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1.
Leaves of fast‐growing, woody bioenergy crops often emit volatile organic compounds (VOC). Some reactive VOC (especially isoprene) play a key role in climate forcing and may negatively affect local air quality. We monitored the seasonal exchange of VOC using the eddy covariance technique in a ‘coppiced’ poplar plantation. The complex interactions of VOC fluxes with climatic and physiological variables were also explored by using an artificial neural network (Self Organizing Map). Isoprene and methanol were the most abundant VOC emitted by the plantation. Rapid development of the canopy (and thus of the leaf area index, LAI) was associated with high methanol emissions and high rates of gross primary production (GPP) since the beginning of the growing season, while the onset of isoprene emission was delayed. The highest emissions of isoprene, and of isoprene photo‐oxidation products (Methyl Vinyl Ketone and Methacrolein, iox), occurred on the hottest and sunniest days, when GPP and evapotranspiration were highest, and formaldehyde was significantly deposited. Canopy senescence enhanced the exchange of oxygenated VOC. The accuracy of methanol and isoprene emission simulations with the Model of Emissions of Gases and Aerosols from Nature increased by applying a function to modify their basal emission factors, accounting for seasonality of GPP or LAI.  相似文献   

2.
Volatile organic compounds (VOCs) have a direct bearing on the levels of ozone and other reactive chemicals in the atmosphere and play an important role in determining air quality Anthropogenic emission of VOCs has greatly increased due to growing consumption of fossil fuels and related activities. This article presents an emissions inventory for VOCs emitted from anthropogenic soutres in India. VOC emissions factors for important source categories and activities are assembled from the literature and an effort is made to use Indian emission factors as far as possible. Important sources of VOCs include livestock, combustion of firewood and fossil fuels, rice paddy fields, manufacturing. petroleum (production and refining), natural gas (production and distribution), vehicular exhaust, and coal mining. The annual anthropogenic VOC emissions for India have been estimated to be 21 million metric tons (mt). A comparison of VOC emissions inventories for a group of countries varying in their industrial and economic development, in terms of income (gross domestic product, or GDP), population, and land area, reflects the differences among the countries. This VOC emissions inventory provides baseline information for comparisons over time and across countries. In addition, it may serve as an important tool for formulating national VOC control policies.  相似文献   

3.
Plant roots interact with a wide variety of rhizospheric microorganisms, including bacteria and the symbiontic arbuscular mycorrhizal (AM) fungi. The mycorrhizal symbiosis represents a series of complex feedbacks between plant and fungus regulated by their physiology and nutrition. Despite the widespread distribution and ecological significance of AM symbiosis, little is known about the potential of AM fungi to affect plant VOC metabolism. The purpose of this study was to investigate whether colonization of plant roots by AM fungi and associated soil microorganisms affects VOC emission and content of Artemisia annua L. plants (Asteraceae). Two inoculum types were evaluated: one consisted of only an arbuscular mycorrhizal (AM) fungus species (Glomus spp.), and the other was a mixture of different Glomus species and associated soil bacteria. Inoculated plants were compared with non-inoculated plants and with plants supplemented with extra phosphorus (P) to obtain plants of the same size as mycorrhizal plants, thus excluding potentially-confounding mycorrhizal effects on shoot growth. VOC emissions of Artemisia annua plants were analyzed by leaf cuvette sampling followed by off-line measurements with pre-concentration and gas chromatography mass spectrometry (GC-MS). Measurements of CO(2) and H(2)O exchanges were conducted simultaneously. Several volatile monoterpenes were identified and characterized from leaf emissions of Artemisia annua L. by GC-MS analysis. The main components identified belong to different monoterpene structures: alpha-pinene, beta-pinene, camphor, 1,8-cineole, limonene, and artemisia ketone. A good correlation between monoterpene leaf concentration and leaf emission was found. Leaf extracts included also several sesquiterpenes. Total terpene content and emission was not affected by AM inoculation with or without bacteria, while emission of limonene and artemisia ketone was stimulated by this treatment. No differences were found among treatments for single monoterpene content, while accumulation of specific sesquiterpenes in leaves was altered in mycorrhizal plants compared to control plants. Growth conditions seemed to have mainly contributed to the outcome of the symbiosis and influenced the magnitude of the plant response. These results highlight the importance of considering the below-ground interaction between plant and soil for estimating VOC emission rates and their ecological role at multitrophic levels.  相似文献   

4.
Plants are known to emit volatile organic compounds (VOC) in response to various biotic or abiotic stresses. Although the VOC emission in the case of insect attacks is well described, there is only little known about the impact of pathogens on plant emission. In the present study, we used a willow-leaf rust system to describe the effects of a biotrophic fungal infection on the VOC emission pattern of willow leaves. We detected that isoprene emissions from rust-infected leaves decreased threefold compared to control. The total monoterpene emissions did not change although a stress-signalling compound (Z)-β-ocimene showed an increase in infected plants on several days. The infection also increased the emission of sesquiterpenes and lipoxygenase products (LOX) by factors of 175-fold and 10-fold, respectively. The volatile emission signals showed two clear peaks during the experiment. At 6, 7 and 12 days post-infection (dpi), the relative volatile emission signal increased to about sixfold compared to uninfected plants. These time points are directly connected to rust infection since at 6 dpi the first rust pustules appeared on the leaves and at 12 dpi necrosis had developed around several pustules. We present correlations between LOX and sesquiterpene emission signals, which suggest at least two different steps in eliciting the volatile emission.  相似文献   

5.
Plant volatile analysis may be the oldest form of what now is called plant "metabolomic" analysis. A wide array of volatile organic compounds (VOCs), such as alkanes, alcohols, isoprenoids, and esters, can be collected simultaneously from the plant headspace, either within the laboratory or in the field. Increasingly faster and more sensitive analysis techniques allow detection of an ever-growing number of compounds in decreasing concentrations. However, the myriads of data becoming available from such experiments do not automatically increase our ecological and evolutionary understanding of the roles these VOCs play in plant-insect interactions. Herbivores and parasitoids responding to changes in VOC emissions are able to perceive minute changes within a complex VOC background. Plants modified in genes involved in VOC synthesis may be valuable for the evaluation of changes in plant-animal interactions compared to tests with synthetic compounds, as they allow changes to be made within the context of a more complex profile. We argue that bioinformatics is an essential tool to integrate statistical analysis of plant VOC profiles with insect behavioural data. The implementation of statistical techniques such as multivariate analysis (MVA) and meta-analysis is of the utmost importance to interpreting changes in plant VOC mixtures. MVA focuses on differences in volatile patterns rather than in single compounds. Therefore, it more closely resembles the information processing in insects that base their behavioural decisions on differences in VOC profiles between plants. Meta-analysis of different datasets will reveal general patterns pertaining to the ecological role of VOC in plant-insect interactions. Successful implementation of bioinformatics in VOC research also includes the development of MVA that integrate time-resolved chemical and behavioural analyses, as well as databases that link plant VOCs to their effects on insects.  相似文献   

6.
Volatile organic compounds (VOCs) released by plants serve as information and defense chemicals in mutualistic and antagonistic interactions and mitigate effects of abiotic stress. Passive and dynamic sampling techniques combined with gas chromatography–mass spectrometry analysis have become routine tools to measure emissions of VOCs and determine their various functions. More recently, knowledge of the roles of plant VOCs in the aboveground environment has led to the exploration of similar functions in the soil and rhizosphere. Moreover, VOC patterns have been recognized as sensitive and time-dependent markers of biotic and abiotic stress. This focused review addresses these developments by presenting recent progress in VOC sampling and analysis. We show advances in the use of small, inexpensive sampling devices and describe methods to monitor plant VOC emissions in the belowground environment. We further address latest trends in real-time measurements of volatilomes in plant phenotyping and most recent developments of small portable devices and VOC sensors for non-invasive VOC fingerprinting of plant disease. These technologies allow for innovative approaches to study plant VOC biology and application in agriculture.  相似文献   

7.
Changes in emission of volatile organic compounds (VOCs) from tomato induced by the fungus Botrytis cinerea were studied in plants inoculated by spraying with suspensions containing B. cinerea spores. VOC emissions were analysed using on-line gas chromatography–mass spectrometry, with a time resolution of about 1 h, for up to 2 days after spraying. Four phases were delimited according to the starting point and the applied day/night rhythm of the experiments. These phases were used to demonstrate changes in VOC flux caused by B. cinerea infestation. Tomato plants inoculated with B. cinerea emitted a different number and amount of VOCs after inoculation compared to control plants that had been sprayed with a suspension without B. cinerea spores. The changes in emissions were dependent on time after inoculation as well as on the severity of infection. The predominant VOCs emitted after inoculation were volatile products from the lipoxygenase pathway (LOX products). The increased emission of LOX products proved to be a strong indicator of a stress response, indicating that VOC emissions can be used to detect plant stress at an early stage. Besides emission of LOX products, there were also increases in monoterpene emissions. However, neither increased emission of LOX products nor of monoterpenes is specific for B. cinerea attack. The emission of LOX products is also induced by other stresses, and increased emission of monoterpenes seems to be the result of mechanical damage induced by secondary stress impacts on leaves.  相似文献   

8.
鲍歆歆  周伟奇  郑重  徐林莉 《生态学报》2023,43(5):1749-1762
近地面臭氧(O3)已成为继PM2.5后影响我国空气质量的一种重要二次污染物。随着氮氧化物浓度的持续下降和气候变暖的加剧,城市O3的形成对挥发性有机化合物的浓度更加敏感。近年来城市绿色空间显著增长,植物源挥发性有机化合物(BVOCs)排放和浓度逐年增加。针对BVOCs与近地面O3之间复杂的交互作用,从植物BVOCs的特性与作用出发,综述了不同因素尤其是O3浓度增加对树木生理状态及BVOCs排放速率的影响,定量分析了已有研究中O3对不同植物异戊二烯和单萜烯排放速率的影响,以及BVOCs对O3形成的贡献,总结了BVOCs与O3相互作用研究领域存在的不足。未来亟需加强的研究包括:(1)城市树种BVOCs排放因子的实测,建立物种的排放速率数据库,优化模型参数,提升精细尺度BVOCs排放量估算模型精度;(2)多种环境因子,比如污染物浓度、温湿度等对城市植物BVOCs排放的交互作用和综合影响的研究;(3)植物BVOCs对O  相似文献   

9.
10.
Nonmethane volatile organic compounds (VOCs) are reactive, low molecular weight gases that can have significant effects on soil and atmospheric processes. Research into biogenic VOC sources has primarily focused on plant emissions, with few studies on VOC emissions from decomposing plant litter, another potentially important source. Likewise, although there have been numerous studies examining how anthropogenic increases in nitrogen (N) availability can influence litter decomposition rates, we do not know how VOC emissions may be affected. In this study, we measured the relative contribution of VOCs to the total carbon (C) emitted from decomposing litter and how N amendments affected VOC emissions. We incubated decomposing litter from 12 plant species over 125 days, measuring both CO2 and VOC emissions throughout the incubation. We found that VOCs represented a large portion of C emissions from a number of the litter types with C emissions as VOCs ranging from 0% to 88% of C emissions as CO2. Methanol was the dominant VOC emitted, accounting for 28–99% of total VOC emissions over the incubation period. N additions increased CO2 production in 7 of the 12 litter types by 5–180%. In contrast, N additions decreased VOC emissions in 8 of the 12 litter types, reducing net VOC emissions to near zero. The decrease in VOC emissions was occasionally large enough to account for the increased CO2 emissions on a per unit C basis, suggesting that N additions may not necessarily accelerate C loss from decomposing litter but rather just switch the form of C emitted. Together these results suggest that, for certain litter types, failure to account for VOC emissions may lead to an underestimation of C losses from litter decomposition and an overestimation of the effects of N additions on rates of litter decomposition.  相似文献   

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