Search results for "SPECIES"
showing 10 items of 4255 documents
Glomales species associated with surface and deep rhizosphere of Faidherbia albida in Senegal
2000
Five arbuscular mycorrhizal (AM) fungal species were isolated and propagated from surface and deep rhizospheres of Faidherbia albida trees growing in two ecoclimatic zones of West Africa: the semi-arid Sahelian and the more humid Sudano-Guinean areas. Of these species, Glomus aggregatum, Glomus caledonium, and Glomus mosseae were trapped by F. albida roots when cultivated with either surface or deep soils. Glomus fasciculatum was found exclusively at the semi-arid Sahelian sites of Louga and Diokoul and Gigaspora margarita was isolated only from 16.5-m and 34-m-deep samples. Comparable glomalean fungal species richness was identified in deep (1.5–34 m) and surface (0.15 m) samples. The isol…
Nitric oxide: comparative synthesis and signaling in animal and plant cells.
2001
Since its identification as an endothelium-derived relaxing factor in the 1980s, nitric oxide has become the source of intensive and exciting research in animals. Nitric oxide is now considered to be a widespread signaling molecule involved in the regulation of an impressive spectrum of mammalian cellular functions. Its diverse effects have been attributed to an ability to chemically react with dioxygen and its redox forms and with specific iron- and thiol-containing proteins. Moreover, the effects of nitric oxide are dependent on the dynamic regulation of its biosynthetic enzyme nitric oxide synthase. Recently, the role of nitric oxide in plants has received much attention. Plants not only…
Mycorrhizae differentially influence the transfer of nitrogen among associated plants and their competitive relationships
2021
Abstract The formation of a common mycorrhizal network among roots of different plant species growing close to each other can influence plant community dynamics, regulating plant relationships through the differential transfer of nutrients from one plant to another. However, knowledge of the mechanisms that regulate this process is poor. Here we quantify the contribution of arbuscular mycorrhizae to the transfer of N among heterospecific plants growing adjacent to each other and examine whether the differential transfer of N within the plant community via mycorrhizae can alter competitive relationships among plant species. Plants of four species (wheat, pea, flax, and chicory) were grown in…
Exploring the presence of pollutants at sea: Monitoring heavy metals and pesticides in loggerhead turtles (Caretta caretta) from the western Mediterr…
2017
Marine turtles are considered good sentinel species for environmental assessment because of their long lifespan, feeding ecology, habitat use and migratory nature. In the present study, we assessed presence of cadmium, lead and mercury, together with organic pollutants, both in fat and muscle tissue of 25 stranded loggerhead turtles (Caretta caretta) stranded along the Valencian Community coast (East Spain) (43.7±13.5cm). Mean concentrations of Cd, Pb and Hg were 0.04μg/g w.w., 0.09μg/g w.w. and 0.03μg/g w.w. in fat and 0.05μg/g, 0.08μg/g and 0.04μg/g in muscle, respectively. These measures indicate a relatively low mean heavy metal concentration, which may be explained by juvenile size and…
Otolith fingerprints reveals potential pollution exposure of newly settled juvenile Sparus aurata
2020
Abstract Coastal ecosystems are increasingly threatened by a wide range of human activities. Fish otolith chemistry, by creating a unique specific signature, can be used as a natural tag for determining life stage dispersal, spatial connectivity and population structure. In this study, we tested whether differences in otolith composition among juveniles of gilthead sea bream, Sparus aurata, could enable their proper allocation to polluted areas based on higher concentrations of elements related to contaminants. Otoliths were embedded, sectioned and analysed by LA-ICP-MS in line scan mode. Multivariate analysis confirmed clear separation between sites and elements. Samples from the site unde…
Identity of the Calcarata species complex in Viola sect. Melanium (Violaceae)
2020
The Calcarata species complex in Viola sect. Melanium (Violaceae) is a group of species from Italy and neighbouring islands. The complex is of considerable evolutionary interest because several hypotheses about hybrid speciation within the group have been previously proposed. Because the Calcarata complex is not well characterized morphologically, we used 142 samples representing 92 (of c. 120) species of V. sect. Melanium plus three outgroup species. Nuclear ITS and ETS and plastid trnS–trnG intergenic spacer sequences were analysed to test the monophyly of the Calcarata complex and to infer relationships among the constituent species. Both nuclear and plastid sequences resulted in very li…
Do invasive alien plants really threaten river bank vegetation? : a case study based on plant communities typical for Chenopodium ficifolium : an ind…
2018
Riparian zones are very rich in species but subjected to strong anthropogenic changes and extremely prone to alien plant invasions, which are considered to be a serious threat to biodiversity. Our aim was to determine the spatial distribution of Chenopodium ficifolium, a species demonstrating strong confinement to large river valleys in Central Europe and an indicator of annual pioneer nitrophilous vegetation developing on river banks, which are considered to be of importance to the European Community. Additionally, the habitat preferences of the species were analysed. Differences in the richness and abundance of species diagnostic for riverside habitats, as well as the contribution of resi…
An Empirical Evaluation of the Utility of Convex Hull and Standard Ellipse Areas for Assessing Population Niche Widths from Stable Isotope Data
2013
Stable isotope analyses are increasingly employed to characterise population niche widths. The convex hull area (TA) in a δ¹³C–δ¹⁵N biplot has been used as a measure of isotopic niche width, but concerns exist over its dependence on sample size and associated difficulties in among-population comparisons. Recently a more robust method was proposed for estimating and comparing isotopic niche widths using standard ellipse areas (SEA), but this approach has yet to be tested with empirical stable isotope data. The two methods measure different kind of isotopic niche areas, but both are now widely used to characterise isotopic niche widths of populations. We used simulated data and an extensive e…
Isozyme analysis of genetic diversity in wild Sicilian populations of Brassica sect. Brassica in view of genetic resources management
2004
In Sicily and in the small surrounding islands the section Brassica of the genus Brassica comprises five species, B. insularis Moris, B. incana Ten., B. macrocarpa Guss., B. rupestris Raf. and B. villosa Biv. These taxa represent a genetic resource as relatives of kale crops but some populations are endangered or threatened, thus isozyme analyses were performed to assess the genetic diversity degree at population and species levels in order to assist the design of conservation management programs. Eleven loci from five enzyme systems (aconitase, leucine aminopeptidase, 6-phosphogluconate dehydrogenase, phosphoglucoisomerase phosphoglucomutase) were analyzed in sixteen natural population (fi…
Hieracium pollinense (Asteraceae), an endemic species to the Pollino National Park (Southern Italy) rediscovered
2017
Abstract The presence of Hieracium pollinense Zahn in Italy is confirmed here after 132 years since its first description based on a single collection made in 1877 in the Mt. Pollino. It is a calcicolous species, so far represented by one population, belongs to the H. sect. Villosa. In line with the IUCN criteria its conservation status assessment is “endangered”.