68 research outputs found
The collection of Brendel Botanical Models at the Botanical Garden of Naples, Italy
The Botanical Garden of Naples has a collection of papier-mâché models that reproduce plant structures, whole plants, or fungi. They are known as Brendel Models, named after the German Company that built and supplied them to the Botanical Garden in the early nineteenth century. For their state of decay, due to time and continuous use for educational purposes, the models have undergone recovery interventions. Given their historical and artistic interest, and in order to preserve them, the models are no longer used today. In order not to completely lose such a cultural heritage for didactics, a CD-ROM has been created which includes, for each species reproduced by the models, photos in nature of the plants represented and didactic cards re-porting all the useful information for the use of models in computer mode
Disentangling historical signal and pollinator selection on the micromorphology of flowers: an example from the floral epidermis of the Nymphaeaceae
The family Nymphaeaceae includes most of the diversity among the ANA‐grade angiosperms. Among the species of this family, floral structures and pollination strategies are quite varied. The genus Victoria, as well as subgenera Lotos and Hydrocallis in Nymphaea, presents night‐blooming, scented flowers pollinated by scarab beetles. Such similar pollination strategies have led to macromorphological similarities among the flowers of these species, which could be interpreted as homologies or convergences based on different phylogenetic hypotheses about the relationships of these groups.
We employed SEM of floral epidermis for seven species of the Nymphaeaceae with contrasting pollination biology to identify the main characters of the floral organs and the potential homologous nature of the structures involved in pollinator attraction. Moreover, we used TEM to observe ultrastructure of papillate‐conical epidermis in the stamen of Victoria cruziana. We then tested the phylogenetic or ecological distribution of these traits using both consensus network approaches and ancestral state reconstruction on fixed phylogenies.
Our results show that the night‐blooming flowers present different specializations in their epidermis, with Victoria cruziana presenting the most elaborate floral anatomy. We also identify for the first time the presence of conical‐papillate cells in the order Nymphaeales. The epidermal characters tend to reflect phylogenetic relationships more than convergence due to pollinator selection.
These results point to an independent and parallel evolution of scarab pollination in Nymphaeaceae, and show the promise of floral anatomy as a phylogenetic marker. Moreover, they indicate a degree of sophistication in the anatomical basis of cantharophilous flowers in the Nymphaeales that diverges from the most simplistic views of floral evolution in the angiosperms.
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Aperture evolution in Nymphaeaceae: insights from a micromorphological and ultrastructural investigation
The evolution of the apertural type in the ANITA-grade family Nymphaeaceae, despite the importance of pollen characters for both palaeobotanical and neobotanical investigations, has not been yet totally understood. To elucidate some unclear aspects regarding the homologies of the apertural condition in basal and core Nymphaeaceae, we examined the pollen grains from five species of this family. We offer for the first time some evidence about the presence of a proper operculum in the pollen grain of Nuphar and for the ring-like status of the aperture of Nymphaea caerulea and Victoria cruziana. Our findings clarify and reinforce the hypothesis of an opercular origin of the distal part of the pollen grain in the core Nymphaeaceae and support the paraphyly of the genus Nymphaea as emerged from recent molecular studies. The diversity and specialisation of this 'basal' family is underlined even by its pollen characters. © 2013 Copyright Collegium Palynologicum Scandinavicum
Stomatal development in the cycad family Zamiaceae
Background and Aims: The gymnosperm order Cycadales is pivotal for our understanding of seed-plant phylogeny because of its phylogenetic placement close to the root node of extant spermatophytes and its combination of both derived and plesiomorphic character states. Although widely considered a ‘living fossil’ group, extant cycads display a high degree of morphological and anatomical variation. We investigate stomatal development in Zamiaceae to evaluate variation within the order and homologies between cycads and other seed plants.
Methods: Leaflets of seven species across five genera representing all major clades of Zamiaceae were examined at various stages of development using light microscopy and confocal microscopy.
Key Results: All genera examined have lateral subsidiary cells of perigenous origin that differ from other pavement cells in mature leaflets and could have a role in stomatal physiology. Early epidermal patterning in a “quartet” arrangement occurs in Ceratozamia, Zamia, and Stangeria. Distal encircling cells, which are sclerified at maturity, are present in all genera except Bowenia, which has relatively rapid elongation and differentiation of the pavement cells during leaflet development.
Conclusions: Stomatal structure and development in Zamiaceae highlights some traits that are plesiomorphic in seed plants, including the presence of perigenous encircling subsidiary cells, and shows a clear difference between the developmental trajectories of cycads and Bennettitales. Our study also shows an unexpected degree of variation among subclades in the family, potentially linked to differences in leaflet development and suggesting convergent evolution in cycads
First finding of a fossil fern (Matoniaceae) in the paleontological site of Pietraroja (Benevento, Southern Italy).
Osservazioni su legni carbonizzati artificialmente
Applicazione di tecniche di carbonizzazione artificiale per lo studio di fossili vegetal
The effect of seasonality on developmental stages of anthetic ovule integuments in Mediterranean orchids
Orchids, differently from most flowering plants, have under-differentiated ovules at anthesis that require pollination to complete differentiation. This ovule developmental stage has been often observed in tropical species in which the absence of an evident seasonality may allow plants to extend their phenology beneficiating of a long time for post-pollination events. Here, we used scanning electron microscopy (SEM) to detect ovule integument developmental stages in 21 species of Mediterranean Orchidoideae and Epidendroideae and in 11 tropical Epidendroideae with the aim of understanding whether species with a seasonal constraint and shorter time for post-pollination ovule maturation are characterized by different stages of ovule development at anthesis. We found that Mediterranean orchids (both Orchidoideae and Epidendroideae) have more developed ovule integuments than tropical orchids. Most species show partially to fully developed ovules at anthesis with the exception of Cephalanthera where ovules are arrested in a very early developmental stage. Despite the phylogenetic signal, anthetic ovule integument development differs between related species (with different pollination strategies or blooming times), suggesting the presence of some ecological constraints. The synchronization between ovule integuments and megagametophyte development, as found in tropical orchids, is also confirmed in Mediterranean orchids. Our data show that Mediterranean and tropical orchids clearly differ in anthetic ovule developmental stages, likely depending on seasonality
Pseudodioon akyoli gen. et sp. nov., an extinct member of Cycadales from Turkish Miocene
The natural and cultural landscape of Naples (southern Italy) during the Graeco-Roman and Late Antique periods
The landscape around the Graeco-Roman town of Neapolis was reconstructed through morphostratigraphic methods and pollen analysis of the sediments filling the bay hosting the ancient harbor. This was discovered in 2004 thanks to excavations for two new lines of the Naples metro network; the harbor's sedimentary record spans the period between the late 4th century BC and the 6th century AD. The main changes occurring in the marine and terrestrial landscape surrounding the ancient town are highlighted through the reconstruction of a detailed geological cross section and four 3D palaeogeographic models. Pollen analysis suggested the presence of mixed oak woods on the slopes surrounding the town and of vegetable gardens around the harbor area. The tree crops mainly consisted of walnut, and to a lesser extent chestnut and grapevines. The horticultural varieties were dominated by Brassicaceae, most likely representing cabbage cultivation which was rather common in Roman times. Comparison with reference pollen material reinforces this hypothesis. During the 3rd century AD a drastic decrease in horticultural activity, in concurrence with an increase in wild vegetation and tree crops, suggest reduced maintenance due to a phase of abandonment. Historical data imply for the same period a phase of economic and social decline which involved the whole Empire. From the end of the 3rd century AD, the growth of a spit bar at the port entrance gave rise to the establishment of a lagoon and then to the final closure of the bay
Pseudodioon akyoli gen. et sp nov., an extinct member of Cycadales from the Turkish Miocene
Fossil cycadalean leaves recorded from the Miocene plant assemblage of Soma, western Turkey, are described and assigned to an extinct genus and species, Pseudodioon akyoli. Leaf macromorphology suggests affinity with members of the Zamiaceae (subfam. Encephalartoideae), particularly with modern Dioon. Micromorphological features on the other hand indicate affinity with modern Cycas (Cycadaceae). Ordinary cells on the adaxial epidermis are isodiametric and are not differentiated into thick- and thin-walled cells. This is similar to Encephalartoideae-like fossils reported from the Cenozoic of the Northern Hemisphere, and even from the Mesozoic. Shared macromorphological traits of P. akyoli and other coeval Encephalartoideae-like fossil cycadalean leaves from Europe suggest that an extinct group of cycads inhabited southern Europe from the western part of Turkey, through Greece and France to Switzerland in the north during the Oligo-Miocene
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