4 research outputs found
Heavy metal tolerance strategies in metallicolous and non-metallicolous populations of mosses: Insights of γ+β-tocopherol regulatory role
As bryophytes present the capacity to colonize a wide range of habitats, including extreme environments (e.g.,
mine areas), we first checked the global response of bryophytes to heavy metals (HM) by a systematic review.
This analysis found i) the lack of studies in a polluted environment and ii) resulted in a global trend of photochemical
efficiency decrease when bryophytes faced heavy metals. Secondly, we characterized the photoprotective
responses of four metallicolous populations of mosses (Lewinskya rupestris, Polytrichum commune,
Ptychostomum compactum and Rhynchostegium confertum) naturally growing in an abandoned mine area by an
experimental field approach. As a result, we found markedly species-specific tolerance patterns: i) less tolerant
species, presenting high pollutants content accompanied by marked dissipative and antioxidative strategies. This
strategy was depicted by the species R. confertum that result to be a good sentinel species due to the high
pollutant content and high physiological sensitivity.; ii) intermediate tolerant species presenting a medium
content of pollutants and less marked photoprotective mechanisms, and iii) most tolerant species minimizing
pollutants content and consequently presenting no changes in their physiological performance. This evidence
support that speciesâ bryological attributes have a key role in determining speciesâ tolerance towards environmental
heavy metals, and should be taken into consideration in future studies. The findings of this study also
pointed out that the higher levels of γ + β-tocopherol in metallicolous populations could play a regulatory role in
metal stress tolerance in mosses and it could be a suitable functional responsive trait for environmental response
prediction to heavy metals in polluted environments
Interactive effects of obligate scavengers and scavenger community richness on lagomorph carcass consumption patterns
Carrion consumption patterns in vertebrate scavenger communities may be influenced by several interacting factors. We assessed the effects of the number of scavenger species and the presence of obligate scavengers (vultures) on carcass detection and consumption times, and the structure (nestedness) of the scavenger assemblage by exploring consumption patterns of lagomorph carcasses provided experimentally. Carcass detection and consumption times were strongly inversely related to vulture presence, whereas scavenger richness had a low contribution, except when interacting with vulture presence. However, none of the scavenger communities presented a nested pattern, perhaps because of the small size of lagomorphs, which prevents large numbers of scavengers and interspecific interactions occurring at one carcass. Our results suggest that scavenger species richness, especially the presence of vultures, increases scavenging efficiency
Some New Generalized Jensen and Hermite-Hadamard Inequalities for Operator hâConvex Functions
In the present paper we introduce the notion of operator h-convex function . Also, we obtain new Jensen and HermiteHadamard inequalities for these operator h-convex functions in Hilbert spaces