Is Ozone Flux Inside Leaves Only a Damage Indicator? Clues from Volatile Isoprenoid Studies

Loreto, Francesco; Fares, Silvano

doi:10.1104/pp.106.091892

Cited by 93 publications

(62 citation statements)

References 26 publications

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“…For high ambient ozone concentrations c i,O 3 was found to be positive (Moldau and Bichele, 2002;Loreto and Fares, 2007), but typically it is assumed to be close to zero (Laisk et al, 1989). Therefore, Eq.…”

Section: Fluid Dynamic Model Calculationsmentioning

confidence: 99%

Plant surface reactions: an opportunistic ozone defence mechanism impacting atmospheric chemistry

et al. 2016

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Abstract. Elevated tropospheric ozone concentrations are considered a toxic threat to plants, responsible for global crop losses with associated economic costs of several billion dollars per year. Plant injuries have been linked to the uptake of ozone through stomatal pores and oxidative damage of the internal leaf tissue. But a striking question remains: can surface reactions limit the stomatal uptake of ozone and therefore reduce its detrimental effects to plants?In this laboratory study we could show that semi-volatile organic compounds exuded by the glandular trichomes of different Nicotiana tabacum varieties are an efficient ozone sink at the plant surface. In our experiments, different diterpenoid compounds were responsible for a strongly varietydependent ozone uptake of plants under dark conditions, when stomatal pores are almost closed. Surface reactions of ozone were accompanied by a prompt release of oxygenated volatile organic compounds, which could be linked to the corresponding precursor compounds: ozonolysis of cis-abienol (C 20 H 34 O) -a diterpenoid with two exocyclic double bonds -caused emissions of formaldehyde (HCHO) and methyl vinyl ketone (C 4 H 6 O). The ring-structured cembratrien-diols (C 20 H 34 O 2 ) with three endocyclic double bonds need at least two ozonolysis steps to form volatile carbonyls such as 4-oxopentanal (C 5 H 8 O 2 ), which we could observe in the gas phase, too.Fluid dynamic calculations were used to model ozone distribution in the diffusion-limited leaf boundary layer under daylight conditions. In the case of an ozone-reactive leaf surface, ozone gradients in the vicinity of stomatal pores are changed in such a way that the ozone flux through the open stomata is strongly reduced.Our results show that unsaturated semi-volatile compounds at the plant surface should be considered as a source of oxygenated volatile organic compounds, impacting gas phase chemistry, as well as efficient ozone sink improving the ozone tolerance of plants.

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Section: Fluid Dynamic Model Calculationsmentioning

confidence: 99%

Plant surface reactions: an opportunistic ozone defence mechanism impacting atmospheric chemistry

et al. 2016

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“…In addition, O 3 is a pollutant and toxic for human beings, animals and plants; O 3 causes not only a direct inhibition of crop and forestry yields (Ashmore, 2005), but may also exert a significant indirect radiative forcing effect following a phytotoxically reduced terrestrial carbon sink (Sitch et al, 2007). A number of studies have investigated the possible protective role against oxidative stress that BVOC may have (Loreto and Velikova, 2001;Velikova et al, 2005;Loreto and Fares, 2007), which so far has not been taken into account in global O 3 -carbon cycle-feedback calculations. Atmospheric reactions of isoprene and monoterpenes can have an important influence on the tropospheric concentration of OH, thereby influencing the atmospheric lifetime of methane.…”

Section: Sourcementioning

confidence: 99%

Why are estimates of global terrestrial isoprene emissions so similar (and why is this not so for monoterpenes)?

et al. 2008

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Abstract. Emissions of biogenic volatile organic compounds (BVOC) are a chief uncertainty in calculating the burdens of important atmospheric compounds like tropospheric ozone or secondary organic aerosol, reflecting either imperfect chemical oxidation mechanisms or unreliable emission estimates, or both. To provide a starting point for a more systematic discussion we review here global isoprene and monoterpene emission estimates to-date. We note a surprisingly small variation in the predictions of global isoprene emission rate that is in stark contrast with our lack of process understanding and the small number of observations for model parameterisation and evaluation. Most of the models are based on similar emission algorithms, using fixed values for the emission capacity of various plant functional types. In some cases, these values are very similar but differ substantially in other models. The similarities with regard to the global isoprene emission rate would suggest that the dominant parameters driving the ultimate global estimate, and thus the dominant determinant of model sensitivity, are the specific emission algorithm and isoprene emission capacity. But the models also differ broadly with regard to their representation of net primary productivity, method of biome coverage determination and climate data. Contrary to isoprene, monoterpene estimates show significantly larger model-tomodel variation although variation in terms of leaf algorithm, emission capacities, the way of model upscaling, vegetation cover or climatology used in terpene models are comparable to those used for isoprene. From our summary of published studies there appears to be no evidence that the terrestrial modelling community has been any more successful in Correspondence to: A. Arneth (almut.arneth@nateko.lu.se) "resolving unknowns" in the mechanisms that control global isoprene emissions, compared to global monoterpene emissions. Rather, the proliferation of common parameterization schemes within a large variety of model platforms lends the illusion of convergence towards a common estimate of global isoprene emissions. This convergence might be used to provide optimism that the community has reached the "relief phase", the phase when sufficient process understanding and data for evaluation allows models' projections to converge, when applying a recently proposed concept. We argue that there is no basis for this apparent relief phase. Rather, we urge modellers to be bolder in their analysis, and to draw attention to the fact that terrestrial emissions, particularly in the area of biome-specific emission capacities, are unknown rather than uncertain.

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“…Current evidence suggests that several global change drivers such as ozone concentration can also affect both constitutive and herbivoreinduced BVOCs production (Loreto et al, 2007;Vuorinen et al, 2005;Blande et al, 2007). Ozone causes biochemical and physiological changes leading to the inhibition of photosynthesis and a consequent decrease in plant growth (Guderian et al, 1985), often associated with visible injuries (Loreto et al, 2001;Vollenweider and Gunthardt-Georg, 2005).…”

Section: E Bourtsoukidis Et Al: Ozone Stress As a Driving Force Of mentioning

confidence: 99%

Ozone stress as a driving force of sesquiterpene emissions: a suggested parameterisation

et al. 2012

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Abstract. Sesquiterpenes (C 15 H 24 ) are semi-volatile organic compounds emitted by vegetation and are of interest in atmospheric research because they influence the oxidative capacity of the atmosphere and contribute to the formation of secondary organic aerosols. However, little is known about their emission pattern and no established parameterisation is available for global emission models. The aim of this study is to investigate a Central European spruce forest and its emission response to meteorological and environmental parameters, looking for a parameterisation that incorporates heat and oxidative stress as the main driving forces of the induced emissions. Therefore, a healthy ca. 80 yr old Norway spruce (Picea abies) tree was selected and a dynamical vegetation enclosure technique was applied from April to November 2011. The emissions clearly responded to temperature changes with small variations in the β-factor along the year (β spring = 0.09 ± 0.01, β summer = 0.12± 0.02, β autumn = 0.11 ± 0.02). However, daily calculated values revealed a vast amount of variability in temperature dependencies ((0.02 ± 0.002) < β < (0.27 ± 0.04)) with no distinct seasonality.By separating the complete dataset in 10 different ozone regimes, we found that in moderately or less polluted atmospheric conditions the main driving force of sesquiterpene emissions is the temperature, but when ambient ozone mixing ratios exceed a critical threshold of (36.6 ± 3.9) ppb v , the emissions become primarily correlated with ozone. Considering the complete dataset, cross correlation analysis resulted in highest correlation with ambient ozone mixing ratios (CC O 3 = 0.63 ± 0.01; CC T = 0.47 ± 0.02 at t = 0 h for temperature) with a time shift 2-4 h prior to the emissions. An only temperature dependent algorithm was found to substantially underestimate the induced emissions (20 % of the measured; R 2 = 0.31). However, the addition of an ozone dependent term improved substantially the fitting between measured and modelled emissions (81 % of the modelled emissions could be explained by the measurements; R 2 = 0.63), providing confidence about the reliability of the suggested parameterisation for the spruce forest site investigated.

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Is Ozone Flux Inside Leaves Only a Damage Indicator? Clues from Volatile Isoprenoid Studies

Cited by 93 publications

References 26 publications

Plant surface reactions: an opportunistic ozone defence mechanism impacting atmospheric chemistry

Plant surface reactions: an opportunistic ozone defence mechanism impacting atmospheric chemistry

Why are estimates of global terrestrial isoprene emissions so similar (and why is this not so for monoterpenes)?

Ozone stress as a driving force of sesquiterpene emissions: a suggested parameterisation

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