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    Biochemical Adaptations in Zea mays Roots to Short-Term Pb2+ Exposure: ROS Generation and Metabolism
    (Springer, 2015) Kaur, Gurpreet; Kaur, Shubhpreet; Singh,Harminder Pal; Batish, Daizy Rani; Kohli, R.K.; Rishi, Valbha
    The present study investigated the effect of lead (0, 16, 40 and 80 mg L?1 Pb2+) exposure for 3, 12 and 24 h on root biochemistry in hydroponically grown Zea mays (maize). Pb2+ exposure (80 mg L?1) enhanced malondialdehyde content (239 %�427 %), reactive carbonyl groups (425 %�512 %) and H2O2 (129 %�294 %) accumulation during 3�24 h of treatment, thereby indicating cellular peroxidation and oxidative damage. The quantitative estimations were in accordance with in situ detection of ROS generation (using 2?,7?-dichlorodihydrofluorescein diacetate dye) and H2O2 accumulation. Pb2+ treatment significantly reduced ascorbate and glutathione content during 3�24 h of exposure. On the contrary, levels of non-protein thiols were enhanced by 3�11.8 time over control in response to 16�80 mg L?1 Pb2+ treatment, after 24 h. A dose-dependent induction in ascorbate peroxidase and lipoxygenase enzyme activity was observed in Z. mays roots. The activities of ascorbate-recycling enzymes (dehydroascorbate reductase and monodehydroascorbate reductase) were significantly increased in relation to concentration and duration of Pb2+ treatment. The study concludes that Pb2+-exposure induces ROS-mediated oxidative damage during early period of exposure despite the upregulation of enzymes of ascorbate�glutathione cycle.
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    Exogenous nitric oxide (NO) interferes with lead (pb)-induced toxicity by detoxifying reactive oxygen species in hydroponically grown wheat (Triticum aestivum) roots,
    (PLOS ONE, 2015) Kaur, Gurpreet; Singh, Harminder Pal; Batish, Daizy R.; Kohli, R.K.; Rishi, Valbha
    Nitric Oxide (NO) is a bioactive signaling molecule that mediates a variety of biotic and abiotic stresses. The present study investigated the role of NO (as SNP [sodium nitroprusside]) in ameliorating lead (Pb)-toxicity in Triticum aestivum (wheat) roots. Pb (50 and 250 ?M) alone and in combination with SNP (100 ?M) was given to hydroponically grown wheat roots for a period of 0�8 h. NO supplementation reduced the accumulation of oxidative stress markers (malondialdehyde, conjugated dienes, hydroxyl ions and superoxide anion) and decreased the antioxidant enzyme activity in wheat roots particularly up to 6 h, thereby suggesting its role as an antioxidant. NO ameliorated Pb-induced membrane damage in wheat roots as evidenced by decreased ion-leakage and in situ histochemical localization. Pb-exposure significantly decreased in vivo NO level. The study concludes that exogenous NO partially ameliorates Pb-toxicity, but could not restore the plant growth on prolonged Pb-exposure.
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    Tunnel Vision In Climate Policy: A Case Study Of CDM Forestry Projects In India
    (Indian Academy of Social Sciences, 2015) Gupta, Himangana; Ahluwalia, Amrik Singh; Kohli, R.K.
    This paper attempts to find out the social, economic andenvironmental impacts of the forestry projects under theClean Development Mechanism (CDM) of the KyotoProtocol. It is a case study of two -reforestation projects-undertaken by the private sector in the forest-richChhattisgarh, Odisha and Andhra Pradesh states of India.Some of the most fertile and forested regions ofChhattisgarh, Odisha and Andhra Pradesh have beendeclared as-severely degraded - on the basis of satellitedata for the purpose of CDM reforestation projects. Theprojects are on the lands owned by poor tribal people whohave been weaned away from subsistence farming. Theeconomic benefits of the project go to private companiesthat manufacture paper and fibre boards while the poorfarmers wait for the next harvest for succor. The project hasalso taken away much of the grazing lands from the villagers.Apart from leading to loss of biodiversity, eucalyptusplantations are known to be bad for total ecologicaleconomics. This is an example of how the market basedmechanisms of the Kyoto Protocol add to the pressure onbiodiversity.
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    Allelopathic potential of essential oil of wild marigold (Tagetes minuta L) against some invasive weeds
    (Open Academic Journals Index, 2015) Arora,Komal; Batish, Daizy R.; Singh,Harminder Pal; Kohli, R.K.
    Tagetes minuta is an aromatic plant native to Tropical America. It exhibits wide range of biological activity against insects, nematodes, microbes including medicinal properties. It also creates nuisance for agricultural land. This may be attributed to its allelopathic properties. Therefore, the present study investigated the allelopathic potential of volatile oil of T. minuta on other invasive weeds - Chenopodium murale L., Phalaris minor Retz. and Amaranthus viridis L. It was observed that the volatile oil of T. minuta significantly reduced the germination, growth, chlorophyll content and respiratory ability of recipient weeds in a dose dependent manner. Mitotic studies revealed a complete arrest of mitotic activity in cells of treated root tips of Allium cepa with various aberrations like distorted, trinucleolated and binucleated cells. Thus, it can be concluded that the volatile oil of T. minuta shows allelopathic potential on other plants and this property could be further explored for weed management.
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    Retraction notice to "Bioaccumulation and physiological responses to lead (Pb) in Chenopodium murale L."[YEESA(2018)83-90]
    (Academic Press, 2018) Sidhu, G.P.S.; Bali, A.S.; Bhardwaj, R.; Singh, H.P.; Batish, Daizy R.; Kohli, R.K.
    Available online This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Author Gagan Preet Singh. The corresponding author Gagan Preet Singh acknowledged Ravinder Kumar Kohli as one of the co-authors, whereas RK Kohli reported that he is neither the author nor part of the communication of this paper.
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    Phytotoxicity and cytotoxicity of Citrus aurantiifolia essential oil and its major constituents: Limonene and citral
    (Elsevier B.V., 2017) Fagodia, S.K.; Singh, H.P.; Batish, Daizy R.; Kohli, R.K.
    The essential oils are fast emerging as the source of natural herbicides owing to their environmentally benign properties. The focus of the present study, thus, was to investigate the phytotoxicity and cytotoxicity of Citrus aurantiifolia oil, and its major constituents-citral and limonene. C. aurantiifolia oil was selected due to its extreme commercialisation and safe nature. GC?MS analysis revealed that C. aurantiifolia oil is rich in monoterpenes (83.93%), with limonene (40.92%) and citral (27.46%) as the major compounds. Phytotoxicity was assessed against three agricultural weeds, Avena fatua, Echinochloa crus-galli and Phalaris minor, at concentration ranging from 0.10?1.50?mg/ml. Percent germination, IC50 value and seedling growth (root and coleoptile length) were significantly reduced in a dose-response manner. C. aurantiifolia oil, citral and limonene caused alteration in the cell cycle of Allium cepa root meristematic cells as evidenced by decrease in mitotic index (MI) and increase in chromosomal aberrations at progressive concentrations (0.01?0.10?mg/ml) and time periods (3?h and 24?h). Cytotoxic evaluation confirmed mitodepressive effect of the tested volatiles though the intensity was variable. Overall, citral was the most toxic followed by C. aurantiifolia oil and limonene. The significant phytotoxic activity of C. aurantiifolia oil and citral suggests the possibility of being developed into eco-friendly and acceptable products for weed management in agriculture system. ? 2017 Elsevier B.V.
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    Ethylenediamine disuccinic acid enhanced phytoextraction of nickel from contaminated soils using Coronopus didymus (L.) Sm.
    (Elsevier Ltd, 2018) Sidhu, G.P.S.; Bali, A.S.; Singh, H.P.; Batish, Daizy R.; Kohli, R.K.
    In a screenhouse, the applicability of biodegradable chelant ethylenediamine disuccinic acid (EDDS) to enhance Ni-phytoextraction by Coronopus didymus was tested for the first time. This study assayed the hypothesis based upon the role of EDDS on physiological and biochemical alterations and ameliorating phytoextraction capacity of C. didymus under nickel (Ni) stress. Pot experiments were conducted for 6 weeks and C. didymus plants were cultivated in soil artificially contaminated with 30, 50, and 70 mg kg?1 Ni treatments. Soil was amended with EDDS (2 mmol kg?1). Plants were harvested, 1 week after EDDS application. At 70 mg kg?1 Ni level, EDDS application dramatically enhanced the root and shoot Ni concentration from 665 and 644 to 1339 and 1338 mg kg?1, respectively. Combination of Ni + EDDS induced alterations in biochemical parameters of plants. EDDS addition posed pessimistic effects on growth, biomass, photosynthetic activity and protein content of the plants. Besides, application of EDDS stimulated the generation of superoxide anion, H2O2 content and MDA level. However, EDDS assisted mount in antioxidant activities (superoxide dismutase, catalase and glutathione peroxidase) considerably neutralised the toxicity induced by reactive oxygen species in plant tissues. The results revealed EDDS efficacy to ameliorate the performance of antioxidant enzymes and improved Ni translocation in plant tissues, thus strongly marked its affinity to be used together with C. didymus for Ni-phytoextraction. ? 2018 Elsevier Ltd