ArticleLiterature Review

Effects of acid rain on plant growth: A meta-analysis

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Abstract

Anthropogenic driven acid gases emission has caused acid rain in many regions globally. Although efforts have been made to assess the effects of acid rain on terrestrial ecosystems, a systematic assessment of growth-related traits across plant aboveground and belowground is lacking. Hence, we performed a phylogenetically controlled meta-analysis of 755 observations from 69 independent studies to quantify the effects of acid rain on six growth-related traits of plant. We estimated the inhibitory effects of acid rain on plant growth in general and found that aboveground and belowground plant parts responded differently. The acidity of acid rain and acid rain interval had direct modulation effects on plant growth. We also found that there were interactions between acid rain pH and other acid rain characteristics (i.e., acid rain interval, mole ratio of S:N, and acid rain rate) and experimental characteristics (i.e., initial soil pH and plant exposure part), indicating that there were pH-dependent interaction patterns. Thus, an effective approach to evaluate and predict the effects of acid rain on plant growth is to fully consider the direct effects of acid rain pH and the interactions between acid rain pH and other factors.

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... It is reported that the wet acid deposition in South China can reach up to 34 kg N ha −1 yr −1 and 33 kg S ha −1 yr −1 (Lu et al. 2014), and the soil pH of some subtropical forests is even lower than 4.2 (Jiang et al. 2018;Lu et al. 2015). The high rate of acid deposition and subsequent soil acidification may significantly affect plant growth dynamics and soil microbial activities Riggs and Hobbie 2016;Shi et al. 2021), ultimately altering ecosystem carbon (C)-cycling processes (Oulehle et al. 2018;Thomas et al. 2013;Yu et al. 2020). ...
... The high accumulation of SO 4 2− in soil may slow down the replenishment of base cations (Driscoll et al. 2001), and thus hinder the nutrient uptake by plants. In contrast, acid deposition in China is a mixed type of S and N depositions (Zhu et al. 2011), the latter usually has a fertilization effect on plant growth Liu et al. 2018a;Shi et al. 2021). Consequently, acid deposition-induced changes in ecosystem C-cycling processes across China's major ecosystems requires to be comprehensively assessed and quantified. ...
... Therefore, the inhibiting effect of acid addition on plant growth may be markedly weak and a fertilizing effect (especially for NO 3 − ) is accompanied by acid addition, which was supported by our result that plant C pools increased under the low-acid addition (Fig. 2). Likewise, the fertilizing effect of low-level acid input on plant growth was found in previous studies in situ or pot experiments Liu et al. 2018a;Shi et al. 2021). Nevertheless, plant C pools would decrease significantly once the acidity of soil solution increases (Figs. 2 and S7). ...
Article
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Background and aims China has experienced a high rate of anthropogenic acid deposition for more than four decades, which can greatly affect ecosystem carbon (C)-cycling processes. However, a comprehensive assessment of how acid deposition alters C input and output and its potential impacts on soil C sequestration across a wide range of terrestrial ecosystems remains lacking. Methods We synthesized 1660 observations from 77 simulated acid deposition experiments in China to quantify the acid-addition effects on ten C-cycling variables. Results We found that acid addition significantly decreased both above-and below-ground biomass (-7.2% and -8.3%, respectively), dissolved organic C (-7.6%), microbial biomass C (-10.2%), and soil respiration (-9.4%) (-7.0% for autotrophic respiration and -5.8% for heterotrophic respiration), but significantly increased soil organic C (2.5%). The significant negative effects of acid addition on both plant biomass and auto-/ hetero-trophic respiration were found in subtropical forests, and the significant positive effect of acid addition on soil organic C was found in all ecosystems except for the temperate forests. The response of plant biomass to acid addition was strongly affected by acid addition strength, and the responses of heterotrophic respiration and soil organic C were significantly correlated with experimental duration or initial soil pH. Conclusion Our results provide direct evidence that anthropogenic acid deposition promotes soil C sequestration mainly through decreasing C output (i.e., heterotrophic respiration), and should be incorporated into C-cycling models for estimating soil C sequestration potential under future environmental changes.
... Acid rain has become one of the most serious environmental problems worldwide because of decades of industrial development as well as increases in energy demands and emissions of certain gases, including sulfur dioxide (SO2) and nitrogen oxides (NOX) (Shi et al., 2021). In terms of the total area affected by acid rain, China ranks third behind Europe and North America (Tomlinson et al., 2003). ...
... Many studies on SAR that mainly focused on its effects on soil microorganisms in the plant rhizosphere revealed that SAR primarily affects soil respiration and soil physicochemical properties (Lv et al., 2013;Berger et al., 2015;Zheng et al., 2022;Zhang et al., 2023). For evergreen trees in the subtropical region, only low pH acidic conditions have a significant effect, while high pH would not (Shi et al., 2021). Studies have been conducted on the effects of SAR on plant leaves (Francisco et al., 2005; and nutrient elements (Diatta et al., 2020). ...
... In terms of plant physiology, subtropical evergreen broad-leaved trees are more tolerant to acidic conditions than coniferous trees (Malla et al.,2023). This is in accordance with the results of an earlier study involving an examination of spectral reflectance, which indicated coniferous tree species are more sensitive to SAR than broad-leaved tree species (Shi et al.,2021). There are few reports describing the changes in the growth characteristics and photosynthetic performance of PM and CL in response to SAR. ...
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The effects of simulated acid rain (SAR) on the photosynthetic performance of subtropical coniferous species have not been thoroughly investigated. In this study, we treated two coniferous species, Pinus massoniana (PM) and Cunninghamia lanceolata (CL), with SAR and then analyzed photosynthetic activities via the simultaneous measurement of prompt fluorescence(PF), delayed fluorescence(DF), and modulated reflection at 820 nm(MR820). Following the low-pH SAR treatment, the I–P phase of the OJIP curves of PM and CL decreased significantly and then the K-band and L-band were detectable. The delayed fluorescence for both PM and CL decreased as the pH of the SAR solution decreased, with a more significant decrease in the I1 peak than in the I2 peak. According to the MR820 curve, the exposure to SAR stress inhibited the rapid decrease and slow increase in the MR820 transients of PM and CL. The gradients of the decreasing and increasing phases were lower for CL than for PM at pH 2.5. In addition, SAR decreased the light energy captured per unit area (ABS/CSm) and the quantum yield of electron transfer per unit area (ETO/CSm), but it increased the accumulation of QA−, thereby decreasing primary photochemical efficiency (TRO/CSm, φPO). These changes in photosystem II (PSII) resulted in a decrease in the maximum quantum yield of PSII (Fv/Fm) and the performance index (PIABS). Moreover, PSII was protected from thylakoid membrane photodamages through the increase in heat dissipation per unit area (DIO/CSm) in response to SAR. The increase in δRO as the pH of the SAR solution decreased was observed for PM, but not for CL. Considered together, the study findings suggest that SAR treatments can decrease chlorophyll contents and damage the OEC in PM and CL, which obstructs the transfer of electrons on the donor and acceptor sides of PSII. However, PM is better able to withstand SAR stress than CL, likely because of the activation of a protective mechanism (reflected by the change in δRO). Therefore, in coniferous forest areas severely affected by acid rain, CL may need to be protected more than PM.
... The effects of acid rain on terrestrial ecosystems have been intensively studied in the past few years (Liu et al. 2019b). Researchers have found that acid rain can cause significant changes in chlorophyll content , photosynthetic rate , plant growth (Shi et al. 2021), soil chemical properties, and biological activities (Meng et al. 2019;Liu et al. 2022). ...
... The unit of H + addition rate and total H + added is kmol ha −1 year −1 and mol m −2 , respectively Fisher's C test (0.05 < p ≤ 1.00) was used to confirm the goodness of the modelling results (rhizosphere: Fisher's C = 0 with p = 1; bulk soil: Fisher's C = 5.267 with p = 0.261) protein to oligopeptides and amino acids (Greenfield et al. 2021). While acid rain has been found to decrease the biomass and biological activity of ecosystems (Liu et al. 2022), several studies have also indicated that the S and N brought by acid rain can act as fertilizers for plants and microbes in certain cases (Wang et al. 2010;Shi et al. 2021). Specifically, when acid rain serves as an N fertilizer, it may decrease the activities of N-cycling related enzymes (Marklein and Houlton 2012;Xiao et al. 2018;Chen et al. 2020a). ...
... We suggest that this may be related to the inhibition of plant growth by acid rain. Plant root biomass was found to decrease with increasing acid rain intensity (Shi et al. 2021). The decrease in root biomass may limit the release of substrates and enzymes (Hosseini et al. 2022). ...
Article
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As a global pollution, acid rain can significantly alter soil physicochemical and biochemical processes, but our knowledge of how acid rain affects soil enzyme activity is still limited. To quantify the overall magnitude and direction of the response of soil enzyme activity to acid rain, we conducted a linear mixed model–based meta-analysis of 40 articles. Our analysis revealed that acid rain decreased enzyme activity by an average of 4.87%. Soil dehydrogenase and protease activities were particularly sensitive to acid rain, with significant inhibitions observed. The effect of acid rain was moderated by acid rain intensity (i.e., H⁺ addition rate, total H⁺ added, and acid rain pH) and soil fraction (i.e., rhizosphere and bulk soil). Structural equation modelling further revealed that acid rain suppressed soil microbial biomass by acidifying the soil and that the reduction in microbial biomass directly led to the inhibition of enzyme activity in bulk soil. However, the enzyme activity in the rhizosphere soil was not affected by acid rain due to the rhizosphere effect, which was also not impacted by the decreased soil pH induced by acid rain in rhizosphere. Our study gives an insight into how bulk soil enzyme activity is impacted by acid rain and highlights the need to incorporate rhizosphere processes into acid rain-terrestrial ecosystem models.
... Therefore, the response patterns of plants to AR can provide researchers with a scientific theoretical basis for addressing related issues while helping land managers to develop technical countermeasures used in the restoration and reconstruction of degraded ecosystems in areas affected by AR (Fu and Tian, 2006). The performance of plants is directly related to the acidity of AR (Fan and Wang, 2000;Du et al., 2017;Shi et al., 2021). Simulation experiments have demonstrated that the growth and development of above-and below-ground organs (leaf and root, respectively) of plants are suppressed in simulated AR (SAR) treatments (Shi et al., 2021); thus, photosynthesis and growth are reduced (Yao et al., 2016;Du et al., 2017;Pham et al., 2021). ...
... The performance of plants is directly related to the acidity of AR (Fan and Wang, 2000;Du et al., 2017;Shi et al., 2021). Simulation experiments have demonstrated that the growth and development of above-and below-ground organs (leaf and root, respectively) of plants are suppressed in simulated AR (SAR) treatments (Shi et al., 2021); thus, photosynthesis and growth are reduced (Yao et al., 2016;Du et al., 2017;Pham et al., 2021). The direct effects of the acidity of AR and the indirect effects of soil chemical characteristics mediated by AR on plants are well studied (Singh and Agrawal, 2008;Shi et al., 2021). ...
... Simulation experiments have demonstrated that the growth and development of above-and below-ground organs (leaf and root, respectively) of plants are suppressed in simulated AR (SAR) treatments (Shi et al., 2021); thus, photosynthesis and growth are reduced (Yao et al., 2016;Du et al., 2017;Pham et al., 2021). The direct effects of the acidity of AR and the indirect effects of soil chemical characteristics mediated by AR on plants are well studied (Singh and Agrawal, 2008;Shi et al., 2021). ...
Article
Acid rain (AR) causes numerous environmental problems and complex negative effects on plants globally. Many studies have previously reported on direct effects of AR or its depositional substances on plant injury and performance. However, few studies have addressed the indirect effects of AR on plants as mediated by soil microorganisms and the abiotic environment of the soil rhizosphere. The indirect effects (e.g., AR → soil microorganisms→plants) need greater attention, because acidic deposition not only affects the distribution, composition, abundance, function, and activity of plant-associated microorganisms, but also influences the dynamics of some substances in the soil in a way that may be harmful to plants. Therefore, this review not only focused on the direct effects of AR on plant performance, growth, and biomass allocations from a whole-plant perspective, but also addressed the pathway of AR-soil chemical characteristics-plants, which explains how soil solute leaching and acidification by AR will reduce the availability of essential nutrients and increase the availability of heavy metals for plants, affecting carbon and nitrogen cycles. Mainly, we evaluated the AR-soil microorganisms-plants pathway by: 1) synthesizing the potential roles of soil microbes in alleviating soil acidic stress on plants and the adverse effects of AR on plant-associated soil microorganisms; 2) exploring how plant mycorrhizal types affect the detection of AR effect on plants. The meta-analysis showed that the effects of AR-induced pH on leaf chlorophyll content, plant height, and plant root biomass were dependent on plant mycorrhizal types. Some possible reasons for different synergy between mycorrhizal symbiotic types and plants were discussed. Future research relating to the effects of AR on plants should focus on the combined direct and indirect effects to evaluate how AR affects plant performance comprehensively.
... Against this background, the implications of acid rain in terrestrial ecosystems, such as its effects on plants, microbes, and soil, invite continuous concerns (Liu et al., 2022a;Shi et al., 2021). Although the ecological effects and risks of acid rain in terrestrial ecosystems have been studied, a comprehensive insight into acid rain impacts is challenging because there remain large uncertainties in many aspects of the C cycle, for example, the response of plant-photosynthesized C allocation to acid rain. ...
... Although many previous studies have ever reported negative acid rain impacts on plant biomass Shi et al., 2021), in this study, acid rain did not change the total plant biomass or the shoot biomass on days 1 and 20 after 13 C labeling, which is inconsistent ...
... In addition, soil pH is an important factor that regulates soil 13 C content by affecting soil NH4 + -N and root 13 C levels. Low soil pH leads to leaching and depletion of N and is not conducive to root growth (Liu et al., 2022a;Shi et al., 2021). Overall, soil pH, NH4 + -N, and root biomass were vital regulators of soil 13 C content. ...
Article
Acid rain threatens the function and structure of terrestrial ecosystems; however, the mechanisms by which acid rain affects the photosynthesized carbon (C) fluxes and soil microbial communities are far less understood, thus impeding accurate projections of regional C flux in plant-soil-atmosphere systems. In this study, we performed an isotopic 13C labeling experiment to trace and quantify C footprints in a maize-soil system under acid rain pollution (pH 4.5 and 3.0; SO42-/NO3- = 2:1). Our results showed that acid rain exerted a negligible effect on total plant biomass as well as shoot biomass. Acid rain of pH 3.0 inhibited plant 13C assimilation and the flow of fixed 13C to the soil. Acid rain decreased soil total C and organic nitrogen (N) but increased inorganic N (i.e., nitrate-N) levels. The acid rain of pH 3.0 enhanced soil bulk density, led to soil acidification, and promoted soil microbial biodiversity. However, acid rain reduced the connectivity and complexity of the soil microbial network. Soil 13C content was mainly regulated by soil pH, ammonium-N, and root biomass. Our findings demonstrated that acid rain reduces photosynthesized C sequestration and soil microbial taxa interactions.
... Nevertheless, acid rain is a wet and dry deposition of mainly large amounts of nitric and sulfuric acids on a pH scale ≤ 5.6. Acid rain causes ecological effects due to the acidification of the soil, streams, lakes, and bodies of water that damage trees, plants, and animals, mainly aquatic [1]. Nature is not the only area damaged by acid rain; it also damages buildings and monuments made of stones (such as marble and limestone) and metals (such as bronze) [2]. ...
... The inhibitor concentrations evaluated were 0, 10, 25, 50, and 100 ppm, in a volume of 40 mL for each electrochemical test. The corrosion velocity (V corr ) was determined by Equation (1). ...
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Acid rain is one of the primary corrosive agents on bronze exposed to the atmosphere. Bronze naturally forms a layer of oxides on its surface called patina, protecting it from corrosion. However, when exposed to acid rain, this layer dissolves, making it necessary to use a corrosion inhibitor or stabilize the patina. This study investigated fatty imidazolines derived from agro-industrial waste bran as a corrosion inhibitor of SAE-62 bronze in simulated acid rain (pH of 4.16 ± 0.1). Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PC) measurements were used to evaluate corrosion inhibition efficiency, which was 90% for an inhibitor concentration of 50 ppm. The EIS measurements showed that the fatty imidazolines formed a protective film that stabilized the patina on the bronze surface to a certain extent by hindering the charge transfer process. SEM–EDS analyzed the morphology and composition of the protective oxide layer. The results were complemented by Raman spectroscopy and XRD analysis, indicating cuprite, tenorite, cassiterite, and covellite in the patina layer formed on the bronze surface. The SEM analysis showed that the protective coating on the bronze surface was homogeneous using a 50-ppm inhibitor concentration. The XRD analysis suggested the presence of an organic complex that stabilizes the corrosion products formed on the bronze surface.
... [7] In urban areas, acid rain can accelerate metal corrosion and deteriorate materials like limestone, marble, and mortar. [8] Hence, it is crucial to not only enhance air quality by diminishing emissions or augmenting SO2 capture but also monitor potentially polluted environments with SO2. Such measures are essential for averting severe health repercussions for individuals laboring in various urban settings. ...
Article
We report the inaugural experimental investigation of covalent organic frameworks (COFs) to address the formidable challenge of SO2 detection. Specifically, an imine‐functionalized COF (SonoCOF‐9) demonstrated a modest and reversible SO2 sorption of 3.5 mmol g‐1 at 1 bar and 298 K. At 0.1 bar (and 298 K), the total SO2 uptake reached 0.91 mmol g‐1 with excellent reversibility for at least 50 adsorption‐desorption cycles. An isosteric enthalpy of adsorption (ΔHads) for SO2 equaled −42.3 kJ mol−1, indicating a relatively strong interaction of SO2 molecules with the COF material. Also, molecular dynamics simulations and Møller–Plesset perturbation theory calculations showed the interaction of SO2 with π density of the rings and lone pairs of the N atoms of SonoCOF‐9. The combination of experimental data and theoretical calculations corroborated the potential use of this COF for the selective detection and sensing of SO2 at the sub‐ppm level (0.0064 ppm of SO2).
... [7] In urban areas, acid rain can accelerate metal corrosion and deteriorate materials like limestone, marble, and mortar. [8] Hence, it is crucial to not only enhance air quality by diminishing emissions or augmenting SO 2 capture but also monitor potentially polluted environments with SO 2 . Such measures are essential for averting severe health repercussions for individuals laboring in various urban settings. ...
Article
Full-text available
We report the inaugural experimental investigation of covalent organic frameworks (COFs) to address the formidable challenge of SO2 detection. Specifically, an imine‐functionalized COF (SonoCOF‐9) demonstrated a modest and reversible SO2 sorption of 3.5 mmol g⁻¹ at 1 bar and 298 K. At 0.1 bar (and 298 K), the total SO2 uptake reached 0.91 mmol g⁻¹ with excellent reversibility for at least 50 adsorption‐desorption cycles. An isosteric enthalpy of adsorption (ΔHads) for SO2 equaled −42.3 kJ mol⁻¹, indicating a relatively strong interaction of SO2 molecules with the COF material. Also, molecular dynamics simulations and Møller–Plesset perturbation theory calculations showed the interaction of SO2 with π density of the rings and lone pairs of the N atoms of SonoCOF‐9. The combination of experimental data and theoretical calculations corroborated the potential use of this COF for the selective detection and sensing of SO2 at the sub‐ppm level (0.0064 ppm of SO2).
... Previous research indicated that acid deposition reduced the biomass production of above-ground plant communities, primarily due to damage to the cuticular structure of plant leaves (Francisco Sant'Anna-Santos et al. 2006), reduced mesophyll conductance to CO 2 , and increased cation leaching and water loss of foliage (Chen et al. 2013;Neufeld et al. 2006). A meta-analysis by Meng et al. (2019) revealed that soil acidification increased the mobilization and release of free Al 3+ to soil solution, negatively impacting fine-root growth and ultimately reducing fine-root production (Shi et al. 2021). However, conflicting findings suggest that fine-root production or necromass accumulation may increase with soil acidity (Godbold et al. 2003) or be higher in soils with low acid buffering capacity (Hirano et al. 2017). ...
Article
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Background and aims As a significant land carbon sink, highly acid subtropical forests in southern China continued to accumulate a significant amount of soil carbon under elevated acid deposition, yet the mechanism of how soil organic carbon (SOC) and its two components: particulate (POC) and mineral-associated (MAOC) organic carbon increased remain unclear. We aim to assess which mechanism and drivers dominated the accumulation of SOC and its two fractions under elevated acid deposition. Methods We conducted a 11-year field acid addition experiment to study how acid deposition affected the accumulation of SOC and its fractions. Lignin phenols and amino sugars were used as two tracers for plant- and microbe-derived carbon. Results We found that both POC (0–20 cm) and MAOC (10–20 cm) were significantly increased by acid addition. Acid addition significantly reduced the contributions of fungal-, bacterial- or total microbial residue carbon to SOC but significantly increased the plant-derived soil carbon in both soil depths. The increase of lignin phenol and suppressed soil organic matter decomposition from soil microbes suggested that soil POC increased with acid addition. Soil acidification strongly enhanced MAOC accumulation through increased lignin and mineral protection by iron-aluminum oxides and cations. Conclusion Our results showed that increased mineral protection of plant-derived carbon was the dominant driver of the increased SOC sequestration under acid addition. This finding identified the dominant pathway for SOC accumulation in a highly acidic subtropical forest and provides new insights into understanding how plant-soil-mineral interact under increasing acid deposition in the region.
... Acid rain has become one of the most serious environmental problems worldwide due to decades of industrial development as well as increases in energy demands and emissions of certain gases, including sulfur dioxide (SO 2 ) and nitrogen oxides (NO X ) [1]. In terms of the total area affected by acid rain, China ranks third behind Europe and North America [2,3]. ...
Article
Full-text available
The effects of simulated acid rain (SAR) on the photosynthetic performance of subtropical coniferous species have not been thoroughly investigated. In this study, we treated two coniferous species, Pinus massoniana (PM) and Cunninghamia lanceolata (CL), with four gradients of SAR and then analyzed their photosynthetic activities through measurements of gas exchange, prompt fluorescence (PF), delayed fluorescence (DF), and modulated reflection at 820 nm (MR820). Gas exchange analysis indicated that the decrease in the net photosynthetic rate (Pn) in PM and CL was unrelated to stomatal factors. For the PF transients, SAR induced positive K-band and L-band, a significant reduction in photosynthetic performance index (PIABS), the quantum yield of electron transfer per unit cross-section (ETO/CSm), and maximal photochemical efficiency of photosystem II (Fv/Fm). Analysis of the MR820 kinetics showed that the re-reduction kinetics of PSI reaction center (P700+) and plastocyanin (PC+) became slower and occurred at later times under SAR treatment. For the DF signals, a decrease in the amplitude of the DF induction curve reduced the maximum value of DF (I1). These results suggested that SAR obstructed photosystem II (PSII) donor-side and acceptor-side electron transfer capacity, impaired the connectivity between PSII and PSI, and destroyed the oxygen-evolving complex (OEC). However, PM was better able to withstand SAR stress than CL, likely because of the activation of a protective mechanism.
... The inhibitory effects of acid rain on plant growth in general, aboveground and belowground plant parts responded differently. The interactions between acid rain pH and other acid rain characteristics and experimental characteristics indicating that there were pH dependent interaction patterns [SHI & al. 2021]. Vigna sinensis L. and Phaseolus mungo L. ...
Article
Full-text available
The wet (rain, snow, fog, sleet, dew) and dry (transport of aerosol, particles and gases) deposition of acidic substance in environment results due to human, automobile, fossil fuel burning and industrial activities. Acid deposition is worldwide environmental degradation problems and in recent years these acidic materials are increasing at alarming scale in the environment both in developed and developing countries, including Pakistan. Some scientific literature survey reports suggest that plant growth and agriculture yield decrease due to consequence of acid rain. In addition, acid rain is found responsible for producing toxic effects on the morphological parameters of agricultural crop. The evidence collected from last more than fifty years showed the common significant effects of acid rain on seed germination percentage, seedling height, root hair and structure, alteration in leaf anatomy, size and area, stomatal structure, size, pollen germination, photosynthetic pigments and physiological changes in herbs, shrubs and trees. Still, little is known on the impact of acid rain on plant growth. This study was aimed to review the effects of acid mist on growth performances of some selected plant species. This review is contributed with the help of literature survey, research work published on the impact of acid rain on the plant growth.
... The inhibitory effects of acid rain on plant growth in general, aboveground and belowground plant parts responded differently. The interactions between acid rain pH and other acid rain characteristics and experimental characteristics indicating that there were pH dependent interaction patterns [SHI & al. 2021]. Vigna sinensis L. and Phaseolus mungo L. ...
Article
Full-text available
The wet (rain, snow, fog, sleet, dew) and dry (transport of aerosol, particles and gases) deposition of acidic substance in environment results due to human, automobile, fossil fuel burning and industrial activities. Acid deposition is worldwide environmental degradation problems and in recent years these acidic materials are increasing at alarming scale in the environment both in developed and developing countries, including Pakistan. Some scientific literature survey reports suggest that plant growth and agriculture yield decrease due to consequence of acid rain. In addition, acid rain is found responsible for producing toxic effects on the morphological parameters of agricultural crop. The evidence collected from last more than fifty years showed the common significant effects of acid rain on seed germination percentage, seedling height, root hair and structure, alteration in leaf anatomy, size and area, stomatal structure, size, pollen germination, photosynthetic pigments and physiological changes in herbs, shrubs and trees. Still, little is known on the impact of acid rain on plant growth. This study was aimed to review the effects of acid mist on growth performances of some selected plant species. This review is contributed with the help of literature survey, research work published on the impact of acid rain on the plant growth.
... This repeated exposure is unhealthy and can cause many serious health problems, such as Parkinson's disease (2). Emissions such as nitrous oxide and sulfur dioxide can also contribute to acid rain, which reduces biomass (3). Excess unburnt hydrocarbons are also prevalent in small engine exhaust and are known to cause smog (4). ...
Article
Small engines create a disproportionate amount of pollutants for their size. No research on the emissions of a small, carbureted engine run on widely available 100% alcohol fuel exists. To address this problem, we hypothesized that an alcohol-based fuel could be used as an effective means of lowering small engine emissions. To investigate the extent of small engine emissions improvement, a Toro push lawn mower with a 6.5 hp engine was modified to run on alcohol fuel. We tested for the common pollutant's nitrous oxide, unburnt hydrocarbons, sulfur dioxide, and carbon monoxide using a Testo 350 portable emissions analyzer. Two fuels were used. The first was Klean Strip Denatured Alcohol, which is a mixture of ethanol and methanol. The second was made up of 10% ethanol and 90% gasoline (E10) and is available at most gas stations. The Klean Strip Denatured Alcohol fuel produced significantly less nitrous oxides, sulfur dioxide, carbon monoxide, and hydrocarbon emissions when compared to the E10 fuel. Of the four measured pollutants, the alcohol-based fuel consistently produced at least 40% less emissions compared to the E10 fuel. The use of a methanol and ethanol blend in small engines could drastically reduce existing small engine emissions.
... (Shi et al. 2021). The various gases react with water, oxygen, and other chemicals to produce different compounds causing acidity. ...
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The impact of acid rain on the germination of seeds is a significant concern in agricultural and environmental studies. Acid rain, characterized by elevated acidity levels due to pollutants like sulfur dioxide and nitrogen oxides, can adversely affect the germination process of various plant species. The objective of this study was to evaluate the impact of simulated acid rain (SAR) on the germination of Brinjal (Solanum melongena Linn.) and Cowpea (Vigna unguiculata ssp. cylindrica L. Walpers) crops. The experiments were conducted using eight plastic trays of approximately 25 cm. x 30 cm dimensions. Four trays were used for experiments with brinjal seeds (Set I), while the other four were used for cowpea seeds (Set II). One tray from each set was used as positive control and treated with normal pH 5.6, while the other three trays from each batch were treated with SAR solutions of pH 4.5, 3.5, and 2.5. Brinjal seed germination percentage and seed vigor were inferior to Cowpea seeds. The seeds treated with SAR (pH 4.5, 3.5, and 2.5) showed hindered seed germination. Furthermore, a more significant inhibitory effect was observed at lower pH values. The mean germination percentage of seeds was highest for standard SAR (pH 5.6) in the case of Brinjal seeds, while it was recorded lowest for Cowpea seeds. The results indicate that plants do not respond uniformly to SAR. To investigate the behavior of the simulated acid rain data, a Machine Learning-based Decision Tree Algorithm was employed to identify and optimize conditions. Cowpea was predicted to get 95% seed germination, whereas brinjal would only be 64% in acid rain of pH value 5.05 for 36 hours. In conclusion, utilizing a Machine Learning-based CART algorithm has provided valuable insights into predicting the germination behavior of seeds under the influence of acid rain.
... In the purple soil, the seedling growth is slightly lower than on the other soils, maybe because of the low pH, which influences the availability of many ions and minerals in the soil, is more mobile under acidic conditions, and can have phytotoxic effects [49]. At low external pH, the net uptake of monovalent cations is generally lower than at neutral pH, and at pH < 4 a net loss of cations may occur. ...
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Soil type is an important environmental factor that affects plant growth and development, especially during the early growth stage. In this study, P. chinense (Phellodendron chinense) seedlings were cultivated on red soil (RS), yellow soil (YS), acidic purple soil (ACPS), and alkaline purple soil (ALPS), and the influence of soil types on the growth parameters and physiological responses at three growth stages were investigated. The results show that soil types and growth stages can significantly influence seedling height, base diameter, and biomass in P. chinense seedlings. Moreover, the significant variations in chlorophyll, total polyphenols, soluble protein, soluble sugar, and malondialdehyde (MDA) content, as well as superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia-lyase (PAL), and polyphenol oxidase (PPO) activity, were recorded at three growth stages among four soil types. These results show that P. chinense seedlings can grow normally in four soil types, and ACPS may be more beneficial for the artificial cultivation of P. chinense seedlings than those of RS, ALPS, and YS. Principal component analysis (PCA) reveals a strong correlation and clear differences in the test parameters between growth stage and organs in four soil types, and the cumulative contribution percentages of the total biplot range from 74.44% to 81.97%. This present information will be helpful for farmers in selecting soil type for the large-scale cultivation of P. chinense seedlings.
... zawiera związki siarki i azotu. W Polsce tylko w 2018 r. do atmosfery dostało się ponad 7,6 mln ton tlenków azotu (Bochenek i współaut. 2020). Związki te dodatkowo przyczyniają się do powstawania kwaśnych opadów, które mogą wpływać na ekosystemy wodno-błotne, przez wymywanie substancji mineralnych z gleby, co skutkuje zaburzeniami w rozwoju roślin (Shi i współaut. 2021). Ponadto, na jakość wody wpływają przedostające się do niej ścieki, wskutek czego aż 31% wód powierzchniowych Polski jest słabej lub złej jakości (Bochenek i współaut. 2020). ...
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Obszary wodno-błotne tworzą wiele siedlisk wykorzystywanych przez ogromne ilości gatunków roślin i zwierząt, a ich zagrożenia wynikają przede wszystkim z wszelakiej działalności człowieka. Spośród przedstawicieli krajowej herpetofauny wszystkie płazy oraz trzy gatunki gadów są w mniejszym lub większym stopniu związane z mokradłami. Zanik tak wartościowych siedlisk nie pozostaje bez wpływu na obie te gromady zwierząt, co skutkuje zmniejszeniem liczby stanowisk oraz spadkami liczebności populacji w obrębie dziewięciu gatunków płazów oraz dwóch gadów. W celu zachowania ich populacji w pierwszej kolejności powinno chronić się miejsca ich występowania, ale zapobieganie temu wymaga także podjęcia działań chroniących bezpośrednio herpetofaunę. Na domiar złego, w Polsce nadal realizowana jest zbyt niewielka liczba projektów mogących pozytywnie wpłynąć na poprawę jakości tych siedlisk oraz liczebności populacji gadów i płazów.
... However, the effects of acid rain on plants are not always negative. Acid rain may be beneficial to the Pn of leaves because NO 3 -in acid rain provides plant nutrients, increasing the Pn [13,21]. Acid rain stress elevates the number of reactive oxygen species (ROS) and induces cell membrane peroxidation, increasing the malondialdehyde (MDA) content. ...
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The physiological and biochemical indicators of plants reflect the plant’s adaptation to environmental changes and provide information for the planting and management of acid-resistant tree species. To analyze the responses of typical tree species to recent changes in acid rain conditions in Jinyun Mountain, Chongqing, we focused on three representative tree species in the Jinyun Mountain area of Chongqing: Pinus massoniana, Phyllostachys edulis, and Cinnamomum camphora. A mixed acid rain experiment with five gradients of natural rainfall (NR) and pH values of 7.0, 4.5, 3.5, and 2.5 was conducted in May 2021. The changes in physiological and biochemical indicators (net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, light saturation point, light compensation point, apparent quantum efficiency, dark respiration rate, soluble sugar, starch, soluble protein, proline, malondialdehyde, and antioxidant enzyme activity) were determined. The results show the following: 1. Compared with other treatments, NR and slightly acidic rain increased the relative chlorophyll content in plant seedlings. 2. The synthesis of soluble sugars, starches, and soluble proteins was inhibited to different degrees in the three species under acid rain stress at pH ≤ 3.5. 3. The enzyme activity of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) initially increased and then decreased with an increase in acidity. 4. Acid rain treatments with pH ≤ 4.5 reduced the net photosynthetic rate (Pn) of plants; the higher the acidity, the lower the Pn. Conclusion: A comprehensive comparison of the indicators revealed that NR and mild acid rain enhanced the plant seedlings’ physiological and biochemical characteristics. A pH of 3.5 was the threshold where acid rain had an adverse effect on Pinus massoniana, Phyllostachys edulis, and Cinnamomum camphora. The high indicator values for NR indicate that these tree species have adapted to current conditions in the Jinyun Mountain area of Chongqing. This study provides new information for selecting tree species adapted to the acid rain environment in Jinyun Mountain, Chongqing.
... With the rapid development of global industrialization, environmental pollution and degradation have led to extensive social concern, especially the problem of acid rain [19,20]. The acid rain environment refers to rain and snow or other forms of precipitation with pH values of lower than 5.6, which makes the environment weakly acidic or acidic [21]. In the acid rain environment, all types of geotechnical engineering materials are affected not only by external loads but also by various types of chemical erosion during their service life [22]. ...
... Acid rain-induced impairments in photosynthetic capability lead to lower biomass production in crop species (Sant'Anna-Santos et al. 2006). According to Shi et al. (2021), acid rain can directly reduce the amount of chlorophyll in leaves by 6.7% for every pH unit. Previous studies (Jacobson et al. 1989;Keevar and Jacobson 1983) revealed that crops are most vulnerable to acid scorching in the early stages of growth. ...
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... Acidity and Sulfate in Clay The pH of acid rain is less than 5.6 [37]. Accordingly, the clay samples in our study were classified as acidic clay (pH≤5.6) ...
... Occasionally, the pH of rain water and fog water goes down to as low as 2.2, this has been reported from Wheeling (West Virginia) and Pitlochry in Scotland (McCormick, 2013). Increasing acidity in natural water and soil is becoming a problem throughout the world including India (Shi et al., 2021). The increased acidity in such rains is attributed largely to various oxides of nitrogen and sulphur, collectively described as NO 2 and SO 2 which are the result of atmospheric pollution. ...
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... Atmospheric NOx also can cause acid rain [32,33]. The acid rain with low pH severely harms animals and plants [34]. ...
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Nowadays, the conceptualization of circular economy is an attractive managerial tool among governments and businesses throughout the word, while ecosystem services are a contentious issue due to the particular needs of humans’ well-being. At this review the interactions between the principles of ecosystem services and the circular economy were investigated in the light of inter-organizational systems. This evaluation was based on more and more complex processes, while the integration of the growing circular economy concept within the shrinking parent ecosystem unveiled challenges and constraints for products’ end of life and quality. It was argued that: (a) The existence of social and people-related barriers can be considered under three groups, namely, the “sustainable provision and modeling schemes”, “socio-cultural appreciation and payment schemes”, and “regulatory and maintenance schemes”, (b) The impacts of circular economy—ecosystem services toward an inter-organizational functional stream model associated with distinguished proactive and post treatment risk values (c) The functionality and the accountability of the technosphere are the two critical components to support the restorative and the regenerative perspectives of the biosphere. The aforementioned findings unveiled new emerging paths to be further investigated, offering a deeper appraisal of circular economy under the inter-organizational perception.
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Acid rain alters nutrient cycling in tea plantations. However, the acquisition of Mg and Ca by plants and their nutrient interactions with Al, N, and P in response to acid rain are poorly understood. Experimental treatments simulating acid rain at various acidities (pH 4.5, 3.5, and 2.5) were performed within a red soil tea plantation in China. The available Mg, Al, Ca, N, and P were analyzed in the rhizosphere and bulk soils. Further, these elements were measured in absorptive, transportive, and storative roots in addition to twigs, tea, and mature leaves. Available soil Mg and Ca exhibited negative and positive rhizosphere effects, respectively, but the levels of both decreased due to acid rain treatment. In addition, average Mg and Ca concentrations generally decreased in plant tissues with increasing acidity. In contrast, average Al concentration increased across all plant tissues with increasing acidity treatment. Meanwhile, the ratios of Al/Mg and Al/Ca increased with increasing acidity but that of N/Al decreased in twigs and roots. Lastly, the ratios of N/Al, P/Ca, and N/P were all altered by acid treatment in tea and/or mature leaves. Taken together, these results indicated that elevated acidity increased the internal cycling of Al in plants but decreased Mg and Ca fluxes between soils and roots. Further, the response of interactions among the five measured elements to different acidities varied with tea plant tissue. Our findings may advance our understanding of plant adaptation to increasing soil acidification and atmospheric acid deposition around the world.
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While phylogenies have been getting easier to build, it has been difficult to reuse, combine and synthesize the information they provide because published trees are often only available as image files, and taxonomic information is not standardized across studies. The Open Tree of Life ( OTL ) project addresses these issues by providing a digital tree that encompasses all organisms, built by combining taxonomic information and published phylogenies. The project also provides tools and services to query and download parts of this synthetic tree, as well as the source data used to build it. Here, we present rotl , an R package to search and download data from the Open Tree of Life directly in R. rotl uses common data structures allowing researchers to take advantage of the rich set of tools and methods that are available in R to manipulate, analyse and visualize phylogenies. Here, and in the vignettes accompanying the package, we demonstrate how rotl can be used with other R packages to analyse biodiversity data. As phylogenies are being used in a growing number of applications, rotl facilitates access to phylogenetic data and allows their integration with statistical methods and data sources available in R.
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Systematic reviews should build on a protocol that describes the rationale, hypothesis, and planned methods of the review; few reviews report whether a protocol exists. Detailed, well-described protocols can facilitate the understanding and appraisal of the review methods, as well as the detection of modifications to methods and selective reporting in completed reviews. We describe the development of a reporting guideline, the Preferred Reporting Items for Systematic reviews and Meta-Analyses for Protocols 2015 (PRISMA-P 2015). PRISMA-P consists of a 17-item checklist intended to facilitate the preparation and reporting of a robust protocol for the systematic review. Funders and those commissioning reviews might consider mandating the use of the checklist to facilitate the submission of relevant protocol information in funding applications. Similarly, peer reviewers and editors can use the guidance to gauge the completeness and transparency of a systematic review protocol submitted for publication in a journal or other medium.
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Significance Scientists have used gene sequences and morphological data to construct tens of thousands of evolutionary trees that describe the evolutionary history of animals, plants, and microbes. This study is the first, to our knowledge, to apply an efficient and automated process for assembling published trees into a complete tree of life. This tree and the underlying data are available to browse and download from the Internet, facilitating subsequent analyses that require evolutionary trees. The tree can be easily updated with newly published data. Our analysis of coverage not only reveals gaps in sampling and naming biodiversity but also further demonstrates that most published phylogenies are not available in digital formats that can be summarized into a tree of life.
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Acid rain pollution is one of the serious environmental problems in China. It is also one of the reasons behind the aggravated pollution situation in the northern regions of the country. Large areas suffering from the continued occurrence of strong acid rains are at risk for serious threats to the health of terrestrial ecosystems. Plants above and below the ground are seriously affected by acid rain, because they are the main receptors of acid pollution. The impacts of acid rain on plants specifically affect their growth and root systems. Therefore, studies on growth and bleeding sap amount of root of typical tree species in reaction to acid rains in northern China have important theoretical and practical values. These can help us understand the effects of acid rain on forest community and vegetation restoration. Quercus mongolica Fisch. ex Ledeb. is one of the main species of deciduous broad-leaved forests in northern China, and is the main associated tree species of pines in temperate coniferous forests. Thus, in the present work, we chose one-year-old Q. mongolica seedlings to study the effects of simulated acid rain on plant growth, biomass, and bleeding sap amount of root. From June to September 2011, Q. mongolica seedlings were exposed to 12 simulated acid rain treatments of 4 different acidities (severe, moderate, slight and control) that are delivered by 3 types of rainfalls (natural rainfall in summer, and increased or decreased amounts by 30%, respectively). Simulated acid rains were applied to the seedlings on a weekly basis. The results demonstrate that an increase of 30% acid rain rainfall significantly raised the biomass and leaf numbers, promoted height growth, and increased bleeding sap amount of root of Q. mongolica seedlings. However, growth and biomass accumulation of Q. mongolica seedlings were slightly influenced by acid rain acidity, such that when acidity increased the bleeding sap amount of root became significantly lower. Furthermore, the root systems of the Q. mongolica seedlings were damaged by the high acidity of simulated acid rain. Compared with other treatments, in the treatment with an increase of 30% in severe acid rain rainfall, Q. mongolica seedlings exhibited significantly higher height levels, grew more leaf numbers, and accumulated more biomass. Based on our estimations, the stimulation of seedling growth and the acceleration of biomass accumulation were caused by the increased concentration of soil N, which came from the added NO-3 in acid rain. The acid rain also served as a fertilizer, thereby promoting the growth of Q. mongolica seedlings. Relative to acidity, acid rain rainfall had greater impact on Q. mongolica seedlings, however, no interaction between two factors was found. In conclusion, Q. mongolica showed resistance and adaptability to acid rain. Thus, they can be considered as pioneer and constructive plant species for use in the recovery of regions suffering from acid rain.
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Understanding the adaptation of plants to acid rain is important to find feasible approaches to alleviate such damage to plants. We studied effects of acid rain on plasma membrane H(+)-ATPase activity and transcription, intracellular H(+), membrane permeability, photosynthetic efficiency, and relative growth rate during stress and recovery periods. Simulated acid rain at pH 5.5 did not affect plasma membrane H(+)-ATPase activity, intracellular H(+), membrane permeability, photosynthetic efficiency, and relative growth rate. Plasma membrane H(+)-ATPase activity and transcription in leaves treated with acid rain at pH 3.5 was increased to maintain ion homeostasis by transporting excessive H(+) out of cells. Then intracellular H(+) was close to the control after a 5-day recovery, alleviating damage on membrane and sustaining photosynthetic efficiency and growth. Simulated acid rain at pH 2.5 inhibited plasma membrane H(+)-ATPase activity by decreasing the expression of H(+)-ATPase at transcription level, resulting in membrane damage and abnormal intracellular H(+), and reduction in photosynthetic efficiency and relative growth rate. After a 5-day recovery, all parameters in leaves treated with pH 2.5 acid rain show alleviated damage, implying that the increased plasma membrane H(+)-ATPase activity and its high expression were involved in repairing process in acid rain-stressed plants. Our study suggests that plasma membrane H(+)-ATPase can play a role in adaptation to acid rain for rice seedlings.
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Increased air pollution in a number of developing African countries, together with reports of vegetation damage typically associated with acid precipitation in commercial forests in South Africa, has raised concerns over the potential impacts of acid rain on natural vegetation in these countries. Recalcitrant (i.e. desiccation sensitive) seeds of many indigenous African species for example, must germinate shortly after shedding and hence, may not be able to avoid exposure to acid rain in polluted areas. This study investigated the effects of simulated acid rain (rainwater with pH adjusted to pH 3.0 and 4.5 with 70:30, H2 SO4 :HNO3 ) on germination, seedling growth and oxidative metabolism in a recalcitrant-seeded African tree species Trichilia dregeana Sond., growing in its natural seed bank. The results suggest that acid rain did not compromise T. dregeana seed germination and seedling establishment significantly, relative to the control (non-acidified rainwater). However, pH 3.0 treated seedlings exhibited signs of stress typically associated with acid rain: leaf tip necrosis, abnormal bilobed leaf tips, leaf necrotic spots and chlorosis, reduced leaf chlorophyll concentration, increased stomatal density and indications of oxidative stress. This may explain why total and root biomass of pH 3.0 treated seedlings were significantly lower than the control. Acid rain also induced changes in the species composition and relative abundance of the different life forms emerging from T. dregeana's natural seed bank and in this way could indirectly impact on T. dregeana seedling establishment success.
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China is pioneering a new sustainable development model which has the ability to overcome current environmental and resource management problems, while achieving improvements in resource productivity and eco-efficiency. This model, formally accepted in 2002 and termed the 'circular economy', is understood to mean the realisation of a closed loop of material flows in the Chinese economic system. Successful implementation of this model is seen as one way in which China can 'leapfrog' past environmental damage that is typically seen as economies industrialise. This paper introduces the development of the model in China, and presents the current situation of circular economy practice in China. The paper describes current measures being implemented in China for the long-term promotion of a circular economy, including the formulation of objectives, legislation, policies and measures, so that the country can 'leapfrog' its way from environmentally-damaging development to a more sustainable path. The paper then identifies a series of barriers and challenges to the implementation of the concept in China. Finally, conclusions on the future of the circular economy concept are drawn. Data were derived primarily from an analysis of secondary sources (i.e. previously published papers). Additional primary data derived from the main author's personal involvement in several circular economy initiatives were also employed.
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For any given research area, one cannot tell how many studies have been conducted but never reported. The extreme view of the "file drawer problem" is that journals are filled with the 5% of the studies that show Type I errors, while the file drawers are filled with the 95% of the studies that show nonsignificant results. Quantitative procedures for computing the tolerance for filed and future null results are reported and illustrated, and the implications are discussed. (15 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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In order to correlate sintomatology with anatomical alterations caused by acid rain in leaves of tropical species, seedlings and saplings of Spondias dulcis Forst. F., Mimosa artemisiana Heringer and Paula and Gallesia integrifolia (Spreng.) Harms were exposed to simulated low-pH acid rain (pH 3.0). Control plants were submitted only to rain with distilled water (pH 6.0). The plants were exposed daily to the acid rain for 20 min for 10 consecutive days. Necrotic spots on the leaf blade occurred and most of the injuries onset on the epidermis in all species studied. S. dulcis displayed epicuticular wax erosion and rupture of epidermis. The abaxial surface of M. artemisiana was colonized by a mass of fungi hyphae and stomatal outer ledge rupture occurred. Some epidermal cells of G. integrifolia showed appearance similar to plasmolysis. The plants accumulated phenolic compounds in necrotic areas. Afterwards, leaves presented injuries in the mesophyll and collapsed completely. Cells surrounding the injured areas accumulated starch grains in S. dulcis. M. artemisiana showed more drastic symptom intensity in response to acidic rain. S. dulcis displayed visual symptoms similar to G. integrifolia, however, anatomical alterations were more severe.
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Quantitative literature reviews such as meta-analysis are becoming common in evolutionary biology but may be strongly affected by publication biases. Using fail-safe numbers is a quick way to estimate whether publication bias is likely to be a problem for a specific study. However, previously suggested fail-safe calculations are unweighted and are not based on the framework in which most meta-analyses are performed. A general, weighted fail-safe calculation, grounded in the meta-analysis framework, applicable to both fixed- and random-effects models, is proposed. Recent meta-analyses published in Evolution are used for illustration.
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Meta-analysis provides formal statistical techniques for summarizing the results of independent experiments and is increasingly being used in ecology. The response ratio (the ratio of mean outcome in the experimental group to that in the control group) and closely related measures of proportionate change are often used as measures of effect magnitude in ecology. Using these metrics for meta-analysis requires knowledge of their statistical properties, but these have not been previously derived. The authors give the approximate sampling distribution of the log response ratio, discuss why it is a particularly useful metric for many applications in ecology, and demonstrate how to use it in meta-analysis. The meta-analysis of response-ratio data is illustrated using experimental data on the effects of increased atmospheric CO{sub 2} on plant biomass responses.
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Acid rain is a widespread environmental issue intensely affecting normal plant growth of crops. Melatonin is well known pleiotropic molecule which improves abiotic and biotic stress tolerance of plants through physiological and molecular mediation. However, the impact of exogenous melatonin on molecular activities under acid rain conditions in plants has never been studied. The objective of the study is to expose the possible role of exogenous melatonin on physiological and molecular changes against acid rain stress in tomato. Transcriptome profile through RNA-sequence analysis identified 1228, 1120 and 1537 differentially expressed genes (DEGs) in control plant (Ctr) vs simulated acid rain stressed plant (P25) comparison, control plant vs melatonin treatment in simulated acid rain stressed plant (P25M) comparison and P25 vs P25M comparison, respectively. Among them, 152 differentially expressed genes (DEGs) were commonly expressed and the expression of secondary metabolites related gene was noticeably observed in all comparison. Moreover, transcript families such as ERF, WRKY, MYB and bZIP related gene accounted more in all treatment comparison. The RNA-sequence and qPCR results indicated that exogenous melatonin is closely associated with acid rain stress moderator and might be involved in alteration of differentially expressed genes (DEGs), biosynthesis of plant secondary metabolites and transcriptional factor encoding genes expression which might have potential application against environmental hazardous conditions.
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Acid rain has been detected in natural protected areas of the Atlantic Rainforest in Brazil. We evaluated the effects of simulated acid rain on the leaf blade surface of Joannesia princeps, aiming to assess the species potential as biosensor of acidic precipitation. Seedlings were subjected to simulated rain prepared with pH 4.5 H2SO4-acidulated water and, in the control treatment, pH 6.0 deionized water. Severe microstructural damage was detected in the youngest leaves, consisting in wilting of epidermal common cells, which resulted on alteration of the epidermal relief due to formation of grooves among these wilted cells. Stomatal guard cells were also structurally altered, no longer presenting the turgid aspect which was visible in the control treatment. Epidermal microrelief is characterized by the presence of cuticular striae, which might have been crucial to determine the species susceptibility due to increased roughness and decreased wettability. The implications of this hypothesis are further discussed in light of recent research addressing the responses of native tree species to acid rain. The micromorphological alterations found occurred prior to the onset of visible symptoms, and therefore suggest the use of J. princeps as a biosensor of the impact by acid precipitation.
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Tea (Camellia sinensis), widely planted in the south of China, and often exposed to acid rain. However, research concerning the impacts of acid rain on physiology and biochemistry of tea plants is still scarce. In this study, we investigated the influence of simulated acid rain (SAR) on plant height, root length, photosynthetic pigment, Fv/Fm, proline, malondialdehyde, antioxidant enzyme activity, total nitrogen, caffeine, catechins, and free amino acids. Our results showed that SAR at pH 4.5 did not hinder plant development because growth characteristics, photosynthesis, and ascorbate peroxidase and catalase activities did not decrease at this pH compared to those at the other investigated pH values. However, at pH 3.5 and pH 2.5, the activities of antioxidase and concentrations of malondialdehyde and proline increased significantly in response to the decrease of photosynthetic pigments and Fv/Fm. In addition, the increase in acidity increased total nitrogen, certain amino acid content (theanine, cysteine), and decreased catechin and caffeine contents, resulting in an imbalance of the carbon and nitrogen metabolisms. Our results indicated that SAR at pH 3.5 and pH 2.5 could restrict photosynthesis and the antioxidant defense system, causing metabolic disorders and ultimately affecting plant development and growth, but SAR at pH 4.5 had no toxic effects on tea seedlings when no other stress factors are involved.
Article
As nitrogen deposition increases, acid rain is gradually shifting from sulfuric acid rain (SAR) to nitric acid rain (NAR). Acid rain can severely affect plant growth, damage ecosystems, and reduce biodiversity. Thus, a shift in acid rain type presents another challenge to the conservation of endangered plant species. We investigated the effect of three acid rain types (SAR, mixed acid rain [MAR], and NAR) and pH on the growth of an endangered Chinese endemic tree, Horsfieldia hainanensis Merr., using simulated rain in a greenhouse environment. Over nine months, growth indices, chlorophyll content, antioxidant enzyme activity, malondialdehyde content, and chlorophyll fluorescence parameters were investigated for treated and control saplings. The results indicated that at a pH of 5.6, H. hainanensis could adapt to SAR and MAR, but NAR inhibited below-ground growth. At a pH of 2.5 and 4.0, SAR inhibited stem and leaf biomass accumulation, whereas NAR inhibited root biomass accumulation and altered root morphology. MAR had intermediary effects between those of SAR and NAR. Adverse effects on leaf physiology were reduced as the rain type shifted from SAR to NAR; however, roots were increasingly adversely affected. Our results suggest that conservation efforts for H. hainanensis should shift from an above-ground to a below-ground focus as acid rain transitions toward NAR.
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After more than fifteen years of existence, the R package ape has continuously grown its contents, and has been used by a growing community of users. The release of version 5.0 has marked a leap towards a modern software for evolutionary analyses. Efforts have been put to improve efficiency, flexibility, support for 'big data' (R's long vectors), ease of use, and quality check before a new release. These changes will hopefully make ape a useful software for the study of biodiversity and evolution in a context of increasing data quantity. Availability: ape is distributed through the Comprehensive R Archive Network: http://cran.r-project.org/package=apeFurther information may be found athttp://ape-package.ird.fr/.
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The influence of acid rain on plant growth includes direct effects on foliage as well as indirect soil-mediated effects that cause a reduction in root growth. In addition, the concentration of NO3- in acid rain increases along with the rapid growth of nitrogen deposition. In this study, we investigated the impact of simulated acid rain with different SO42-/NO3- (S/N) ratios, which were 1:0, 5:1, 1:1, 1:5 and 0:1, on Chinese fir sapling growth from March 2015 to April 2016. Results showed that Chinese fir sapling height growth rate (HGR) and basal diameter growth rate (DGR) decreased as acid rain pH decreased, and also decreased as the percentage of NO3- increased in acid rain. Acid rain pH significantly decreased the Chlorophyll a (Chla) and Chlorophyll b (Chlb) content, and Chla and Chlb contents with acid rain S/N 1:5 were significantly lower than those with S/N 1:0 at pH 2.5. The chlorophyll fluorescence parameters, maximal efficiency of Photosystem II photochemistry (Fv/Fm) and non-photochemical quenching coefficient (NPQ), with most acid rain treatments were significantly lower than those with CK treatments. Root activities first increased and then decreased as acid rain pH decreased, when acid rain S/N ratios were 1:1, 1:5 and 0:1. Redundancy discriminant analysis (RDA) showed that the Chinese fir DGR and HGR had positive correlations with Chla, Chlb, Fv/Fm ratio, root activity, catalase and superoxide dismutase activities in roots under the stress of acid rain with different pH and S/N ratios. The structural equation modelling (SEM) results showed that acid rain NO3- concentration and pH had stronger direct effects on Chinese fir sapling HGR and DGR, and the direct effects of acid rain NO3- concentration and pH on HGR were lower than those on DGR. Our results suggest that the ratio of SO42- to NO3- in acid rain is an important factor which could affect the sustainable development of monoculture Chinese fir plantations in southern China.
Article
Objective: Comparisons of direct, indirect and composition effects of acid rain treatments on biomass allocation and physiological characteristics in Elaeocarpus glabripetalus seedlings were carried out in order to provide a scientific basis to study the mechanism of E. glabripetalus seedlings responding to simulated acid rain. Method: Potted plants were used to establish the experiment, treatments included 2 different pH values of acid rain (pH2.5 and pH5.6) and 4 different models of exposure to acid rain, including 1) aboveground exposure: only the aboveground of seedlings were exposed to acid rain; 2) soil exposure: only the soil around seedlings was exposed to acid rain; 3)whole exposure: the seedlings and soil were both exposed to acid rain; 4) Control: exposed to distilled water with pH7.0. Biomass accumulation and allocation, chlorophyll content and chlorophyll fluorescence characteristics, malondialdehyde(MDA) content and membrane permeability, the activity of antioxidant enzymes were measured. Result: 1)The growth of seedlings were inhabited to different extents when exposed to acid rain at pH2.5 level, and significant differences were found among the 3 models of exposure to acid rain. Compared with the control, total biomass, height increment, diameter increment of seedlings for the model of aboveground exposure decreased by 16.7%, 28.1% and 25.7% respectively; those of soil exposure decreased by 10.9%, 4.7% and 17.5% respectively; those of whole exposure decreased by 18.5%, 5.2% and 27.5% respectively. For the underground exposure, the ratio of leaf biomass to total biomass increased, and those of stem and root biomass decreased. The chlorophyll a (Chl a) content, total chlorophyll (total Chl) content, chlorophyll a/b(Chl a/b) were significantly lower than those of the control. For the aboveground exposure, primary photochemical efficiency of PSII(Fv/Fm) and potential activity of PSII(Fv/Fo) were significantly lower than those for the control; for the whole exposure the Fv/Fo and actual photochemical efficiency of PSII (ΦPSII) were significantly lower than those for the control; No significant differences were found between the soil exposure and the control in Fv/Fm, Fv/Fo and ΦPSII. For all the 3 exposure models, membrane permeability, MDA content and antioxidant enzymes activity were significantly higher than those for the control, and those for the soil exposure were the highest. 2)At the pH5.6 level, there were no significant difference in biomass of seedlings between the 3 exposure models and the control, but Chl a content, total Chl content and Chl a/b decreased significantly, and membrane permeability, MDA content, peroxidase (POD), catalase (CAT) activity increased significantly compared with the control. For the aboveground exposure and the whole exposure, Fv/Fo and ΦPSII were significantly lower than those for the control. Conclusion: The soil exposure had both negative and positive effect on the seedlings, while the aboveground and whole exposures inhabited the seedlings, and the effect of whole exposure was greater than that of aboveground exposure, but the whole exposure did not change the biomass allocation of seedlings. The effect of acid rain at pH5.6 on seedlings was significantly lower than that of acid rain at pH2.5. © 2016, Editorial Department of Scientia Silvae Sinicae. All right reserved.
Article
Co-occurring invasive plant species (invaders hereafter) and natives receive similar or even the same environmental selection pressures. Thus, the differences in functional traits between natives and invaders have become widely recognized as a major driving force of the success of plant invasion. Meanwhile, increasing amounts of acid are deposited into ecosystems. Thus, it is important to elucidate the potential effects of acid deposition on the functional traits of invaders in order to better understand the potential mechanisms for the successful invasion. This study aims to address the differences in functional traits between native red amaranth (Amaranthus tricolor L.; amaranth hereafter) and invasive redroot pigweed (A. retroflexus L.; pigweed hereafter) under simulated acid deposition with a gradient of pH levels. Pigweed was significantly taller than amaranth under most treatments. The greater height of pigweed can lead to greater competitive ability for resource acquisition, particularly for sunlight. Leaf shape index of pigweed was also significantly greater than that of amaranth under all treatments. The greater leaf shape index of pigweed can enhance the efficiency of resource capture (especially sunlight capture) via adjustments to leaf shape and size. Thus, the greater height and leaf shape index of pigweed can significantly enhance its competitive ability, especially under acid deposition. Acid deposition of pH 5.6 significantly increased amaranth leaf width in the co-cultivation due to added nutrients. The pH 4.5 acid deposition treatment significantly increased the specific leaf area of amaranth in the monoculture compared with the pH 5.6 acid deposition treatment and the control. The main mechanism explaining this pattern may be due to acid deposition mediating a hormesis effect on plants, promoting plant growth. The values of the relative competition intensity between amaranth and pigweed for most functional traits were lower than zero under most treatments. Thus, competitive performance arose in most treatments when the two species were grown together. This may be due to the enhanced competitive intensity under interspecific coexistence. However, the values of the relative competition intensity of the leaf functional traits between amaranth and pigweed were all higher than zero under the pH 5.6 simulated acid deposition treatment. Thus, interspecific facilitation occurs when the two species are co-cultivated under the pH 5.6 simulated acid deposition treatment. This may be due the positive nutritional effects induced in the pH 5.6 simulated acid deposition treatment.
Article
Anthropogenic emissions of acid precursors in China have resulted in widespread acid rain since the 1980s. Although efforts have been made to assess the indirect, soil mediated ecological effects of acid rain, a systematic assessment of the direct foliage injury by acid rain across terrestrial plants is lacking. Leaf chlorophyll content is an important indicator of direct foliage damage and strongly related to plant productivity. We synthesized data from published literature on experiments of simulated acid rain, by directly exposing plants to acid solutions with varying pH levels, to assess the direct effect of acid rain on leaf chlorophyll content across 67 terrestrial plants in China. Our results indicate that acid rain substantially reduces leaf chlorophyll content by 6.71 % per pH unit across the recorded plant species. The direct reduction of leaf chlorophyll content due to acid rain exposure showed no significant difference across calcicole, ubiquist or calcifuge species, implying that soil acidity preference does not influence the sensitivity to leaf injury by acid rain. On average, the direct effects of acid rain on leaf chlorophyll on trees, shrubs and herbs were comparable. The effects, however varied across functional groups and economic use types. Specifically, leaf chlorophyll content of deciduous species was more sensitive to acid rain in comparison to evergreen species. Moreover, vegetables and fruit trees were more sensitive to acid rain than other economically used plants. Our findings imply a potential production reduction and economic loss due to the direct foliage damage by acid rain.
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Most results with simulated acid-rain exposure experiments have suggested that rain acidity below pH 3.0 could induce direct or indirect deleterious effects on crops and other herbaceous plants, with visible injury development and reductions in growth and yield; however, plants show different sensitivities to acidity below pH 3.0 in terms of visible acute injury or reductions in growth and yield. Current rain acidity, which is regarded as over pH 4.0, may not induce direct adverse effects on field-grown plants. However, acidic precipitation may have a potential threat to induce increasing availability and toxicity of rare earth and heavy metals in plants.
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We summarized the results obtained from experimental studies on the growth and physiological responses of Japanese and Chinese tree species to simulated acid rain, mist, or fog. Based on the studies conducted in Japan and China, exposure to simulated acid rain, mist, or fog at pH 4.0 or above for one to three growing seasons did not induce any adverse effects on the growth and physiological functions of Japanese and Chinese tree species. Current acidic rain monitored in Japan and China, where the lowest acidity of ambient precipitation was around pH 4.0, was not found to induce any direct significant effects in the tree species examined.