The assessment of Visible Foliar Symptoms (VFS) is commonly adopted by forest monitoring programs to evaluate ozone impact on vegetation. The occurrence of ozone VFS may differ among individuals of ...the same species at the same site, and within leaves of the same individual. The aim of this study was to identify site and plant characteristics as well as functional leaf traits associated with the occurrence and severity of VFS in Viburnum lantana (an ozone-sensitive species) and at the scale of an individual site. V. lantana plants growing at one site of the ViburNeT monitoring network (Trentino, North Italy) experiencing high ozone levels were surveyed in relation to 1) sun exposure, 2) shading effect from neighbor vegetation, 3) plant height and 4) presence and severity of VFS. Leaves from three different sections of each plant were subjected to a phenotypic characterization of leaf area, dry weight, specific leaf area (SLA), chlorophyll content (Chl.sub.SPAD ), percentage of VFS, and adaxial and abaxial trichome density (Tr). We showed that plants at high irradiation levels had significantly lower SLA (p<0.05), higher Tr (p<0.01) and greater Chl.sub.SPAD (p<0.01) when compared to shaded and/or west- and north-exposed plants, thus indicating a strong influence of site-specific characteristics on leaf trait plasticity. Similar differences were observed for taller vs. shorter plants and apical vs. basal branches (p<0.05). Ozone-induced VFS at leaf level were associated with lower SLA (p<0.001) and higher Tr in the abaxial leaf surface (p<0.05). Both leaf traits showed significant differences also within the south and east exposed plant category, thus suggesting the increase in leaf thickness and Tr as a potential adaptive strategy under multiple stress conditions. Our results provide evidence of a strong relationship between VFS, leaf traits and site-specific variables, offering new insights for interpreting data on the impact of ozone on vegetation.
Particulate matter (PM) as an air pollutant can be harmful for human health through allergic, mutagenic and carcinogenic effects. Although the main focus is on decreasing air pollution, after PM has ...been emitted to the atmosphere, one of the realistic options to decrease it's concentrations in urbanized area will be phytoremediation. This study compared the capacity to capture PM from air of seven tree species commonly cultivated in Poland (Catalpa bignonioides Walter, Corylus colurna L., Fraxinus pennsylvanica Marsh., Ginkgo biloba L., Platanus × hispanica Mill. ex Muenchh., Quercus rubra L., Tilia tomentosa Moench ‘Brabant’) and six shrub species (Acer tataricum subsp. ginnala (Maxim.) Wesm., Sambucus nigra L., Sorbaria sorbifolia (L.) A.Br., Spiraea japonica L.f., Syringa meyeri C.K. Schneid. ‘Palibin’, Viburnum lantana L.). Significant differences were found between species in mass of total PM accumulation for two PM categories and three size fractions determined and in amount of waxes. A positive correlation was found between in-wax PM of diameter 2.5–10 μm and amount of waxes, but not between amount of waxes and amount of total PM or of any size fraction.
Many
Viburnum
species are popular ornamental shrubs and, simultaneously, highly valued medicinal plants as a source of many bioactive compounds, including antioxidants.
Viburnum
bark, flowers, and ...fruits are widely used in traditional and folk medicine, and the fruits of some species are used as cooking ingredients. The knowledge of the microstructure of
Viburnum
fruits and the accumulation sites of bioactive substances in these organs is rather poor. Comparative analyses of the microstructure of ripe
Viburnum opulus
and
Viburnum lantana
drupes were carried out using light, scanning, and transmission electron microscopes. The location of various groups of metabolites in the fruits of both species was determined with the use of histochemical tests and fluorescence microscopy. Additionally, the major antioxidants, i.e. carotenoids, polyphenols, and flavonoids, were quantified and a number of morphometric traits of the drupes were presented. The
V. opulus
and
V. lantana
fruits were found to differ in some morphological traits and in many characteristics of the pericarp anatomy and ultrastructure. It was shown that the
Viburnum
fruits contained lipids and lipid compounds (carotenoids, essential oils, steroids, and saponins), polyphenols (tannins, flavonoids, and anthocyanins), pectins, and proteins. The fruits of
V. opulus
contained greater quantities of carotenoids, polyphenols, flavonoids, steroids, and pectins than the
V. lantana
drupes, whereas the latter were characterised by higher contents of essential oils, saponins, and proteins. The metabolites were located in different pericarp layers, but the greatest amounts were identified in the drupe skin.
Understanding of biodiversity status can be applied as a guide to better ecosystem management. The ecosystem ecological sustainability is ensured by high species diversity and better conservation. ...Therefore, the purpose of this research is to identify the species diversity of trees and shrubs in the Guijeh-bel region of Ahar and to determine species diversity using related indicators, as well as the relationship between biodiversity and physiographic factors. Sampling was done in 48 circular sample plots, each 314m2, by a random-systematic method within a 150×200m network. In each sample plot, a list of all of tree and shrub species with abundant-overcome values was recorded based on the Brown Blanche scale. The results showed that there were 13 woody species. Smilax excelsa L. and Rhamnus sp. had the highest (39%) and the lowest (0.04%) presence in the sample plots, respectively. The number of stems varied from 10 to 110 stems of different species in the sample plots. Two index species of Arasbaran region, Acer campestre L. and Viburnum lantana L., were observed in this area. Viburnum lantana and Acer campestre were often found on the western and the eastern aspects, respectively. The main effects of slope on the Taxa, Simpson, Shannon-Weiner and Margaleff indicators were not significant. The main effect of aspect was significant on the taxa index at 1% level and on other indicators at 5% level. The average of all indicators of diversity in the western aspect was higher than those of other aspects. The results of clustering of vegetation composition confirmed the results of the comparison of the site diversity indices. According to the results of the coefficient of variation, the taxa and Margalaf indices had the highest coefficient of variation. Therefore, in other studies, as well as assessment of the effects of management and monitoring of vegetation changes, it is recommended to use the indicators. Based on the results of this study, the high values of slope steepness and biodiversity, provides the protection of the area.
•Two Viburnum lantana populations exposed to different ozone levels were monitored.•Time courses of visible foliar symptoms, ChlSPAD and Chl a FT were assessed.•Symptomatic plants had different ...ChlSPAD and Chl a FT, the latter even before symptom onset.•ChlSPAD and Chl a FT are linked to visible injury and can complement the assessment.•Suitable sample size for chlorophyll-related indicators was calculated.
Ozone may cause functional alterations on plants without, before and besides the onset of visible foliar symptoms. While field assessment techniques for foliar symptoms have been developed and applied even at the large-scale, methods to detect functional alterations were mostly used under controlled experiments with little (if any) formalized field test. During a five-month field survey, two populations of Viburnum lantana L. plants growing at sites characterized by different ozone levels (+62.6% at the high-ozone with respect to the low-ozone, in terms of cumulated exposure) and visible foliar ozone symptoms (from negligible to frequent) were examined in Trentino (North Italy). For each site, five haphazardly selected leaves from six randomly selected plants were monitored to evaluate the temporal trend in the chlorophyll content (ChlSPAD) and chlorophyll a (Chl a) fluorescence transient (FT) in relation to the onset and development of foliar injury. The FT variables considered were: basal (F0) and maximal (FM) fluorescence in the dark-adapted state; maximum quantum yield efficiency (FV/FM); J phase; I-P phase; performance index total (PITOT). We investigated (i) whether the physiological indicators are linked to the development of visible ozone injury on native vegetation; (ii) whether they can be an early indicator of ozone effect on a sensitive species before the onset of visible foliar symptoms; and (iii) what is the appropriate sample size for their reliable measurements. Results show that (i) ChlSPAD and FM decreased concurrently with the onset and time development of foliar injury (suggesting a degradation of chlorophyll due to an excess of the total oxidative stress), with a much stronger reduction when the injury becomes widespread (reduction of chlorophyll due to increased necrotic surface). (ii) At the high ozone site visible foliar symptoms were frequent and appeared on plants displaying significant differences in most of the Chl a FT variables even before the onset of symptoms. (iii) Given the reported variability of the ChlSPAD and Chl a FT data, and assuming a randomized sampling design, an acceptable precision level (defined as SE=10% of the mean estimated value at P=95%) can be achieved in most cases by sampling four leaves for each V. lantana plant and five plants per site. Under these conditions, the concurrent measurements of Chl a FT variables together with ozone-specific visible foliar symptoms and ChlSPAD can provide a set of valuable diagnostic indicators for the early identification and assessment of ozone effects on native vegetation and – potentially – for the phenotyping of ozone-sensitive individuals.
Seed germination requirements of Viburnum lantana were investigated by experiments both in the laboratory and outdoors. Embryo length, radicle emergence and shoot emergence were analysed to determine ...the level of morphophysiological dormancy (MPD) of seeds. Mean embryo length in fresh seeds was 1.30 mm, and required growth to at least 2.51 mm to germinate. The critical embryo length was 4.1 mm. In the laboratory, the embryo reached 3 mm length after 20 weeks of warm-temperature incubation (20/7 or 25/10°C), which in fact represents a combination of warm + cold stratification. In seeds subjected to cold stratification (1.5 or 5°C) for 24 weeks, embryos hardly grew. Gibberellic acid stimulated embryo growth and germination. In the outdoor phenology test, the embryos grew from 1.30 mm, i.e. fresh seeds sown in September, to 2.98 mm at the end of the following March. In the ‘move-along’ test (laboratory), starting with temperatures of warm stratification i.e. 25/10°C (4 weeks) → 20/7°C (4 weeks) → 15/4°C (4 weeks) → 5°C (12 weeks) → 15/4°C (4 weeks), and in the outdoor phenology study on seeds exposed to a similar temperature sequence, radicle emergence percentages reached 73% after 28 and 35 weeks, respectively. V. lantana does not exhibit a delay between root and shoot emergence, dismissing any kind of epicotyl dormancy. Seeds of V. lantana have non-deep simple MPD, a level not detected previously in the genus Viburnum, with the physiological dormancy component overcome by a combination of warm and cold stratification, preferably in that order.
Animals are assumed to play a key role in ecosystem functioning through their effects on seed set, seed consumption, seed dispersal, and maintenance of plant communities. However, there are no ...studies investigating the consequences of animal scarcity on seed set, seed consumption and seed dispersal at large geographical scales. We exploited the unprecedented scarcity of pollinating bumblebees and butterflies in the vicinity of Chernobyl, Ukraine, linked to the effects of radiation on pollinator abundance, to test for effects of pollinator abundance on the ecosystem. There were considerably fewer pollinating insects in areas with high levels of radiation. Fruit trees and bushes (apple Malus domestica, pear Pyrus communis, rowan Sorbus aucuparia, wild rose Rosa rugosa, twistingwood Viburnum lantana, and European cranberry bush Viburnum opulus) that are all pollinated by insects produced fewer fruit in highly radioactively contaminated areas, partly linked to the local reduction in abundance of pollinators. This was the case even when controlling for the fact that fruit trees were generally smaller in more contaminated areas. Fruit-eating birds like thrushes and warblers that are known seed dispersers were less numerous in areas with lower fruit abundance, even after controlling for the effects of radiation, providing a direct link between radiation, pollinator abundance, fruit abundance and abundance of frugivores. Given that the Chernobyl disaster happened 25 years ago, one would predict reduced local recruitment of fruit trees if fruit set has been persistently depressed during that period; indeed, local recruitment was negatively related to the level of radiation and positively to the local level of fruit set. The patterns at the level of trees were replicated at the level of villages across the study site. This study provides the first large-scale study of the effects of a suppressed pollinator community on ecosystem functioning.
Plant responses to enhanced ozone levels have been studied in two pairs of evergreen-deciduous species (
Pistacia terebinthus vs.
P. lentiscus;
Viburnum lantana vs.
V. tinus) in Open Top Chambers. ...Ozone induced widespread visible injury, significantly reduced CO
2 assimilation and stomatal conductance (
g
s
), impaired Rubisco efficiency and regeneration capacity (
V
c,max,
J
max) and altered fluorescence parameters only in the deciduous species. Differences in stomatal conductance could not explain the observed differences in sensitivity. In control plants, deciduous species showed higher superoxide dismutase (SOD) activity than their evergreen counterparts, suggesting metabolic differences that could make them more prone to redox imbalances. Ozone induced increases in SOD and/or peroxidase activities in all the species, but only evergreens were able to cope with the oxidative stress. The relevancy of these results for the effective ozone flux approach and for the current ozone Critical Levels is also discussed.
Mediterranean evergreen shrubs have a constitutively higher capacity to tolerate ozone stress than their deciduous relatives.
Ozone (O
3) is well known to affect photosynthesis on tree seedlings under experimental conditions. In natural conditions, young trees grow under a competitive environment that may alter light ...availability. Such conditions were simulated in an open-top chamber (OTC) experiment carried out in Southern Switzerland (Lattecaldo). The experimental set-up consisted of
Fagus sylvatica (beech) seedling plots (planted within the same chamber) either in a monospecific population (Mono, leaves grown in full sunlight conditions—FL) or under competition with taller plants of
Viburnum lantana (Mixed, shaded leaves—SH). These cultures were treated with ambient air (NF, not filtered, 92% of ozone in ambient air) and with charcoal filtered air (CF, 50% of ozone in ambient air). Measures of net photosynthesis (
P
N) and chlorophyll a fluorescence (with the analysis of the OKJIP transient) were performed over a growing season, from June to September. Net photosynthesis (
P
N) and the maximum quantum yield of electrons reaching the acceptor side (
φ
Ro
=
RE
0/ABS) were higher in Mono conditions (full light leaves). Vice versa, quantum yield of primary photochemistry (
φ
Po
=
TR
0/ABS
=
F
V/
F
M) and Performance Index on absorption basis (PI
ABS) were higher in Mixed plots (shaded leaves). Changes due to ozone occurred only at the end of the growing season (September). Ozone affected mainly
P
N, that was lower in the NF-OTCs, both Mono (−19%) and Mixed (−28%) plots, compared to the CF ones. Fluorescence parameters were affected much more by light conditions (full light vs. shaded leaves) than ozone exposure, but ozone enhanced the action of high light by lowering the values of TR
0/ABS and PI
ABS. The most specific effect of ozone concerned the decrease in RE
0/ABS, that indicates the inactivation of the end acceptors of electrons, so producing an excess of oxidative pressure. Results are discussed in relation to the impact of ozone on the processes of the regeneration of forests.
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