Structural and Cytochemical Characteristics of the Stigma and Style in Vitis vinifera L. var. Sangiovese (Vitaceae)

Studies were carried out on structural and cytochemical aspectsof the stigma and style ofVitis vinifera . The stigma is ofthe wet papillate type with a continuous cuticle and pellicle.During the development of the papillae, the cell walls increasein thickness and produce a secretion product constituted oflipids that pass through the wall forming the exudate. The styleis solid with a central core of transmitting tissue which hasconspicuous intercellular spaces that increase remarkably fromthe periphery to the centre where the cuticle is present. Theintercellular spaces, where the pollen tubes grow, contain amatrix that includes polysaccharides, pectic substances andscattered areas of lipidic nature. Cytochemistry; stigma; style; ultrastructure; Vitis vinifera     

Intraguild predation in raptor assemblages: a review

Intraguild predation, the killing of species that use similar resources, has been largely overlooked in raptor investigations. To help fill this gap in knowledge, we conducted a literature review, focusing on studies that tested the behavioural and demographic impact of intraguild predation on individuals, populations, and assemblages of diurnal and nocturnal raptorial species. Overall, data were available for 39 empirical and experimental studies on 63 populations belonging to 11 killer species and 15 victim species. An overview of these studies suggested that intraguild predation was a widespread, size-based phenomenon. Results from multiple studies on the same species at different locations were usually consistent across wide geographical areas. Individual-level demographic impacts included reduced site-occupancy, breeding success and survival. Individuals of the prey species responded to predation pressure through direct spatial avoidance, risk-sensitive habitat selection, short-term behavioural avoidance (e.g. reduced vocal activity and escape to refugia after predator detection) and, possibly, temporal segregation. Population-level effects were common but mainly examined as spatio-temporal correlations between the abundance of killer and victim species. Correlative evidence also suggested that intraguild predation may have the potential to structure whole raptor assemblages. More studies on other species and different geographic areas are needed to increase our understanding of the causes and consequences of this widespread interaction. From a conservation point of view, intraguild predation may limit the success of raptor preservation programmes and could be used as a management tool through its effect on mesopredator release and its potentially positive, indirect effects on game species.     

Gagea tisoniana, a new species of Gagea Salisb. sect. Gagea (Liliaceae) from central Italy

Gagea tisoniana Peruzzi et al. sp. nov. is described and its taxonomic relationship is discussed. The new species, which appears to be endemic to central Italy, is close to G. pratensis (Pers.) Dumort., G. pusilla (F. W. Schmidt) Sweet, and other mainly poorly known [i.e. G. succedanea Griseb. et Schenk, G. transversalis Stev., and G. paczoskii (Zapal.) Grossh.] or as yet undescribed taxa from eastern Europe and the eastern Mediterranean area. The recognition of the new taxon G. tisoniana is claimed on the basis of anatomical, karyological, ecological, and phytogeographical data. Maps of the Italian distribution of G. pratensis (2 n  = 60), G. pusilla (2 n  = 24), and G. tisoniana (2 n  = 24) are presented, together with an analytical identification key. Finally, G. pratensis is recorded here for the first time in Tuscany (Monte Cetona).  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 337–347.     

The two Early Toarcian (Early Jurassic) extinction events in ammonoids

The Early Toarcian (Early Jurassic) biological crisis was one of the ‘minor’ mass extinctions. It is linked with an oceanic anoxic event. Fossil data from sections located in northwestern European (epicontinental platforms and basins) and Tethyan (distal, epioceanic) areas indicate that Late Pliensbachian–Early Toarcian ammonoids experienced two extinction events during the Early Toarcian. The older one is linked with disruption of the Tethyan–Boreal provinciality, whereas the younger event correlates with the onset of anoxia and corresponds with the Early Toarcian mass‐extinction event. These two extinctions cannot be interpreted as episodes of a single, stepwise, event. Values of the net diversification, more than the number of extinctions, allow the two extinction events to be clearly recognized and distinguished. Values of regional net diversification for northwestern European and Tethyan faunas point to greater evolutionary dynamics in the epioceanic areas. The inclusion of Mediterranean faunas in the database proves that the ammonite turnover at the Early Toarcian mass‐extinction event was more important than previously thought. Progenitor (evolute Neolioceratoides), survivor (Dactylioceras, Polyplectus pluricostatus) and Lazarus (Procliviceras) taxa have been recognized. Different selectivity patterns are shown for the two events. The first one, linked to the disruption of the Tethyan–Boreal provinciality, has mainly affected ammonites adapted to epicontinental platforms. In the mass‐extinction event, no selectivity is recognized, because also Phylloceratina and Lytoceratina were deeply affected at species level, although their wide biogeographical distribution at clade level was a significant buffer against extinction. In contrast to Palaeozoic mass extinctions, ammonoid survivors and Lazarus taxa are characterized by complex sutures: Phylloceratina (long‐ranging ammonoids) and Polyplectus (relatively long‐ranging compared to other Ammonitina).     

Historical isolation and Quaternary range expansion of divergent lineages in wild grapevine

Vitis vinifera subsp. silvestris, the wild subspecies of Vitis vinifera L., is a unique and valuable genetic resource for cultivated grapevines. At present, this wild form is rare and is spread from the Southern Atlantic coast of Europe to the Western Himalayas. In the present study, six nuclear microsatellite DNAs were analysed in 301 wild grape samples, using factorial correspondence analysis and the Bayesian model. The aim was to detect the distribution of genetic variability and admixture proportions and thus to identify the main routes of recolonization after the quaternary glaciation, as well as signals of secondary contacts in Europe. The results obtained show that some Caucasus and Italian areas played key roles as refugial areas. Moreover, the data suggest the existence of two main migration routes through central Europe during the post‐glacial or the inter‐glacial periods. The first started from Southern Italy and moved northward, whereas the second originated from refugia possibly located in eastern areas and migrated westwards. This scenario is most likely associated with the population expansion that followed the European Quaternary glaciations. In accordance with this assumption, central Europe is proposed as an admixture confluence of migration routes radiating from separate grapevine refugia. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 611–619.     

Diversity of mitochondrial DNA of the endangered white-clawed crayfish (Austropotamobius italicus) in the Po River catchment

1. The strong contraction of the European populations of white‐clawed crayfish has stimulated research of its population genetics. As part of a conservation project to introduce and improve Italian populations of Austropotamobius italicus, the genetic diversity of 16 populations from 10 tributaries of the Po River drainage was evaluated by sequencing a 494 bp length of cytochrome oxidase subunit I (COI mtDNA). 2. The evolutionary tree topologies and the parsimony network of 26 haplotypes separated into two clusters, on the basis of high average genetic distance (6.51 ± 0.42%). This finding indicated the presence of distinct evolutionary lineages, other than different allopatric sources. 3. An ancestral haplotype (Nav) was identified and 13 haplotypes, found mainly as singletons, were independently connected to Nav by short branches with one mutation site. Unimodal mismatch distribution and the goodness‐of‐fit of the observed data reflected a model of sudden population expansion, after the last glacial bottleneck event. 4. A general moderate level of genetic variability (h = 0.22–0.7 and π = 0.045–0.27%) was highlighted within A. italicus populations inhabiting Alpine and Apennine tributaries of the Po River. Analysis of molecular variance (amova ) revealed significant genetic structuring across all hierarchical levels, indicating that a major proportion of genetic variance is structured among localities within drainages. Multiple adjacent localities, strictly connected by the Po River, shared the two most frequent haplotypes (Nav and Laz), while remote populations, far from the Po River inflow, move towards a mtDNA fixation. 5. The results of this study indicate that distinct populations should be treated as separate entities for management. The key implication of the data is that ad hoc measures for successful programmes of recovery and management strategies for A. italicus conservation, such as the phylogeographic study of haplotype distribution at a local scale and the genetic variability of populations used as stock breeders, should be considered.