Stress interactions and mycorrhizal plant response: understanding carbon allocation priorities

In this paper, a framework is presented for studying responses of mycorrhiza to external stresses, including possible feedback effects which are likely to occur. The authors review recent literature linking carbon allocation and host/fungal response under natural and anthropogenic stress, and present a conceptual model to discuss how carbon may be involved in singular and multiple stress interactions of mycorrhizal seedlings. Due to an integral integral role in metabollic processes, characterizing carbon allocation in controlled laboratory environments could be useful for understanding host/fungal responses to a variety of natural and anthropogenic stresses. Carbon allocation at the whole-plant level reflects an integrated response which links photosynthesis to growth and maintenance processes. A root-mycocosm system is described which permits spatial separation of a portion of extramatrical hyphae growing in association with seedling roots. Using this system, it is shown that root/hyphal respiratory release of pulse-labeled 14C follows a sigmoidal pattern, with typical lag, exponential and saturation phases. Total respiratory release of 14C per mg root and the fraction respired of total 14C allocated to the root is greater in ponderosa pine inoculated with Hebeloma crustuliniforme than in noninoculated controls. Results illustrate the nature of information than can be obtained using this system. Current projects using the mycocosms include characterizing the dynamics of carbon allocation under ozone stress, and following the fate of organic pollutants. The authors believe that the system could be used to differentiate fungal- and host-mediated responses to a large number of other stresses and to study a variety of physiological processes in mycorrhizal plants.     

Ozone alters carbon allocation in loblolly pine: assessment with carbon-11 labeling

Loblolly pine (Pinus taeda L.) seedlings were exposed to 0.120 micromol mol(-1) (ppm) ozone for 7 h per day, 5 days per week for 12 weeks. No visible damage resulted from this regime. A short-lived radioisotope of carbon ((11)C) was used to characterize changes in plant physiology caused by ozone, the first time this technique has been used for ozone exposure studies. In comparison to plants kept in charcoal-filtered air, pines exposed to ozone exhibited reductions in photosynthesis (16%), speed of phloem transport (11%), phloem photosynthate concentration (40%) and total carbon transport toward roots (45%). Photosynthate not transported to the roots appeared to accumulate in the stems. Primary branches of pines exposed to ozone were some 50-60% heavier than those of control pines. Ozone was thus shown to have a significant short-term impact on phloem transport processes that results in a shift in allocation of photosynthate favoring stems.     

The effect of ozone on below-ground carbon allocation in wheat

Short-term (14)CO(2) pulse and chase experiments were conducted in order to investigate the effect of ozone on below-ground carbon allocation in spring wheat seedlings (Triticum aestivum L. 'ANZA'). Wheat seedlings were grown in a sand-hydroponic system and exposed to either high ozone (38-40 ppm-h) or low ozone (23-31 ppm-h) for 21 days in a series of replicated experiments. Following the ozone exposures, the plants were pulsed with (14)CO(2) and allocation of (14)C-labeled photosynthate was measured in the plant and growth media. Soluble root exudates were measured, without disturbing the plant roots, 24 h after the (14)CO(2) pulse. Shoot biomass was reduced by 17% for the high ozone and 9% for the low ozone exposures, relative to control treatments. Root biomass was reduced by 9% for the high ozone exposures, but was not significantly different than the controls for the low ozone. The amount of (14)C activity in the shoot and root tissue 24 h after the (14)CO(2) pulse, normalized to tissue weight, total (14)CO(2) uptake, or the total (14)C retention in each plant, was not affected by either high or low ozone exposures. The amount of (14)C activity measured in the growth media solution surrounding the roots increased 9% for the high ozone exposures, and after normalizing to root size or root (14)C activity, the growth media solution (14)C activity increased 29 and 40%, respectively. Total respiration of (14)CO(2) from the ozone-treated plants decreased, but the decrease was not statistically significant. Our results suggest that soluble root exudation of (14)C activity to the surrounding rhizosphere increases in response to ozone. Increased root exudation to the rhizosphere in response to ozone is contrary to reports of decreased carbon allocation below ground and suggests that rhizosphere microbial activity may be initially stimulated by plant exposure to ozone.     

Regional differences in carbon trading prices and their spatially driven mechanisms: evidence from China

Environmental Science and Pollution Research - With ecological civilization becoming an increasingly high profile topic, terms such as carbon neutrality and carbon markets have entered the research...     

Energy and redox status, and carbon allocation in one- to three-year-old spruce needles

Metabolite pools were determined in lyophilized homogenates of one- to three-year-old needles from 13-year-old spruce trees. These were exposed in open-chambers for five consecutive years to SO(2) (30 microg m(-3)) and O(3) (50 to 180 microg m(-3)), singly and in combination. The samples were taken shortly before bud break (mid-March). The energy (ATP/ADP) and redox status (NAD(P)H/NAD(P)) increased with needle age. This increase was most pronounced in needles exposed to both pollutant gases. To evaluate carbohydrate metabolism, levels of starch, sugars (sucrose, fructose, glucose), sugar phosphates (dihydroxyacetone phosphate, glyceraldehyde 3-phosphate (triose phosphates, TP), fructose 6-phosphate, fructose 2,6-bisphosphate: F2,6BP) and 3-phosphoglyceric acid (PGA) were measured. The concentrations of starch, glucose, fructose and TP on a dry weight basis increased with needle age, while those of sucrose and F2,6BP decreased. Interestingly, the total amount of soluble sugars remained constant in needles from control chambers and large fluctuations mainly occurred after a single application of the pollutants. Needles from fumigated trees generally showed somewhat lower starch and sugar, and fructose 6-phosphate levels. The content of TP increased with needle age while that of sucrose and F2,6BP decreased. This inverse behavior was even more prominent in the presence of both pollutants and is discussed in the context of recent knowledge on the regulation of carbon partitioning. There was a significant increase in the ratio of TP/PGA in samples from the combined exposure treatments. This also indicates an increase in the redox charge and corroborates the data on both the redox status of the pyridine nucleotide system and the significantly increased ATP/ADP ratio. The results are indicative of a switch in metabolism, from anabolic to predominantly catabolic reactions, which is most pronounced in the samples fumigated with both O(3) and SO(2). The data are compared to those obtained from naturally exposed trees in the southern Black Forest (K?lbelescheuer/Haldenhof, near Freiburg, Germany).     

Inter-provincial responsibility allocation of carbon emission in China to coordinate regional development

Environmental Science and Pollution Research - To establish the carbon emission trading scheme and achieve the carbon emission reduction goals in China, it is critical to allocate the carbon...     

Atmospheric phenanthrene pollution modulates carbon allocation in red clover (Trifolium pratense L.)

The influence of atmospheric phenanthrene (PHE) exposure (160 μg m⁻³) during one month on carbon allocation in clover was investigated by integrative (plant growth analysis) and instantaneous ¹³CO₂ pulse-labelling approaches. PHE exposure diminished plant growth parameters (relative growth rate and net assimilation rate) and disturbed photosynthesis (carbon assimilation rate and chlorophyll content), leading to a 25% decrease in clover biomass. The root-shoot ratio was significantly enhanced (from 0.32 to 0.44). Photosynthates were identically allocated to leaves while less allocated to stems and roots. PHE exposure had a significant overall effect on the ¹³C partitioning among clover organs as more carbon was retained in leaves at the expense of roots and stems. The findings indicate that PHE decreases root exudation or transfer to symbionts and in leaves, retains carbon in a non-structural form diverting photosynthates away from growth and respiration (emergence of an additional C loss process).     

Polycyclic aromatic hydrocarbon and n-alkane pollution characteristics and structural and functional perturbations to the microbial community: a case-study of historically petroleum-contaminated soil

Characterization of the typical petroleum pollutants, polycyclic aromatic hydrocarbons (PAHs) and n-alkanes, and indigenous microbial community structure and function in historically contaminated soil at petrol stations is critical. Five soil samples were collected from a petrol station in Beijing, China. The concentrations of 16 PAHs and 31 n-alkanes were measured by gas chromatography-mass spectrometry. The total concentrations of PAHs and n-alkanes ranged from 973 ± 55 to 2667 ± 183 μg/kg and 6.40 ± 0.38 to 8.65 ± 0.59 mg/kg (dry weight), respectively, which increased with depth. According to the observed molecular indices, PAHs and n-alkanes originated mostly from petroleum-related sources. The levels of ΣPAHs and the total toxic benzo[a]pyrene equivalent (ranging from 6.41 to 72.54 μg/kg) might exert adverse biological effects. Shotgun metagenomic sequencing was employed to investigate the indigenous microbial community structure and function. The results revealed that Proteobacteria and Actinobacteria were the most abundant phyla, and Nocardioides and Microbacterium were the important genera. Based on COG and KEGG annotations, the highly abundant functional classes were identified, and these functions were involved in allowing microorganisms to adapt to the pressure from contaminants. Five petroleum hydrocarbon degradation-related genes were annotated, revealing the distribution of degrading microorganisms. This work facilitates the understanding of the composition, source, and potential ecological impacts of residual PAHs and n-alkanes in historically contaminated soil.

     

Fine particle formation and transport in the Colstrip,Montana, powerplant plume

Smoke plumes of greater width but lesser thickness than predicted by Gaussian diffusion models have been documented by measurements from aircraft of the Colstrip, Montana, powerplant plume at downwind distances of 4–25 km. The plume has also been shown to be deflected as much as 20° away from the prevailing wind direction by the terrain. A particle formation rate of ~ 10¹⁶ s⁻¹ in the plume over down-wind distances of 25–30 km has been estimated by using the plume profile measurements.     

Exploring development and evolutionary trends in carbon offset research: a bibliometric perspective

Environmental Science and Pollution Research - This study proposes a bibliometric measure to visualize and analyze the research status and development trend of carbon offset based on 1,581 articles...     

Below-ground carbon allocation in mature beech and spruce trees following long-term, experimentally enhanced O3 exposure in Southern Germany

Canopies of adult European beech (Fagus sylvatica) and Norway spruce (Picea abies) were labeled with CO₂ depleted in ¹³C to evaluate carbon allocation belowground. One-half the trees were exposed to elevated O₃ for 6 yrs prior to and during the experiment. Soil-gas sampling wells were placed at 8 and 15 cm and soil CO₂ was sampled during labeling in mid-late August, 2006. In beech, δ¹³CO₂ at both depths decreased approximately 50 h after labeling, reflecting rapid translocation of fixed C to roots and release through respiration. In spruce, label was detected in fine-root tissue, but there was no evidence of label in δ¹³CO₂. The results show that C fixed in the canopy rapidly reaches respiratory pools in beech roots, and suggest that spruce may allocate very little of recently-fixed carbon into root respiration during late summer. A change in carbon allocation belowground due to long-term O₃ exposure was not observed.     

广州典型灰霾期有机碳和元素碳的污染特征

使用小流量Partisol model 2000采样器每2 h采集广州典型灰霾期(2006年1月7～20日)PMlo样品,并用美国Sunset Laboratory Inc.的碳分析仪分析了有机碳和元素碳.结果显示,灰霾期PM10、有机碳和元素碳污染严重,最高浓度日均值(1月13日)分别为最低浓度日均值(1月20日)的10.1、7.6、3.0倍;大气污染存在一个明显的逐日上升和下降过程,上升期间PM10、有机碳和元素碳的日均增长率分别为(127±24)%、(125±16)%和(116±17)%.下降期间日均增长率分别为(-143±25)%、(-135±13)%和(-118±11)%.计算表明,二次有机碳污染严重,并随着灰霾污染的持续,占总有机碳比例增加.气团轨迹分析说明,珠江三角洲其他地区的污染对广州地区灰霾污染过程存在影响.     

Resource allocation in transboundary tuna fisheries: A global analysis

Resource allocation is a fundamental and challenging component of common pool resource governance, particularly transboundary fisheries. We highlight the growing importance of allocation in fisheries governance, comparing approaches of the five tuna Regional Fisheries Management Organizations (tRFMOs). We find all tRFMOs except one have defined resources for allocation and outlined principles to guide allocation based on equity, citizenship, and legitimacy. However, all fall short of applying these principles in assigning fish resources. Most tRFMOs rely on historical catch or effort, while equity principles rarely determine dedicated rights. Further, the current system of annual negotiations reduces certainty, trust, and transparency, counteracting many benefits asserted by rights-based management proponents. We suggest one means of gaining traction may be to shift conversations from allocative rights toward weighting of principles already identified by most tRFMOs. Incorporating principles into resource allocation remains a major opportunity, with important implications for current and future access to fish.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01371-3) contains supplementary material, which is available to authorized users.     

The effect of a woodstove changeout on ambient levels of PM2.5 and chemical tracers for woodsmoke in Libby,Montana

Residential woodstoves are the single largest source of PM_2.5 in Libby, MT, resulting in the community being designated as a nonattainment area for PM_2.5. Beginning in 2005, a community-wide woodstove changeout program was implemented that replaced nearly 1200 old stoves with EPA-certified units. In an effort to track the reduction of woodsmoke particles throughout the program, ambient PM_2.5 samples were collected before, during, and after the changeout. These samples were analyzed for seven selected woodsmoke tracers, including vanillin, acetovanillone, guaiacol, 4-ethylguaiacol (methoxyphenols), levoglucosan (sugar anhydride), abietic acid, and dehydroabietic acid (resin acids). Results of the changeout showed that PM_2.5 levels decreased by 20% during the changeout period, while levels of the seven chosen tracer compounds gave variable responses. Levoglucosan levels decreased by 50% while both resin acids increased after the changeout, suggesting a change in the chemistry of the particles. No trend was observed in the levels of methoxyphenols as a group over the changeout period. The results suggest that the concentrations of woodsmoke related PM_2.5 in the Libby airshed have decreased; however, the chemistry of the emitted particles also changed when old woodstoves were replaced with new EPA-certified stoves.     

Introducing integrated product and process development into the education of science and engineering undergraduates: a lecture course with an accompanying case-study programme at the ETH chemistry department

Increased quality requirements in the development of chemical products and a growing awareness within society of the activities of chemical companies present a new challenge to the education of young scientists. Nowadays, the teaching of chemists, chemical engineers and environmental scientists at universities has to go beyond the traditional, discipline-orientated knowledge acquisition. The students also have to learn to work and communicate in interdisciplinary teams, to solve application-oriented tasks and to integrate scientific, economical, ecological and social aspects into their work. For this reason, a case-study programme was launched at the chemistry department of the Swiss Federal Institute of Technology. In this paper, we describe the organisational aspects of the programme, its inclusion into academic and industrial environments and summarise some of the scientific methodologies applied. One of the seven case-studies, an assessment of a modern insecticide, is presented in more detail. Finally, we discuss how far the case-study programme is suitable for introducing a new mode of knowledge production to universities.     

Dissolved organic carbon in rainwater: Glassware decontamination and sample preservation and volatile organic carbon

The efficiency of different methods for the decontamination of glassware used for the analysis of dissolved organic carbon (DOC) was tested using reported procedures as well as new ones proposed in this work. A Fenton solution bath (1.0 mmol L⁻¹ Fe²⁺ and 100 mmol L⁻¹ H₂O₂) for 1 h or for 30 min employing UV irradiation showed to combine simplicity, low cost and high efficiency. Using the optimized cleaning procedure, the DOC for stored UV-irradiated ultra-pure water reached concentrations below the limit of detection (0.19 μmol C L⁻¹). Filtered (0.7 μm) rain samples maintained the DOC integrity for at least 7 days when stored at 4 °C. The volatile organic carbon (VOC) fraction in the rain samples collected at two sites in São Paulo state (Brazil) ranged from 0% to 56% of their total DOC content. Although these high-VOC concentrations may be derived from the large use of ethanol fuel in Brazil, our results showed that when using the high-temperature catalytic oxidation technique, it is essential to measure DOC rather than non-purgeble organic carbon to estimate organic carbon, since rainwater composition can be quite variable, both geographically and temporally.     

多孔碳材料对二噁英吸附性能的研究评述及展望

活性炭吸附已成为垃圾焚烧企业脱除烟气中二噁英类有机污染物最常用的方法。介绍了活性炭在垃圾焚烧企业的应用现状及存在的问题,系统分析了活性炭对二噁英的吸附特点,总结了烟气温度、活性炭喷入量、二噁英同系物分布、活性炭的孔结构等对二噁英脱除效率的影响。此外,概述了活性碳纤维、碳纳米管在二噁英吸附方面的研究动态。分析了碳纳米管在吸附二噁英过程中不同于活性炭的吸附机制,探讨了其未来替代活性炭作为二噁英吸附材料的可能性。     

Global trends and prospects of blue carbon sinks: a bibliometric analysis

Environmental Science and Pollution Research - Blue carbon sinks (mangroves, saltmarshes, and seagrasses) are considered an effective nature-based approach for climate change mitigation. Despite...     

含碳气溶胶研究进展：有机碳和元素碳

含碳气溶胶是我国大气区域性复合型污染的重要物种,对全球气候变化、辐射强迫、能见度、环境质量、人类健康等会产生重要影响.主要从含碳气溶胶来源及成因、环境影响、样品采集及测试等方面对国内外相关研究进行了评述,讨论了有机碳和元素碳研究中存在的关键和难点问题,并对其发展前景进行了展望.