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Talat Afreen

Bio: Talat Afreen is an academic researcher from Banaras Hindu University. The author has contributed to research in topics: Precipitation & Climate change. The author has an hindex of 5, co-authored 10 publications receiving 110 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, experimental data were collected for soil organic carbon (SOC) along with soil physico-chemical, microbial and aggregate characteristics across adjacent secondary forest (SF)-grassland (GL)-cropland (CL) sequence in dry tropical ecosystems.

50 citations

Journal ArticleDOI
TL;DR: The value of sampling from different tissues of a host plant for the greater species diversity, and the antibacterial screening of some endophytic fungi from this specific medicinal plant may represent a unique source for many of the useful antibacterial compounds are explained.
Abstract: A study was conducted for isolation, identification and antibacterial potential of fungal endophytes of Adenocalymma alliaceum Miers., (Bignoniaceae), a medicinal shrub vine plant which has long history for its usages in curing various disorders. A total of 149 isolates of endophytic fungi representing 17 fungal taxa were obtained from 270 segments (90 from each stem, leaf and petiole) of this plant. Hyphomycetes (77.85%) were the most prevalent, followed by Ascomycetes (8.05%) and Coelomycetes (4.03%) respectively. A considerable amount of fungal isolates was kept under (10.07%) Mycelia-Sterilia (MS). Leaf harboured maximum colonization of endophytic fungi (72.22%) which was greater than stem (67.78%) and petiole (25.54%). The Jc similarity index was maximum (0.619) between stem vs leaf followed by leaf vs petiole (0.571) and stem vs petiole (0.428). The dominant endophytic fungi were Alternaria alternata, Aspergillus niger, Stenella agalis, Fusarium oxysporum, Curvularia lunata and Fusarium roseum. Among twelve endophytic fungi tested for antibacterial activity, crude extracts of nine endophytic fungi (75%), showed antibacterial potential against one or more clinical human pathogens. Alternaria alternata, Curvularia lunata, Penicillium sp. and Chaetomium globosum exhibited significant antibacterial activity against 4 of 5 tested pathogens, showing broad spectrum activity. This investigation explains the value of sampling from different tissues of a host plant for the greater species diversity, and additionally, the antibacterial screening of some endophytic fungi from this specific medicinal plant may represent a unique source for many of the useful antibacterial compounds.

32 citations

Journal ArticleDOI
TL;DR: In this article, the impact of riparian land use on soil CO 2 efflux and its governing variables under different land uses of dry tropical riparian ecosystems are measured at 54 locations distributed in six sites having these land uses, in dry season of 2014-15.

23 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of H. suaveolens invasion on plant diversity across the seasons in the dry tropical grassland and found that Hyptis invasion negatively affects plant diversity, with relatively higher impact in rainy season as compared to the winter season.
Abstract: Aims Hyptis suaveolens (L.) Poit is an important invader of the tropical and sub-tropical regions of the world. In our study, it has been investigated that how does the H. suaveolens invasion regulate plant species diversity across the seasons in the dry tropical grassland. We hypothesized that a shift in soil inorganic-N availability is caused by invasion, and this shift is integral to access the invasion effect on plant diversity. Methods The study was performed in experimental plots at the Botanical Garden of the Banaras Hindu University (25°16′3.3′′ N and 82°59′22.7′′ E), Varanasi, Uttar Pradesh, India. Five replicates (each, 2 × 2m) of non-invaded grassland plots (NIG) and five grassland plots invaded with H. suaveolens (IG) were established. These plots were constructed by transplanting indigenous grassland patches from an adjacent native grassland. In the invaded plots, 20 individuals of H. suaveolens were transplanted per plot. After 1 year of establishment, diversity attributes and soil properties were recorded from these plots in three seasons as per standard protocol. Important Findings The results indicated that Hyptis invasion negatively affects plant diversity, with relatively higher impact in rainy season as compared to the winter season. IG exhibited lower soil moisture content and temperature than NIG in rainy season, whereas soil ammonium-N, nitrate-N, total inorganic-N, N mineralization registered higher values for IG than NIG in both rainy and winter season. Diversity indices were negatively correlated with soil inorganic-N pool and N mineralization. However, these indices were positively correlated with microbial biomass carbon (MBC), and the correlation coefficient for this relationship was higher for rainy season as compared to winter. Species richness (r = 0.65) and Shannon diversity (r = 0.757) were significantly correlated with the ratio of ammonium-N to nitrate-N. The negative effect of invasion by H. suaveolens on the plant diversity is possibly mediated by the effect of invasion on N mineralization processes (mainly nitrification) and the availability of soil inorganic-N pools. The study indicates that Hyptis invasion has an enormous potential to change the structure and composition of plant communities in the dry tropical grasslands.

13 citations

Journal ArticleDOI
TL;DR: In this article, the impact of change in precipitation regime on soil CO2 flux in a constructed tropical grassland with and without an invasive plant, Hyptis suaveolens, was assessed.

13 citations


Cited by
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01 Dec 2012
TL;DR: In this paper, the magnitude and evolution of parameters that characterize feedbacks in the coupled carbon-climate system are compared across nine Earth system models (ESMs), based on results from biogeochemically, radiatively, and fully coupled simulations in which CO2 increases at a rate of 1% yr−1.
Abstract: The magnitude and evolution of parameters that characterize feedbacks in the coupled carbon–climate system are compared across nine Earth system models (ESMs). The analysis is based on results from biogeochemically, radiatively, and fully coupled simulations in which CO2 increases at a rate of 1% yr−1. These simulations are part of phase 5 of the Coupled Model Intercomparison Project (CMIP5). The CO2 fluxes between the atmosphere and underlying land and ocean respond to changes in atmospheric CO2 concentration and to changes in temperature and other climate variables. The carbon–concentration and carbon–climate feedback parameters characterize the response of the CO2 flux between the atmosphere and the underlying surface to these changes. Feedback parameters are calculated using two different approaches. The two approaches are equivalent and either may be used to calculate the contribution of the feedback terms to diagnosed cumulative emissions. The contribution of carbon–concentration feedback to...

454 citations

Journal ArticleDOI

397 citations

01 Dec 2012
TL;DR: In this article, a new global measure of precipitation seasonality is proposed, and application of this method to observations from the tropics shows that increases in variability were accompanied by shifts in seasonal magnitude, timing and duration.
Abstract: Climate change is altering the seasonal distribution, interannual variability and overall magnitude of precipitation. A new global measure of precipitation seasonality is proposed, and application of this method to observations from the tropics shows that increases in variability were accompanied by shifts in seasonal magnitude, timing and duration.

314 citations

10 Jul 2008
TL;DR: In this paper, the authors present the rationale for the increasing frequency and magnitude of extreme weather events in the near future, discuss recent findings on meteorological extremes and summarize their effects on ecosystems and identify gaps in current ecological climate change research.
Abstract: Climate change will increase the recurrence of extreme weather events such as drought and heavy rainfall. Evidence suggests that modifications in extreme weather events pose stronger threats to ecosystem functioning than global trends and shifts in average conditions. As ecosystem functioning is connected with ecological services, this has far-reaching effects on societies in the 21st century. Here, we: (i) present the rationale for the increasing frequency and magnitude of extreme weather events in the near future; (ii) discuss recent findings on meteorological extremes and summarize their effects on ecosystems and (iii) identify gaps in current ecological climate change research.

288 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed a commercial ecological agriculture, which is an amalgamation of sustainable agricultural practices and supported by a progressive co-ordination among all the stakeholders via participatory learning and adaptation with time.

91 citations