SciCombinator

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Concept: Orchidaceae

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Stelis (Orchidaceae) encompasses approximately 1100 species of epiphytic orchids distributed throughout the Neotropics, with the highest diversity in Andean South America. Sixty-two species were recorded previously in Mexico.

Concepts: Pacific Ocean, North America, South America, Americas, Latin America, Pleurothallis, Orchidaceae, Masdevallia

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The great majority of plant species in the tropics require animals to achieve pollination, but the exact role of floral signals in attraction of animal pollinators is often debated. Many plants provide a floral reward to attract a guild of pollinators, and it has been proposed that floral signals of non-rewarding species may converge on those of rewarding species to exploit the relationship of the latter with their pollinators. In the orchid family (Orchidaceae), pollination is almost universally animal-mediated, but a third of species provide no floral reward, which suggests that deceptive pollination mechanisms are prevalent. Here, we examine floral colour and shape convergence in Neotropical plant communities, focusing on certain food-deceptive Oncidiinae orchids (e.g. Trichocentrum ascendens and Oncidium nebulosum) and rewarding species of Malpighiaceae. We show that the species from these two distantly related families are often more similar in floral colour and shape than expected by chance and propose that a system of multifarious floral mimicry-a form of Batesian mimicry that involves multiple models and is more complex than a simple one model-one mimic system-operates in these orchids. The same mimetic pollination system has evolved at least 14 times within the species-rich Oncidiinae throughout the Neotropics. These results help explain the extraordinary diversification of Neotropical orchids and highlight the complexity of plant-animal interactions.

Concepts: Evolution, Insect, Tropics, Mimicry, Polymorphism, Batesian mimicry, Orchidaceae, Oncidium

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BACKGROUND AND AIMS: Dendrobium longicornu, commonly known as the ‘Long-horned Dendrobium’, is an endangered and medicinally important epiphytic orchid. Over-exploitation and habitat destruction seriously threaten this orchid in Northeast India. Our objective was to develop an efficient protocol for the mass propagation of D. longicornu using axillary bud segments. METHODOLOGY AND PRINCIPAL RESULTS: Axillary buds cultured in Murashige and Skoog semi-solid medium supplemented with α-naphthalene acetic acid (NAA), 2,4-dichlorophenoxy acetic acid (2,4-D) and 6-benzylaminopurine (BAP) readily developed into plantlets. These formed either directly from shoot buds or from intermediary protocorm-like bodies (PLBs). The maximum explant response (86.6 %) was obtained in medium supplemented with NAA at 30 µM, while the maximum number of shoots (4.42) and maximum bud-forming capacity (3.51) were observed in medium containing 15 µM BAP and 5 µM NAA in combination. Protocorm-like bodies were obtained when the medium contained 2,4-D. The maximum number of explants forming PLBs (41.48 %) was obtained in medium containing 15 µM BAP and 15 µM 2,4-D. Well-developed plantlets obtained after 20-25 weeks of culture were acclimatized and eventually transferred to the greenhouse. Over 60 % of these survived to form plants ∼3-4 cm tall after 90 days in glasshouse conditions using a substrate of crushed brick and charcoal, shredded bark and moss. CONCLUSIONS: The method described can readily be used for the rapid and large-scale regeneration of D. longicornu. Its commercial adoption would reduce the collection of this medicinally important and increasingly rare orchid from the wild.

Concepts: Bud, Culture, Acetic acid, Plant stem, Vinegar, Shoot, Orchidaceae

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Swarna Jibanti scientifically known as Coelogyne cristata Lindley (Orchidaceae), an orchid mentioned in Ayurvedic medicine is used to promote healthy life span.

Concepts: Medicine, Ayurveda, Surgery, Alternative medicine, Chronic fatigue syndrome, Traditional medicine, Orchidaceae, Coelogyne

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Background and AimsA positive correlation between tissue thickness and crassulacean acid metabolism (CAM) expression has been frequently suggested. Therefore, this study addressed the question of whether water availability modulates photosynthetic plasticity in different organs of two epiphytic orchids with distinct leaf thickness.MethodsTissue morphology and photosynthetic mode (C3 and/or CAM) were examined in leaves, pseudobulbs and roots of a thick-leaved (Cattleya walkeriana) and a thin-leaved (Oncidium ‘Aloha’) epiphytic orchid. Morphological features were studied comparing the drought-induced physiological responses observed in each organ after 30 d of either drought or well-watered treatments.Key ResultsCattleya walkeriana, which is considered a constitutive CAM orchid, displayed a clear drought-induced up-regulation of CAM in its thick leaves but not in its non-leaf organs (pseudobulbs and roots). The set of morphological traits of Cattleya leaves suggested the drought-inducible CAM up-regulation as a possible mechanism of increasing water-use efficiency and carbon economy. Conversely, although belonging to an orchid genus classically considered as performing C3 photosynthesis, Oncidium ‘Aloha’ under drought seemed to express facultative CAM in its roots and pseudobulbs but not in its leaves, indicating that such photosynthetic responses might compensate for the lack of capacity to perform CAM in its thin leaves. Morphological features of Oncidium leaves also indicated lower efficiency in preventing water and CO2 losses, while aerenchyma ducts connecting pseudobulbs and leaves suggested a compartmentalized mechanism of nighttime carboxylation via phosphoenolpyruvate carboxylase (PEPC) (pseudobulbs) and daytime carboxylation via Rubisco (leaves) in drought-exposed Oncidium plants.ConclusionsWater availability modulated CAM expression in an organ-compartmented manner in both orchids studied. As distinct regions of the same orchid could perform different photosynthetic pathways and variable degrees of CAM expression depending on the water availability, more attention should be addressed to this in future studies concerning the abundance of CAM plants.

Concepts: Photosynthesis, Carbon dioxide, RuBisCO, C4 carbon fixation, C3 carbon fixation, Crassulacean acid metabolism, Orchidaceae, Carbon fixation

27

Both floral development and evolutionary trends of orchid flowers has long attracted the interest of biologists. However, expressed sequences derived from the flowers of other orchid subfamilies are still scarce except few species in Epidendroideae. For broadly increasing our scope on Orchidaceae genetic information, we updated the OrchidBase to version 2.0 which newly added 1,562,071 floral non-redundant transcribed sequences (unigenes) collected comprehensively from ten orchid species across five subfamilies of Orchidaceae. Total 662,671,362 reads were obtained by using next generation sequencing (NGS) Solexa Illumina sequencers. After assembly, in average 156,207 unigenes were generated for each species. The average length of unigene is 347 bp. We made detailed annotation including general information, relative expression level, gene ontology (GO), KEGG pathway mapping, and gene network prediction. The online resources for putative annotation can be searched either by text or by using BLAST, and the results can be explored on the website and downloaded. We have re-designed the user interface in the new version. Users can enter Phalaenopsis transcriptome or Orchidaceae floral transcriptome to browse or search the unigenes. The OrchidBase 2.0 is freely available at http://orchidbase.itps.ncku.edu.tw/.

Concepts: DNA, Genetics, Gene expression, Evolution, Biology, Flowers, Orchidaceae, Bioinformatics databases

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In our continued efforts to contribute to the general knowledge on the chemical diversity of orchids, we have decided to focus our investigations on the Aeridinae subtribe. Following our previous phytochemical study of Vanda coerulea, which has led to the identification of phenanthrene derivatives, a closely related species, Aerides rosea Lodd. ex Lindl. & Paxton, was chosen for investigation.

Concepts: Orchidaceae, Vanda coerulea, Aeridinae, Phalaenopsis, Vanda, Aerides, Vanda tricolor, Aerides rosea

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Vandaceous orchids are a group of orchid genera in the subfamily Vandoideae. Among this group, Mokara, Phalaenopsis, and Vanda are the most popular and commercially important orchids in Thailand. Novel microsatellite markers were developed from Mokara, the intergeneric hybrid from 3 genera Vanda, Ascocentrum, and Arachnis by using enriched method. Six primers from this study plus one primer previously developed from Vanda genome, a total of 7 markers, were selected to characterize 4 orchid genera (Mokara, Vanda, Rhynchostylis, and Ascocenda). The observed and expected heterozygosities varied in the 4 genera from 0.0000-1.0000 and 0.0000-0.8765, respectively. The transferability of these primers was also investigated in 76 vandaceous orchids from 12 genera. Three primer pairs, MOK26, MOK29, and MOK62, could successfully amplify the DNA of all samples, while MOK103 could be used with most of the samples. The total number of alleles from 76 samples ranged from 3 to 19 alleles per locus, with an average of 8.5714. Therefore, these markers could be used for variety/ species identification, certification and protection, genetic diversity, and evolutionary studies.

Concepts: Gene, Genetics, Biology, Species, Orchidaceae, Phalaenopsis, Ascocentrum, Vanda

25

Vanda tessellata (Orchidaceae) has been used in different sorts of ailments such as inflammations, rheumatism, dysentery, bronchitis, dyspepsia and fever in folk medicine. In this study we evaluated the antinociceptive and cytotoxic effect of methanol and aqueous extracts of V. tessellata leaf.

Concepts: Medicine, Immunology, Rheumatology, Gastroenterology, Orchidaceae, Vanda, Vanda tricolor, Vanda tessellata

11

The wildlife trade is a lucrative industry involving thousands of animal and plant species. The increasing use of the internet for both legal and illegal wildlife trade is well documented but there is evidence that trade may be emerging on new online technologies such as social media. We carry out the first systematic survey of trade on an international social-media website, using the orchid trade as a case study. We analyzed an online community consisting of 150 orchid focused groups on a large social media website, using social network analysis. Closely linked communities were found reflecting language groups, with most trade occurring in a community of English-speaking and Southeast Asian groups. In addition we randomly sampled 30 groups to assess the prevalence of trade in cultivated and wild plants. We found that 8.9% of posts contained trade, 22-46% of which was in wild-collected orchids. Although total numbers of trade posts are relatively small, the high proportion of wild plants for sale supports calls for better monitoring of social media for trade in wild-collected plants. This article is protected by copyright. All rights reserved.

Concepts: Plant, Sociology, All rights reserved, Social network, Virtual community, Copyright, Orchidaceae, Information science