203 research outputs found
Morphological character evolution of Amorphophallus (Araceae) based on a combined phylogenetic analysis of trnL, rbcL, and LEAFY second intron sequences
Sequences of three different genes in 69 taxa of Amorphophallus were combined to reconstruct the molecular phylogeny of this species-rich Aroid genus. The data set was analyzed by three different methods, Maximum Parsimony, Maximum Likelihood and Bayesian analysis, producing slightly different tree topologies. Three major clades identified in all analyses reflect the biogeographical distribution of Amorphophallus. Some clades were supported by morphological characters such as sessile/nonsessile stigma, pollen opening mechanism, shape of the main segments of the lamina, growth cycle, and berry colour. When optimised, a nonsessile stigma may have evolved from a sessile one with several reversals. Pollen opening by connective rupturing evolved from pollen opening by pores. Unequally shaped segments of the lamina evolved from equally shaped segments. Simultaneously existing leaf and inflorescences evolved from alternating leaves and inflorescences. Blue, purple, green, and yellow berries evolved from red/orange/white ones
Imaging dielectric relaxation in nanostructured polymers by frequency modulation electrostatic force microscopy
We have developed a method for imaging the temperature-frequency dependence of the dynamics of nanostructured polymer films with spatial resolution. This method provides images with dielectric compositional contrast well decoupled from topography. Using frequency-modulation electrostatic-force-microscopy, we probe the local frequency-dependent (0.1â100 Hz) dielectric response through measurement of the amplitude and phase of the force gradient in response to an oscillating applied electric field. When the phase is imaged at fixed frequency, it reveals the spatial variation in dielectric losses, i.e., the spatial variation in molecular/dipolar dynamics, with 40 nm lateral resolution. This is demonstrated by using as a model system; a phase separated polystyrene/polyvinyl-acetate (PVAc) blend. We show that nanoscale dynamic domains of PVAc are clearly identifiable in phase images as those which light-up in a band of temperature, reflecting the variations in the molecular/dipolar dynamics approaching the glass transition temperature of PVAc
Specklinia lugduno-batavae (Pleurothallidinae: Orchidaceae), a new species in the S-digitalis group
Specklinia lugduno-batavae from the Caribbean lowlands of Nicaragua and Costa Rica is formally described and illustrated. The new species belongs to the Specklinia digitalis group and can be recognised by the creeping habit, purple spotted abaxial surface of the leaf and the almost immaculate whitish cream flowers, which are produced in succession on a very short, flexuous inflorescence. The name honours Leiden University and the Hortus botanicus Leiden. The novelty is compared with its closest relatives, Specklinia digitalis, S. pisinna and S. succulenta.Plant science
Possible chemical mimicry of the European ladyâs slipper orchid (Cypripedium calceolus)
Pollination based on insect deception has been debated in the scientific community since it was first reported over two hundred years ago. A vast majority of deceptive syndromes occur within the orchid family. While many cheating flowers have been described and are well known, there are still many curious cases that need further investigation. One prime example of such a case is Cypripedium calceolus, known as European ladyâs slipper orchid. While the flower has been of interest to many prominent scientists for over a century, its pollination is still not fully understood. Both visual and olfactory cues seem to play an important role in pollinator attraction. In this study we focussed on the olfactory cues in order to explore their relationship (in future experiments) with floral visual cues, including the unique asymmetry of these flowers. Some of the plantsâ floral fragrances were used in Electroantennography experiments. Eleven chemical compounds were applied to the antennae of Bombus terrestris and Apis mellifera. Even though these species are not regular visitors of C. calceolus, we were interested to see whether there were common principles in their responses to the flowersâ scent that might justify extrapolating to other pollinator species such as sand bees that get trapped in these orchids and fly out of the flowers afterwards with pollen smeared on their body. The results show that while both species react similarly to most of the odours, some of the tested acetates induced a significantly greater reaction in B. terrestris antennae. These acetates play an important role in bumblebee pheromones, but their relevance for the natural pollinators of C. calceolus remains to be confirmed to see whether chemical mimicry by these flowers is deliberately employed to attract pollinators
The effects of COVID-19 litter on animal life
During the COVID-19 pandemic, Personal Protective Equipment (PPE) is massively used, resulting in a new wave of litter: protective face masks and gloves. Here we present the first case of a fish entrapped in a medical glove, encountered during a canal clean-up in Leiden, The Netherlands. We also report the first cases of birds using medical face masks as nesting material, which were also found in the Dutch canals. To place these new findings in context, we collected online reported interactions of animals with PPE litter, since the start of the pandemic. This resulted in the first overview of cases of entanglement, entrapment and ingestion of COVID-19 litter by animals and the use of it as nesting material. We signal COVID-19 litter as a new threat to animal life as the materials designed to keep us safe are actually harming animals around us. To understand the full scale of this problem, we welcome anyone to contribute to our overview by submitting their observations online at www.covidlitter.com. To further prevent PPE litter, it is recommended that, when possible, reusable alternatives are used.Environmental Biolog
Ebony wood identification to battle illegal trade
Horizon 2020(H2020)Computer Systems, Imagery and Medi
Lynx presence in Roman times in the lower germanic <i>Limes</i> region: The case of Alphen aan den Rijn
DNA barcoding of tuberous Orchidoideae: a resource for identification of orchids used in Salep.
Tubers of terrestrial orchids are harvested and traded from the eastern Mediterranean to the Caspian Sea for the traditional product Salep. Overexploitation of wild populations and increased middleâclass prosperity have escalated prices for Salep, causing overharvesting, depletion of native populations and providing an incentive to expand harvesting to untapped areas in Iran. Limited morphological distinctiveness among traded Salep tubers renders species identification impossible, making it difficult to establish which species are targeted and affected the most. In this study, a reference database of 490 nrITS, trnLâF spacer and matK sequences of 133 taxa was used to identify 150 individual tubers from 31 batches purchased in 12 cities in Iran to assess species diversity in commerce. The sequence reference database consisted of 211 nrITS, 158 trnLâF and 121 matK sequences, including 238 new sequences from collections made for this study. The markers enabled unambiguous species identification with treeâbased methods for nrITS in 67% of the tested tubers, 58% for trnLâF and 59% for matK. Species in the genera Orchis (34%), Anacamptis (27%) and Dactylorhiza (19%) were the most common in Salep. Our study shows that all tuberous orchid species in this area are threatened by this trade, and further stresses the urgency of controlling illegal harvesting and crossâborder trade of Salep tubers.Plant science
Pollination strategy of Gennaria diphylla (Orchidaceae) on the Canary Islands and on Madeira
Gennaria diphylla (Link) Parl. is a terrestrial, inconspicuous green orchid. Its distribution includes the central and western Mediterranean region as well as the Canary Islands and Madeira. Investigations on its pollination biology are scarce. In literature, there are mentions of autogamy and of allogamy. Pollination and pollen import and export were studied on Tenerife and Madeira. The investigations showed autogamy plays a less important role than thought, although a caging experiment showed that the species is well capable of self-pollination. The orchid is pollinated by a variety of small moths, especially of the families Geometridae, Pyralidae and Crambidae. It is flowering in a period when few other plants flower, so there is little competition for pollinators. Complemented by autogamy this seems to be a successful strategy, as the species shows a relatively high average fruit set of 73 %.Naturali
The Complete Chloroplast Genome of 17 Individuals of Pest Species Jacobaea vulgaris: SNPs, Microsatellites and Barcoding Markers for Population and Phylogenetic Studies
Invasive individuals from the pest species Jacobaea vulgaris show different allocation patterns in defence and growth compared with native individuals. To examine if these changes are caused by fast evolution, it is necessary to identify native source populations and compare these with invasive populations. For this purpose, we are in need of intraspecific polymorphic markers. We therefore sequenced the complete chloroplast genomes of 12 native and 5 invasive individuals of J. vulgaris with next generation sequencing and discovered single-nucleotide polymorphisms (SNPs) and microsatellites. This is the first study in which the chloroplast genome of that many individuals within a single species was sequenced. Thirty-two SNPs and 34 microsatellite regions were found. For none of the individuals, differences were found between the inverted repeats. Furthermore, being the first chloroplast genome sequenced in the Senecioneae clade, we compared it with four other members of the Asteraceae family to identify new regions for phylogentic inference within this clade and also within the Asteraceae family. Five markers (ndhC-trnV, ndhC-atpE, rps18-rpl20, clpP and psbM-trnD) contained parsimony-informative characters higher than 2%. Finally, we compared two procedures of preparing chloroplast DNA for next generation sequencing
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