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Item Evaluating the role of phenology in managing urban invasions: A case study of Broussonetia papyrifera(Elsevier GmbH, 2020) Maan I.; Kaur A.; Singh H.P.; Batish D.R.; Kohli R.K.Multidisciplinary approaches are required for the management of invasive woody species in urban areas. In this context, phenological studies are a useful tool to understand tree development and devise suitable management strategies under urban forestry conditions. The significant role of phenology in attributing competitive advantages to invasive alien species has also been long recognized by community ecologists. Therefore, phenological calendars of invasive species may help in their detection, management and mitigation. In the present study, an attempt has been made to understand the invasive potential of an emerging invasive tree of urban landscapes, Broussonetia papyrifera (paper mulberry; Moraceae), through its phenological assessment by using a standardized numerical scale, BBCH (Biologische Bundesanstalt, Bundessortenamt, CHemische Industrie). The tree is native to southeastern and eastern Asia and the Pacific Islands, and is rapidly spreading across various tropical and subtropical regions. The phenology of B. papyrifera was described in eight principal growth stages (PGSs) with two developmental cycles in a year, presented as primary (January-June) and secondary (June-November) flushes. The observations were further supported by the corresponding dates, photographs, meteorological data (air temperature, precipitation, and photoperiod), and climatic water balance of the study area. Results suggest that the occurrence of two developmental cycles, a prolonged reproductive period, strategy to attract frugivores with brightly colored pulpy fruits, and ability to survive under a wide temperature range help in the spread of B. papyrifera. The phenological scale provided in this study describes accurate and precise developmental stages of the tree that can be used to devise efficient management strategies for its control in urban areas. The information can also be exploited for assessing the climatic conditions required for its prevalence, predicting its future geographic range, and further research.Item Comparative cyto- and genotoxicity of 900 MHz and 1800 MHz electromagnetic field radiations in root meristems of Allium cepa(Academic Press, 2020) Kumar A.; Kaur S.; Chandel S.; Singh H.P.; Batish D.R.; Kohli R.K.In the last few decades, tremendous increase in the use of wireless electronic gadgets, particularly the cell phones, has significantly enhanced the levels of electromagnetic field radiations (EMF-r) in the environment. Therefore, it is pertinent to study the effect of these radiations on biological systems including plants. We investigated comparative cytotoxic and DNA damaging effects of 900 and 1800 MHz EMF-r in Allium cepa (onion) root meristematic cells in terms of mitotic index (MI), chromosomal aberrations (CAs) and single cell gel electrophoresis (comet assay). Onion bulbs were subjected to 900 and 1800 MHz (at power densities 261 ± 8.50 mW m?2 and 332 ± 10.36 mW m?2, respectively) of EMF-r for 0.5 h, 1 h, 2 h, and 4 h. Root length declined by 13.2% and 12.3%, whereas root thickness was increased by 46.7% and 48.3% after 4 h exposure to 900 MHz and 1800 MHz, respectively. Cytogenetic studies exhibited clastogenic effect of EMF-r as depicted by increased CAs and MI. MI increased by 36% and 53% after 2 and 4 h exposure to 900 MHz EMF-r, whereas it increased by 41% and 67% in response to 1800 MHz EMF-r. Aberration index was increased by 41%–266% and 14%–257% during 0.5–4 h of exposure to 900 MHz and 1800 MHz, respectively, over the control. EMF-r exposure decreased % head DNA (DNAH) and increased % tail DNA (DNAT) and olive tail moment (OTM) at both 900 and 1800 EMF-r. In 4 h exposure treatments, head DNA (%) declined by 19% and 23% at 900 MHz and 1800 MHz, respectively. DNAT and OTM were increased by 2.3 and 3.7 fold upon exposure to 900 MHz EMF-r over that in the control, whereas 2.8 and 5.8 fold increase was observed in response to 1800 MHz EMF-r exposure for 4 h and the difference was statistically significant. The study concludes that EMF-r in the communication range (900 and 1800 MHz) adversely affect root meristems in plants and induce cytotoxic and DNA damage. EMF-r induced DNA damage was more pronounced at 1800 MHz than that at 900 MHz.Item Insights into the tolerance and phytoremediation potential of Coronopus didymus L. (Sm) grown under zinc stress(Elsevier Ltd, 2020) Sidhu G.P.S.; Bali A.S.; Singh H.P.; Batish D.R.; Kohli R.K.Zinc (Zn) is a vital micronutrient for plants, but its abundance can be calamitous. In this study, a screenhouse experiment was conducted over a 6-week period to assess the effect of soil enrichment with Zn regimes (100, 250 and 500 mg kg?1) on growth, Zn accumulation, photosynthetic pigment concentration, oxidative stress markers and activities of antioxidant enzymes in Coronopus didymus. Results revealed that Zn concentration in C. didymus roots and shoots reached up to 1848 mg kg?1 DW and 1845 mg kg?1 DW at 500 mg kg?1 Zn regime, respectively. The plant growth (root-shoot length and biomass) increased, while leaf pigment concentration and soluble protein content in C. didymus tissues decreased progressively with the increased Zn regimes in the soil. At 500 mg kg?1 Zn regime, hydrogen peroxide and malondialdehyde level increased ?219% and 111% in roots, while ?170% and 105% in shoots, with respect to the control. Likewise, superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase and glutathione reductase activities increased significantly with elevated Zn levels. Contrarily, compared to the control, CAT activity declined gradually and reached a minimum of ?45% in roots and 12% in shoots under highest Zn regime. The results suggested that C. didymus displayed high Zn accumulation and emerged as a tolerant plant species towards Zn stress. Elevated Zn regimes provoked reactive oxygen species generation in C. didymus tissues which was effectively neutralised and scavenged by the antioxidant enzymes, thus marked its efficacy to be potentially employed in phytoremediation and reclamation of Zn-contaminated soils.Item Patterns of plant communities along vertical gradient in Dhauladhar Mountains in Lesser Himalayas in North-Western India(Elsevier B.V., 2020) Ahmad M.; Uniyal S.K.; Batish D.R.; Singh H.P.; Jaryan V.; Rathee S.; Sharma P.; Kohli R.K.Mountains are definitely the most rugged, yet frail resources and biodiversity-rich regions of the world. Environmental variables directly affect species composition, growth patterns, and the ecosystem resulting in a drastic change in the vegetation composition along ascending elevations. The present study investigated vegetation composition, nestedness, and turnover in plant communities along a vertical gradient (2000 to 4000 m) in Dhauladhar Mountains, Lesser Himalayas, India. We determined how ?-diversity pattern and nestedness-related processes or turnover (?-diversity) causes dissimilarity in plant communities' composition along the vertical gradient. Overall, 21 permanent plots (20 � 20 m2) at every 100 m interval from 2000 to 4000 m were established. A sampling of shrubs and herbaceous species was done by marking sub-plots of 5 � 5 m2 and 1 � 1 m2, respectively, within permanent plots. We observed an inverted hump-shaped pattern for evenness index (E), a unimodal hump-shaped pattern for Shannon index (H?), Margalef's richness index, and ?-Whittaker (?w) diversity, and mild-hump-shaped pattern for Simpson index (?) across the elevational gradient. Turnover (?sim) and the nestedness-resultant component of ?-diversity (?sne) significantly differed across the elevational gradient. The observed ?-diversity patterns revealed that the species replacement rate was less in the mid-altitude communities as compared to lower and higher altitude communities. It was largely attributed to the ecotonic nature of mid-altitudes, which benefited mid-elevational communities rather than low or high altitude communities. Besides lower altitudes, the increased human interference has led to disturbance and subsequent homogenization of flora across the mid-altitudes. With respect to this, the present study signifies the need for preserving the mid-altitudinal communities, without undermining the importance of conserving the low and high altitude communities. � 2020 Elsevier B.V.