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Item β-Pinene moderates Cr(VI) phytotoxicity by quenching reactive oxygen species and altering antioxidant machinery in maize(Springer, 2019) Mahajan, P; Singh, H.P; Kaur, S; Batish, D.R; Kohli, R.K.We examined the possible role of monoterpene β-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. β-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 β-pinene quenches/neutralizes enhanced ROS generated under Cr(VI) exposure. β-Pinene also reduced Cr(VI)-induced electrolyte leakage, thereby suggesting its role in membrane stabilization. Further, β-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 β-pinene has a protective role against Cr(VI) stress and provides resistance to maize against Cr(VI) toxicity. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.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, 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 μM), 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 Exposure to mobile phone radiations at 2350 MHz incites cyto- and genotoxic effects in root meristems of Allium cepa(BioMed Central Ltd., 2019) Chandel, S; Kaur, S; Issa, M; Singh, H.P; Batish, D.R; Kohli, R.K.Background: The exponential increase of electromagnetic field radiations (EMF-r) in the natural environment has raked up the controversies regarding their biological effects. Concern regarding the putative capacity of EMF-r to affect living beings has been growing due to the ongoing elevation in the use of high frequency EMF-r in communication systems, e.g. Mobile phones. Methods: In the present study, we tried to examine the cyto- and genotoxic potential of mobile phone EMF-r at 2350 MHz using onions (Allium cepa L.). Fresh adventitious onion roots were exposed to continuous EMF-r at 2350 MHz for different time periods (1 h, 2 h and 4 h). The evaluation of cytotoxicity was done in terms of mitotic index (MI), phase index and chromosomal aberrations. Genotoxicity was investigated employing comet assay in terms of changes in % HDNA (head DNA) and % TDNA (tail DNA), TM (tail moment) and OTM (olive tail moment). Data were analyzed using one-way ANOVA and mean values were separated using post hoc Tukey's test. Results: The results manifested a significant increase of MI and chromosomal aberrations (%) upon 4 h, and ≥ 2 h of exposure, respectively, as compared to the control. No specific changes in phase index in response to EMF-r exposure were observed. The % HDNA and % TDNA values exhibited significant changes in contrast to that of control upon 2 h and 4 h of exposure, respectively. However, TM and OTM did not change significantly. Conclusions: Our results infer that continuous exposures of radiofrequency EMF-r (2350 MHz) for long durations have a potential of inciting cyto- and genotoxic effects in onion root meristems. © 2019 Springer Nature Switzerland AG.Item Chemical profiling, cytotoxicity and phytotoxicity of foliar volatiles of Hyptis suaveolens(Academic Press, 2019) Sharma, A; Singh, H.P; Batish, D.R; Kohli, R.K.In the present study, the essential oil (EO) of Hyptis suaveolens has been explored for the first time for its phytotoxic and cytotoxic activities. The phytotoxic activity was assessed against rice (Oryza sativa) and its major troublesome weed, Echinochloa crus-galli, under laboratory and screenhouse conditions. GC-MS analysis revealed EO to be monoterpenoid (~ 79% monoterpenes) in nature with α-phellandrene (22.8%), α-pinene (10.1%) and limonene (8.5%) as the major chemical constituents. The laboratory bioassay showed a complete growth inhibitory effect of EO (≥ 2 mg mL −1 ) towards the germination and seedling growth of E. crus-galli. However, the inhibitory effect on rice was much less (~40% inhibition). EO caused visible injury, reduction in chlorophyll content, cell viability and ultimately led to complete wilting of E. crus-galli plants. In addition, EO altered the cell division in the meristematic cells of Allium cepa as depicted by ~63% decrease in mitotic index. EO exposure induced several aberrations at chromosomal (c-mitosis, anaphase bridges, chromosomal breakage, vagrant chromosomes, and sticky chromosomes) and cytological level (cytoplasm destruction, peripheral nuclei, and bi-nucleate cells). The present study concludes that H. suaveolens EO possesses phytotoxic activity due to its mito-depressive activity, and could serve as a natural herbicide under sustainable agricultural practices. © 2018 Elsevier Inc.Item Nitric oxide induced modulations in adventitious root growth, lignin content and lignin synthesizing enzymes in the hypocotyls of Vigna radiata(Elsevier, 2019) Sharma, S; Singh, H.P; Batish, D.R; Kohli, R.K.The present study evaluated the role of nitric oxide (NO) in mediating adventitious root (AR) growth, lignification and related enzymatic changes in the hypocotyls of Vigna radiata. To meet the objectives, the changes in AR growth, lignin content, and the activities of enzymes−peroxidases, polyphenol oxidases, and phenylalanine ammonia lyases− with NO donor and its scavenger were monitored. Hypocotyls were cultivated in aqueous solution supplemented with different concentrations of SNP (sodium nitroprusside, NO donor compound) and its scavenging compound (2,4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; cPTIO). Specifically, at low concentrations, SNP induced AR growth, increased the total lignin content and altered the activities of related oxidoreductases- peroxidases, polyphenol oxidases and phenylalanine ammonia lyases- which are involved in lignin biosynthesis pathway. At higher concentrations, a decline in AR growth and lignification was noticed. We analysed the function of NO in AR formation by depleting the endogenous NO using scavenging compound cPTIO. Hypocotyls grown in a medium supplemented with scavenger cPTIO exhibited significant decline in AR growth and the activities of lignin synthesizing enzymes. Application of NO scavenger showed that stimulatory properties on root lignification may be owing to NO itself. In addition, changes in AR growth were significantly correlated with these modified biochemical activities. Our analysis revealed that NO supplementation induces prominent alterations in lignin level during AR formation and this might be due to an alteration in the activity of lignin biosynthetic enzymes, which further affected the polymerization of monolignols and AR growth. © 2019 Elsevier Masson SASItem 24-Epibrassinolide pre-treatment reduces alkaline-induced oxidative stress in red rice seedlings(Springer, 2019) Sharma, M; Mahajan, P; Singh, H.P; Batish, D.R; Kohli, R.K.Soil alkalinity caused by salts, such as sodium bicarbonate (NaHCO3), and the frequently associated waterlogging problems are pervasive in agriculture and have a deleterious impact on crop production. However, various plant growth regulators, including brassinosteroids, are considered to be important against different abiotic stresses experienced by plants due to drought, salinity, and heavy metal stress. We investigated the putative role of 24-epibrassinolide (EBL), an active brassinosteroid, on red rice plants experiencing alkaline stress. Seedlings were pre-treated with 0.01 μM EBL for 30 min and later, exposed to NaHCO3 (25 mM) and were sampled, 5 days after treatments. Results showed that the pre-treatment of seedlings with EBL under non-stress conditions could promote rice plant growth. Growth parameters including dry weight (DW), root and coleoptile lengths were reduced under alkaline stress, whereas EBL application reduced the level of inhibition, as compared with NaHCO3 treatment. Enhanced levels of malondialdehyde content, hydrogen peroxide, and superoxide radicals were significantly diminished by EBL pre-treatment. Moreover, pre-treatment of EBL to alkaline-treated rice seedlings largely stimulated the enzymatic activities of ascorbate peroxidase, catalase, and superoxide dismutase. Thus, the results suggest that pre-application of EBL significantly ameliorates alkaline stress in rice. © 2019, Springer-Verlag GmbH Germany, 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.