Search results for "Botanica"

Seed morphology and seed coat structure in Mediterranean plants: implication for evolution, taxonomy and germinative performance.

2015

A better understanding of morphological, ultra-structural and anatomical seed coat characteristics can contribute to explain and predict seed performance under certain environmental conditions and select the most suitable treatments promoting seed germination. The Seed Banks at the Botanic Gardens of Catania and Palermo (Sicily) are particularly involved in research studies aimed to detect and describe macro- and micro-morphological features of seeds from different plant families and genera, using both light and scanning electron microscopy. These studies mainly aim to 1) recognize and compare inter- and intra-specific variation of seed coat traits, with particular attention on rare and thr…

Rare-earth elements and yttrium distributions in mangrove coastal water systems: The western Gulf of Thailand

2005

The concentration of rare-earth elements and yttrium (REY) was investigated in dissolved phase, suspended particulate matter, and seafloor sediments of the western coastal area of the Gulf of Thailand. The samples show Eu and Gd positive anomalies in the shale-normalized REY patterns, especially in the suspended particulate matter. On the other hand, a very high REE content was detected in the coastal waters, probably due to the weathering produced by the Mae Klong river waters on rare-earth element (REE)-rich accessory minerals coming from terrains and mineral deposits cropping out in the studied area. The shale-normalized patterns of yttrium and REE estimated for the dissolved phase show …

Francesco Minà Palumbo e l'agricoltura in Sicilia.

2011

Proposal for a parametrization of site conditions in the Mitrakos' indices.

2001

The influence of slope gradient and exposure, of altitude and of distance from the sea on the winter and summer stresses sustained by the Mediterranean vegetation have been parametrized. An example of vegetation changes driven by the variation of any of such environmental factors is reported, and a mathematical formula is proposed to determine a monthly value to add to or subtract from the drought stress and cold stress values, estimated by the Mitrakos' index, in order to better approximate reality. Values obtained in such way can be used in synecology and phytosociology to express in a synthetic-correlative way the ecological valence of plant communities with respect to the main physiogno…

The non-bilayer lipid MGDG stabilizes the major light-harvesting complex (LHCII) against unfolding.

2017

Abstract In the photosynthetic apparatus of plants a high proportion of LHCII protein is needed to integrate 50% non-bilayer lipid MGDG into the lamellar thylakoid membrane, but whether and how the stability of the protein is also affected is not known. Here we use single-molecule force spectroscopy to map the stability of LHCII against mechanical unfolding along the polypeptide chain as a function of oligomerization state and lipid composition. Comparing unfolding forces between monomeric and trimeric LHCII demonstrates that the stability does not increase significantly upon trimerization but can mainly be correlated with specific contact sites between adjacent monomers. In contrast, unfol…

MONOTROPA HYPOPHEGEA WALLR., A NEW RECORD FOR THE SICILIAN FLORA

2014

During field investigations in the Mountains around Palermo, an unusual population of Monotropa sp. was found. After revision of the taxonomic literature and herbarium specimens, it was referred to Monotropa hypophegea Wallr. This species is closely related to M. hypopytis L., and in the past was considered only a variety (Pignatti 1982) or a subspecies (Křisa 1972) ) of it. More recently this entity has been considered an independent taxon deserving the rank of species (Conti et al. 2005). The most important morphological differences between the two taxa are the number of flowers in the raceme and the hairiness of sepals, petals and capsule. The individuals of the observed population have …

I grandi alberi dei Nebrodi

2012

In questo libro sono presentati i risultati di una ricerca portata avanti dagli Autori, botanici del Dipartimento di Biologia ambientale e Biodiversità dell’Università di Palermo. L’indagine ha riguardato sia ambienti di tipo forestale sia di tipo agricolo tradizionale ed ha messo in luce un ricco patrimonio arboreo di tipo monumentale. Significative sono le immagini relative ai grandi aceri, ai ragguardevoli individui di due specie endemiche dei Nebrodi (Pyrus vallis-demonis e Malus crescimannoi) e al faggio di Fago scuro che rappresenta il patriarca di tutti i faggi d’Italia. Dopo il 150° dell’Unità d’Italia non poteva mancare il Grande Pino piantato in concomitanza dello sbarco di Giusep…

Pluriannual morphological variability in a highly productive Mediterranean reservoir (Lake Arancio, southwestern Sicily)

2007

The progressive decrease in water quality experienced by the Mediterranean, nutrient rich reservoir, Lake Arancio (Southwestern Sicily, Italy), has been accompanied by modifications in both phytoplankton shape and size. Since nutrient concentrations are always far from being limiting, in the present paper attention was focussed on the effects exerted by physical constraints (e.g., mixing, light availability) on the morphological variation observed in phytoplankton. The surface-volume ratio and its product with the maximal linear dimension were chosen as morphological descriptors to trace the trajectories followed by the dominant morphotypes in Lake Arancio. One of these descriptors was comp…

The Isoetes longissima complex (Isoetaceae) in Italy: observations on the morphology of spores and leaves, and taxonomic implications

2014

The morphological variability of the Isoetes longissima complex in Italy has been analyzed, on the basis of selected herbarium specimens. Observations were made on spore ornamentation and size, number of leaves per plant and maximum leaf length, velum extension and alae width in the basal portion of leaves. The first count of chromosome number on plants from Italy is also made. On the basis of our observations, the five taxa here considered are attributed to two taxa, treated at the species level as follows: I. longissima (incl. I. velata and I. velata [unranked] sicula), and I. tiguliana (incl. I. dubia). Italian distribution of these species is also given.

Investigation on the pollen morphology of traditional cultivars of Prunus species in Sicily

2012

In this study pollen grains of 13 cultivars and 3 rootstocks belonging to 5 species (<em>P. armeniaca</em>, <em>P. domestica</em>, <em>P. dulcis</em>, <em>P. persica</em>, <em>P. avium</em>) of the genus <em>Prunus </em>collected from North-East Sicily were examined for the micromorphological characterization through the scanning electron microscopy (SEM). The length of polar axis (<em>P</em>) and the equatorial diameter (<em>E</em>) of grain, <em>P/E </em>ratio, the length of colpi (<em>C</em>), diameter of perforations (<em>DP</em>) and the number of perforat…