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Item ?-Pinene moderates Cr(VI) phytotoxicity by quenching reactive oxygen species and altering antioxidant machinery in maize(Springer Verlag, 2019) Mahajan P.; Singh H.P.; Kaur S.; Batish D.R.; Kohli R.K.We examined the possible role of monoterpene ?-pinene in providing protection against Cr(VI) toxicity in maize (Zea mays). Treatment with β-pinene (10 μM) significantly alleviated Cr(VI) accumulation and recuperated Cr(VI) caused decline in root and coleoptile growth in maize. ?-Pinene addition caused a decline in Cr(VI)-induced accumulation of superoxide anion, hydroxyl ion, hydrogen peroxide and confirmed by in-situ detection of ROS using histochemical localization. It suggested that the ?-pinene quenches/neutralizes enhanced ROS generated under Cr(VI) exposure. ?-Pinene also reduced Cr(VI)-induced electrolyte leakage, thereby suggesting its role in membrane stabilization. Further, ?-pinene regulated the activity of scavenging enzymes, thereby suggesting a role in modulating Cr(VI)-induced oxidative damage. In conclusion, our results suggest that the addition of ?-pinene has a protective role against Cr(VI) stress and provides resistance to maize against Cr(VI) toxicity.Item Appraisal of immediate and late effects of mobile phone radiations at 2100�MHz on mitotic activity and DNA integrity in root meristems of Allium cepa(Springer-Verlag Wien, 2019) Chandel S.; Kaur S.; Issa M.; Singh H.P.; Batish D.R.; Kohli R.K.The present study evaluated the potential of 2100�MHz radiofrequency radiations to act as cytotoxic and genotoxic agent. Fresh onion (Allium cepa L.) roots were exposed to electromagnetic field radiations (EMF-r) for different durations (1�h and 4�h) and evaluated for mitotic index (MI), phase index, chromosomal aberrations, and DNA damage. DNA damage was investigated with the help of the comet assay by assessing various parameters like % head DNA (HDNA), % tail DNA (TDNA), tail moment (TM), and olive tail moment (OTM). Effects of EMF-r exposure were also compared with that of methyl methanesulfonate (MMS; 90�?M), which acted as a positive control. The post-exposure effects of EMF-r after providing the test plants with an acclimatization period of 24�h were also evaluated. Compared to the control, a significant increase in the MI and aberration percentage was recorded upon 4�h of exposure. However, no specific trend of phase index in response to exposure was detected. EMF-r exposure incited DNA damage with a significant decrease in HDNA accompanied by an increase in TDNA upon exposure of 4�h. However, TM and OTM did not change significantly upon exposure as compared to that of control. Analysis of the post-exposure effects of EMF-r did not show any significant change/recovery. Our data, thus, suggest the potential cytotoxic and genotoxic nature of 2100�MHz EMF-r. Our study bears great significance in view of the swiftly emergent EMF-r in the surrounding environment and their potential for inciting aberrations at the chromosomal level, thus posing a genetic hazard. � 2019, Springer-Verlag GmbH Austria, part of Springer Nature.Item 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, ValbhaThe 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.Item 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, ValbhaNitric 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.Item 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.Item 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.Item Eugenol-inhibited root growth in Avena fatuainvolves ROS-mediated oxidative damage(Elsevier, 2015) Ahuja, Nitin; Singh, Harminder Pal; Batish, Daizy. R.; Kohli, R.K.,Plant essential oils and their constituent monoterpenes are widely known plant growth retardants but their mechanism of action is not well understood. We explored the mechanism of phytotoxicity of eugenol, a monoterpenoid alcohol, proposed as a natural herbicide. Eugenol (100–1000 µM) retarded the germination of Avena fatua and strongly inhibited its root growth compared to the coleoptile growth. We further investigated the underlying physiological and biochemical alterations leading to the root growth inhibition. Eugenol induced the generation of reactive oxygen species (ROS) leading to oxidative stress and membrane damage in the root tissue. ROS generation measured in terms of hydrogen peroxide, superoxide anion and hydroxyl radical content increased significantly in the range of 24 to 144, 21 to 91, 46 to 173% over the control at 100 to 1000 µM eugenol, respectively. The disruption in membrane integrity was indicated by 25 to 125% increase in malondialdehyde (lipid peroxidation byproduct), and decreased conjugated diene content (~10 to 41%). The electrolyte leakage suggesting membrane damage increased both under light as well as dark conditions measured over a period from 0 to 30 h. In defense to the oxidative damage due to eugenol, a significant upregulation in the ROS-scavenging antioxidant enzyme machinery was observed. The activities of superoxide dismutases, catalases, ascorbate peroxidases, guaiacol peroxidases and glutathione reductases were elevated by ~1.5 to 2.8, 2 to 4.3, 1.9 to 5.0, 1.4 to 3.9, 2.5 to 5.5 times, respectively, in response to 100 to 1000 µM eugenol. The study concludes that eugenol inhibits early root growth through ROS-mediated oxidative damage, despite an activation of the antioxidant enzyme machinery.Item 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.Item Bioaccumulation and physiological responses to lead (Pb) in Chenopodium murale L(Academic Press, 2018) Sidhu, G.P.S.; Bali A.S.; Bhardwaj R.; Singh H.P.; Batish D.R.; Kohli R.K.Identification and screening of wild, wasteland plants for the remediation of heavy metal contaminated soils is a crucial phytotechnological approach. In a pot experiment, Chenopodium murale was tested for the phytoextraction of lead (Pb) from the contaminated soils. The experiment was conducted for 8 weeks to appraise the effect of varied Pb regimes (300, 400, 500 mg kg?1) on the bioaccumulation and physiological responses of C. murale plants. At 500 mg kg?1 Pb regime, the concentration of Pb in roots and shoots reached a maximum of 2513 and 2301 mg kg?1 DW, respectively. The plants highlighted a very high tolerance with 100% survival towards Pb toxicity, although exhibited a slight decrease in biomass yield, chlorophyll content and protein levels. However, a dramatic mount in H2O2 content, MDA level and bio-activities of antioxidant enzymes (SOD, CAT and POD) was noticed. BCF and TF values were more than unity at all the Pb regimes. Results were scrutinized, accentuating the profit of raising C. murale in Pb-contaminated soils as this plant species can be a promising candidate for soil remediation and their restoration purposes.Item 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.