect to (i) the micro-site conditions and (ii) the type and intensity of land use. The occurrence of epiphytic orchids was recorded for a grid with 1.5 km cell size. The cells represent different types and intensities of human impact. Site factors such as bark rugosity, bark pH, diameter at breast height (dbh; 1.3 m) of host trees, exposure to wind and sunlight intensity were recorded. With regard to the species richness and abundance of epiphytic orchids, we compared different human impact categories from very strong human impact (settlement area) to very low human impact (national park). Remote sensing was used for a supervised classification of land cover. Ficus religiosa turned out to be the most important host species for orchids in urban areas, while Schima wallichii and Alnus nepalensis significantly host orchids in the other categories. Both species richness and abundance of epiphytic orchids were significantly higher under very low human impact (forest in national park) and also some remaining patches of primary forest than the other regions. Micro-climate is crucial for orchid populations. Host bark pH, bark rugosity, sunlight intensity and host exposure were significantly different for all human impact categories in order to harbour epiphytic orchid species. Habitats with a mixture of mature trees are suitable and essential for the conservation of viable populations of epiphytic orchids in settled areas. The study reveals that to improve the population size of orchids it is essential for future urban forestry to: (i) Protect old trees as carriers of existing epiphytic orchid diversity, (ii) protect medium old trees to ensure that they may become old trees, (iii) plant new host trees for the future, (iv) plant in groups instead of single isolate trees. Trees should especially be planted in areas where orchids still exist to provide more trees for orchid population enlargement (e.g. along riparian system). Native species should be favoured; the pool of such native host species is wide.
文摘We used standard isolation protocols to explore the endophytic fungal communities in three tissue types of two dominant orchids （Bulbophyllum neilgherrense and Vanda testacea） of the Kaiga forest of the Western Ghats. We surface sterilized and assessed 90 segments of each orchid for the occurrence and diversity of endophytic fungal taxa. The 118 fungal isolates were obtained from root, bulb and leaves of B. neilgherrense, consisting of 17 anamorphic taxa （range, 10-15 taxa） with 1.3 fungal taxa per segment （range, 1.2-1.4 taxa）. Four taxa （Aspergillus flavus, A. niger, Penicillium sp. and morpho sp. 1） belonged to the core group （11.1%--32.2%）. The relative abundance of A. flavus and morpho sp. 1 was more than 10%. A total of 130 fungal isolates from roots, stems and leaves of V. testacea yielded 20 anamorphic taxa （range, 11-15 taxa） with 1.4 fungal taxa per segment （range, 1.4-1.5 taxa）. Aspergillusflavus, A. niger, A. ochraceus, Gliocladium viride, Penicillium sp. and morpho sp. 1 belonged to the core group. Relative abundance exceeded 10% for A. flavus, A. niger, and morpho sp. 1. The Simpson and Shannon diversity indices were higher in leaf than root or bulb/stem of both orchids. Jaccard＇s similarity coefficient was higher between root and leaf in both orchids （56.3%-60%） than between other pairs. Our study revealed that the endophytic fungal assemblage and diversity orB. neilgherrense and E testacea of Kaiga forest of the Western Ghats were relatively similar between orchids and their tissues.
基金The study was carried out with the support of CONACyT,which awarded an M.Sc.scholarship to BEGR(CVU935962)through the Instituto de Ecología,A.C.
文摘Orchid diversity provides a unique opportunity to further our understanding of biotic and abiotic factors linked to patterns of richness,endemism,and phylogenetic endemism in many regions.However,orchid diversity is consistently threatened by illegal trade and habitat transformation.Here,we identified areas critical for orchid conservation in the biogeographic province of Megamexico.For this purpose,we evaluated orchid endemism,phylogenetic diversity,and phylogenetic endemism within Megamexico and characterized orchid life forms.Our results indicate that the majority of the regions with the highest estimates of endemism and phylogenetic endemism are in southern Mexico and northern Central America,mostly located on the Pacific side of Megamexico.Among the most important orchid lineages,several belong to epiphytic lineages such as Pleurothallidinae,Laeliinae and Oncidiinae.We also found that species from diverse and distantly related lineages converge in montane forests where suitable substrates for epiphytes abound.Furthermore,the southernmost areas of phylogenetic diversity and endemism of Megamexico are in unprotected areas.Thus,we conclude that the most critical areas for orchid conservation in Megamexico are located in southern Mexico and northern Central America.We recommend that these areas should be given priority by the Mexican system of natural protected areas as complementary conservation areas.
文摘Explants,namely the seeds (Cymbidium faberi) and buds (Cymbidium goeringii) of local Hunan orchids were disinfected with 75% ethanol, 0.1% mercuric chloride,and 10% sodium hypochlorite in six different disinfection treatments. Results showed that The treatment with 75% ethanol (contact time: 45 s) and 0.1% mercuric chloride (contact time: 8 min) proved to be the most effective one in disinfecting the explants of Cymbidium faberi seeds.The combination of 75% ethanol (contact time: 45 s) and 0.1% mercuric chloride (contact time: 5 min) provided the optimal disinfection effects when disinfecting Cymbidium goeringii buds.In general, the disinfection effect of mercuric chloride was found to be superior to that of sodium hypochlorite,but care should be taken with the disinfection time to avoid damage to the explants.
文摘Microsatellites, or simple sequence repeats (SSRs), are highly polymorphic, co-dominant genetic markers commonly used for population genetics analyses although de novo development of species specific microsatellites is cost-and time-intensive. Orchidaceae is one of the most species-rich families of angiosperms with more than 30,000 species estimated. Despite its high species-diversity, microsatellites are available only for a few species and all were developed by only using Sanger sequencing methods. For the first time in orchids, we used 454 GS-FLX sequencing to isolate microsatellites in two species (Cypripedium kentuckiense and Pogonia ophioglossoides), and report preliminary results of the study. From 1/16th plate that was subjected to sequencing, 32,665 reads were generated, from which 15,473 fragments contained at least one SSR. We selected 20,697 SSRs representing di-, tri-, and tetra-nucleotides. While 3,674 microsatellites had flanking regions on both sides, useable primer pairs could be designed for 255 SSRs. The mean numbers of reads, SSRs, and SSR-containing reads useful for primer design estimated for other 15 orchid species using Sanger sequencing method were 166, 78 and 31, respectively. Results demonstrate that the efficiency of microsatellite isolation in orchids is substantially higher with 454 GS-FLX sequencing technique in comparison to the Sanger sequencing methods.
基金supported by the National Natural Science Foundation of China(31670342,31370362)the Natural Science Foundation of Yunnan Province(2018FA016)
文摘The Orchidaceae is a diverse and wide spread family of flowering plants that are of great value in ornamental, medical, conservation, and evolutionary research. The broad diversity in morphology,growth form, life history, and habitat mean that the members of Orchidaceae exhibit various physiological properties. Epiphytic orchids are often characterized by succulent leaves with thick cell walls,cuticles, and sunken stomata, whereas terrestrial orchids possess rhizomes, corms, or tubers. Most orchids have a long juvenile period, slow growth rate, and low photosynthetic capacity. This reduced photosynthetic potential can be largely explained by CO_2 diffusional conductance and leaf internal structure. The amount of light required for plant survival depends upon nutritional mode, growth form,and habitat. Most orchids can adapt to their light environments through morphological and physiological adjustments but are sensitive to sudden changes in irradiance. Orchids that originate from warm regions are susceptible to chilling temperatures, whereas alpine members are vulnerable to high temperatures.For epiphytic orchids, rapid water uptake by the velamen radicum, water storage in their pseudobulbs and leaves, slow water loss, and Crassulacean Acid Metabolism contribute to plant-water balance and tolerance to drought stress. The presence of the velamen radicum and mycorrhizal fungi may compensate for the lack of root hairs, helping with quick absorbance of nutrients from the atmosphere.Under cultivation conditions, the form and concentration of nitrogen affect orchid growth and flowering.However, the limitations of nitrogen and phosphorous on epiphytic orchids in the wild, which require these plants to depend on mycorrhizal fungi for nutrients throughout the entire life cycle, are not clearly understood. Because they lack endosperm, seed germination depends upon obtaining nutrients via mycorrhizal fungi. Adult plants of some autotrophic orchids also gain carbon, nitrogen, phosphorus, and other elements from their mycorrhizal partners. Future studies should examine the mechanisms that determine slow growth and flower induction, the physiological causes of variations in flowering behavior and floral lifespan, the effects of nutrients and atmospheric-nitrogen deposition, and practical applications of mycorrhizal fungi in orchid cultivation.
基金We thank Jia-Lin Huang and Jia-Wei Li for their kind help with field work.John Meadows and Raymond Porter are acknowledged for improvements of the manuscript.This study was supported by the National Natural Science Foundation of China(Nos.31670342 and 31700026)Yunnan Applied Basic Research Project(2019FB019)+1 种基金the Science and Technology Plan of Yunnan(2018BB010)the Scientific and Technological Leading Talent Project of Yunnan Province(2016HA005).
文摘Mycorrhizal fungi are essential for the growth and development of both epiphytic(growing on trees)and lithophytic(growing on rocks)orchids.Previous studies indicate that in lowland tropical areas,orchid mycorrhizal fungal compositions are correlated with the life form(i.e.,epiphytic,lithophytic,or terrestrial)of their host plants.We therefore tested if a similar correlation exists in an orchid distributed at higher elevations.Coelogyne corymbosa is an endangered ornamental orchid species that can be found as a lithophyte and epiphyte in subtropical to subalpine areas.Based on high-throughput sequencing of the fungal internal transcribed spacer 2(ITS2)-rDNA region of mycorrhizae of C.corymbosa,we detected 73 putative mycorrhizal fungal Operational Taxonomic Units(OTUs).The OTUs of two dominant lineages(Cantharellales and Sebacinales)detected from C.corymbosa are phylogenetically different from those of other species within the genus Coelogyne,indicating that different orchid species prefer specific mycorrhizal fungi.We also found that the Non-metric multidimensional scaling(NMDS)plots of orchid mycorrhizal fungi were not clustered with life form,the variations among orchid mycorrhizal fungal communities of different life forms were not significant,and most of the OTUs detected from epiphytic individuals were shared by the lithophytic plants,suggesting that orchid mycorrhizal associations of C.corymbosa were not affected by life form.These findings provide novel insights into mycorrhizal associations with endangered ornamental orchids.
文摘Native orchid species of Singapore in their natural conditions experience stress from high irradiance, high temperatures and periods of extended low rainfall, which impact orchid plant physiology and lead to reduced growth and productivity. In this study, it was found that there was a reduction in photochemical efficiency of photosystem II (PSII) in 6 native orchid species under high light (HL) and Bulbophyllum membranaceum under low light (LL). There was chronic photoinhibition in these 6 orchid species over a period of 3 months after transplanting onto the tree trunks without watering and fertilization, especially in Coelogynes mayeriana and Bulbophyllum membranaceum under both HL and LL. This chronic photoinhibition caused by sustained period of water deficit in their natural conditions was later reversed by natural re-watering conditions from higher rainfall. These results indicate that water deficit has a greater impact on photosynthetic light utilization efficiency than excess light. The present study also showed that after natural rewatering, relative water content (RWC) of leaves and pseudobulbs generally increased. During the natural re-watering, total leaf area also gradually increased and reached maximum expansion after 7 weeks under both HL and LL, with some exceptions due to leaf abscission or decline in total leaf area, possibly a strategy for water conservation.
基金Supported by the Multi-Stakeholder Forestry Programme Nepal under the project Traded Medicinal Orchids of Nepal and their in-situ and ex-situ Conservation by Means of People’s Participation in Some Selected Community Forests of Nepal(Grant No.SSU_2012_007G).
文摘Objective:To assess the antioxidant activity as well as the total polyphenolics and flavonoids content of thirteen extracts from nine wild orchids of Nepal.Methods:First,a preliminary phytochemical screening of thirteen extracts of nine orchids was carried out using established protocols.Then,the total polyphenolic and flavonoid contents of each extract were evaluated using the Folin-Ciocalteu's phenol reagent and aluminium chloride methods respectively.Finally,antioxidant activity was determined by 2,2-diphenyl-1-picryl hydrazyl free radical scavenging assay and expressed in terms of half inhibition concentrations(IC50 values).Results:All the tested parameters showed significant variation at P=0.05.The total flavonoids varied with the greatest amounts found in the leaves of Rhynchostylis retusa and the smallest amounts found in the roots of Gastrochilus acutifolius(G.acutifolius).The amount of total polyphenolics was highest in the stems of Vanda cristata and lowest in the leaves of G.acutifolius.Antioxidant activity was highest in the stems of Vanda cristata and lowest in the leaves of G.acutifolius.Conclusions:Some of the orchid extracts studied exhibited levels of antioxidant activity which were comparable to or even higher than those found for extracts of medicinal plants and orchids studied previously.It is suggested that drugs and natural food additives can be extracted from those wild orchids with high levels of antioxidant activity.
文摘Nigeria’s first female train driver honoured for promoting understanding between China and Africa In mid-July,vips gathered at the Beijing Hotel in China’s capital to witness the presentation of Orchid Awards to 10 ambassadors of culture from di!erent continents.They were chosen from over 300 candidates from around 80 countries.
基金supported by the Teamwork Projects Funded by Guangdong Natural Science Foundation,China(Grant No.2017A030312004)The National Natural Science Foundation of China(Grant No.31870199)+2 种基金The National Key Research and Development Program of China(Grant No.2018YFD1000401)Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization Construction Funds(Grant No.115/118990050115/KJG18016A)。
文摘Orchid origin and evolution are common topics in evolutionary biology. Orchidaceae have approximately 30 000 orchid species distributed in diverse habitats and account for approximately 10% of the flowering plant species worldwide. Orchids provide us with materials to explore coevolution and organic evolution. In this review, we highlighted the genome study progress of orchids. In addition, we revealed the role of MADS-box gene families in the floral morphology and evolution of orchids. Genomics studies confirmed that all five subfamilies of existing orchids evolved from a common ancestor. Loss of Mβ MADS-box genes resulted in the endosperm from the seed of all existing orchids being absent. Perianth reversion to the ancestral state occurred because Apostasia and Apostasioideae lost B-AP3 and E class paralogous genes. Loss of P-subclade members of MIKC*-Type in Phalaenopsis equestris, Dendrobium catenatum, and Epidendroideae caused the formation of pollinium.In addition, the combined loss of AGL12 and contraction of ANR1 gave orchids the ability to be successfully epiphytic on trees or rocks and to develop a unique root system. Both pollinium and epiphytic production on trees are beneficial for orchid adaptations, and Epidendroideae evolved more species(~ 20 000) than Apostasioideae(16 species). Genome studies shed new light on determining the evolutionary history of orchids and understanding the genetic mechanisms of orchid morphological evolution.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA0420203)the National Natural Science Foundation of China (32270214 to XJ)China's National Basic Science and Technology Program (2018FY100801)。
文摘Orchidaceae are one of the largest families of angiosperms in terms of species richness.In the last decade,numerous studies have delved into reconstructing the phylogenetic framework of Orchidaceae,leveraging data from plastid,mitochondrial and nuclear sources.These studies have provided new insights into the systematics,diversification and biogeography of Orchidaceae,establishing a robust foundation for future research.Nevertheless,pronounced controversies persist regarding the precise placement of certain lineages within these phylogenetic frameworks.To address these discrepancies and deepen our understanding of the phylogenetic structure of Orchidaceae,we provide a comprehensive overview and analysis of phylogenetic studies focusing on contentious groups within Orchidaceae since 2015,delving into discussions on the underlying reasons for observed topological conflicts.We also provide a novel phylogenetic framework at the subtribal level.Furthermore,we examine the tempo and mode underlying orchid species diversity from the perspective of historical biogeography,highlighting factors contributing to extensive speciation.Ultimately,we delineate avenues for future research aimed at enhancing our understanding of Orchidaceae phylogeny and diversity.
文摘With nylon mesh bags, the decomposition and nutrients release characteristics of two kinds of green manure crops, February orchid （Orychophragmus violaceus） and Hair Vetch （Vicia villosa Roth）, were investigated in this study. The results showed that these two kinds of green manure crops were decomposed rapidly in the first 14 days, and then decomposed slowly. After 80 days of incubation, the decomposition rates of February orchid and Hair Vetch were 66.92% and 63.12%, respectively. Different nutrients had different release rates from the green manures. Nitrogen （N） and potassium （K） were released rapidly in the initial 7 days, and phosphorus （P） was released steadily in the 80 days of incubation. In the two kinds of green manures, the release rates all ranked as K＇s〉N＇s〉P＇s. The release rates of nutrients, especially P （P〈0.05）, of February orchid were higher than those of Hair Vetch.
基金Funding (No. U1302262) to W.B. Sun from the NSFC-Yunnan joint fund on key projects is gratefully acknowledgedThe Royal Botanic Gardens, Kew receives grant-in-aid from Defra+1 种基金This joint work was undertaken under the Memorandum of Agreement (2014e24) on Plant and Fungal Science between the Chinese Academy of Sciences and the Trustees of the Royal Botanic Gardens, KewHWP thanks Darwin Initiative Project 21-003 on cycads for funding
文摘Approximately one fifth of the world's plants are at risk of extinction.Of these,a significant number exist as populations of few individuals,with limited distribution ranges and under enormous pressure due to habitat destruction.In China,these most-at-risk species are described as 'plant species with extremely small populations'(PSESP).Implementing conservation action for such listed species is urgent.Storing seeds is one of the main means of ex situ conservation for flowering plants.Spore storage could provide a simple and economical method for fern ex situ conservation.Seed and spore germination in nature is a critical step in species regeneration and thus in situ conservation.But what is known about the seed and spore biology(storage and germination) of at-risk species? We have used China's PSESP(the first group listing) as a case study to understand the gaps in knowledge on propagule biology of threatened plant species.We found that whilst germination information is available for 28 species(23%of PSESP),storage characteristics are only known for 8%of PSESP(10 species).Moreover,we estimate that 60%of the listed species may require cryopreservation for long-term storage.We conclude that comparative biology studies are urgently needed on the world's most threatened taxa so that conservation action can progress beyond species listing.
