Drought versus heat: What's the major constraint on Mediterranean green roof plants?

Green roofs are gaining momentum in the arid and semi-arid regions due to their multiple benefits as compared with conventional roofs. One of the most critical steps in green roof installation is the selection of drought and heat tolerant species that can thrive under extreme microclimate conditions. We monitored the water status, growth and survival of 11 drought-adapted shrub species grown on shallow green roof modules (10 and 13cm deep substrate) and analyzed traits enabling plants to cope with drought (symplastic and apoplastic resistance) and heat stress (root membrane stability). The physiological traits conferring efficiency/safety to the water transport system under severe drought influenced plant water status and represent good predictors of both plant water use and growth rates over green roofs. Moreover, our data suggest that high substrate temperature represents a stress factor affecting plant survival to a larger extent than drought per se. In fact, the major cause influencing seedling survival on shallow substrates was the species-specific root resistance to heat, a single and easy measurable trait that should be integrated into the methodological framework for screening and selection of suitable shrub species for roof greening in the Mediterranean

Photobiont diversity in lichen symbioses from extreme environments

Fungal–algal relationships—both across evolutionary and ecological scales—are finely modulated by the presence of the symbionts in the environments and by the degree of selectivity and specificity that either symbiont develop reciprocally. In lichens, the green algal genus Trebouxia Puymaly is one of the most frequently recovered chlorobionts. Trebouxia species-level lineages have been recognized on the basis of their morphological and phylogenetic diversity, while their ecological preferences and distribution are still only partially unknown. We selected two cosmopolitan species complexes of lichen-forming fungi as reference models, i.e., Rhizoplaca melanophthalma and Tephromela atra, to investigate the diversity of their associated Trebouxia spp. in montane habitats across their distributional range worldwide. The greatest diversity of Trebouxia species-level lineages was recovered in the altitudinal range 1,000–2,500 m a.s.l. A total of 10 distinct Trebouxia species-level lineages were found to associate with either mycobiont, for which new photobionts are reported. One previously unrecognized Trebouxia species-level lineage was identified and is here provisionally named Trebouxia “A52.” Analyses of cell morphology and ultrastructure were performed on axenically isolated strains to fully characterize the new Trebouxia “A52” and three other previously recognized lineages, i.e., Trebouxia “A02,” T. vagua “A04,” and T. vagua “A10,” which were successfully isolated in culture during this study. The species-level diversity of Trebouxia associating with the two lichen-forming fungi in extreme habitats helps elucidate the evolutionary pathways that this lichen photobiont genus traversed to occupy varied climatic and vegetative regimes

Environmental DNA assessment of airborne plant and fungal seasonal diversity

Environmental DNA (eDNA) metabarcoding and metagenomics analyses can improve taxonomic resolution in biodiversity studies. Only recently, these techniques have been applied in aerobiology, to target bacteria, fungi and plants in airborne samples. Here, we present a nine-month aerobiological study applying eDNA metabarcoding in which we analyzed simultaneously airborne diversity and variation of fungi and plants across five locations in North and Central Italy. We correlated species composition with the ecological characteristics of the sites and the seasons. The most abundant taxa among all sites and seasons were the fungal genera Cladosporium, Alternaria, and Epicoccum and the plant genera Brassica, Corylus, Cupressus and Linum, the latter being much more variable among sites. PERMANOVA and indicator species analyses showed that the plant diversity from air samples is significantly correlated with seasons, while that of fungi varied according to the interaction between seasons and sites. The results consolidate the performance of a new eDNA metabarcoding pipeline for the simultaneous amplification and analysis of airborne plant and fungal particles. They also highlight the promising complementarity of this approach with more traditional biomonitoring frameworks and routine reports of air quality provided by environmental agencies

Aspetti metodologici del monitoraggio di inquinanti aerodiffusi persistenti mediante “MOSS-BAGS” di nuova generazione

I muschi, grazie alla loro elevata efficienza nell’accumulo di particolato atmosferico, sono considerati degli ottimi biomonitor. Una tecnica oramai diffusa prevede l’esposizione del materiale all’interno di reticelle, formando le cosiddette “moss-bags”, che possono essere distribuite sul territorio secondo schemi espositivi ottimali. Tra i principali limiti di questa tecnica si ricorda che il muschio viene raccolto in natura, e ciò ha un certo impatto ambientale, mentre l’operazione di preparazione delle bags presenta aspetti “artigianali” che rappresentano un serio handicap per la sua diffusione. Per ovviare a questi problemi un team di ricercatori europei ha sviluppato il progetto FP7 MOSSCLONE, che ha tra gli obiettivi anche quelli di (1) individuare e caratterizzare un muschio particolarmente performante per clonarlo, coltivarlo in condizioni controllate, e quindi usarlo come materiale di uso standard, dopo un processo di devitalizzazione; (2) ottimizzare le moss-bags per forma, taglia, ampiezza delle maglie della rete di contenimento e quantità di muschio, proponendo un prototipo di nuova concezione da sottoporre a brevetto internazionale; (3) standardizzare le condizioni di esposizione, in termini di altezza e durata di esposizione; (4) confrontare i dati ottenuti con le moss-bags di nuova generazione con i dati ottenuti con i metodi chimicofisici tradizionali. In questa sede si presentano i risultati del primo anno e mezzo di attività, in particolare quelli relativi ai punti (2) e (3), basati sull’esposizione di più di 250 bags di vecchia e nuova generazione per periodi di diversa durata, da 3 a un massimo di 12 settimane, in sette siti campani con diverso uso del suolo; ciò in attesa di avere a disposizione i dati relativi ad altre esposizioni condotte in due regioni europee climaticamente molto diverse, la Galizia e l’Austria orientale. Viene inoltre illustrato in prima nazionale il nuovo prototipo

Notulae to the Italian flora of algae, bryophytes, fungi and lichens: 5

In this contribution, new data concerning bryophytes, fungi, and lichens of the Italian flora are presented. It includes new records and confirmations for the bryophyte genera Diplophyllum and Ptychostomum, the fungal genera Arrhenia, Gymnosporangium, and Sporidesmium and the lichen genera Arthonia, Coenogonium, Flavoplaca, Gyalolechia, Parmotrema, Peltigera, Pterygiopsis, Squamarina, Tornabea, and Waynea

Notulae to the Italian flora of algae, bryophytes, fungi and lichens: 5

In this contribution, new data concerning bryophytes, fungi, and lichens of the Italian flora are presented. It includes new records and confirmations for the bryophyte genera Diplophyllum and Ptychostomum, the fungal genera Arrhenia, Gymnosporangium, and Sporidesmium and the lichen genera Arthonia, Coenogonium, Flavoplaca, Gyalolechia, Parmotrema, Peltigera, Pterygiopsis, Squamarina, Tornabea, and Waynea

Biofouling of crypts of historical and architectural interest at la Plata Cemetery (Argentina)

Cemeteries are part of the cultural heritage of urban communities, containing funerary crypts and monuments of historical and architectural interest. Efforts aimed at the conservation of these structures must target not only the abiotic stresses that cause their destruction, such as light and humidity, but also biofouling by biotic agents. The purpose of this study was to assess the development of biofouling of several historically and architecturally valuable crypts at La Plata Cemetery (Argentina). Samples obtained from the biofilms, lichens, and fungal colonies that had developed on the marble surfaces and cement mortar of these crypts were analyzed by conventional microbiological techniques and by scanning electron microscopy. The lichens were identified as Caloplaca austrocitrina, Lecanora albescens, Xanthoparmelia farinosa and Xanthoria candelaria, the fungi as Aspergillus sp., Penicillium sp., Fusarium sp., Candida sp. and Rhodotorula sp., and the bacteria as Bacillus sp. and Pseudomonas sp. The mechanisms by which these microorganisms cause the aesthetic and biochemical deterioration of the crypts are discussed

Functional Implication of Dp71 in Osmoregulation and Vascular Permeability of the Retina

Functional alterations of Müller cells, the principal glia of the retina, are an early hallmark of most retina diseases and contribute to their further progression. The molecular mechanisms of these reactive Müller cell alterations, resulting in disturbed retinal homeostasis, remain largely unknown. Here we show that experimental detachment of mouse retina induces mislocation of the inwardly rectifying potassium channels (Kir4.1) and a downregulation of the water channel protein (AQP4) in Müller cells. These alterations are associated with a strong decrease of Dp71, a cytoskeleton protein responsible for the localization and the clustering of Kir4.1 and AQP4. Partial (in detached retinas) or total depletion of Dp71 in Müller cells (in Dp71-null mice) impairs the capability of volume regulation of Müller cells under osmotic stress. The abnormal swelling of Müller cells In Dp71-null mice involves the action of inflammatory mediators. Moreover, we investigated whether the alterations in Müller cells of Dp71-null mice may interfere with their regulatory effect on the blood-retina barrier. In the absence of Dp71, the retinal vascular permeability was increased as compared to the controls. Our results reveal that Dp71 is crucially implicated in the maintenance of potassium homeostasis, in transmembraneous water transport, and in the Müller cell-mediated regulation of retinal vascular permeability. Furthermore, our data provide novel insights into the mechanisms of retinal homeostasis provided by Müller cells under normal and pathological conditions

The interaction of graphene oxide with the pollen 12stigma system: In vivo effects on the sexual reproduction of Cucurbita pepo L.

Applications involving graphene-related materials (GRMs) are becoming very common, raising concerns for their environmental impact. GRMs induce various effects on plants, but those on the sexual reproduction are still largely unknown. Here, the effects of graphene oxide (GO) and GO purified from production residues (PGO) were tested in vivo on the stigma of Cucurbita pepo L. ssp. pepo \u201dGreyzini\u201d (summer squash). Stigmas were exposed to GO or PGO for three hours and were then analyzed by environmental scanning electron microscopy to verify possible alterations to their surface. Stigmas were then hand-pollinated to verify the effects of the two GOs on pollen adhesion and germination on the stigma, and, subsequently, on the development of fruits and seeds. Severe damages to the stigma were not detected; nevertheless, both pollen adhesion and germination on the stigma decreased. Moreover, fruits developed defectively with signs of necrosis in the case of GO, whereas fruits did not ripen in the case of PGO and ovules did not develop seeds after both GOs treatments. These results highlight different mechanisms of interaction of the two materials with the pollen-stigma system, suggesting a possible negative impact of GO on the sexual reproduction of other seed plants