302 research outputs found
Coastal and Granitic landforms of southeastern Sardinia Cagliari- Villasimius - Field Trip Guidebook
Su Fossu de Cannas Cave (Sadali, central-eastern Sardinia, Italy): the earliest deposit holding Pleistocene megacerine remains in Sardinia
Recentment s'han descobert diverses restes de cèrvids als sediments arenosos, vermells i fortament cimentats que omplen la cavitat superior de la Cava Su Fossu de Cannas (Sadali, Sardenya centre-oriental), tallada a les calcĂ ries del Mesozoic de Barbagia di Seulo. Es varen trobar les restes a la part de dalt d'una cova horitzontal, estreta. L'origen d'aquest passadĂs es pot deure a una fase erosiva antiga (Pleistocè MitjĂ ?) que va afectar els sediments que primĂ riament omplien la cova, com s'evidencia per l'erosiĂł del conglomerat superior i la deposiciĂł posterior de sediments vermellosos lleugerament cimentats. Els espècimens analitzats fins ara mostren afinitats morfològiques estretes amb el megacerĂ endèmic de Sardenya "Praemegaceros" cazioti (DepĂŠret, 1897). No obstant això, el cèrvid de Sadali es diferencia del darrer per la seva mida mĂŠs gran, que supera l'espectre de variabilitat calculat per a l'espècie endèmica, i en alguns trets morfològics (tal com el corpu.s rnandibulae fondo i corbat), aixi com per presentar unes dents proporcionalment mĂŠs petites Ă, sobretot, per un metacarpiĂ mĂŠs grĂ cil. Els trets peculiars dels espècimens de Sadali suggereixen la seva pertinença a una nova espècie. No obstant això, de moment ens estimem mĂŠs no batejar-la i anomenar el cèrvid de Sad ali "Praemegaceros" n. sp., a l'espera de noves dades que permetin afinar la seva diagnosi. El cèrvid de Su Fossu de Cannas es pot considerar com el representant mĂŠs primitiu del gènere "Praemegaceros" a Sardenya i l'ancestre de "Praemegaceros" cazioti.Several cervid remains have recently been discovered in the sandy, red-coloured and strongly cemented sediment filling the uppermost cavity of the Su Fossu de Cannas Cave (Sadali, central-eastern Sardinia), cut into the Mesozoic limestone in the Barbagia ofSeulo. The remains were found on the ceiling ofa narrow, horizontal underground cave. The origin of this passage may be due to an ancient erosional phase (Middle Pleistocene?), which affected the sediments formerly filling up the cave, as evidenced by the erosion of the uppermost conglomerate and by the further deposition of reddish, slightly cemented sediments. The specimens analysed thus far show close morphological affinities with the endemic Sardinian megacerine "Praemegaceros" cazioti (DepĂŠret, 1897). However, the Sadali cervid differs from the latter in its larger size, exceeding the range of variability calculated for the endemic species, and in some morphological features (such as the depth and curved corpu.s mandibulaei, as well as in its proportionally smaller teeth and, notably, its elongated, slender metacarpal. The peculiar features of the SadalĂ specimens suggest its attribution to a new species. Nevertheless, for the moment, we prefer to name the Sadali cervid "Praemegaceros" n. sp., awaiting new data to present the diagnosis. The Su Fossu de Cannas cervid can be regarded as the most primitive representative of the genus "Praemegaceros" in Sardinia and the ancestor of the endemic species "Praemegaceros" cazioti
Su alcune toposequenze di suoli nel Bacino del Rio S'Acqua Callenti (Sardegna meridionale)
Nel presente lavoro vengono descritte e commentate tre sequenze di suoli in funzione della morfologia, studiate in altrettanti piccoli bacini idrografici nel Sarrabus-Gerrei (Sardegna centro-meridionale).
Lo scopo principale della ricerca è quello di chiarire alcuni rapporti esistenti tra morfologia e suoli derivati dalle rocce metamorfiche e cristalline diffuse nella zona centrale e meridionale dell'isola.
Tale immagine vuole essere anche un contributo alla soluzione di alcuni problemi di cartografia pedologica che si sono manifestati durante i rilevamenti che si stanno effettuando nella suddetta area
Mid to late Holocene environmental changes along the coast of western Sardinia (Mediterranean Sea)
Multiproxy analysis composed of biostratigraphy and pollen analysis allowed reconstructing the palaeoecological and palaeoenvironmental evolution of the Tirso river coastal plain in Sardinia (NW Mediterranean) in the last 6 millennia. We demonstrated that interplay between littoral and fluvial processes have significantly controlled the environmental evolution of the area and have played a key role in the pattern of historical and prehistorical settlements of this wide portion of western Sardinian coastline. At the end of Neolithic period (ca. 6.0 to 5.5 cal. ka BP) the area close to the shoreline was most likely characterized by large coastal lagoons intermittently connected to the open sea. Such saltwater influence is corroborated by faunal and pollen assemblages found in the landward portion of the Tirso coastal plain up to 2 km inland from the modern shoreline. Our data robustly document the end of the transgressive trend at ca. 5.5 cal. ka BP, and a dominant fluvial sedimentation since Final Neolithic period. At this time, a progradational trend started, causing the seaward migration of shoreline and, consequently, of the barrier-lagoon system. The major landscape modification tracked along the last 6 millennia may also explain the low density of historical and prehistorical remains in the Tirso coastal plain, especially if compared to the nearby rocky area of Sinis Peninsula densely inhabited since the Neolithic. Our data further provide new insights into the Relative Sea Level (RSL) evolution in this sector of the Mediterranean. In particular, we improved the mid-Holocene RSL record in Sardinia, where only scarce data were previously available
Influence of enviromental and cultural factors on structure, conposition and aganic propagation of turo mediterranean scrubs (<i>myrtus communis</i> L. - Pistacia lentiscus L.)
The crucial point for the exploitation of Mediterranean species for agronomic
purposes relies on the availability of planting material with high physiological
quality. As it is known, the plant propagation may be realized by seed or by asexual
or vegetative propagation. The latter has an unquestionable advantage for the
propagator because it allows obtaining plants that reproduce exactly the genetic and
morphological characteristics of the parent plant and, theoretically, it allows to obtain
a large number of individuals in a short time.
Among the various types of asexual propagation used in the nursery industry, cutting
propagation finds the greater application as it is technically easier to run and
economically profitable in respect to all possible alternative methods.
It would be advantageous to set up such propagation method for Mediterranean
shrubs that are difficult-to-root, on the one hand selecting superior genotypes and on
the other hand developing technical strategies for the improvement of donor
physiology and the rooting competence.
The environmental factors, irradiance above all, but also nutrient and water
availability in the substrate for growth, influence the physiological, hormonal and
nutritional status of stock plants and may influence the cuttings quality and their
rooting ability. The ontogenetic age of cutting may also influence the propagating
attitude of the species.
As regards myrtle and lentisk, few studies have been done concerning the influence
of stock plant physiology on rooting. Crobeddu and Pignatti (2005) studied the
rooting results of rejuvenated plants, many other Authors focused on
micropropagation but no considerations were done about the physiology of donors.
The primary objective of the present research was to enhance the use as ornamental
plants of two typical species of the Mediterranean environment, by means of the
optimization of nurseries cycles.
In particular, the study focused on physiological and morphological features
potentially related to adventitious rooting in myrtle and lentisk.
The specific objectives aimed at:
- Determining the influence of light availability and rejuvenation on the
morphological, chemical and ecophysiological features of mature plants
- Assessing the eventual influences on rooting
- Assessing the influence of intra-specific variability on propagation trials, with
the declared aim to look for genotypes offering an economically supportable
option to propagate the studied species
Influence of Growing Area, Year, Season, and Cultivar on the Composition of Myrtle Leaves and Infusions
Leaves of five myrtle cultivars were analyzed for chlorophyll a and b, polyphenol, and tannin contents in two years (2000 and 2001), two seasons (spring and winter), and two growing areas (Alghero and Oristano, Sardinia, Italy). The hydroalcoholic leaf infusions obtained from the same cultivars were analyzed for the above-mentioned compounds and for their chromatic values as well. L* chromatic component ranged from 44.22 to 49.94, a* values ranged between â5.82 and â2.50, and b* values ranged between 10.74 and 18.40. The relationships between leaf and infusion characteristics were evaluated. Chlorophyll a content ranged from 1.9 to 4.7 mg¡gâ1 of dry weight in leaves and from 14.8 to 35.2 mg¡Lâ1 in infusions. Chlorophyll b ranged between 0.3 and 2.9 mg¡gâ1 of dry weight in leaves and between 3.4 to 12.1 mg¡Lâ1 in infusions. Polyphenols ranged between 6.8 and 15.3 g/100 g of dry weight in leaves and between 2.6 and 13.9 g¡Lâ1 in hydroalcoholic infusions. Tannins ranged from 140 to 516 mg¡gâ1 of dry weight in leaves and from 57 to 291 mg¡Lâ1 in infusions. Significant interactions among year, growing area, season, and cultivar effects occurred for all leaf and infusion parameters, except for leaf chlorophyll a. Strong correlations between leaf and infusion composition were not found. Because infusion quality was little influenced by the studied variables, to the best of our knowledge, winter harvest of myrtle leaves for white myrtle liqueur is feasible
Pattern of Hard Seed Breakdown in Some Annual Self-Reseeding Legumes under Mediterranean Field Conditions
In the last decade a new generation of annual pasture legumes was released and introduced in the seed market for the Australian ley systems. In Sardinia (Italy), despite good agronomic performances in the first year, several of these new varieties showed low autumn re-establishment, reducing their competitiveness against native species and depressing any attempt for a long term pasture improvement (Porqueddu et al. 2010). Hardseedness may influence legume persistence. A study on the pattern of hard seed breakdown on some self-reseeding annual pasture legumes was carried out
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