Browsing by Author "Arideep Mukherjee"

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A global perspective of fine particulate matter pollution and its health effects
(Springer New York LLC, 2018) Arideep Mukherjee; Madhoolika Agrawal
Fine particulate matter (PM) in the ambient air is implicated in a variety of human health issues throughout the globe. Regulation of fine PM in the atmosphere requires information on the dimension of the problem with respect to variations in concentrations and sources. To understand the current status of fine particles in the atmosphere and their potential harmful health effects in different regions of the world this review article was prepared based on peer-reviewed scientific papers, scientific reports, and database from government organizations published after the year 2000 to evaluate the global scenario of the PM2.5 (particles <2.5 μm in aerodynamic diameter), its exceedance of national and international standards, sources, mechanism of toxicity, and harmful health effects of PM2.5 and its components. PM2.5 levels and exceedances of national and international standards were several times higher in Asian countries, while levels in Europe and USA were mostly well below the respective standards. Vehicular traffic has a significant influence on PM2.5 levels in urban areas; followed by combustion activities (biomass, industrial, and waste burning) and road dust. In urban atmosphere, fine particles are mostly associated with different health effects with old aged people, pregnant women, and more so children being the most susceptible ones. Fine PM chemical constituents severely effect health due to their carcinogenic or mutagenic nature. Most of the research indicated an exceedance of fine PM level of the standards with a diverse array of health effects based on PM2.5 chemical constituents. Emission reduction policies with epidemiological studies are needed to understand the benefits of sustainable control measures for fine PM mitigation. © Springer International Publishing AG 2017.
Air pollutant levels are 12 times higher than guidelines in Varanasi, India. Sources and transfer
(Springer Verlag, 2018) Arideep Mukherjee; Madhoolika Agrawal
Air quality in an urban atmosphere is regulated by both local and distant emission sources. For air quality management in urban areas, identification of sources and their relationships with local meteorology and air pollutants are essential. The critical condition of air quality in Indo-Gangetic plain is well known, but lack of data on both local and distant emission sources limits the scope of improving air quality in this region. Concentrations of particulate matter of size lower than 10 μm (PM10) were assessed in the highly urbanized Varanasi city situated in middle Indo-Gangetic plain of India from 2014 to 2017, to identify the distant air pollution sources based on trajectory statistical models and local sources by conditional bivariate probability function. Modifying effects of meteorology and air pollutants on PM10 were also explored. Mean PM10 concentration for the study period was 244.8 ± 135.8 μg m−3, which was 12 times higher than the WHO annual guideline. Several distinct sources of traffic as the major source of PM10 were identified in the city. Trajectory statistical models like cluster analysis, potential source contribution function and concentration-weighted trajectory showed significant contributions from north-west and eastern directions in the transport of polluted air masses to the city. Dew point, wind speed, temperature and ventilation coefficient are the major factors in PM10 formation and dispersion. © 2018, Springer International Publishing AG, part of Springer Nature.
Air pollution governance in China and India: Comparison and implications
(Elsevier Ltd, 2023) Pu Wang; Dachuan Liu; Arideep Mukherjee; Madhoolika Agrawal; Huawei Zhang; Evgenios Agathokleous; Xue Qiao; Xiaobin Xu; Yan Chen; Tong Wu; Mengye Zhu; Eri Saikawa; Shashi Bhushan Agrawal; Zhaozhong Feng
Severe air pollution in China and India threatens the health of over one-third of the global population. When it comes to air pollution governance, the two countries have vastly different approaches. China's approach features centralized target-setting and implementation, with policies enforced primarily through top-down administrative lines. While India's approach reflects the division of power among central and state governments and relies substantially on legislative and judiciary systems for accountability. We conduct a detailed review of the trends and sources of six air pollutants in China and India, and make a structured comparison of China and India's air pollution policy frameworks. An extensive literature review is conducted to evaluate the effectiveness of policies in each country. The studies show that China's policy efforts have achieved significant improvements in air quality, while India's policies have been largely ineffective. Nevertheless, both approaches have the potential to lead to effective air pollution governance, if a country can build strong political will and clearly defined accountability systems. We further identify key lessons learned from the two countries for air pollution policymaking in developing countries, including taking good advantage of “post-crisis policy window”, and targeting “low-hanging fruits” to make incremental improvements in a cost-effective way. © 2023 Elsevier Ltd
Alterations in growth, antioxidative defense and medicinally important compounds of Curcuma caesia Roxb. under elevated ultraviolet-B radiation
(Elsevier B.V., 2020) Deepanshi Jaiswal; Avantika Pandey; Arideep Mukherjee; Madhoolika Agrawal; Shashi Bhushan Agrawal
Ultraviolet-B (UV-B) radiation is a well-known stress factor, as involved in the generation of free radicals, and induction factor which permutates growth, metabolic processes, and secondary metabolites synthesis of plants. However, its impact on medicinal plants is less explored particularly in relation to secondary metabolites associated with the medicinally important rhizomes. An endangered medicinal plant (Curcuma caesia Roxb.) grown under natural field conditions was exposed to elevated UV-B (ambient ± 9.6 kJ m−2 d-1) to assess changes in growth, antioxidant profile, defense strategy and the secondary metabolites of the rhizome. Results showed that eUV-B induced the generation of different reactive oxygen species (·O2- radical and H2O2) which were counteracted by induction of UV absorbing pigments (flavonoids and anthocyanin), non-enzymatic (ascorbic acid) and enzymatic antioxidants (peroxidase, ascorbate peroxidase and catalase) at different growth stages. However, phenol, thiol and superoxide dismutase activity showed reduction at all the growth stages. Protection from UV-B was also manifested by an increase in total free radical scavenging activity, metal chelation and reducing activity. Alterations in biomass allocation might be a possible mechanism of defense which persuaded to higher increment in above ground biomass and tuber biomass with 47 % diminution of rhizome biomass. Among the four classes of compounds identified, sterols were increased whereas reductions were more prominent in fatty acids followed by monoterpenes and sesquiterpenes. Increased production of epicurzereonone, elemene, pinandiol, and 1,8-cineole whereas curcumenol, D-camphor, eucalyptol, curcumenone, isocurcumenol, and zederone were reduced. Elevated UV-B also induced the production of some anti-cancerous compounds such as furanodiene and caryophyllene. © 2020 Elsevier B.V.
Ascorbic acid and thiols as potential biomarkers of ozone tolerance in tropical wheat cultivars
(Academic Press, 2019) Adeeb Fatima; Aditya Abha Singh; Arideep Mukherjee; Madhoolika Agrawal; Shashi Bhushan Agrawal
Tropospheric ozone (O 3 ) has been identified as the most damaging air pollutant to crop plants in terms of growth and yield reductions. Considering the negative effect of O 3 in tropical regions, fourteen commonly grown Indian wheat cultivars with known sensitivity to O 3 were tested for their sensitivity/tolerance with respect to two major antioxidants (ascorbic acid and thiols) and grain yield responses against elevated O 3 (ambient + 30 ppb) exposure. The objectives of the study were to assess the usefulness of the biochemical markers in the screening of wheat cultivars having differential level of sensitivity to O 3 and different release time (modern and old cultivars). Ozone exposure led to an upsurge of ascorbic acid, thiols as well as their ratio greatly in the tolerant group followed by the intermediately sensitive group while least in sensitive one. Both ascorbic acid and thiol contents offered more resistance to early released cultivars compared to modern ones. Ascorbic acid served to be the most influential parameter for determining varietal response under elevated O 3 stress and directly linked with O 3 tolerance. Overall, the sensitive group suffered maximum yield losses while the minimum was observed in the tolerant group due to the differential enhancement of tolerance offered by antioxidants. Higher concentrations of antioxidants at early growth stages were highly correlated with final yield responses suggesting the role of antioxidants as a determinant of final yield. Findings of this study will help in the identification of O 3 tolerant and sensitive wheat cultivars for future screening programs using ascorbic acid and thiols as important markers of O 3 tolerance. © 2019 Elsevier Inc.
Assessment of local and distant sources of urban PM2.5 in middle Indo-Gangetic plain of India using statistical modeling
(Elsevier Ltd, 2018) Arideep Mukherjee; Madhoolika Agrawal
Ambient air particulate matter is regulated by source complexity, short and distant sources, associated meteorological and atmospheric factors. For the implementation of appropriate policies for mitigation of air pollutants, information regarding air pollution status, sources and modifying factors are needed. Previous studies in Indo-Gangetic plain (IGP) have identified PM2.5 (particles 2.5 μm or less in size) variations and its sources but no studies have yet identified the local and long-range sources of PM2.5 and their relationships with other air pollutants and meteorology. The local and distant sources of PM2.5 were investigated from 2014 to 2017 in Varanasi city located in middle IGP of India by conditional bivariate probability function (CBPF), land use regression (LUR) and trajectory statistical models (TSM) like potential source contribution function (PSCF), concentration weighted trajectory (CWT) and trajectory cluster analysis. Fine PM levels in Varanasi city exceeded the daily mean 24-h national Central Pollution control board (CPCB) and WHO standards for ~75 and 93% of monitoring days, indicating the alarming status of PM pollution in this area. CBPF identified traffic as the major probable local source which contributed maximally to high PM level followed by paved road dust and local combustion activities. LUR also identified traffic variables such as heavy vehicle intensity, distance from the highway, traffic intensity (within 500 m buffer) and percent green cover as major predictor variables influencing PM2.5 distribution in the city. PSCF, CWT and cluster analysis identified the north-western part of India as the most probable source region for contributing higher PM2.5 mass to Varanasi city. Dewpoint temperature, ventilation coefficient, wind speed and daily minimum temperature were identified as major meteorological variables and NO2 and CO as major gaseous air pollutants which modified PM concentrations. Outcomes of the study will be helpful in source identification and PM2.5 abatement in cities of IGP. © 2018 Elsevier B.V.
Assessment of ozone sensitivity in three wheat cultivars using ethylenediurea
(MDPI AG, 2019) Adeeb Fatima; Aditya Abha Singh; Arideep Mukherjee; Tsetan Dolker; Madhoolika Agrawal; Shashi Bhushan Agrawal
Three wheat (Triticum aestivum L.) cultivars [HD 2987 (ozone (O 3 ) sensitive), PBW 502 (intermediately sensitive) and Kharchiya 65 (O 3 tolerant)] with known sensitivity to O 3 were re-evaluated using ethylenediurea (EDU; 400 ppm) to ascertain the use of EDU in determiningO3 sensitivity under highly O3-polluted tropical environments. EDU treatment helped in improving the growth, biomass, photosynthetic pigments and the antioxidative defense system of all the wheat cultivars. Under EDU treatment, PBW 502 retained more biomass, while HD 2987 showed better performance and ultimately the greatest increment in yield. Cultivar Kharchiya 65 also showed a positive response to EDU as manifested with an increase in pigment contents, total biomass and enzymatic antioxidants; however, this increment was comparatively lower compared to the other two cultivars. The results indicated that EDU did not have many physiological effects on cultivars but helped in counteracting O 3 primarily by scavenging reactive oxygen species and enhancing the antioxidative defense system where superoxide dismutase emerged as the major responsive biochemical parameter against ambient O 3 . The observed results clearly indicated that differential O 3 sensitivity in three wheat cultivars established by the previous study is in accordance with the present study using EDU as a sensitivity tool, which is an easy and efficient technology in comparison to chamber and Free-Air Carbon dioxide Enrichment (FACE) experiments although its mechanistic understanding needs to be further validated. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
Assessment of ozone toxicity among 14 Indian wheat cultivars under field conditions: growth and productivity
(Springer International Publishing, 2018) Aditya Abha Singh; Adeeb Fatima; Amit Kumar Mishra; Nivedita Chaudhary; Arideep Mukherjee; Madhoolika Agrawal; Shashi Bhushan Agrawal
Tropospheric ozone (O3) is a well-known threat to global agricultural production. Wheat (Triticum aestivum L.) is the second most important staple crop in India, although little is known about intra-specific variability of Indian wheat cultivars in terms of their sensitivity against O3. In this study, 14 wheat cultivars widely grown in India were exposed to 30 ppb elevated O3 above ambient level using open top chambers to evaluate their response against O3 stress. Different growth and physiological parameters, foliar injury and grain yield were evaluated to assess the sensitivity of cultivars and classified them on the basis of their cumulative stress response index (CSRI). Due to elevated O3, growth parameters, plant biomass, and photosynthetic rates were negatively affected, whereas variable reductions in yield were observed among the test cultivars. Based on CSRI values, HD 2987, DBW 50, DBW 77, and PBW 550 were classified as O3 sensitive; HD 2967, NIAW 34, HD 3059, PBW 502, HUW 213, and HUW 251 as intermediately sensitive, while HUW12, KUNDAN, HUW 55, and KHARCHIYA 65 were found to be O3-tolerant cultivars. Cultivars released after year 2000 were found to be more sensitive compared to earlier released cultivars. Path analysis approach showed that leaf area, plant biomass, stomatal conductance, net assimilation rate, and absolute growth rate were the most important variables influencing yield under O3 stress. Findings of the current study highlight the importance of assessing differential sensitivity and tolerance of wheat cultivars and response of different traits in developing resistance against elevated O3. © 2018, Springer International Publishing AG, part of Springer Nature.
Emission of Greenhouse Gases from Soil: An Assessment of Agricultural Management Practices
(Springer Singapore, 2020) Bhavna Jaiswal; Arideep Mukherjee; Bhanu Pandey; Madhoolika Agrawal
Increasing concentrations of the atmospheric greenhouse gases (GHGs) are serious threats to the living beings and their niches. The rapid increase in GHGs is undoubtedly related to anthropogenic activities. Literature related to GHG emissions and mitigation approaches is widely available, but very few reviews concentrated on spatial-temporal trends of GHG emission from the agriculture sector. Agriculture is a potent contributor to GHG emissions, involving different agricultural practices followed by the farmers, which affect the rate of emission either positively or negatively. Agricultural soil management practices add excess nutrients, which disturb the natural mineral cycling leading to soil and water pollution and increase emission from soil to atmosphere, thus contributing to climate change. Research papers and reports related to GHG emission from different agricultural sectors in different parts of the world were reviewed to find the variations in emission pattern and intensities, and the factors influencing the emissions from the soil. The soil GHG emissions are directly or indirectly modified by natural as well as anthropogenic factors, like pH, soil texture, tilling, fertilizer application, mulching, irrigation, etc. The determinants taking part in the soil GHG emissions varied with region and different agricultural practices. Different mitigation approaches for GHGs from the agriculture sector were also compared for their efficacy in reducing emissions. A variety of advanced techniques developed to enhance the yield of crops were found to influence GHG emissions by direct influence on soil pH, temperature, and moisture. The conditions favorable for GHG emissions can be modified to reduce the emissions as the soil acts both as a reservoir and as an emitter of GHGs based on local natural and anthropogenic factors. © Springer Nature Singapore Pte Ltd. 2020.
Heavy metal accumulation potential and tolerance in tree and grass species
(Springer Singapore, 2016) Arideep Mukherjee; Shashi Bhushan Agrawal; Madhoolika Agrawal
Heavy metals (HM) are nondegradable, persistent, and toxic elements. Heavy metal contamination is a global concern and a major health hazard throughout the world. However, plants have evolved different mechanisms to combat these stresses and even have potential to accumulate them in large quantity. Natural flora has differential ability to metal tolerance with some plants showing induced tolerance at metal-enriched medium, whereas others find it difficult to sustain. Bioaccumulation potential of trees and grasses will be assessed based on peer-reviewed publications. Plants will be classified based on their accumulation potential of different heavy metals. Metal accumulation ability in plants and sources of heavy metals will be assessed for different regions of the world. Anthropogenic input of heavy metals from different sources significantly affects the biogeochemical cycling. Heavy metal depositions considerably affect the plant response. Heavy metal tolerance, uptake, and accumulation in different parts of the plant and possible metal-chelating compounds and their role in metal chelation in trees and grasses will be discussed. Morphological, physiological, biochemical, and molecular biomarkers of heavy metal tolerance or sensitivity among the trees and grasses will be correlated with bioaccumulation potential and heavy metal tolerance. This article will provide a broad overview of higher plant abilities and tolerance capabilities in heavy metal accumulation. © Springer Nature Singapore Pte Ltd. 2016.
Intra-urban variability of ozone in a tropical city—characterization of local and regional sources and major influencing factors
(Springer Netherlands, 2018) Arideep Mukherjee; Shashi Bhushan Agrawal; Madhoolika Agrawal
Tropospheric ozone (O3), a secondary air pollutant, was assessed to evaluate the intra-urban variability of O3, its local and distant sources, and the influence of O3 precursor gases and meteorological variables on seasonal and temporal trends of O3 from 2013 to 2017 in a tropical urban city located in the middle Indo-Gangetic Plains of India. Passive samplers and data from real-time air quality monitoring station were considered. Trajectory statistical models, multivariate statistical methods, and geographic information system were further used to identify spatial-temporal variability and source apportionment. O3 concentrations showed significant intra-urban variability with higher concentrations in suburban or background regions of the city, which were mostly attributed to the transport of O3 at high wind speed from distant and rural areas away from the city, while lower concentrations in traffic and commercial areas were due to titration of O3 by nitric oxide (NO). Variations in meteorological variables (temperature, relative humidity, wind speed) and planetary boundary layer height were responsible for seasonal variations in O3 concentrations. Long-range and regional transport of O3 and its precursors such as volatile organic compounds and NOx from the northwestern and eastern directions of the city significantly influenced O3 variability with distinct seasonal patterns. A negative trend in O3 levels was recorded during the study period which may be due to increase in NOx emission in the city. The observed outcomes suggest significant intra-urban variability of O3 in the city which is influenced by traffic as well as by distant and local sources. © 2018, Springer Nature B.V.
Ozone a persistent challenge to food security in India: Current status and policy implications
(Elsevier B.V., 2021) Arideep Mukherjee; Durgesh Singh Yadav; Shashi Bhushan Agrawal; Madhoolika Agrawal
With the rising population, urbanization and industrialization, tropospheric ozone (O3) pollution has become a serious challenge to India's food security. We have reviewed the O3 exposure-based Indian studies on yield and quality losses in important crops under the current and future concentrations of O3 to identify the current challenges and policy interventions to reduce the risk of O3 threat to food security in India. The order of sensitivity in major crops is wheat ˃ mustard > rice > maize under ambient O3 concentration. However, the sensitivity of crops at elevated O3 (10–30 ppb) varied with exposure dose, stomatal flux, intrinsic defense response, etc. Effective implementation of the reduction in emission of O3 precursor gases and growing O3 tolerant crops might be helpful to mitigate the O3 impacts at local and national levels. © 2020 Elsevier B.V.
Ozone phytotoxicity to Panicum maximum and Cenchrus ciliaris at Indo-Gangetic plains: an assessment of antioxidative defense and growth responses
(Springer New York LLC, 2019) Tsetan Dolker; Arideep Mukherjee; Shashi Bhushan Agrawal; Madhoolika Agrawal
Two common tropical grassland species, Panicum maximum Jacq. (Guinea grass) and Cenchrus ciliaris (Buffel grass) of Indo-Gangetic plains were assessed for their responses under future level of O3 (ambient +30 ppb) using open top chambers. Plants were assessed for foliar injuries, pigments, growth, biomass accumulation, histochemical localization of reactive oxygen species (ROS), antioxidant defense system and ROS scavenging activities at two stages. Foliar injuries were noticed at an early stage in P. maximum compared to C. ciliaris. Significant reductions were observed in total chlorophyll, growth and total biomass in both species. Significant increases in contents of melondialdehyde and ascorbic acid in P. maximum while total phenolics and thiols in C. ciliaris were found. Histochemical analysis showed more production of superoxide radicals and hydrogen peroxide in leaf tissues of P. maximum compared to C. ciliaris. It can be concluded that higher level of primary antioxidants (total phenolics and thiols) along with superoxide dismutase and ascorbate peroxidase scavenged O3 effectively in C. ciliaris causing less reduction of biomass which is used as a feed for cattles. In P. maximum, more photosynthates were allocated for defense, leading to higher reduction in total biomass compared to C. ciliaris. The leaf area ratio was higher in P. maximum compared to C. ciliaris under elevated O3. The study further suggests higher susceptibility of P. maximum compared to C. ciliaris under future level of O3 exposure. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
Ozone pollution threatens the production of major staple crops in East Asia
(Springer Nature, 2022) Zhaozhong Feng; Yansen Xu; Kazuhiko Kobayashi; Lulu Dai; Tianyi Zhang; Evgenios Agathokleous; Vicent Calatayud; Elena Paoletti; Arideep Mukherjee; Madhoolika Agrawal; Rokjin J. Park; Yujin J. Oak; Xu Yue
East Asia is a hotspot of surface ozone (O3) pollution, which hinders crop growth and reduces yields. Here, we assess the relative yield loss in rice, wheat and maize due to O3 by combining O3 elevation experiments across Asia and air monitoring at about 3,000 locations in China, Japan and Korea. China shows the highest relative yield loss at 33%, 23% and 9% for wheat, rice and maize, respectively. The relative yield loss is much greater in hybrid than inbred rice, being close to that for wheat. Total O3-induced annual loss of crop production is estimated at US$63 billion. The large impact of O3 on crop production urges us to take mitigation action for O3 emission control and adaptive agronomic measures against the rising surface O3 levels across East Asia. © 2022, The Author(s), under exclusive licence to Springer Nature Limited.
Pollution Response Score of Tree Species in Relation to Ambient Air Quality in an Urban Area
(Springer New York LLC, 2016) Arideep Mukherjee; Madhoolika Agrawal
Multivariate statistical techniques were employed on twelve leaf traits in four selected common tree species (Mangifera indica L., Polyalthia longifolia Sonn., Ficus benghalensis L. and Psidium guajava L.) to evaluate their responses with respect to major air pollutants in an urban area. Discriminant analysis (DA) identified chlorophyll/carotenoid ratio, leaf dry matter content, carotenoids, net water content and ascorbic acid as the major discriminating leaf traits, which varied maximally with respect to the pollution status. Pollution response score (PRS), calculated on the basis of discriminate functional coefficient values, increased with an increase in air pollution variables for all the tested species, with the highest increase in P. longifolia and the lowest in F. benghalensis. The study highlights the usefulness of DA for evaluation of plant specific traits and PRS for selection of tolerant species. © 2015 Springer Science+Business Media.
Response of plants to atmospheric air pollution: An Asian perspective
(Elsevier, 2021) Arideep Mukherjee; Srishti Mishra; S.B. Agrawal; Madhoolika Agrawal
Plants are the most dynamic, unique, plastic, adaptive, and fascinating organisms in the world, since evolutionary changes in climate, geography, and biogeochemical cycling have caused plants to uniquely adapt to their surroundings and sustain for long periods of time. Increasing concentrations of atmospheric gases and particulate matter (PM) have raised serious concerns over human and plant health. In this chapter, we have made efforts to understand the unique response of different plant types in Asian countries under different pollution loads with the following goals: (i) to understand the current status of air pollution-induced plant response in different vegetation types, (ii) to understand the differential ability of plants in coping with the air pollution stress, (iii) to understand the response of plants to emerging air pollutants, (iv) to understand the urban greenery and its relationship with air pollution, and (v) to provide future recommendations in fulfilling the research gap in the area of plant stress response assessment under air pollution stress. © 2022 Elsevier Inc All rights reserved.
Responses of a semi-natural grassland community of tropical region to elevated ozone: An assessment of soil dynamics and biomass accumulation
(Elsevier B.V., 2020) Tsetan Dolker; Arideep Mukherjee; Shashi Bhushan Agrawal; Madhoolika Agrawal
Despite knowing the phytotoxic effects of tropospheric ozone (O3), which is of global concern, there is no study so far reported about its impacts on grassland community of tropical regions. Therefore, we assessed the responses of a semi-natural grassland community of Indo-Gangetic plains to elevated O3 exposure (Ambient + 20 ppb) compared to ambient after three years of exposure using open-top chambers. Percent decreases were found in above (26%; p ≤ 0.002) and belowground (30%; p ≤ 0.003) biomass under elevated compared to ambient O3 exposure. Percent decrements in total organic carbon (TOC; 24%; p ≤ 0.001), total nitrogen (29%; p ≤ 0.001) and available phosphorus (11%; p ≤ 0.002) in the soil were also observed under elevated O3 exposure. Exposure at elevated O3 reduced soil microbial biomass and activities of β-glucosidase, amylase, urease and phosphatase, while polyphenol oxidase and peroxidase showed enhancement in their activities, showing negative effects on belowground soil health. Percent reduction in root shoot ratio (10%; p ≤ 0.05) depicts that less C-allocation towards root system led to a reduction in TOC in the soil, which could affect C-sequestration under elevated O3 condition in the semi-natural grasslands. Elevated O3 also affected enzymes participating in N and P-cycles, causing reductions in total nitrogen and phosphorus. The study concludes that projected O3 concentrations have serious implications for aboveground biomass as well as belowground soil health in tropical areas, identified as hotspots of O3 in the world. © 2018 Elsevier B.V.
Responses of an old and a modern Indian wheat cultivar to future O3 level: Physiological, yield and grain quality parameters
(Elsevier Ltd, 2020) Durgesh Singh Yadav; Amit Kumar Mishra; Richa Rai; Nivedita Chaudhary; Arideep Mukherjee; S.B. Agrawal; Madhoolika Agrawal
A field study was conducted to understand the physiological responses, yield and grain quality of an old (HUW234) and a modern (HD3118) wheat cultivar exposed to elevated ozone (O3). The cultivars were grown under ambient O3 (NF) and ambient +20 ppb O3 (NF+) conditions using open-top chambers (OTCs). The comparative study of an old and a modern cultivar showed variable physiological responses under elevated O3 exposure. Elevated O3 in old cultivar caused high reductions in Rubisco activity (Vcmax) and electron transport rate (J) compared to modern cultivar with simultaneous reductions in the rate of photosynthesis and chlorophyll fluorescence. In modern cultivar, high stomatal density and conductance caused higher O3 uptake thereby triggering more damage to the adjacent stomatal cells and photosynthetic pigments coupled with reductions in photosynthetic rate and photosynthetic nitrogen use efficiency (PNUE). Modern cultivar also showed relatively high reduction in grain yield compared to old one under NF + treatment. Furthermore, grain quality traits (such as starch, protein and amino acids) of modern cultivar were better than old cultivar under ambient O3, but showed more deterioration under NF + treatment. Results thus indicated that modern cultivar is relatively more susceptible to O3 and showed more negative impacts on plant performance, yield and quality of grains compared to old cultivar. © 2020 Elsevier Ltd
Responses of tropical and subtropical plants to air pollution
(Springer Singapore, 2019) Arideep Mukherjee; Bhanu Pandey; S.B. Agrawal; Madhoolika Agrawal
The tropical and subtropical regions of the world are facing strong negative effects of globalization, weakening the critical balance between ecosystem stability and socioeconomic development. Apart from increasing pressures of global climate change, deforestation, and shifts in land use pattern, air pollution is emerging as one of the major factors influencing ecosystem structure and function. Issues related to health, agricultural production, and economic losses due to air pollution in the tropical and subtropical regions are well known; however, information on air pollution-related effects on the tropical vegetation is limited. Therefore, based on the current literature, the status of air pollution and its effects on vegetation in the tropical and subtropical regions of the globe are explored in this chapter to understand the current scenario and to identify the knowledge gaps. Spatial and temporal variations were detected among different regions for particulate matter, its constituents, and gaseous pollutants including identification of the factors and sources influencing the air quality. Air pollution impacts were assessed based on changes in ecosystem structure and functions such as the patterns of biodiversity change, alteration in litterfall and decomposition, the response of leaf functional traits, and bioaccumulation in the community or individual plant species. Air pollution significantly influenced major ecological processes such as litterfall, decomposition, and plant diversity indirectly through changes in soil quality as well as through a direct effect on growth and physiol ogy of native plants. Plants respond to changes in air quality through alternation in growth and morphology, physiological plasticity, and modifying leaf functional traits. These responses are both species- and pollutant-specific, as not all species responded equally to air pollution. Bioaccumulation pattern also showed a distinct relationship between pollutant accumulation and species specificity. © Springer Nature Singapore Pte Ltd. 2019.
Responses of tropical tree species to urban air pollutants: ROS/RNS formation and scavenging
(Elsevier B.V., 2020) Arideep Mukherjee; Shashi Bhushan Agrawal; Madhoolika Agrawal
Air pollution in an urban environment is the major stress factor for vegetation due to the direct generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). To quantify urban air pollution-induced ROS/RNS formation, damage and detoxification, nine different biochemical parameters related to free radical formation, scavenging and membrane damage were estimated in twelve tropical tree species. The experiment was performed in three different seasons at four distinct urban environments in Varanasi city located in the Indo-Gangetic plain of India. Redundancy analysis was performed to statistically assess the relationship between air pollutants (PM2.5, NO2, SO2 and O3) and temperature with ROS/RNS generation and their detoxification. Significant effects of air pollution exposure and temperature on ROS/RNS formation, scavenging and membrane damage were recorded with increasing pollution load in the city for all the tree species. The extent of variability (47–87%) in responses of different tree species was due to their intrinsic ability to scavenge free radicals which minimized the membrane damage. PM2.5, NO2 and O3 were identified as major pollutants that influenced trees to different extents in regulating ROS/RNS. However, the response was maximum against NO2 (34–72%) followed by PM2.5 (16–64%) and O3 (3–31%), indicating that under urban environment, trees are considerably sensitive to the combined effects of both particulate and gaseous pollutants. Reactive oxygen intermediate release, total free radical scavenging activity, NO scavenging activity and membrane stability index were identified as major parameters which showed distinct responses with increasing pollution load. Caesalpinia sappan, Ficus religiosa and Albizia lebbeck were identified as most tolerant tree species having higher ROS/RNS scavenging potential resulted in lower membrane damage. Thus responses of urban trees to air pollution are governed by their intrinsic defence mechanisms to scavenge ROS/RNS by maintaining the membrane integrity through integrated cross-talk between different antioxidative pathways. © 2018