Effects of Ambient and Acute Partial Pressures of Ozone on Leaf Net CO(2) Assimilation of Field-Grown Vitis vinifera L

Tropospheric ozone - hidden cost for the financial performance of French wineries

The paper investigates how tropospheric ozone affects the financial performance of French wine companies by influencing their operating income, using the Structural Equation Modeling (SEM) methodology. The study encompasses 487 active French wine industry companies from 2010 to 2022, considering various market, climate, and financial factors. The main findings show that high concentrations of tropospheric ozone negatively affect both the quality and quantity of grapes, thereby reducing the operating income of French wine companies and, consequently, their financial performance. More precisely, within the current market conditions and climate context, a 1% rise in tropospheric ozone levels leads to a 10.4% decrease in the operating income of French wine companies, which translates to a 0.7-0.8% decline in their financial performance. A strong market position enables French wine companies to achieve higher revenues, increased profit margins, and sustainable growth. Additionally, lower soil wetness, humidity, and temperature under higher atmospheric pressure improve grapevine growth and grape quality, further boosting revenue. Policy implications for wine producers include adopting site selection, irrigation, and canopy management strategies to enhance grape quality and financial health. Public authorities can address tropospheric ozone pollution through air quality standards, monitoring systems, financial incentives, and educational programs to mitigate its adverse effects.

Phosphoproteomic analysis of ozone stress-responsive mechanisms in grapevine identifies KEG required for stress regulation

The environmental damage caused by ozone is of increasing concern globally. The phosphoproteomics approach was used to explore the mechanisms underlying grapevine tolerance to ozone stress and identify phosphoproteins altered by ozone treatment. Results revealed that 194 of 2275 quantitatively analyzed phosphoproteins were significantly regulated after ozone treatment. Biological pathways related to transport were significantly enriched by the differentially regulated phosphoproteins. Among these phosphoproteins, the phosphorylation of RING E3 ligase in grape (V. vinifera KEEP ON GOING, VvKEG) decreased after ozone treatment. Over-expression of VvKEG in Arabidopsis decreased abscisic acid (ABA) sensitivity and enhanced ozone tolerance. Furthermore, VvKEG interacted with the ABA-responsive transcription factor ABSCISIC ACID-INSENSITIVE3 (ABI3). The exogenous application of ABA on grapevine leaves significantly influenced chlorophyll fluorescence, chlorophyll, and malondialdehyde (MDA) contents under ozone treatment; however, treatment with 150 μmol ABA aggravated ozone stress. These results indicate that phosphorylation modification provides information on ozone-induced processes and that VvKEG plays a critical role in these processes via regulation of the ABA signaling pathway in grape.

Grapevine and Ozone: Uptake and Effects

The grapevine (Vitis vinifera, L.) has been long since recognized as an ozone-sensitive plant. Ozone molecules can penetrate grapevine leaf tissues when the concentration of ozone in the atmosphere is high due to air pollution. This causes cell damage and interferes with photosynthetic mechanisms, subsequently slowing down plant growth and resulting in premature leaf senescence. Secondary effects include changes in biochemical processes that affect the chemical composition of the must and are likely to alter the quality of the wine. An experiment was conducted during two grapevine-growing seasons in 2010 and 2011 to gain knowledge of the effect of high ozone levels on the yield and on several biochemical characteristics of the plant which could influence the quality of the final product. These factors are economically important for agricultural production; this is especially true for Italy, which is one of the largest wine producers worldwide. The method used was a facility consisting of open top chambers operated at a vineyard in Angera (northern Italy). This facility permitted the study of the effects of different ozone levels. At the end of the experiment, the grapes were weighed and chemical analyses were carried out in order to understand the effects of ozone on the different characteristics of the grapes and on concentrations of several of its chemical substances. In particular, concentrations of yeast assimilable nitrogen, degrees Brix, pH, tartaric and malic acids, and polyphenols, including resveratrol, were considered, as these influence the quality of the wine. Parameters characterizing the different ozone levels were expressed in terms of ozone exposure (AOT40) and phytotoxic ozone dose (POD). The results showed that high ozone levels affect grapevine weight and thus its yield. In addition, the quality of the wine is affected by reductions of polyphenols which diminish the nutritional benefits of the product. In addition, these reductions cause the wine to have a more aggressive taste. These results emphasize the practical importance of the present study.

The climate benefits of high-sugar grassland may be compromised by ozone pollution

High sugar ryegrasses (HSG) have been developed to improve the uptake, digestion and nitrogen (N)-utilisation of grazing stock, with the potential to increase production yields and benefit climate by reducing methane (CH4) and nitrous oxide (N2O) emissions from livestock farming. In this study, the effects of tropospheric ozone pollution on the seasonal growth dynamics of HSG pasture mesocosms containing Lolium perenne cv. AberMagic and Trifolium repens cv. Crusader were investigated. Species-specific ozone (O3) dose-response relationships (seasonal means: 35, 41, 47, 51, 59 & 67ppb) based on the Phytotoxic Ozone Dose (PODy) were constructed for above and below ground biomass, injury, N-fixation and forage quality. The dynamics of effects of ozone exposure on HSG pasture changed over the course of a season, with the strongest responses occurring in the first 4-8weeks. Overall, strong negative responses to ozone flux were found for root biomass, root nodule mass and N-fixation rates, and ozone adversely impacted a range of forage quality parameters including total sugar content and relative and consumable food values. These results indicate that increasing ozone pollution could decrease the N-use efficiency and reduce the sugar content of managed pasture, and thereby partially detract from some of the suggested benefits of HSG.

Ozone impacts on cotton: towards an integrated mechanism

Vegetation removes tropospheric ozone (O(3)) mainly through uptake by stomata. O(3) reduces growth, photosynthesis, and carbohydrate allocation. Effects on mesophyll photosynthesis, may reducing carbohydrate source strength and, indirectly, carbohydrate translocation. Alternatively direct translocation, itself, could explain all of these observations. O(3)-reduced root proliferation inhibits exploitation of soil resources and interferes with underground carbon sequestration. Simulations with cotton suggest O(3)-disrupted root development could indirectly reduce shoot photosynthesis. Strong evidence for O(3) impacts on both carbon assimilation and carbon translocation exists, but data determining the primacy of direct or indirect O(3) effects on either or both processes remain inconclusive. Phloem loading may be particularly sensitive to O(3). Further research on metabolic feedback control of carbon assimilation and phloem loading activity as affected by O(3) exposure is required.

An in vivo analysis of photosynthesis during short-term O3 exposure in three contrasting species

The depressions of photosynthetic CO2 uptake following O3 exposures of 200 and 400 nmol mol(-1) for between 4 and 16 h were compared between Pisum sativum, Quercus robur and Triticum aestivum, and the potential causes of change identified in vivo. Photosynthetic change was examined by analysis of CO2, O2, O3 and water vapour exchanges together with chlorophyll fluorescence in controlled environments. Under identical fumigation conditions, each species showed very similar rates of O3 consumption. The light-saturated rate of CO2 uptake showed a statistically significant decrease in each species with increasing O3 dose. Although stomatal conductance declined in parallel with CO2 uptake this did not account for the observed decrease in photosynthesis. The decrease in mesophyll conductance resulted primarily from a decrease in the apparent carboxylation capacity, implying in decreased activity of ribulose 1,5-bisphosphate carboxylase/oxygenase. The maximum capacity of carboxylation was consequently reduced by over 30% and 50% after 16 h fumigation with 200 and 400 nmol mol(-1) O3 respectively. Additionally, in Q. robur, a statistically significant inhibition of the CO2 saturated rate of photosynthesis occurred after 16 h with 400 nmol mol(-1) O3, suggesting that the ability to regenerate ribulose 1,5-bisphosphate was also impaired. None of the species showed any significant decrease in the efficiency of light-limited photosynthesis following fumigation at 200 nmol mol(-1) O3, but effects were apparent at 400 nmol mol(-1) O3. The common feature in all three species was a decline in carboxylation capacity which preceded any other change in the photosynthetic apparatus.

Differential response of CO2 uptake parameters of soil- and sand-grown phaseolus vulgaris (L.) plants to absorbed ozone flux

Shoots of a soil- or sand-grown dwarf bean variety were exposed to O(3) concentrations in the range of 500 to 900 ppb for up to 5 h. The measured exchange rates of water vapor and CO(2) during exposures were used to calculate stomatal and mesophyll conductances averaged across all leaves. Changes in conductances were related to exposure duration and absorbed O(3) totals (AOT). Both conductances were more sensitive to AOT in sand-grown plants, which also had more visible injury under comparable AOT values. Measurements of the relationship between CO(2) exchange and internal CO(2) concentration of single leaflets of treated plants also showed greater sensitivity of CO(2)-saturated photosynthesis in sand-grown plants. Diffusional processes were not likely to have been the cause of dissimilar responses because the O(3) absorption rate was lower in sand-grown plants. A difference in the scaveninng capacities in cells is suggested to be the cause of the differences in sensitivity to acute O(3) exposure.