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Mohamed E, Ansari N, Yadav DS, Agrawal M, Agrawal SB. Salinity alleviates the toxicity level of ozone in a halophyte Mesembryanthemum crystallinum L. ECOTOXICOLOGY (LONDON, ENGLAND) 2021; 30:689-704. [PMID: 33742348 DOI: 10.1007/s10646-021-02386-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/01/2021] [Indexed: 05/26/2023]
Abstract
Mesembryanthemum crystallinum (Ice plant) is an annual halophytic plant species spread in the coastal areas of the Mediterranean Sea, Egypt. Information about the behaviour of halophytes under the future concentration of ozone (O3) is scanty. Therefore, we have assessed the effects of elevated O3 (ambient + 20 ppb), moderate salinity (200 mM NaCl), and their combined treatment (salinity + elevated O3) on various morphological, growth, physiological, biochemical and anatomical parameters of Egyptian ice plant. Under salinity stress, plant growth, percentage of pigmented leaf and its thickness, ROS levels, antioxidative enzymes, and ROS scavenging activities were increased, while photosynthetic pigments and efficiency were decreased compared to the control. Elevated O3 exposure led to reductions in most of the growth parameters and pigments, while ROS levels, histochemical localization of H2O2 and ·O2-, antioxidative enzymes and non-enzymatic antioxidants (betacyanin, phenolics, thiols and ascorbic acid) showed increases. Surprisingly, salinity alleviated the oxidative stress of elevated O3 due to the rise of SOD activity, antioxidant compounds, and a decrease of ·O2- production rate with concomitant increases of most of the growth parameters. Thick lower collenchyma and enhancement of xylem parenchyma under O3 and combined treatment suggested that anatomical acclimation also operated under O3 stress and salinity played a vital role in the growth of this plant under combined stress. Results showed that salt is essential for the optimum development of this species and its role is extended to alleviate the oxidative damage caused by elevated O3. The results further recommend the use of Egyptian M. crystallinum as a O3 tolerant crop for saline areas along the Mediterranean Sea coast.
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Affiliation(s)
- Elsayed Mohamed
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
- Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Assuit, 71524, Egypt
| | - Naushad Ansari
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Durgesh Singh Yadav
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Madhoolika Agrawal
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Shashi Bhushan Agrawal
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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Dolker T, Mukherjee A, Agrawal SB, Agrawal M. Responses of a semi-natural grassland community of tropical region to elevated ozone: An assessment of soil dynamics and biomass accumulation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 718:137141. [PMID: 32086084 DOI: 10.1016/j.scitotenv.2020.137141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 02/04/2020] [Accepted: 02/04/2020] [Indexed: 06/10/2023]
Abstract
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.
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Affiliation(s)
- Tsetan Dolker
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Arideep Mukherjee
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Shashi Bhushan Agrawal
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Madhoolika Agrawal
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, India.
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Dolker T, Mukherjee A, Bhushan Agrawal S, Agrawal M. Ozone phytotoxicity to Panicum maximum and Cenchrus ciliaris at Indo-Gangetic plains: an assessment of antioxidative defense and growth responses. ECOTOXICOLOGY (LONDON, ENGLAND) 2019; 28:853-868. [PMID: 31392634 DOI: 10.1007/s10646-019-02088-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/22/2019] [Indexed: 06/10/2023]
Abstract
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.
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Affiliation(s)
- Tsetan Dolker
- Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Arideep Mukherjee
- Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Shashi Bhushan Agrawal
- Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Madhoolika Agrawal
- Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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Hewitt DKL, Mills G, Hayes F, Davies W. The climate benefits of high-sugar grassland may be compromised by ozone pollution. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 565:95-104. [PMID: 27161131 DOI: 10.1016/j.scitotenv.2016.04.151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/20/2016] [Accepted: 04/21/2016] [Indexed: 06/05/2023]
Abstract
High sugar ryegrasses (HSG) have been developed to improve the uptake, digestion and nitrogen (N)-utilisation of grazing stock, with the potential to increase production yields and benefit climate by reducing methane (CH4) and nitrous oxide (N2O) emissions from livestock farming. In this study, the effects of tropospheric ozone pollution on the seasonal growth dynamics of HSG pasture mesocosms containing Lolium perenne cv. AberMagic and Trifolium repens cv. Crusader were investigated. Species-specific ozone (O3) dose-response relationships (seasonal means: 35, 41, 47, 51, 59 & 67ppb) based on the Phytotoxic Ozone Dose (PODy) were constructed for above and below ground biomass, injury, N-fixation and forage quality. The dynamics of effects of ozone exposure on HSG pasture changed over the course of a season, with the strongest responses occurring in the first 4-8weeks. Overall, strong negative responses to ozone flux were found for root biomass, root nodule mass and N-fixation rates, and ozone adversely impacted a range of forage quality parameters including total sugar content and relative and consumable food values. These results indicate that increasing ozone pollution could decrease the N-use efficiency and reduce the sugar content of managed pasture, and thereby partially detract from some of the suggested benefits of HSG.
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Affiliation(s)
- D K L Hewitt
- Centre for Ecology & Hydrology, Environment Centre Wales, Deinol Road, Bangor, Gwynedd LL57 2UW, UK,; Lancaster University, Lancaster Environment Centre, Lancaster, Lancashire LA1 4YQ, UK,.
| | - G Mills
- Centre for Ecology & Hydrology, Environment Centre Wales, Deinol Road, Bangor, Gwynedd LL57 2UW, UK
| | - F Hayes
- Centre for Ecology & Hydrology, Environment Centre Wales, Deinol Road, Bangor, Gwynedd LL57 2UW, UK
| | - W Davies
- Lancaster University, Lancaster Environment Centre, Lancaster, Lancashire LA1 4YQ, UK
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De Kok LJ, Grantz DA, Burkey KO. Plants and the changing environment. PLANT BIOLOGY (STUTTGART, GERMANY) 2016; 18 Suppl 1:3-4. [PMID: 26769096 DOI: 10.1111/plb.12413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- L J De Kok
- Laboratory of Plant Physiology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, P.O. Box 11103, 9700 CC, Groningen, The Netherlands.
| | - D A Grantz
- Department of Botany and Plant Sciences, University of California, Riverside, Parlier, 93648, CA, USA.
| | - K O Burkey
- U.S. Department of Agriculture, Agricultural Research Service, Plant Science Research, Department of Crop Science, North Carolina State University, 3127 Ligon Street, Raleigh, 27607, NC, USA.
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