1,721,010 research outputs found
Is the length of the drying period critical for photosynthesis reactivation in lichen and moss components of biological soil crusts?
No full textLichens and mosses represent the macroscopic components of biological soil crusts (biocrusts). Their ability to exploit short periods of water availability and reversibly deactivate metabolism is crucial for their growth and survival. In this work we investigated photosynthesis reactivation, respectively after long (65–66 days) and short (15 days) dry periods, in lichen and moss species widespread in two Mediterranean environments (Portugal and Italy). Chlorophyll a fluorescence emission of the samples was investigated and the parameter Fv/Fm, an indicator of vitality of photosynthetic organisms, was used as a proxy for photosynthesis reactivation. The fruticose lichens Cladonia convoluta and C. rangiformis, and the moss Pleurochaete squarrosa, typical of Mediterranean environments, showed a significantly slower reactivation of photosynthetic activity when subjected to a longer period of drought. Conversely, the alien invasive moss Campylopus introflexus was not affected by prolonged dry conditions. The study showed that drought duration influences the reactivation of photosynthetic activity in terricolous lichens and mosses forming biocrusts in re-hydration cycles. These results indicate the likelihood of a reduction in biocrust productivity as a consequence of climate change in Mediterranean drylands
Epiphytic lichens as environmental bioindicators in Rome, Italy
No full textEpiphytic lichens as environmental bioindicators in Rom
Risultati preliminari del monitoraggio della città di Roma tramite IBL
No full textmonitoraggio della città di Roma tramite IB
Can we trust iNaturalist in lichenology? Evaluating the effectiveness and reliability of artificial intelligence in lichen identification
Full text linkiNaturalist is a widely-utilized platform for data collection and sharing among non-professional volunteers and is widely employed in citizen
science. This platform’s data are also used in scientific studies for a wide range of purposes, including tracking changes in species distribution,
monitoring the spread of alien-invasive species, and assessing the impacts of urbanization and land-use change on biodiversity.
Lichens, due to their year-round presence on trees, soil and rocks, and their diverse shapes and colours, have captured the attention of
iNaturalist users, and lichen records are widely represented on the platform. However, due to the complexity of lichen identification,
the use of data collected by untrained, or poorly trained volunteers in scientific investigation poses concerns among lichenologists. To
address these concerns, this study assessed the reliability of lichen identification by iNaturalist users by comparing records on the platform
with identifications carried out by experts (experienced lichenologists) in three cities where citizen science projects were developed. Results
of this study caution against the use of unchecked data obtained from the platform in lichenology, demonstrating substantial inconsistency
between results gathered by iNaturalist users and experts
Do lichens have "memory" of their native nitrogen environment?
No full textThis study aimed to deepen the knowledge about intraspecific mechanisms regulating nitrogen tolerance in lichens to wet nitrogen deposition. Thalli of the nitrophilous lichen Xanthoria parietina were collected from environments with different nitrogen availabilities and immersed in 80 mL of ammonium sulphate (NH(4))(2)SO(4) solutions with distinct concentrations (0, 0.025, 0.05 and 0.25 M) for 5 h per day during 3 days in a week. After each soaking event, lichens were air dried. After each treatment, maximal PSII efficiency, localization of ammonium ions, concentrations of K(+) and Mg(2+) and thalli buffer capacity were determined. Our results show that lichens are marked by their native nitrogen environment, since there were important differences between the physiological responses of X. parietina thalli previously grown in an area with high nitrogen deposition (nitrogen emissions of ca. 13,000 t/year) and those previously grown in an unpolluted area (nitrogen emissions of ca. 500 t/year). Greater N availability seems to enable X. parietina to cope better with the effects of nitrogen pollution
Evaluating Seawater and Wood Distillate for Sustainable Hydroponic Cultivation: Implications for Crop Growth and Nutritional Quality
Full text linkThe adoption of innovative cultivation methods, such as hydroponics and aeroponics, is gaining attention due to the unprecedented demand for food that an increasing population is posing on agricultural systems, exacerbating the pressure on already limited arable land. Seeking sustainable and circular economy solutions is imperative, aiming to optimize water consumption and enhance crop yields and quality without resorting to synthetic chemical fertilizers. This study investigated the use of seawater at various concentrations as a base for nutrient solutions, with and without the addition of a natural biostimulant, wood distillate (WD). Four seawater (SW) concentrations (0, 3, 6, and 12%) and two wood distillate concentrations (0 and 0.2%) were applied to assess their impacts on lettuce growth. Findings reveal that seawater at low concentrations (< 6%) serves as an effective water-saving strategy, despite the reduction in the plant ascorbic acid contents. The addition of WD did not inflate growth; in fact, the results obtained are comparable to that of the controls for each concentration of seawater, except at the highest concentration (12% SW), resulting in reduced fresh leaf weights and root areas. Significantly, there was a notable increase in the ascorbic acid contents in all plants grown with WD. Moreover, the WD increased the leaf concentrations in Ca, Mg, P, and K, indicating the higher nutritional value of the crop. This research highlights the potential of combining seawater and WD for sustainable and efficient plant cultivation, suggesting new strategies for exploration across diverse plant species and hydroponic applications
The influence of growth form and substrate on lichen ecophysiological responses along an aridity gradient
No full textIn this paper, we investigated whether growth form and substrate in lichens influence their physiological responses along an aridity gradient. Thalli of the foliose lichen Parmotrema perlatum and the fruticose lichen Ramalina canariensis were transplanted in selected rural/forested sites of Southern Portugal characterized by a different aridity index. Physiological parameters including photosynthetic performances, assimilation pigments, ergosterol content and sample viability were measured prior to exposure (winter) and after 6-month exposure (summer). Photosynthetic performances were also investigated in common native foliose and fruticose epiphytic lichens and in fruticose terricolous species. Both transplanted and native lichens showed a decrease in photosynthetic performances in summer and lower performances in sites classified as drier and higher performances in humid forested sites. No relevant differences occurred between epiphytic foliose and fruticose growth forms. However, terricolous fruticose samples showed a significant difference in humid and drier sites and between winter and summer, probably due to microclimatic conditions similarly to other biological crusts
Physiological effects of arsenic in the lichen Xanthoria parietina (L.) Th. Fr.
No full textThe aim of this study was to test in a short term laboratory experiment the accumulation and physiological effects of As in the epiphytic lichen Xanthoria parietina. Arsenic content in treated samples increased progressively with increasing concentration in treatment solutions. Treatment of X. parietina thalli with 0.1, 1, 10 ppm As solutions caused significant decrease of viability, measured as intensity of respiratory activity, and damages to cell membranes, assessed by increase of electric conductivity of rinsing water and lipid peroxidation products. Soluble proteins content decreased and H(2)O(2) content increased already at the lowest As concentration tested (0.01 ppm). Photosynthetic efficiency, measured in terms of F(V)/F(M) ratio, decreased significantly only at the highest As concentration (10 ppm). It was concluded that As exposure causes physiological stress both on the mycobiont and the photobiont and that cell membrane damage, expressed in terms of electric conductivity of rinsing water, is the parameter most affected by As treatment. (C) 2010 Elsevier Ltd. All rights reserved
Integration of ecological indicators to assess a multitemporal impact of cement industries
Full text linkThe present study evaluated an integrated biomonitoring approach based on three different bioindicators: tree rings, lichens,
and beetles in a complex environment (urban-industrial-forest). In Central Italy, four sampling sites were selected to assess
the anthropogenic impact of cement plants taking into account (1) long-term exposure (1988–2020) through the analysis
of trace elements in tree rings of Quercus pubescens; (2) medium-term exposure (2020–2021) through the analysis of trace
elements in thalli (outermost portions) of the lichen Xanthoria parietina; (3) short-term exposure in spring 2021 through
the bioaccumulation and evaluation of sample vitality in transplants of the lichen Evernia prunastri and a periodic survey
of entomological biodiversity carried out during spring and summer 2021. Trace elements of industrial origin were found in
tree rings, with different levels of accumulation between 1988 and 2020 and a maximum in 2012. Native thalli of the lichen
X. parietina showed an overall low bioaccumulation of trace elements except for Cr, probably reflecting the influence of
national lockdown measures. The transplants of E. prunastri showed a weak stress response in the industrial and urban sites,
but not in the forest, and identified Tl and V as the main elements contributing to atmospheric contamination, with peaks at
the industrial sites. Concerning the beetles, a significantly lower number of species was found at the Semonte industrial site
Influence of angular exposure and proximity to vehicular traffic on the diversity of epiphytic lichens and the bioaccumulation of traffic-related elements
Full text linkThis study investigated the influence of angular
exposure and distance from vehicular traffic on the diversity
of epiphytic lichens and the bioaccumulation of traffic-
related elements in a town of central Italy. An Index of
Lichen Diversity (ILD) was calculated on the street-facing
and the opposite side of road-lining trees and in a urban park
250 m away, and the content of selected trace elements (Al,
Ba, Ce, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, V, and Zn) was
determined in samples of the lichen Punctelia borreri (Sm.)
Krog growing on tree bark, both on the exposed and opposite
sides. ILD increases with distance from traffic emissions.
However, at the site with vehicle traffic, non-nitrophilous
lichens decreased while nitrophilous ones increased. The con-
centration of the traffic-related elements Ba, Cr, Cu, Mn, Sb,
and Zn accumulated in thalli of P. borreri was higher on
roadside trees than in trees from the urban park. ILD was
not affected by the angular exposure to the road and the
bioaccumulation of traffic-related elements was similar in
lichens from the side of the bole exposed to traffic emissions
and particulate resuspension and from the opposite side. The
angular exposure in respect to the traffic source does not
influence trace element accumulation. These results are im-
portant when using lichens for biomonitoring purposes, both for planning future studies and for the reliability of the inter-
pretation of past surveys that do not report information about
the angular exposure of the collected lichen material
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