Bioindication of troposheric ozone by native vegetation: the potential of Viburnum lantana for large-scale surveys

Tropospheric ozone is one of the most important phytotoxic air pollutant. Biomonitoring by native plants is an option when the assessment of its impact on vegetation in large-scale surveys and in remote areas is of concern. The shrub species Viburnum lantana L. (wayfaring tree) is known to be sensitive to ozone, develops specific symptoms consisting in red stipples on the upper surface, and has a wide spatial distribution. However it is not fully known if it meets all the requirements to be used as an in situ bioindicator (Doley, 2010). In particular, the actual responsiveness to ozone of native plants and the relationship between the intensity of responses and the levels of exposure to the pollutant under field conditions remain to be evaluated. For these purposes, two field studies were carried out in Trentino (North Italy) at local (1) and large scale (2). (1) Firstly, at local level, we considered two 1x1 km quadrates characterized by different ozone levels. A fully randomized design was adopted to ensure within-quadrate replications and to select V. lantana plants for the monitoring of ozone-specific foliar symptoms development, the chlorophyll (Chl) content and the fluorescence of Chl a during the entire growing season. (2) Secondly, a stratified (elevation x ozone) random design was used to test the response of V. lantana in terms of symptomatic plant percentage at larger scale (6200 km2). Overall, the results of the two field studies allowed to verify a temporal development of the responses of V. lantana consistent with the trend of ozone exposure (Gottardini et al., 2010), and an higher frequency of symptomatic plants where ozone levels were also higher. However, the frequency of symptoms was not always proportionate to the level of ozone exposure. At the same time of the onset and spread of foliar symptoms, a decrease in the foliar Chl content and in photosynthetic performance occurred. V. lantana seems suitable as a bioindicator in situ to qualitatively assess the potential impact of ozone

Rilevamento di ozono presso i siti forestali UN/ECE Level I nella Provincia di Trento nel 2007

A causa del suo alto potere ossidante, dei suoi elevati livelli e della sua ampia diffusione in aree rurali e forestali, l’ozono troposferico (O3) è ritenuto il contaminante gassoso di potenziale maggiore pericolosità per la vegetazione agraria, semi-naturale e forestale. L’obiettivo del presente studio è ottenere stime realistiche dell’esposizione ad O3 della vegetazione forestale della provincia di Trento, essenziali per poter valutare se siano ipotizzabili effetti di questo inquinante sulla vegetazione. A tale scopo sono stati installati 15 siti di misura delle concentrazioni di O3, riferendosi ai punti della rete UE e UN/ECE di monitoraggio delle foreste di Livello I della provincia di Trento; l’ozono è stato misurato utilizzando campionatori passivi, che forniscono un dato settimanale, successivamente convertito in valori di concentrazione media oraria. L’affidabilità dei dati ottenuti è stata verificata per confronto con i dati forniti in parallelo da centraline automatiche. Le concentrazioni medie settimanali di O3 rilevate nel periodo 6 giugno - 19 settembre 2007 sono risultate comprese tra 62.4±12.4 e 130.6±22.3 μg*m-3. In termini di AOT40, l’indicatore di rischio utilizzato dalla normativa UE e dall’UN/ECE, i valori sono tali da prefigurare frequenti superamenti dei livelli critici nel corso della stagione estiva 2007. Si discutono nel dettaglio andamenti spaziali e temporali dei dati raccolti e si ipotizza una linea futura per la prosecuzione del lavoro nell’ottica di una maggiore comprensione del fenomeno

The impact of temperature on increased airborne pollen and earlier onset of the pollen season in Trentino, Northern Italy

The impact of climate change on ecosystems can be assessed through pollen dispersion data, which acts as a proxy for the plant flowering stage. The aim of this study is to verify if changes occurred in the season and concentration of airborne pollen in Trentino (Northern Italy), and to evaluate if temperature (T), precipitation (P), and/or land use influenced such changes in the period 1989–2018. Airborne pollen, sampled by a Hirst-type trap, was analyzed by light microscopy, and pollen concentrations were obtained. Twenty-four taxa, covering 95% of the local pollen spectrum, were considered for this study. A significant upward trend in annual pollen integral (APIn) is the main outcome over the study period. The increase in APIn is more evident when analyzing the data in three decadic blocks, both for all the considered taxa (+ 58%) and for Arboreal Pollen (AP; + 155%). Considering both the annual data and the decadic blocks, APIn shows a significant positive trend for Cupressaceae/Taxaceae, Ulmus, Populus, Salix, Ostrya, Quercus, Olea (AP), and Plantago, Cannabaceae, Ambrosia (non-arboreal pollen, NAP); a significantly earlier start of the Main Pollen Season (MPS) is proved for Rumex and Poaceae. APIn for 24 taxa shows a significant positive correlation with annual T min (< 0.005) and T mean (< 0.001), both of which showing a significant increase, and a negative correlation (< 0.025) with the number of frost days. From a human health perspective, higher temperatures, driven by climate changes, lead to higher concentrations of allergenic airborne pollen, turning into a higher risk for allergy sufferer

Do ecosystem services have a biological cost? Ozone and climate regulation by Norway spruce forests along an Alpine altitudinal transect in Trentino, northern Italy

Regulating air pollution and climate are important ecosystem services provided by forests. Among air pollution, ozone is particularly important because its high values and wide distribution in remote forest areas. Forests may help in reducing ozone concentration because stomatal and non-stomatal deposition. Ozone, however, can potentially affect the vegetation, leading to a reduction of photosynthesis with consequences, from plant to ecosystem level. In a cost-benefit approach, this may be considered as a biological cost. To assess the size of ozone and climate regulating services provided by Alpine forests, a fully randomized study was established along an altitudinal gradient (900 - 1500 m a.s.l.) in Trentino, northern Italy. Environmental variables (O3, NO2, T, RH, LAI) were measured between May and August 2013. Tree response variables (crown condition, needle weight, shoot length, chlorophyll fluorescence, C and O isotopes) were also investigated on mature Norway spruce trees. Ozone concentration increased with altitude, both inside and outside forests. Significant (P<0.001; Wilcoxon test) lower ozone concentrations, however, were observed within the forest (64.8 g m-3) with respect to open areas (71.3 g m-3). Effect of forests on temperature was particularly marked for maximum daily values. As for response indicators, a distinct elevation pattern with concurrent increase of crown transparency and decrease of shoot growth, needle weight and photosynthetic activity potential was obvious. Nested within such a superimposed effect, the various response indicators were related to each other. Estimates of ozone removal in terms of AOT40, relationship between exposure to ozone, ozone removal and tree- and plot-related variables will be presented and discussed. This will allow (i) the evaluation of possible biological costs of removing air pollutants and (ii) the functional interpretation of monitoring data. All together, this will help understanding the role of tree health on the regulating services provided by forests and vice versa

Studio di un modello per la stima dell’ozono troposferico in provincia di Trento: relazione tecnica dello studio realizzato nell’ambito della convenzione tra IASMA e Servizio Foreste e Fauna della Provincia Autonoma di Trento (Convenzione N. 4297 del 12/3/08)

Nel 2007 sono state condotte due campagne di misura dell’ozono troposferico in provincia di Trento, una a scala locale (Maggio-Giugno) ed una provinciale (Giugno- Settembre). I dati così raccolti, unitamente a quelli della rete di centraline automatiche APPA, ai dati meteoclimatici (Temperatura e Precipitazioni) ed ai dati territoriali (quote, uso del suolo) sono stati considerati per valutare la possibilità di modellare le concentrazioni di ozono sul territorio provinciale. Sono stati seguiti due approcci, uno di tipo statistico, mediante l’uso della PLSR (Partial Least Square Regression), ed uno di tipo geostatistico, che ha considerato la dipendenza spaziale dei dati. Questi due approcci sono stati dapprima studiati relativamente ad un periodo di due settimane, tra il 13 ed il 27 Giugno 2007, considerando separatamente ciascuna settimana e poi la media delle due. Questo periodo è stato scelto perché era quello comune alle due campagne di misurazione e permetteva di massimizzare la numerosità delle osservazioni. Entrambi gli approcci hanno identificato la quota, la temperatura e le precipitazioni come i principali predittori dei livelli di ozono in Trentino, seppur con pesi diversi a seconda del periodo considerato. La validazione su siti indipendenti ha evidenziato errori medi assoluti pari al 28.6% (approccio statistico) e 16.1% (approccio geostatistico). L’RMSEP (Root- Mean-Square-Error of Prediction, una misura delle differenze tra il valore vero ed il valore predetto, espressa nella stessa unità di misura della variabile di interesse) è risultato leggermente migliore nel modello derivante dall’approccio geostatistico, per il quale anche la varianza spiegata è risultata superiore. In virtù dei minori errori, l’approccio geostatistico è stato quindi applicato per le stime a scala provinciale e per la previsione delle concentrazioni medie sul periodo Giugno-Settembre. Quota e precipitazioni sono risultati i predittori significativi che permettono di massimizzare la prestazione del modello con il minor numero di predittori. Le stime così ottenute sono state validate mediante Cross-Validation attraverso la procedura di Leave-One-Out, che ha evidenziato scostamenti medi dai dati misurati pari a 13.98 μg*m-3. Le stime indicano valori di ozono superiori (fino anche ad oltre 180 μg*m-3) nella parte occidentale della provincia, a ridosso dell’Adamello, e nel settore nord-orientale, dalla Marmolada al Primiero (120-180 μg*m-3). In queste zone l’AOT40 (stimato sul periodo metà Giugno-metà Settembre) arriva a valori 3-4 volte superiori al Target stabilito dalla Direttiva EU per la protezione della vegetazione. Merita ricordare tuttavia che esistono aree con misurazioni assenti (es. area centro-occidentale della provincia) che possono avere influenza nella formulazione del modello e sulla precisione delle stime. I risultati ottenuti sono promettenti e dimostrano la praticabilità dell’approccio seguito, che potrebbe portare a sviluppi applicativi interessanti: con l’aggiunta di una componente dinamica (tempo), si potrebbero ottenere stime e previsioni più robuste; sovrapponendo le stime dei livelli di ozono con altri layer informativi sarebbero possibili stime di rischio, oltrechè per la popolazione, anche per ecosistemi e vegetazione; diventerebbero fattibili una mappatura routinaria delle aree a rischio e studi correlativi sul possibile ruolo dell’ozono sulle condizioni dei boschi trentini

Somatic variants for seed and fruit set in grapevine

Background: Grapevine reproductive development has direct implications on yield. It also impacts on berry and wine quality by affecting traits like seedlessness, berry and bunch size, cluster compactness and berry skin to pulp ratio. Seasonal fluctuations in yield, fruit composition and wine attributes, which are largely driven by climatic factors, are major challenges for worldwide table grape and wine industry. Accordingly, a better understanding of reproductive processes such as gamete development, fertilization, seed and fruit set is of paramount relevance for managing yield and quality. With the aim of providing new insights into this field, we searched for clones with contrasting seed content in two germplasm collections. Results: We identified eight variant pairs that seemingly differ only in seed-related characteristics while showing identical genotype when tested with the GrapeReSeq_Illumina_20K_SNP_chip and several microsatellites. We performed multi-year observations on seed and fruit set deriving from different pollination treatments, with special emphasis on the pair composed by Sangiovese and its seedless variant locally named Corinto Nero. The pollen of Corinto Nero failed to germinate in vitro and gave poor berry set when used to pollinate other varieties. Most berries from both open- and cross-pollinated Corinto Nero inflorescences did not contain seeds. The genetic analysis of seedlings derived from occasional Corinto Nero normal seeds revealed that the few Corinto Nero functional gametes are mostly unreduced. Moreover, three genotypes, including Sangiovese and Corinto Nero, were unexpectedly found to develop fruits without pollen contribution and occasionally showed normal-like seeds. Five missense single nucleotide polymorphisms were identified between Corinto Nero and Sangiovese from transcriptomic data. Conclusions: Our observations allowed us to attribute a seedlessness type to some variants for which it was not documented in the literature. Interestingly, the VvAGL11 mutation responsible for Sultanina stenospermocarpy was also discovered in a seedless mutant of Gouais Blanc. We suggest that Corinto Nero parthenocarpy is driven by pollen and/or embryo sac defects, and both events likely arise from meiotic anomalies. The single nucleotide polymorphisms identified between Sangiovese and Corinto Nero are suitable for testing as traceability markers for propagated material and as functional candidates for the seedless phenotype

The fingerprint of tropospheric ozone on broadleaved forest vegetation in Europe

Tropospheric ozone (O3) increased globally in the 20th century, contributes to climate change and can have adverse effects on terrestrial ecosystems. The response of forest vegetation to ozone is modulated by species- and site-specific factors and visible foliar symptoms (VFS) are the only direct evidence of ozone effects on vegetation. VFS have been observed and reproduced under (semi-) controlled conditions and their field assessment has been largely harmonized in Europe. We analyzed ozone concentration and VFS data as measured at (respectively) 118 and 91 intensive monitoring sites of the International Co-Operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) spanning over five European biogeographic regions from 2005 to 2018. Average values for VFS were calculated accounting for the number of species present and their observed frequency. Spatial and temporal variation of ozone concentrations, VFS, and their relationships across Europe were then investigated by applying Generalized Linear Mixed Models (GLMMs) and combined GLMMs. Ozone concentrations exceeded 40 ppb on 37.3 % of the sites and were significantly higher (p &lt; 0.05) in the Alpine and the Mediterranean regions. Over the 2005–2018 period there was a substantial stagnation of ozone concentrations with a tendency towards decreasing values in the Alpine-Boreal sites and increasing values in the Atlantic sites. Ozone left a “fingerprint” in terms of VFS on 38 % of the observed broadleaved woody species across Europe, with no significant difference among biogeographic regions. Overall, and again with the exception of an increase at the Atlantic sites, the frequency of VFS remained unchanged or has been slightly declining over the investigated period. We found positive relationship between ozone concentrations and VFS across Europe (p &lt; 0.05), while their temporal trends (both insignificant) were not related. The species with the highest frequency of VFS were those classified as sensitive species under controlled/semi-controlled experimental conditions. Frequency of VFS tends to be modulated by vegetation traits such as specific leaf area and leaf thickness (p &lt; 0.10). Our results showed that, although ozone levels suggested a North-to-South gradient of increasing potential risk to vegetation with hot spots in the Alps and in the Mediterranean, VFS observed on the actual species assemblage at the sites modifies this picture. According to frequency of VFS, ozone risk for vegetation may be higher in parts of the Alpine and Continental Europe than in the Mediterranean regio

Forests Attenuate Temperature and Air Pollution Discomfort in Montane Tourist Areas

Forests deliver many ecosystem services, from provisioning to regulating and cultural services. We aimed at demonstrating microclimatic regulation and pollutant removal as especially relevant ecosystem services when considering the tourism vocation of the Alpine regions. A study was realized along an altitudinal gradient (900&ndash;1600 m a.s.l.) in Trentino, northern Italy, an area with high touristic presence (ca. 9.3 million overnight stays in summer 2021). Nitrogen dioxide (NO2, &micro;g m&minus;3), ozone (O3, &micro;g m&minus;3) concentrations, air temperature (T, &deg;C), and relative humidity (RH, %) were simultaneously measured in three open-field sites (OF) and below-canopy Norway spruce forest stands (FO) during the period 23 May&ndash;7 August 2013. The temperature&ndash;humidity index (THI) was calculated. We found a distinct mitigating effect of forest on T, with lower maximum (&minus;30.6%) and higher minimum values (+6.3%) in FO than in OF. THI supported a higher comfort sensation in FO than in OF, especially in the central part of the day. NO2 concentrations did not differ between OF and FO; ozone concentrations were lower in FO than OF. This study confirms the role of forests in providing several ecosystem services beneficial for forest users, especially relevant for promoting nature-based tourism in the Alpine region