Atmospheric nitrogen deposition poses a major threat to global biodiversity. Tropical epiphytic plants are especially at risk given their reliance on atmospheric sources of nutrients. The leaf, ...pseudobulb, and root carbon and nitrogen content, C:N ratio, as well as the nitrogen isotopic composition were studied for individuals of Laelia speciosa from a city and from an oak forest in Mexico. The nitrogen content of leaves was similar between the city and the oak forest, reaching 1.3 plus or minus 0.2 % (dry mass). The delta super(15)N of leaves, pseudobulbs, and roots reached 5.6 plus or minus 0.2 ppt in the city, values found in sites exposed to industrial and vehicular activities. The delta super(15)N for plant from the oak forest amounted to -3.1 plus or minus 0.3 ppt, which is similar to values measured from sites with low industrial activities. Some orchids such as Laelia speciosa produce a single pseudobulb per year, i.e., a water and nutrient storage organ, so the interannual nitrogen deposition was studied by considering the ten most recent pseudobulbs for plants from either site formed between 2003 and 2012. The C:N ratio of the ten most recent pseudobulbs from the oak forest, as well as that of the pseudobulbs formed before 2010 for plants in the city were indistinguishable from each other, averaging 132.4 plus or minus 6.5, while it was lower for the two most recent pseudobulbs in the city. The delta super(15)N values of pseudobulbs from the oak forest averaged 4.4 plus or minus 0.1 ppt for the entire series. The delta super(15)N ranged from 0.1 plus or minus 1.6 ppt for the oldest pseudobulb to 4.7 plus or minus 0.2 ppt for the pseudobulb formed in the city from 2008 onwards. Isotopic analysis and the C:N ratio for L. speciosa revealed that rates of nitrogen deposition were higher in the city than in the forest. The delta super(15)N values of series of pseudobulbs showed that it is possible to track nitrogen deposition over multiple years.
The largest subfamily of orchids, Epidendroideae, represents one of the most significant diversifications among flowering plants in terms of pollination strategy, vegetative adaptation and number of ...species. Although many groups in the subfamily have been resolved, significant relationships in the tree remain unclear, limiting conclusions about diversification and creating uncertainty in the classification. This study brings together DNA sequences from nuclear, plastid and mitochrondrial genomes in order to clarify relationships, to test associations of key characters with diversification and to improve the classification.
Sequences from seven loci were concatenated in a supermatrix analysis for 312 genera representing most of epidendroid diversity. Maximum-likelihood and parsimony analyses were performed on this matrix and on subsets of the data to generate trees and to investigate the effect of missing values. Statistical character-associated diversification analyses were performed.
Likelihood and parsimony analyses yielded highly resolved trees that are in strong agreement and show significant support for many key clades. Many previously proposed relationships among tribes and subtribes are supported, and some new relationships are revealed. Analyses of subsets of the data suggest that the relatively high number of missing data for the full analysis is not problematic. Diversification analyses show that epiphytism is most strongly associated with diversification among epidendroids, followed by expansion into the New World and anther characters that are involved with pollinator specificity, namely early anther inflexion, cellular pollinium stalks and the superposed pollinium arrangement.
All tested characters show significant association with speciation in Epidendroideae, suggesting that no single character accounts for the success of this group. Rather, it appears that a succession of key features appeared that have contributed to diversification, sometimes in parallel.
Several factors may have interactive effects on natural 15N abundance of plant species. Some of these effects could be associated with different plant functional types, including mycorrhizal ...association type. Due to its high taxonomic and functional diversity, the alpine heath community in the Caucasus is a suitable object for studying 15N natural abundance of plants in relation to different functional/mycorrhizal groups, contrasting with the limited numbers of plant groups or species considered in previous studies of individual communities. The N concentration and δ15N were determined in leaves of 25 plant species from 8 functional/mycorrhizal groups from an alpine lichen heath in the Teberda Reserve, Northern Caucasus, Russia. Functional groups were represented by ericoid mycorrhizal species (ERI), ectomycorrhizal species (ECT), arbuscular mycorrhizal forbs (AM—FORB), arbuscular mycorrhizal grasses (AM—GRA), arbuscular mycorrhizal nodulated legumes (FAB—N), non-mycorrhizal graminoids (sedges and rushes) (NOM—GRA), non-mycorrhizal hemiparasites (NOM—SP), and orchids (ORC). We can summarize our results in two rankings for leaf N concentration (FAB—N > ORC > AM—FORB, ECT > NOM—SP, ERI ≥⃒ NOM—GRA, AM—GRA) and leaf δ15N signature (ORC > NOM—GRA, FAB—N > ECT ≥⃒ ERI ≥⃒ AM—FORB, NOM—SP, AM—GRA) of alpine heath species. We conclude that, within the alpine lichen heath in the Northern Caucasus, the δ15N signature of plant foliage is a relevant indicator of plant functional groups with relatively high 15N content (ORC, FAB-N, NOM-GRA), while the absence of a significant difference between relatively 15N-depleted groups (AM, ERI, and ECT species) isn't clear and may result from both processes, as the increased N isotope fractionation by arbuscular mycorrhizal fungi as the decreased role of ecto- and ericoid mycorrhizal fungi in the flux of N.
Bletilla is a temperate, terrestrial genus of orchids containing 6 species. For the species whose whole genome is unknown, we used magnetic bead hybridization method to develop microsatellite Simple ...Repeat Polymorphoresis (SSR) for Bletilla striata and 9 primer sets were characterized in two wild populations of B. striata and one wild population of Bletilla ochracea. The number of alleles per locus ranged from 1 to 12. The expected and observed heterozygosities ranged from 0 to 0.7646 and 0 to 0.950 in B. striata, respectively. In B. ochracea, the expected and observed heterozygosities ranged from 0.296 to 0.871 and 0.05 to 1, respectively. The 9 pairs of primers we designed can be used to distinguish different ecotypes and species, and might be used for other subspecies or species in genera Bletilla.
Recent phylogenomic analyses based on the maternally inherited plastid organelle have enlightened evolutionary relationships between the subfamilies of Orchidaceae and most of the tribes. However, ...uncertainty remains within several subtribes and genera for which phylogenetic relationships have not ever been tested in a phylogenomic context. To address these knowledge-gaps, we here provide the most extensively sampled analysis of the orchid family to date, based on 78 plastid coding genes representing 264 species, 117 genera, 18 tribes and 28 subtribes. Divergence times are also provided as inferred from strict and relaxed molecular clocks and birth-death tree models. Our taxon sampling includes 51 newly sequenced plastid genomes produced by a genome skimming approach. We focus our sampling efforts on previously unplaced clades within tribes Cymbidieae and Epidendreae. Our results confirmed phylogenetic relationships in Orchidaceae as recovered in previous studies, most of which were recovered with maximum support (209 of the 262 tree branches). We provide for the first time a clear phylogenetic placement for Codonorchideae within subfamily Orchidoideae, and Podochilieae and Collabieae within subfamily Epidendroideae. We also identify relationships that have been persistently problematic across multiple studies, regardless of the different details of sampling and genomic datasets used for phylogenetic reconstructions. Our study provides an expanded, robust temporal phylogenomic framework of the Orchidaceae that paves the way for biogeographical and macroevolutionary studies.
The Brazilian Atlantic Forest presents high levels of richness and endemism of several taxonomic groups. Within this forest, the Orchidaceae may be highlighted as the richest family of Angiosperms ...found there, and is highly threatened due to collection and habitat destruction. The objectives of this study were to conduct a floristic survey of the Orchidaceae species on the Macico do Itaoca, an inselberg located in the Northern region of the State of Rio de Janeiro, make a comparative analysis with other sites in Eastern Brazil, and discuss the geographic distribution, floristic relationships and conservation status of the orchid species present on the inselbergs. The threats observed to the species on this inselberg are the same as for other inselbergs and include the collection of ornamental species, fire and quarrying. Specifically for the Macico do Itaoca, a possibility for conservation may be the annexation of this area to the Desengano State Park, an important conservation area in the Northern of the State of Rio de Janeiro.Original Abstract: La Mata Atlantica brasilena presenta altos niveles de riqueza y endemismo de varios grupos taxonomicos. Los inselbergs de la Mata Atlantica de Brasil son, en su mayoria, desconocidos en cuanto a su composicion floristica. Los objetivos de este estudio fueron hacer un analisis comparativo de las especies de Orchidaceae en el Macizo de Itaoca, un inselberg ubicado en la region norte del Estado de Rio de Janeiro, con otros sitios en el este de Brasil, y discutir la distribucion geografica, las relaciones floristicas y el estado de conservacion de las especies de orquideas presentes en los inselbergs. La composicion floristica de la zona de estudio se comparo con otras 24 localidades en el este de Brasil (13 de las cuales son inselbergs) y la influencia de los tipos de vegetacion aledana en la composicion de la flora de Orchidaceae en los inselbergs. En Macizo de Itaoca registramos 18 especies de 17 generos. La mayor similitud floristica fue con la Pedra da Botelha (0,43), en Espirito Santo. Al parecer, los tipos de vegetacion aledana ejercen poca influencia sobre la flora de los inselbergs.
Production of synthetic seeds has unraveled new vistas in in vitro plant propagation technology, because it offers many useful advantages on a commercial scale for the propagation of a variety of ...crop plants. These tools provide methods for production of synthetic seeds for conversion into plantlets under in vitro and in vivo conditions. This technology is useful for multiplying and conserving the elite agricultural and endangered medicinal plant species, which are difficult to regenerate through conventional methods and natural seeds. The synthetic seed technology was developed in different economically important plant species such as vegetable crops, forage legumes, industrially important crops, cereals, spices, plantation crops, fruit crops, ornamental plants, orchids, medicinal plants and wood yielding forest trees etc. All these aspects are presented in this review.
Paphiopedilum orchids are generally propagated through the division of axillary buds from mother plant, which limits commercial production due to its unproductive proliferation and time consuming. In ...this study, the effect of in vitro cutting methods and medium composition on efficient shoot multiplication of Paphiopedilum Hsinying Rubyweb was investigated. Among three different in vitro stem cutting methods used, vertical cutting was able to produce more new shoots than horizontal and cross cutting when cultured on Hyponex based medium. After 12 weeks of culture, plantlets regenerated from vertical cutting were able to produce new healthy and well rooted shoots higher than without cutting on the same medium. Moreover, the newly-formed shoots which were divided into single plantlets and subcultured onto half-strength Murashige and Skoog (MS) medium without growth regulators could remain higher shoot multiplication than in other media. The micropropagation procedure developed in this study provides a simple means to in vitro propagate Paphiopedilum plantlets which are able to produce large numbers of uniform plantlets in a shorter time compared to the conventional propagation method.
The Andean mountains of South America are the most species-rich biodiversity hotspot worldwide with c. 15% of the world’s plant species, in only 1% of the world’s land surface. Orchids are a key ...element of the Andean flora, and one of the most prominent components of the Neotropical epiphyte diversity, yet very little is known about their origin and diversification.
We address this knowledge gap by inferring the biogeographical history and diversification dynamics of the two largest Neotropical orchid groups (Cymbidieae and Pleurothallidinae), using two unparalleled, densely sampled orchid phylogenies (including more than 400 newly generated DNA sequences), comparative phylogenetic methods, geological and biological datasets.
We find that the majority of Andean orchid lineages only originated in the last 20–15 million yr. Andean lineages are derived from lowland Amazonian ancestors, with additional contributions from Central America and the Antilles. Species diversification is correlated with Andean orogeny, and multiple migrations and recolonizations across the Andes indicate that mountains do not constrain orchid dispersal over long timescales.
Our study sheds new light on the timing and geography of a major Neotropical diversification, and suggests that mountain uplift promotes species diversification across all elevational zones.
Esmeralda clarkei is an epiphytic native orchid species of Nepal growing under medium amount of light with fragrant flowers. Reliable protocols for in vitro plant regeneration of E. clarkei via ...protocorm explants were developed. Protocorms obtained from in vitro germinated seeds cultured on Murashige and Skoog's (MS) medium supplemented with 6-benzylaminopurine (BAP) and alpha -naphthalene acetic acid (NAA) individually and in combinations responded positively by induction of multiple shoots. The cultures were maintained at 25 plus or minus 2 degree C under a 16/8h light/dark cycle photoperiod provided by fluorescent lamps (Philips, India). BAP increased from 0.5 to 2.0 mg/l individually induced the maximum number of shoots (11 to 14 shoots per treatment) which is followed by combinations of BAP (0.5, 1.0 and 1.5mg/l) and NAA (0.5mg/l) which induced 7 to 8 shoots per treatment. The highest number of roots (3 roots per treatment) was observed in NAA (0.5 and 1.0 mg/l) supplemented medium among the other tested medium.
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