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The study was undertaken to determine the effects of different red mud treatments (0, 5, 10, and 15% w/w) in sewage-sludge amended soil (soil:sludge:2:1 w/w) on quantity, quality, and safety of essential oil extracted from the roots of Chrysopogon zizanioides (vetiver), when used for the phytoremediation of red mud. Garden soil without red mud and sewage-sludge served as control and there were 10 replicates for each treatment. Essential oil content in roots increased under all soil treatments except maximum red mud addition in sludge-amended soil compared to the control. Gas chromatography and mass spectroscopic analysis of oil revealed that 36, 35, 33, and 31 compounds contributed nearly 87.7, 90, 92.1, and 87% of total volatiles under 0, 5, 10, and 15% red mud treatments, respectively. Contents of rosifoliol, α-muurolol, farnesol, γ-costol, isovalencene, and vetivone increased, while selina-6-en-ol, cadin-4-en-10-ol, vetiselinenol, and aristolone decreased with increasing red mud treatments. In essential oil, contents of metals were within the safe limits for food by Food Safety and Standard Authority of India. The study insinuate utilization of 5 and 10% red mud in sludge-amended soil for improved quantity and quality of essential oil, without any metal contamination coupled with enhanced phytoremediation potential of vetiver. The present study is of significant importance because phytoremediation of metals in red mud using essential oil-bearing plants such as Chrysopogon zizanioides (commonly known as vetiver) is a potential alternative for on-site management of the waste in most economical and sustainable way. Vetiver is a potential metal tolerant plant with high economic value; therefore the present study was accomplished to evaluate the impacts of metals in red mud on essential oil content and composition, used for remediation and stabilization of dumps. Novelty of the study is that, it aimed to utilize red mud along with sewage-sludge to cultivate vetiver which offers twin benefits, i.e. phytoremediation of metals in red mud coupled with improved quantity and quality of high valued essential oil without metal contamination. [ABSTRACT FROM AUTHOR]

Red mud (RM) with organic manure may offer suitable substratum to support plant growth. The present study was conducted to evaluate the effects of 0, 5, 10 and 15% (w/w) RM additions in soil fertilized with cowdung manure (soil: manure: 2:1 w/w) on available metal contents, growth performance and metal accumulation in Brassica juncea cultivars Kranti and Pusa Bold. Increasing RM concentrations in manure-amended soil caused a significant increase in total metal contents but their phytoavailable contents decreased. A significant increase in plant growth performance and seed yield was observed up to 10% RM treatment compared to the control (without RM and manure). Maximum increase in seed yield (140.5%) of Pusa Bold and Kranti (120.3%) was found under 10% RM treatment. Metal contents in seeds were within the FAO/WHO safe limits. The study suggests utilization of 10% (w/w) RM in soil fertilized with cowdung manure for cultivation of Kranti and Pusa Bold. Based on plant performance, the study encourages the cultivation of Pusa Bold. [ABSTRACT FROM AUTHOR]

Bauxite residue (red mud) generation is increasing largely following the high demand for aluminium worldwide. Thus to manage the residue, different phytotechnologies need to be developed which offer sustainable and eco-friendly options. Considering this, the present study was conducted to assess the phenotype and distribution of metals in herbaceous species at forest (FS) and abandoned red mud dumping (RMD) sites. The study also encompassed the categorization of dominant species in relation to their metal tolerance capabilities at RMD site. Soil at RMD site was marked by high alkalinity, salinity and poor nutrient status. Also, contents of Fe, Zn, Cu, Mg, Mn, Ni, Co, Cr, Cd and Pb in soil at RMD site were higher, but their phytoavailabilties were less as compared to FS site. Herbaceous community at both the sites were dominated by Poaceae and Asteraceae families. Biological spectrum of vegetation at FS site showed predominance of therophytes followed by chamaephytes and hemicryptophytes, whereas RMD site showed preponderance of therophytes followed by hemicryptophytes and chamaephytes. Based on metal tolerance index, 51.4, 10.8 and 37.8% of herbaceous species exhibited sensitive, moderate and high metal tolerant behaviour, respectively. Dominant species e.g. Brachiaria mutica , Cynodon dactylon , Dactyloctenium aegyptium , Digitaria ischaemum , Digitaria longiflora , Eragrostis cynosuroides , Launaea asplenifolia , Parthenium hysterophorus , Sporobolus diander and Stylosanthes scabra with high metal tolerance capabilities indicated their tendency towards a definite selection strategy in response to altered soil properties at RMD site. The study thus offers a potential avenue towards phytomanagement of abandoned red mud dumps by reclamation using dominant and metal tolerant plant species. • Poaceae and Asteraceae prevailed the forest and abandoned red mud dumping sites. • Herbaceous community at both the study sites was dominated by therophytes. • Metal contents in herbs were higher at forest than abandoned red mud dumping sites. • Contents of Pb, Cr and Cd in herbs were less at both the study sites. • Dominant species at abandoned red mud dumps showed high metal tolerance index. [ABSTRACT FROM AUTHOR]

Ambient air particulate matter is regulated by source complexity, short and distant sources, associated meteorological and atmospheric factors. For the implementation of appropriate policies for mitigation of air pollutants, information regarding air pollution status, sources and modifying factors are needed. Previous studies in Indo-Gangetic plain (IGP) have identified PM 2.5 (particles 2.5 μm or less in size) variations and its sources but no studies have yet identified the local and long-range sources of PM 2.5 and their relationships with other air pollutants and meteorology. The local and distant sources of PM 2.5 were investigated from 2014 to 2017 in Varanasi city located in middle IGP of India by conditional bivariate probability function (CBPF), land use regression (LUR) and trajectory statistical models (TSM) like potential source contribution function (PSCF), concentration weighted trajectory (CWT) and trajectory cluster analysis. Fine PM levels in Varanasi city exceeded the daily mean 24-h national Central Pollution control board (CPCB) and WHO standards for ~75 and 93% of monitoring days, indicating the alarming status of PM pollution in this area. CBPF identified traffic as the major probable local source which contributed maximally to high PM level followed by paved road dust and local combustion activities. LUR also identified traffic variables such as heavy vehicle intensity, distance from the highway, traffic intensity (within 500 m buffer) and percent green cover as major predictor variables influencing PM 2.5 distribution in the city. PSCF, CWT and cluster analysis identified the north-western part of India as the most probable source region for contributing higher PM 2.5 mass to Varanasi city. Dewpoint temperature, ventilation coefficient, wind speed and daily minimum temperature were identified as major meteorological variables and NO 2 and CO as major gaseous air pollutants which modified PM concentrations. Outcomes of the study will be helpful in source identification and PM 2.5 abatement in cities of IGP. [ABSTRACT FROM AUTHOR]

Air quality in an urban atmosphere is regulated by both local and distant emission sources. For air quality management in urban areas, identification of sources and their relationships with local meteorology and air pollutants are essential. The critical condition of air quality in Indo-Gangetic plain is well known, but lack of data on both local and distant emission sources limits the scope of improving air quality in this region. Concentrations of particulate matter of size lower than 10 μm (PM10) were assessed in the highly urbanized Varanasi city situated in middle Indo-Gangetic plain of India from 2014 to 2017, to identify the distant air pollution sources based on trajectory statistical models and local sources by conditional bivariate probability function. Modifying effects of meteorology and air pollutants on PM10 were also explored. Mean PM10 concentration for the study period was 244.8 ± 135.8 μg m−3, which was 12 times higher than the WHO annual guideline. Several distinct sources of traffic as the major source of PM10 were identified in the city. Trajectory statistical models like cluster analysis, potential source contribution function and concentration-weighted trajectory showed significant contributions from north-west and eastern directions in the transport of polluted air masses to the city. Dew point, wind speed, temperature and ventilation coefficient are the major factors in PM10 formation and dispersion. [ABSTRACT FROM AUTHOR]

Globally, 120 million tonnes of red mud is generated whose disposal and storage occupy large areas of potentially important arable lands. Red mud dumps are physically, nutritionally and biologically poor in nature. Vetiver ( Chrysopogon zizanioides (L.) Roberty), a medicinally important perennial plant, known to control soil erosion, tolerates a wide range of pH and elevated levels of toxic metals. This information prompted to make use of red mud with sewage sludge, a nutrient rich bio-waste for growing vetiver. An experimental study was conducted using red mud at four rates (0, 5, 10 and 15% w/w) in soil amended with sewage sludge (soil: sludge: 2:1 w/w) to evaluate the effects on physico-chemical properties, plant growth performance, biomass and metal contents in vetiver under control (without sewage sludge and red mud) and different soil treatments. Application of red mud with sludge enhanced the levels of organic matter and nutrient status of the soil which offered suitable substrata to support plant growth. Heavy metal contents (Fe, Mn, Mg, Zn, Cu, Ni, Pb, Cd and Cr) increased with increase in red mud levels, however, their phytoavailable contents decreased. Addition of red mud resulted in significant improvement in root-shoot lengths, number of tillers culm − 1 , root-shoot ratio and biomass compared to the control. However, maximum improvement occurred in root (125.27%), shoot (79.91%) and total plant biomass (88.07%) under 10% red mud treatment compared to control. Vetiver is found to be a potential metal tolerant plant as tolerance index was > 100%. Based on translocation and bioconcentration factors, the plant was found efficient in translocation of Mn and Cu from roots to shoot, whereas it acted as a potential phytostabilizer for Fe, Zn, Mg, Cd, Pb, Ni and Cr. The study suggests utilization of 10% red mud in sludge amended soil to sustain maximum plant growth coupled with enhanced phytoremediation potential of vetiver. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) is both a major driver of climate change and a source of toxicity for health. In the upper atmosphere, particulate matter modifies the earth radiation budget, cloud formation and acts as a reaction center for air pollutants. In the lower atmosphere, particulate matter changes atmospheric visibility and alters biogeochemical cycles and meteorology. Most critical effects are observed in ambient air, where particulate matter degrades human health. Here we review the sources, spatial and temporal variability, and toxicity of PM, the particulate matter having particle sizes 10 micrometers or less in diameter, in world regions. For that we analyzed information from the world wide web and databases from government organizations after the year 2000. Findings show that PM is a major risk in both developed and developing countries. This risk is more severe in Asian countries compared to Europe and USA, where decreasing trends are recorded during the last two decades. Meteorological factors modify particulate matter variations at local and regional levels. PM/PM ratio provides information of particulate matter sources under different environment conditions. Crustal matter, road traffic and combustion of fuels are major sources of particulate matter pollution. Health studies indicate that long-term exposure to particulate matter has multiple health effects in people from all age groups. Identification of possible sources and their control with regular epidemiological monitoring could decrease the impact of particulate matter pollution. [ABSTRACT FROM AUTHOR]

Lemongrass is a commercially important perennial herb with medicinal value and ability to tolerate high alkaline and saline conditions. Essential oil bearing plants can grow safely in soil contaminated with heavy metals without severe effects on morphology and oil yield. The present study was aimed to assess the essential oil content and composition in lemongrass in response to elevated metals in above-ground plant parts. Pot experiment was conducted for six months using sewage sludge as soil amendment (soil: sludge: 2:1 w/w) followed by red mud treatments (0, 5, 10 and 15% w/w). Garden soil without sludge and red mud was control and there were ten replicates of each treatment. Oil content in leaves was differently affected due to presence of metals in soil under different treatments. Oil content under S RM5 (5% red mud) treatment was raised by 42.9 and 11.5% compared to the control and S RM0 treatment, respectively. Among identified compounds in oil under red mud treatments, 17 compounds contributed more than 90% of total volatiles (citral contributing approximately 70%). Under S RM10 treatment, essential oil showed maximum citral content (75.3%). Contents of Fe, Zn, Cu, Cd, Ni and Pb in above-ground plant parts exceeded, whereas Mn was detected within WHO permissible limits for medicinal plants. However, metal contents in essential oil were well within FSSAI limits for food. The study suggests utilization of 5 and 10% red mud in sludge amended soil for lemongrass cultivation to have better oil yield and quality, without metal contamination. [ABSTRACT FROM AUTHOR]

Microbial processes, particularly enzyme activities, play crucial functional roles in soil ecology, hence serving as sensitive indicators of soil quality. We assessed the temporal dynamics of microbial biomass and selected soil enzymes (β-d-glucosidase, cellobiohydrolase, polyphenol oxidase, urease, glycine-aminopeptidase and alkaline phosphatase) during wheat cultivation, under four different tillage practices in the rice–wheat system. The four practices involved conventional tilling of soil before cultivating each crop (CTR-CTW); no tilling before cultivating rice but conventional tillage before wheat (NTR-CTW); conventional tilling before cultivating rice but no tilling before wheat (CTR-NTW) and no tilling before cultivation of each crop (NTR-NTW). Microbial biomass and activities of hydrolytic enzymes increased under NTR-NTW followed by CTR-NTW and NTR-CTW with respect to the conventional practice CTR-CTW, thus reflecting improvement in microbial activities with reduced tillage frequency. Enzyme activities generally depended on soil moisture and temperature, but nature of relationships varied among different practices. Nutrient demand appeared to be the strongest driver of alkaline phosphatase and urease, and soil temperature for glycine-aminopeptidase. Under CTR-CTW, activities of most of the extracellular enzymes were related with β-d-glucosidase or urease, but such relations altered under rest of the practices. The study showed that extracellular soil enzymes respond sensitively to tillage practices as well as environmental variables, particularly soil temperature and moisture and hence can serve as a sensitive indicator of changes in soil processes. Considering improvement in microbial biomass and enzymatic activities as indicators of better soil quality, adoption of no tillage apparently improved soil quality. Still, more number of field studies are required under tillage managements to explore the relationships between different enzyme activities and environmental factors. [ABSTRACT FROM PUBLISHER]

The effects of ambient ozone (O 3 ) on wheat ( Triticum aestivum L.) varieties HUW 510 and LOK-1 were studied at recommended and 1.5 times recommended NPK under natural field conditions using open top chambers under varying NPK levels. Ambient O 3 was filtered out from air through charcoal filters for control plants (FCs), while non-filtered chambers received ambient O 3 (NFCs). Twelve hourly mean concentrations of O 3 varied from 10.3 to 110 ppb. Plants growing in FCs showed better growth performance and higher biomass accumulation compared to those in NFCs at both NPK levels. There were improvements in yield and its quality parameters in FCs compared to NFCs at both NPK levels with no significant difference in yield between FCs and NFCs at 1.5 times recommended NPK in LOK-1 and at RNPK in HUW 510. Nitrogen utilization efficiency increased in NFCs compared to FCs in both the varieties, but lower capability of N acquisition under ambient O 3 led to higher magnitude of reduction in yield of LOK-1 compared to HUW 510 at recommended NPK. The results clearly showed that 1.5 times recommended NPK alleviated the negative effects of ambient O 3 pollutant in LOK-1 variety whereas recommended NPK in HUW 510. [ABSTRACT FROM AUTHOR]

The present study was performed to evaluate the effects of different levels of carbon dioxide (ambient (382 ppm) and elevated (570 ppm)) and O 3 (ambient (50 ppb) and elevated (70 ppb)) on physiological and biochemical characteristics of potato ( Solanum tuberosum L. cv. Kufri chandramukhi) using open top chambers. Ozone flux in leaves at 60 days after emergence (DAE) showed a trend in decreasing order as ACO 2 + EO 3 > ACO 2 + AO 3 > ECO 2 + EO 3 > ECO 2 + AO 3 > ACO 2 . Ozone flux was found to correlate directly with the plant’s photosynthetic performance and antioxidative response under different combinations of ambient and elevated CO 2 and O 3 . Maximum O 3 flux under ambient CO 2 and elevated O 3 (ACO 2 + EO 3 ) caused the highest increase in lipid peroxidation and solute leakage and reductions in chlorophyll content along with photosynthesis rate. Elevated O 3 stimulated the activities of superoxide dismutase (SOD), glutathione reductase (GR) and ascorbate peroxidase (APX) under ambient (ACO 2 + EO 3 ) and elevated CO 2 (ECO 2 + EO 3 ). However, all these alterations were alleviated by elevated CO 2 , indicating that oxidative stress on cell membrane was minimized and depression in photosynthesis rate recovered under combination of ECO 2 + EO 3 . Elevated CO 2 increased antioxidative enzymes and total phenolics in the leaves under ECO 2 + EO 3 at 30 DAE, contributing to the protection against O 3 induced oxidative stress. However, at 60 DAE, the protection provided by ECO 2 was mainly by reducing the ozone flux inside the leaves under ECO 2 + EO 3 . The study suggests that future increase in atmospheric concentrations of CO 2 will ameliorate O 3 damage to potato due to reduced O 3 uptake, increased carbon assimilation and by enhancing antioxidative property of leaves as an additional factor. [ABSTRACT FROM AUTHOR]

In order to utilize agricultural soils as an option to offset atmospheric carbon, it is essential to ascertain the degree of stability of the accrued carbon. A two step acid hydrolysis technique was used to separate labile and recalcitrant carbon pools in soil upto 30 cm depth to analyze their responses to different tillage managements after eight years of continuous practice in a sub-humid tropical rice-wheat system of Indo-Gangetic plains. There were four tillage practices; tillage before sowing/transplantation of every crop (RCT-WCT), tillage before transplanting of rice but no tillage before sowing the succeeding wheat crop (RCT-WNT), tillage before sowing of wheat but no tillage before sowing of rice (RNT-WCT), and no tillage before sowing of rice as well as wheat (RNT-WNT). It was observed that reduction in tillage frequency enhanced the total and recalcitrant carbon contents in soil with the maximum rate of sequestration recorded under RNT-WNT (0.59 tC ha-1 yr-1). The fraction of carbon translated into recalcitrant pool was constant under all the tillage combinations indicating that carbon stabilization was dependent predominantly on organic matter input in the rice-wheat system. Conventional tillage on the other hand caused loss of carbon from the soil as observed by reduction in total soil carbon content under RCT-WCT. Reduction in recalcitrant carbon content under RCT-WCT further indicated that acid hydrolysis might not represent long term carbon accumulation reliably. Concentration of phenolics in labile pool increased under RNT-WNT, RCT-WNT and RNT-WCT practices which also had higher total and recalcitrant carbon pools. This indicated towards contribution of phenolics in carbon stabilization in the soil. Results of the present study further suggested that adoption of no till agriculture in the region offers significant carbon sequestration opportunity under proper agricultural management. [ABSTRACT FROM AUTHOR]

Highlights: [•] Tillage permutations modified soil enzymes and microbial biomass N. [•] Continuous no tillage improved soil quality during rice cultivation. [•] Most of the extracellular enzymes showed dependence on soil temperature and moisture as per PCA. [•] β-Glucosidase and its relation with other enzymes could indicate impact of tillage permutations. [ABSTRACT FROM AUTHOR]

Highlights: [•] Conventional tillage left negative carbon footprint. [•] CH4 was largest contribution to carbon footprint. [•] Continuous no tillage was highest yielding practice. [•] Discontinuous tillage practice was worst environmental performer. [ABSTRACT FROM AUTHOR]

Abstract: Global agriculture lies in intersection of two inescapable issues of the present times, viz. keeping pace with growing food demand and participating in climate change mitigation efforts. Rice cultivation is a major emitter of greenhouse gases (GHGs) and no tillage of soil is becoming popular due to low economic investments with improved soil conditions. However, how these arrangements will affect GHG emissions need to be quantified. Therefore, monitoring over diverse agricultural practices is essential for optimum utilization of cultivable land and resources, while identifying the chances of emission reductions. We assessed the impacts of four tillage practices in rice–wheat cultivation system on fluxes of GHGs (CH4, N2O and CO2) and yield of rice. The tillage practices were tilling of soil before sowing of every crop (RCT-WCT), tillage before sowing of rice but no tillage before sowing of wheat (RCT-WNT), tillage before sowing of wheat but no tillage before sowing of rice (RNT-WCT), and no tillage before sowing of rice as well as wheat (RNT-WNT). Reduction in tillage frequency led to significant reductions in fluxes of CH4 and N2O, but increased CO2 while permutations of tillage and no tillage influenced grain yield. RNT-WCT produced next to or comparable to the most yielding RCT-WCT. Although it is difficult to select the best performer since no single tillage permutation showed consistent increment in yield with accompanied emission reductions, RNT-WCT, however may be considered as better agricultural practice for the study region. Long term and extensive spatio-temporal monitoring is still required before making any recommendation. It is also essential for understanding the factors that cause declination in yields under no tillage. [Copyright &y& Elsevier]

Abstract: Long-term use of industrial and domestic wastewater for irrigation leads to accumulation of heavy metals in the soil and consequently in the edible portion of the plants. This study examined the role of fertilizers in reducing the heavy metal availability in the soil, and subsequent uptake in Beta vulgaris L. (var. All green). The effects of organic fertilizer as farmyard manure (FYM), commercial inorganic nitrogen, phosphorus and potassium (NPK) and a combination of FYM+N were compared with control having no fertilization on physico-chemical properties of the soil and heavy metal concentrations in the soil and plants. Soil treatments led to changes in the physico-chemical properties of the soil, modifying the phytoavailability of heavy metals. Phytoavailabilty of Cd, Cu, Pb, Zn, Mn, Ni and Cr was lowest in FYM- and highest in NPK- treated soil, compared to the untreated control. The yield of B. vulgaris was also highest in FYM-treated soil. As the application of FYM alone and in combination with N resulted in reduced heavy metal uptake and better yield, it may be considered an easy and cost-effective technique for reducing the levels of contamination in food crops. [ABSTRACT FROM AUTHOR]

Abstract: A higher ozone concentration in rural agricultural region poses threat to food production in developing countries. The present study was conducted to evaluate the growth, biomass accumulation and allocation pattern, quantitative and qualitative characteristics of grains for two tropical rice cultivars (Oryza sativa L. cv NDR 97 and Saurabh 950) at ambient O3 concentrations at a rural site in the Indo Gangetic plains of India. Percent inhibition in number of leaves was higher for NDR 97, but in leaf area for Saurabh 950 grown in non filtered chambers (NFCs) compared to filtered chambers (FCs). Higher inhibition in root biomass was recorded in Saurabh 950 and in leaf and standing dead biomass for NDR 97. During vegetative phase, relative growth rate showed more percent inhibition in Saurabh 950, but at reproductive phase in NDR 97. Net assimilation rate showed higher values for Saurabh 950 than NDR 97 in NFCs but percent inhibition in leaf area ratio was higher for former than latter cultivar in NFCs. The ozone resistance was higher in NDR 97 during vegetative phase, but in Saurabh 950 at reproductive phase. Number of grains was higher in NDR 97 than Saurabh 950, but test weight and weight of grains m−2 showed reverse trends. Concentrations of starch, protein, P, N, Ca, Mg and K decreased, while reducing and total soluble sugar increased in grains of both the cultivars in NFCs compared to FCs. The study concluded that under ambient condition of O3 exposure, the two cultivars responded differently. Saurabh 950 favoured biomass translocation priority towards ear in reproductive phase and hence showed higher resistivity due to maintenance of higher test weight. NDR 97, however, showed better growth during vegetative period, but could not allocate efficiently to developing ears, hence higher number of unfilled grains in NFCs led lower test weight. [Copyright &y& Elsevier]

The interactive effect of cadmium (Cd) and zinc (Zn) bioaccumulation on physiological and biochemical characteristics of carrot (Daucus carota L. var Pusa Kesar) plants grown with different levels of Cd and Zn was examined. The combined application of Cd and Zn (Cd+Zn) had synergistic and antagonistic effects at low and high concentrations, respectively, on Cd accumulations in plants, chlorophyll b, and photosynthesis and transpiration rates. Whereas both low and high Cd+Zn concentrations had synergistic effects on Zn accumulation, ascorbic acid, protein content, total phenols, peroxidase activity, chlorophyll a, total, carotenoids and stomatal conductance. Bioaccumulation of Cd had strong and negative relationships with measured physiological and biochemical parameters. The study further showed that Cd and Zn in combination have more toxic effects on carrot plants as compared to their individual treatments. This study concludes that interactive effects of Cd and Zn on test plant depend on their ratios present in plants. [ABSTRACT FROM AUTHOR]

Ameliorative effects of ethylenediurea (N-[2-(2-oxo-1-imidazolinidyl) ethyl]-N′ phenylurea, abbreviated as EDU) against ozone stress were studied on selected growth, biochemical, physiological and yield characteristics of palak (Beta vulgaris L. var Allgreen) plants grown in field at a suburban site of Varanasi, India. Mean eight hourly ozone concentration varied from 52 to 73ppb which was found to produce adverse impacts on plant functioning and growth characteristics. The palak plants were treated with 300ppm EDU at 10days after germination at 10days interval up to the plant maturity. Lipid peroxidation in EDU treated plants declined significantly as compared to non-EDU treated ones. Significant increment in F v/F m ratio in EDU treated plants as compared to non-EDU treated ones was recorded. EDU treated plants showed significant increment in ascorbic acid contents and reduction in peroxidase activity as compared to non-EDU treated ones. As a result of the protection provided by EDU against ozone induced stress on biochemical and physiological characteristics of palak, the morphological parameters also responded positively. Significant increments were recorded in shoot length, number of leaves plant−1, leaf area and root and shoot biomass of EDU treated plants as compared to non-EDU treated ones. Contents of Na, K, Ca, Mg and Fe were higher in EDU treated plants as compared to non-EDU treated ones. The present investigation proves the usefulness of EDU in partially ameliorating ozone injury in ambient conditions. [Copyright &y& Elsevier]

Abstract: Vegetables (Beta vulgaris L., Abelmoschus esculentus L. and Brassica oleracea L.) from the production and market sites of India were tested for Cu, Cd, Zn and Pb. At market sites, the mean concentration of Cu in cauliflower, and of Zn and Cd in both palak and cauliflower had exceeded the PFA standard. Zn at the production sites also exceeded the PFA standard in cauliflower. Cd concentration in vegetables tested from both production and market sites was many folds higher than the EU standard. In contrast, Pb in vegetables tested from both production and market sites was below the PFA limit, but was considerably higher than the current EU and WHO standards. Heavy metals accumulation in vegetables tested are higher at market sites than those at the crop production sites. The contributions of these vegetables to dietary intake of Cu, Zn, Cd and Pb were 13%, 1%, 47% and 9% of provisional tolerable daily intake, respectively. The study concludes that the transportation and marketing systems of vegetables play a significant role in elevating the contaminant levels of heavy metals which may pose a threat to the quality of the vegetables with consequences for the health of the consumers of locally produced foodstuffs. [Copyright &y& Elsevier]

Air pollutant concentrations are rising in India, causing potential threats to crop production. As air pollutants are known to interfere with physiological processes, this study was conducted to assess the relative responses of physiological and biochemical characteristics of two cultivars of rice (Oryza sativa L. cv. Saurabh 950 and NDR 97) leading to variable yield responses. Twelve hour monitoring of ambient concentrations of SO2, NO2 and O3 in filtered chambers (FCs), non-filtered chambers (NFCs) and open plots (OPs) showed that O3 was the main pollutant at the experimental site. Ozone concentrations often exceeded 40 ppb during anthesis but not during the vegetative growth period. Photosynthetic rate (Ps), stomatal conductance (g s) and Fv/Fm ratio, superoxide dismutase (SOD) and peroxidase (POD) activities and photosynthetic pigments, ascorbic acid, total phenolics and protein contents were assessed at different developmental stages and yield of grains were quantified. Lipid peroxidation, SOD and POD activities, ascorbic acid and total phenolics were higher, whereas Ps, g s, Fv/Fm ratio and contents of protein and photosynthetic pigment were lower in plants of NFCs as compared to FCs. Yield decreased significantly in both cultivars grown in NFCs. NDR 97 showed less reductions in physiological characteristics, photosynthetic pigments and protein, but a greater increase in the antioxidative defense system as compared to Saurabh 950. Yield reduction was higher in NDR 97 than in Saurabh 950. This suggested that NDR 97 utilized more photosynthate in maintaining the metabolic machinery against O3 stress leading to lower translocation of photosynthate to reproductive parts. The study concluded that under natural field conditions, physiological and biochemical responses of plants varied with pollutant concentrations leading to different translocation strategies in plants, modifying their yield responses. NDR 97, a fast growing and high yielding cultivar was more sensitive than slow growing Saurabh 950. [Copyright &y& Elsevier]

The present study was conducted to evaluate the effects of different concentrations of cadmium (Cd) and zinc (Zn), singly and in combination, on uptake and bioaccumulation of Cd and Zn in Daucus carota L. (carrot) grown under natural field conditions. Carrot plants were treated with two Cd concentrations (10 and 100 μg mL -1 ), two Zn concentrations (100 and 300 μg mL -1 ), and two combined concentrations of Cd and Zn (10 + 100 and 100 + 300 μg mL -1 ) 15 d after seed germination. Treatments were repeated at 10 d intervals up to 90 d of plant age. A control was also kept without a Cd or Zn treatment. Uptake, total accumulation rate (TAR), bioconcentration factor (BCF), primary transport index (PTI), secondary transport index (STI), and accumulation of Cd and Zn in root, stem, and leaf were quantified. The results show that uptake, TAR, and accumulation of Cd and Zn are concentration-dependent phenomena. Highest accumulation of Cd and Zn was found in the root, followed by the stem and then leaves. The results also showed that bioaccumulation of Cd in root, stem, and leaf was greater at the low metal-application rates of Cd and Zn in combination than at the higher rate. This study further showed that interactions of Zn and Cd are dependent on the concentrations of those metals in the soil. [ABSTRACT FROM AUTHOR]

Growth performance, biomass accumulation, and net primary productivity (NPP) of five exotic plant species planted to stabilize and improve the coal mine spoils in India were assessed. The selected exotic species were very successful under afforestation programs on wastelands. Plant species showed a considerable variations in growth characteristics with response to their ages on coal mine spoils. The shoot height was found to be maximum in Eucalyptus hybrid and minimum for Cassia siamea during whole course of study. The circumference of plants varied significantly due to plant species as well as age. Shoot biomass increased by 2.5–3 times in 7 years old plantations of different plant species as compared to those of 4 years. Marked increments were also observed in the major root and fine root biomass with increasing age of plantations. Total biomass accumulation was recorded maximum in E. hybrid and minimum in C. siamea. The NPP also followed a similar trend as total biomass. The maximum contribution was made by stem with branch in comparison to other components in NPP among different plant species. Shoot production including branches was found to be maximum in E. hybrid and minimum in C. siamea, whereas the NPP of major roots did not show a similar trend as that of shoot. On the basis of biomass and primary productivity, E. hybrid and Acacia auriculiformis were found suitable for plantation on coal mine spoil land. [Copyright &y& Elsevier]

Tropospheric ozone (O3) is an important abiotic stress to plants and its rising concentration adversely affects crop yield. The studies associated with differential responses of tomato (Solanum lycopersicum L.) cultivars to chronic elevated O3 are lacking and need to be further explored for the recognition of O3 resistant cultivars as an adaptive strategy. In the present research, differentially heat sensitive tomato cultivars were treated with elevated O3 (ambient + 20 ppb) to determine their responses by estimating the foliar injury symptoms, variations in growth, physiology, reproductive and yield related attributes. All the tomato cultivars exhibited foliar injury symptoms under elevated O3 treatment, and the intensity of injury corroborated with yield loss. Elevated O3 treatment negatively impacted biomass, growth, physiological and reproductive characteristics of all cultivars. The hierarchal cluster analysis, cumulative stress response index and yield indices differentiated cultivars into sensitive, moderately sensitive and O3 tolerant categories. The thermotolerant, VRT02 and Kashi chayan cultivars (O3 resistant) demonstrated lower yield losses, whereas the thermotolerant (O3 sensitive) Superbug exhibited higher foliar injury, greater alterations in physiology, growth and reproductive traits resulting in greater yield losses than other cultivars. The cultivars with different heat sensitivity did not respond similarly towards O3 stress. Cultivars VRT 02 and Kashi chayan can be recommended for cultivation in areas experiencing high O3 vis-à-vis high temperature conditions. [ABSTRACT FROM AUTHOR]

This study investigates the impact of elevated ozone (eO 3) levels on the growth and yield of the wheat cultivar HD 2967 under different sowing dates in open-top chambers. Wheat was sown early on November 1st and timely on November 20th, 2017, under ambient and elevated O 3 (ambient + 20 ppb), resulting in four treatment groups: AT (ambient + timely), ET (elevated + timely), AE (ambient + early), and EE (elevated + early). Results showed significant reductions in morphological traits and gas-exchange parameters, including photosynthetic rate, stomatal conductance, and water use efficiency under eO 3. The most notable decreases were observed 40 days after germination (DAG) compared to 80 DAG. Interestingly, while a higher percentage reduction was observed under ET at 80 DAG, a reversal in the trend of percentage reduction between the two stages was noted, suggesting a dynamic response of the wheat cultivar to stress across the growth stage. However, compared with ET's results, early sowing mitigated these negative effects under a futuristic O 3 level scenario, showing no significant impact on grain yield and productivity factors. This resilience is attributed to the extended growth period, enhancing photosynthesis and biomass accumulation while avoiding high eO 3 concentrations during critical reproductive stages. Furthermore, a trade-off in ET plants suggests resources are allocated towards defense (enzymatic and non-enzymatic antioxidants) at the expense of growth, while EE conditions favor growth at later stages, maintaining reproductive fitness despite eO 3 levels. Under conventional timely sowing, wheat may suffer yield declines of up to 30 % amidst rising eO 3 levels. Early sowing emerges as a proactive strategy to maintain wheat productivity under increasing O 3 stress. Future studies should explore the effectiveness of early sowing across multiple wheat cultivars and climatic conditions to inform sustainable agricultural practices in high O 3 areas. [Display omitted] • Early sowing mitigates adverse effects of eO 3 on wheat biomass and photosynthesis. • Extended growth period under early sowing compensates for grain yield loss despite increased O 3. • Conventional timely sowing risks significant wheat yield decline under projected higher O 3 levels. • Trade-off observed between growth and defense mechanisms under timely sowing and eO 3 conditions. • Early sowing can be akey strategy to safeguard wheat productivity in the IGP region against escalating O 3 concentrations. [ABSTRACT FROM AUTHOR]

Examines the responses of two cultivars of wheat to sulphur dioxide when grown at six different nutrient levels. Wheat varieties; Soil fertility regimes and sulphur dioxide treatments; Effect of sulphur dioxide on carbohydrate metabolism.

Plants are inevitably grown in presence of sunlight, therefore bound to be exposed to natural UV‐B radiation. Several studies have already been conducted with UV‐B and medicinal plants and only few studies showed dose dependent variation. The present study aims to find out the variations and adaptation in Chlorophytum borivillianum under two different doses of UV‐B radiation; ambient + low (3.2 kJm−2 d−1) and high (7.2 kJm−2 d−1) UV‐B dose, denoted as LD and HD, respectively. Reduction in photosynthetic rate was higher at HD, while plants receiving LD displayed nonsignificant variation. During vegetative and reproductive stage, significant reduction (P ≤ 0.001) in stomatal conductance was obtained when exposed to HD‐eUV‐B. Fv/Fm showed more reductions in HD‐eUV‐B (12.6%) followed by LD‐eUV‐B (7.9%). Low and high doses of UV‐B enhanced the anthocyanin content but the increase was significant in HD, indicates epidermal protection strategy by the plants. Under LD‐eUV‐B, the content of saponin, a major phytochemical constituent was enhanced by 26%. Phytochemical analysis of roots revealed reduction mostly in fatty acid components whereas the steroidal components (stigmasterol and sarsasapogenin) showed enhancement in response to LD. The study suggests the importance of LD‐eUV‐B in the stimulation of medicinal compounds in C. borivillianum. [ABSTRACT FROM AUTHOR]

A pot study was performed to evaluate the influence of O 3 stress with different biochar treatments on a wheat cultivar (HD 2967). Plants were subjected to ambient and elevated (ambient+20 ppb) O 3 along with three doses of biochar (0%, 2.5%, and 5%). Elevated ozone alone reduced most of the growth parameters, negatively affecting the test cultivar's physiology. Although enzymatic antioxidants were up-regulated by elevated O 3 , damage to the membrane integrity was evident by higher MDA content in the wheat leaves. Besides, the uptake of nutrients was observed to be reduced under elevated O 3 due to the reduced phyto-availability of the soil's nutrients and cation exchange capacity. Such limitation of assimilates and nutrients marked a trade-off between growth and defence, translating to grain yield loss. However, applying biochar as a soil conditioner ameliorated the detrimental effects of O 3 with respect to the economic yield of wheat. Biochar alone improved soil properties and nutrient phyto-availability, which translated to better plant growth, stronger physiological capacity, and higher crop productivity. Thus, the study inferred that altered nutrient phyto-availablity and its uptake, likely associated with biochar-induced improved soil properties, relayed stronger plant physiology and antioxidative defence system to combat O 3 induced oxidative stress. ga1 • Applying biochar proved beneficial in ameliorating the adversity of O 3 stress. • A trade-off between growth and defence was observed under O 3 + 0% biochar addition. • Availability of nutrients and assimilates was observed to be the controlling factor. • 5% biochar dose noted a higher grain yield (+29%) than 2.5% (+17%) under ambient O 3. • Under elevated O 3 , biochar was effective in doses up to 2.5% but not at 5%. [ABSTRACT FROM AUTHOR]

The response of a wheat cultivar (HD 2967) under the combination of elevated ozone (O 3) and water deficit stress (WS) was evaluated in terms of morphological, physiological and yield parameters along with nutrient uptake and their redistribution to different plant parts. An open-top chamber experiment has been conducted under O 3 exposures (ambient (A) and ambient +20 ppb O 3 (E)) along with two different water regimes (well-watered; WW and water deficit with 50% of soil capacity; WS). Most of the growth parameters showed significant reductions due to elevated O 3 under both WW and WS conditions. Stomatal conductance and assimilation rate reduced significantly under the combined stress as compared to their controls (AWW). The maximum decrease in grain yield was observed under the additive effect of both the stresses of water deficit and elevated O 3 (−43.6%), followed by water deficit stress (−19.8%) and elevated O 3 (−17.9%) as compared to the control (AWW). Furthermore, the study displayed that reduced water availability has checked the uptake of nutrients in the roots, shoot and leaves, while, a higher carbon accumulation has been observed with subsequent increases in C: N and C: K ratios in the leaves. Such limitation of nutrients uptake and photosynthates availability weakened the antioxidative defense system of the test cultivar, making it more sensitive against combined stresses. Besides, the study displayed that the defense system has been remarkably suppressed under the presence of interactive stress factors, which allowed us to predict that the distribution of limited carbon pool has inverse relationship between the plant's defense system and growth. Flow diagram showing the mechanism of detoxification process by enzymatic and non ezymatic antioxidants along with changes in the nutrient content in the leaves in the test cultivar HD 2967 at vegetative stage (40 DAG) under (a) elevated O 3 (b) water deficit stress (WS) (c) O 3 + WS. .O 2 superoxide anions;.OH‐ hydroxyl radical content; 1O 2 singlet oxygen; APX ascorbate peroxidase; Asc ascorbate; C carbon (total sugar); Ca calcium; CAT catalase; Cu copper; GPX glutathione peroxidase; GSH reduced glutathione; GSSG oxidised glutathione; H 2 O water; H 2 O 2 hydrogen peroxide radicals content; K potassium; MDA monodehydroascorbate; Mg Magnesium; N 2 nitrogen; O 2 oxygen; O 3 ozone; P phosphate; POX peroxidase; ROS reactive oxygen species; SOD superoxide dismutase; WS water deficit stress; Zn zinc. Unlabelled Image • Possible stomatal exclusion of O 3 uptake does not govern the interaction of elevated O 3 and water deficit stress • Nutrients uptake and distribution patterns to different plant parts was affected • Limitation of nutrients uptake and photosynthates availability weakened the defence system of the cultivar • An additive effect on grain yield has been observed under the interaction of elevated O 3 and water deficit stress [ABSTRACT FROM AUTHOR]

Tropospheric ozone (O3) is a global air pollutant that causes deleterious effect to the plants. The present objective was to investigate the growth response, foliar injury, reactive oxygen species (ROS) accumulation and metabolites production in Costus pictus D. Don (insulin plant) at two developmental stages under ambient O3 (AO) and ambient + 20 ppb O3 (EO) using the open-top chambers (OTCs). A significant reduction in leaf area and total biomass was observed under EO as compared with AO. EO induced ROS (.O2– and H2O2) and lipid peroxidation led to more significant foliar injury and solute leakage. Image obtained from the fluorescence microscope and biochemical estimations reflected high levels of ROS under EO. A differential response in flavonoids and anthocyanin content, ascorbic acid, and antioxidative enzymes such as catalase (CAT), superoxide dismutase (SOD) and peroxidase (POX) has been observed with the growth stages of C. pictus plant. EO exposure negatively affected thiols and protein contents at all the growth stages. Secondary metabolites (tannins, lignin, saponins and alkaloids) were increased in both leaves and rhizomes due to EO, whereas phytosterols were induced only in rhizomes. Apart from other metabolites, the key bioactive compound (corosolic acid) showed its synthesis to be stimulated under EO at later growth stage. The study concludes that O3 is a potent stimulating factor for changing the levels of secondary metabolites and antioxidants in an antidiabetic C. pictus plants as it can alter its medicinal properties. Costus pictus D. Don is an important medicinal plant with a key bioactive compound known as corosolic acid, which is used in the treatment of diabetes. Tropospheric ozone pollution is very high in Indo-Gangetic Plain of India and its effect on C. pictus is still unexplored. Corosolic acid content was found to be increased at later stages of growth under elevated ozone. [ABSTRACT FROM AUTHOR]

The article offers the comments of the authors on the establishment of the Ministry for Water Resources, River Development and Ganga Rejuvenation by the Government of India. According to the authors, this would help to increase the water quality of the River Ganga. They adds that it is important to focus on land use patterns along the banks of the river.

Exposure to elevated UV‐B (eUV‐B) is well known for its phytotoxicity, although studies made with UV‐B exposure and its impact on grasses are limited especially from tropical countries including India. In this study, responses of a valuable grass species, Heteropogon contortus BL‐1, were assessed under eUV‐B (over ambient UV‐B) at different growth stages. Damage caused by eUV‐B was observed in the form of membrane damage and loss of pigments at early stages of growth, whereas tannin, phenol, and protein contents showed their increments at all the growth stages, to overcome the imposed stress. Reducing sugar showed its decline at all the growth stages, whereas starch and sucrose contents were higher mostly at later ages of plant growth. eUV‐B caused a marked variations in anatomical structures with increase of mesophyll and spongy parenchymatous cells in leaves to reduce severity of irradiation, to maintain the growth and productivity. The study also highlights the significant negative influence of eUV‐B on the growth of H. contortus BL‐1 and its adaptive strategy to minimize the negative impacts. With the progression of age, plants although adopted to UV‐B stress with maintenance of productivity, but palatability of forage was affected due to increment of tannin content. Heteropogon contortus BL‐1 (Pilli grass) responses to elevated UV‐B (eUV‐B) were depended on ambient UV‐B and plant age. Under eUV‐B, plants developed array of strategies to deal with imposed stress as the age progressed. Most of the variations were observed at vegetative and prereproductive stages. Tannin, phenol, and protein contents increased under eUV‐B at all growth stages thus developed resistance but also affected the palatability. 1‐22 represent root length, plant height, number of leaves, leaf area, number of tillers, total biomass, MDA, chlorophyll, carotenoids, phenolics, ascorbic acid, tannin, protein, APX, CAT, GR, POX, SOD, sucrose, reducing sugar, total sugar, and starch. [ABSTRACT FROM AUTHOR]

Tropospheric ozone (O3) is a significant abiotic stressor whose rising concentration negatively influences plant growth. Studies related to the differential response of Abelmoschus cytotypes to elevatedO3 treatment are scarce and need further exploration to recognise the role of polyploidisation in stress tolerance. In this study, we analysed the changes in growth pattern, ultrastructure, physiology and foliar protein profile occurring under O3 stress in Abelmoschus moschatus (monoploid), Abelmoschus esculentus (diploid) and Abelmoschus caillei (triploid). Our findings showed that higher stomatal conductance in A. moschatus triggered higher O3 intake, causing damage to stomatal cells and photosynthetic pigments. Additionally, it caused a reduction in photosynthetic rates, leading to reduced plant growth, total biomass and economic yield. ThisO3-induced toxicity was less in diploid and triploid cytotypes of Abelmoschus. Protein profiling by sodium dodecyl sulpate-polyacrylamide gel electrophoresis showed a significant decrease in the commonly found RuBisCO larger and smaller subunits. The decrease was more prominent in monoploid compared to diploid and triploid. This study provides crucial data for research that aim to enhance plant ability to withstand O3 induced oxidative stress. Our findings may help in developing a tolerant variety through plant breeding techniques, which will be economically more advantageous in reaching the objective of sustainable production at the high O3 levels projected under a climate change scenario. [ABSTRACT FROM AUTHOR]

Tropospheric ozone (O3) is considered harmful to agriculture production and soil community. Wheat cultivars HD 2987 (O3 sensitive) and Kharchiya 65 (O3 tolerant) were grown under ambient and elevated (ambient + 30 ppb) levels of O3 (EO) using open top chambers, and microbial biomass and enzymatic activities were investigated in soil rhizosphere. Elevated O3 declined soil enzymatic activities related to carbon cycling viz. β-glucosidase, cellobiohydrolase, cellulase and amylase more in sensitive cultivar compared to tolerant. Enzymatic activities linked to nitrogen cycling like N-acetyl-glucosaminidase and urease decreased while protease and glycine aminopeptidase increased. Microbial biomass carbon and nitrogen declined more in sensitive cultivar by 11.1 and 21.2%, respectively. Root biomass reduced in wheat cultivars with an increase of their phenolics contents by 34.3 and 10.2% in HD 2987 and Kharchiya 65, respectively at 60 days after germination. Non-significant changes were observed in soil organic carbon and total nitrogen in both the cultivars. Redundancy analysis suggested that soil enzymatic activities were predominantly affected by O3 induced changes in microbial biomass carbon and root biomass. Study also showed that rhizosphere of sensitive cultivar HD 2987 was affected more under EO as compared to tolerant Kharchiya 65. [ABSTRACT FROM AUTHOR]

Plant community structure studies on derelict sites are providing significant insights into vegetation dynamics to ensure the success of future revegetation projects in such areas. Therefore, the present study was conducted to evaluate the changes in soil physico-chemical and biological properties at abandoned red mud dumps (RMD) compared to residential (RS) and forest (FS) sites, coupled with their consequent impacts on the plant community structure. An attempt was also made to identify the indicator species that thrive only under unfavourable red mud conditions. Soil at RMD showed relatively high bulk density, alkalinity, salinity and exchangeable sodium percentage along with poor nutrient status and low microbial activity. Though toxic metals (Cd, Cr and Pb) were higher at RMD, their phytoavailabilities were lower compared to FS site. Number of herb-, shrub- and woody species at RMD were although low, but a significant number of species were acclimatized to the unfavourable soil conditions. Shrub species were maximally affected at RMD, followed by woody- and herbaceous species. Important value index of sensitive species was low while that of tolerant species was higher, and was accredited to altered soil properties. Presence of invasive species such as Acacia nilotica , Caesalpinia bonduc , Stylosanthes scabra and Urena lobata at only RMD may be used as an indication for high toxic metal contamination along with high alkalinity, salinity and poor nutrient contents. Principal component and canonical correspondence analyses revealed that woody and herbaceous species were mainly affected by soil alkalinity, salinity, exchangeable cations, bulk density, porosity, moisture content and phytoavailable metals. Shrub species were primarily influenced by soil organic carbon, nitrogen, available phosphorus, bulk density, porosity, moisture content, soil biological parameters, total (Fe, Mg, Cd, Cr and Pb) and phytoavailable metals. Domination of herbaceous species in the plant community indicated their tendency towards a definite selection strategy in response to altered soil properties. The identified tolerant herbaceous species may be suitable candidates for future red mud reclamation strategies. [ABSTRACT FROM AUTHOR]

The prevailing tropospheric ozone (O3) concentration is escalating the productivity loss of crop and vegetables due to enhanced oxidative stress. Ozone itself is very reactive and can interact with mesophyll regions and components of cell walls after gaining entry from stomata. Apoplastic O3 activates a number of signal transduction pathways that regulate the cellular response to increased reactive oxygen species (ROS) load. The overproduction of ROS under O3 stress causes lesions as a hypersensitive or defensive response in the leaves of the sensitive plant. Ozone induced phytohormone signaling interacts with ROS signaling to change the plants' performance in various aspects of plant physiology and metabolism. High O3 exposure promotes the accumulation of salicylic acid, which is essential for maintaining the cellular redox state and is important for plant defense responses. Salicylic acid concentration helps in regulating the production of ethylene during O3 exposure, which alters the magnitude of chlorotic spots on leaf surfaces. The review summarizes some recent findings about the target sites for O3 in plants, O3 induced stomatal regulation by phytohormone signaling, and plants' responses related to phytohormone biosynthesis, ROS generation and signaling in exposure to O3. [ABSTRACT FROM AUTHOR]

Due to hostile condition of red mud (RM), its utilization for vegetation is restricted. Therefore, RM with biowastes as soil amendment may offer suitable combination to support plant growth with reduced risk of metal toxicity. To evaluate the effects of RM on soil properties, plant growth performance, and metal accumulation in lemongrass, a study was conducted using different RM concentrations (0, 5, 10, and 15% w/w) in soil amended with biowastes [cow dung manure (CD) or sewage-sludge (SS)]. Application of RM in soil with biowastes improved organic matter and nutrient contents and caused reduction in phytoavailable metal contents. Total plant biomass was increased under all treatments, maximally at 5% RM in soil with SS (91.4%) and CD (51.7%) compared to that in control (no RM and biowastes). Lemongrass acted as a potential metal-tolerant plant as its metal tolerance index is >100%. Based on translocation and bioconcentration factors, lemongrass acted as a potential phytostabilizer of Fe, Mn, and Cu in roots and was found efficient in translocation of Al, Zn, Cd, Pb, Cr, As, and Ni from roots to shoot. The study suggests that 5% RM with biowastes preferably SS may be used to enhance phytoremediation potential of lemongrass. [ABSTRACT FROM AUTHOR]

In India, road transport sector is one of the major anthropogenic contributor of GHGs and other pollutants into the atmosphere which have significant adverse human health effects. National and state level pollutants’ emissions from road transport in India have been estimated by using VKT approach for the period of 2001–2013 which includes the values of average vehicle kilometres travelled (VKT) by different vehicle types and emission factors (EF) for different vehicle types. The results revealed a Compound Annual Growth Rate (CAGR) of 8.5%, 8.5%, 8.1%, 8.3%, 8.4%, 8.2% and 9% respectively of carbon dioxide (CO 2 ), methane (CH 4 ), nitrogen oxides (NO x ), carbon monoxide (CO), sulphur dioxide (SO 2 ), particulate matters (PM) & hydrocarbon (HC) emissions from vehicles in road transport sector during the periods 2001–2013 due to increase of vehicle population. The study also showed a negative temporal trend in the CO 2 emissions per unit of GDP indicating reduced CO 2 emission intensities in transport sector. Statewise emission estimates from different vehicle categories confirmed that states like Maharashtra, Gujarat, Tamil Nadu, Kerala, Uttar Pradesh, Rajasthan, Andhra Pradesh, Karnataka and Delhi are responsible for about 68% of total emissions of CO 2 , CO, CH 4 , NO x , SO 2 , HC and PM. [ABSTRACT FROM AUTHOR]

The UV-B photoreceptor UVR8 regulates the expression of several genes leading to acclimation responses in plants. Direct role of UVR8 in maintaining the photosynthesis is not defined but it is known to increase the expression of some chloroplastic proteins like SIG5 and ELIP. It provides indirect protection to photosynthesis by regulating the synthesis of secondary metabolites and photomorphogenesis. Signaling cascades controlled by UVR8 mediate many protective responses thus promotes plant acclimation against stress and secures its survival. [ABSTRACT FROM AUTHOR]

Ground-level ozone (O3) is well recognized as a secondary air pollutant with detrimental effects on plant growth and biochemistry. In a field study, Andrographis paniculata (King of Bitter) was exposed to ambient O3 and elevated O3 (AO + 20 ppb) at three growth stages [45, 90, and 135 days after treatment, (DAT)] using open-top chambers. Elevated O3 stress negatively impacted plant growth, increased cell damage, and induced foliar injuries. However, elevated O3 also boosted antioxidant production such as proline, phenol, and enzymatic antioxidants, as well as certain secondary metabolites such as tannins, phytosterols, saponins, and alkaloids. This may enhance the plant's medicinal properties, including compounds limonene dioxide, phytol, palmitic acid, and androstadiene. While, certain metabolites like Citronellol, Khusenol, and tocopherol displayed an adverse reaction under elevated O3 exposure. The novel detection of acrodiene, squalene, and neophytadiene under O3 stress emphasizes their medicinal significance. Notably, an important bioactive compound andrographolide in A. paniculata showed increased synthesis under elevated O3 at 45 and 90 DAT, suggesting that O3 exposure could enhance the plant's pharmaceutical value. [ABSTRACT FROM AUTHOR]

Current and projected increases in ultraviolet-B (UV-B; 280-315 nm) radiation may alter crop growth and yield by modifying the physiological and biochemical functions. This study was conducted to assess the possibility of alleviating the negative effects of supplemental UV-B (sUV-B; 7.2 kJ m−2 day−1; 280-315 nm) on radish ( Raphanus sativus var Pusa Himani) by modifying soil nitrogen (N), phosphorus (P) and potassium (K) levels. The N, P and K treatments were recommended dose of N, P and K, 1.5 times recommended dose of N, P and K, 1.5 times recommended dose of N and 1.5 times recommended dose of K. Plants showed variations in their response to UV-B radiation under varying soil NPK levels. The minimum damaging effects of sUV-B on photosynthesis rate and stomatal conductance coupled with minimum reduction in chlorophyll content were recorded for plants grown at recommended dose of NPK. Flavonoids increased under sUV-B except in plants grown at 1.5 times recommended dose of N. Lipid peroxidation (LPO) also increased in response to sUV-B at all NPK levels with maximum at 1.5 times recommended dose of K and minimum at recommended dose of NPK. This study revealed that sUV-B radiation negatively affected the radish plants by reducing the photosynthetic efficiency and increasing LPO. The plants grown at 1.5 times recommended dose of NPK/N/K could not enhance antioxidative potential to the extent as recorded at recommended dose of NPK and hence showed more sensitivity to sUV-B. [ABSTRACT FROM AUTHOR]

Abstract: The present study was conducted to assess the risk to human health by heavy metals (Cd, Cu, Pb, Zn, Ni and Cr) through the intake of locally grown vegetables, cereal crops and milk from wastewater irrigated site. Milk is not directly contaminated due to wastewater irrigation, but is an important route of food chain transfer of heavy metals from grass to animals. Heavy metal concentrations were several fold higher in all the collected samples from wastewater irrigated site compared to clean water irrigated ones. Cd, Pb and Ni concentrations were above the ‘safe’ limits of Indian and WHO/FAO standards in all the vegetables and cereals, but within the permissible limits in milk samples. The higher values of metal pollution index and health risk index indicated heavy metal contamination in the wastewater irrigated site that presented a significant threat of negative impact on human health. Rice and wheat grains contained less heavy metals as compared to the vegetables, but health risk was greater due to higher contribution of cereals in the diet. The study suggests that wastewater irrigation led to accumulation of heavy metals in food stuff causing potential health risks to consumers. [Copyright &y& Elsevier]

Abstract: Global mean tropospheric ozone concentration is expected to increase by more than 20% by 2050. Although the present levels of ozone may not induce visible symptoms in most of the plants, they can result in substantial production losses and reproductive output. There are wide variations in ozone sensitivity among varieties in same species. This paper reports variations in ozone sensitivity for two tropical soybean (Glycine max L.) varieties (PK 472 and Bragg) exposed to projected elevated ozone concentrations of 70 and 100ppb for 4h daily from germination to maturity under natural field conditions. Differential sensitivities of cultivars to ozone were assessed by comparing the levels of antioxidative potential, metabolite production, growth behaviour, biomass accumulation and yield responses. The activity of catalase decreased whereas peroxidase increased in both the varieties upon exposure to O3, however, the magnitude of change was always higher in PK 472 as compared to Bragg. The larger magnitude of reductions in the levels of antioxidants, metabolites and nutrients also reflected the greater sensitivity of PK 472 compared to Bragg. The differential response of biochemical characteristics corresponded to significant reductions in plant length, number and area of leaves, component-wise biomass and yield parameters of PK 472 as compared to Bragg. This work emphasizes the greater sensitivity of a newly developed variety PK 472 of soybean compared to that of the older variety, Bragg. Further, the effects of ozone on different plant characteristics were found to be more prominent during reproductive than vegetative growth in these two varieties. In view of the anticipated increasing tropospheric O3 concentrations the in near future, the results of the present study can be utilized in screening out more resistant varieties of soybean for greater agricultural productivity. [Copyright &y& Elsevier]

The present study investigated the impact of irrigation with wastewater on nutritional property and heavy-metal concentrations in the soil and consequent accumulation in vegetables at sites having long-term uses of wastewater for irrigation. Samples of irrigation water, soil, and root and shoot parts of palak plants were analyzed to determine the concentration of heavy metals. Wastewater irrigation led to increases in the total and phytoavailable heavy-metal concentrations in the soil at all the sites. Heavy-metal concentrations in soil under wastewater irrigation were negatively and positively correlated with soil hydrogen potential (pH) and organic carbon (OC), respectively. The enrichment factor and metal pollution index were higher at wastewater-irrigated sites as compared to the clean water-irrigated ones. The study concludes that wastewater irrigation modified the physicochemical properties of the soil, leading to more availability of heavy metals in the soil and consequently to the plant. [ABSTRACT FROM AUTHOR]

The article focuses on the effects of ultraviolet-B (UV-B) radiations to plants. It notes that the depletion of the ozone layer in the atmosphere of the Earth has increased the amount of ultraviolet radiations. UV-B induces the development of reactive oxygen species (ROS) which affects plants that causes oxidative stress, effects to antioxidants and change in gene expression of plants. Moreover, it also affects thylakoid membranes which are responsible to photosynthesis in plants.

Enterococci serve as an "indicator" of fecal contamination for recreational water quality. The vancomycin-resistant-enterococci (VRE) are emerging environmental contaminants in the surface waters. The aim of this study was to develop a rapid and specific molecular beacon probe (MBP)-based real-time PCR assay for detection of vanA gene in surface waters and aquatic macrophyte. The limit of detection (LOD) of the MBP assay was 1 CFU/mL of VRE [r = 0.943; PCR efficiency = 99.7%] in 2-fold dilution format within 2.5 h and demonstrated high specificity for environmental enterococci isolates exhibiting VanA phenotype (n = 25). VRE were detected from downstream surface waters of the dyers impacted by point sources of pollution and recreational activities. The probe detected vanA gene in root-mat associated microbiota of E. crassipes (Mart) Solms. an aquatic nuisance weed, at eutrophic sites of the surface waters (ANOVA p < 0.001). In addition, the assay enabled detection of otherwise nondetectable vanA gene concentration in the upstream sites of two Indian rivers (Student's t test p < 0.001). The MBP assay developed can be used for sensitive and rapid detection of VRE in surface waters and identification of nonpoint sources of pollution for implementation of preventive measures to protect human health. [ABSTRACT FROM AUTHOR]

Abstract: The decrease in stratospheric ozone has heightened concern over the consequences of increasing solar UV-B radiation on plants. The present study was conducted to evaluate the interactive effects of supplemental UV-B (sUV-B: 280–320nm) and mineral nutrients on a leafy vegetable amaranthus (Amaranthus tricolor L. var Pusa badi) under natural field conditions in a dry tropical environment. The nutrient treatments were recommended dose of NPK, 1.5 times recommended dose of NPK, 1.5 times recommended dose of N and 1.5 times recommended dose of K sUV-B radiation inhibited growth and biomass accumulation and altered the patterns of biomass partitioning. In K amended plants larger proportion of biomass has been translocated to roots which further increased under sUV-B treatment. The application of 1.5 times recommended dose of NPK reduced the magnitude of yield loss. The study shows that amaranthus is a potentially UV-B sensitive species and a higher NPK dose above the recommended is required to minimize the adverse impact of sUV-B. [Copyright &y& Elsevier]

This study examines the annual, seasonal and diurnal variations in the ambient concentrations of ozone at a suburban site of Varanasi, India, during 2002-2006. Prominent seasonal variations in ozone concentrations were recorded. Ozone concentrations were higher during the warmer months. Daytime 12-hourly mean monthly ozone concentrations varied from 45.18 to 62.35 ppb during summer, from 28.55 to 44.25 ppb during winter and from 24 to 43.85 ppb during the rainy season from 2002 to 2006. Distinct diurnal variations in ozone concentrations were also observed. Daytime maxima in ozone concentration were recorded between 1200 and 1400 h, whereas morning and evening hours showed lower concentrations of ozone. Ozone concentrations in the atmosphere depended on several meteorological factors. Monthly average ozone concentration was significantly correlated with maximum temperature (p<0.001) and mean monthly temperature (p<0.05), maximum relative humidity (p<0.001), minimum relative humidity (p<0.001) and mean monthly relative humidity (p<0.001), and sunshine hours (p<0.001). Ozone concentrations in the ambient air have shown an increase in the past decade that was more in the winter and rainy seasons than in the summer. This study suggests that ozone concentrations around Varanasi were sufficiently high to cause significant damage to agricultural production. The present work can be extended to a regional level by incorporating modelling studies using recent remote sensing tools. [ABSTRACT FROM AUTHOR]

Temporal and spatial variations in litterfall, leaf litter decomposition and nutrient release were quantified along an air pollution gradient around an industrial area in a dry tropical region of India. Significant differences were found in litterfall between the sites. Litter decomposition rates also significantly varied among the study sites. Litter decomposition was faster at sites away from the industrial region with coal-fired power plants. The concentrations of N and P increased, whereas that of Ca and SO4-S decreased in decomposing litter over time. The nutrient release pattern was also modified by atmospheric deposition. Concentrations of SO2 and NO2 were negatively correlated with relative mass loss. Turnover time of nutrients, except SO4-S in decomposing litter was maximal at the site receiving highest atmospheric depositions. The study documents that industrial emissions significantly modified nutrient cycling in adjacent terrestrial ecosystems. [Copyright &y& Elsevier]

• Sensitivity of early and late sown Indian wheat cultivars to O 3 were evaluated. • O 3 flux-effect relationships were investigated for AGB and yield in wheat plants. • Higher accumulation of POD 6 SPEC was found in early sown than late sown cultivar. • Higher longevity, g max and lower critical level made early sown cultivars more sensitive. • The grain yield loss under EO 3 was 30.5 % in early and 23 % in late sown cultivars. Precise ozone (O 3) flux models remain helpful to identify the sensitivity of crops and their cultivars under high O 3 levels by assessing biomass and yield losses under natural climate and future O 3 levels. In this study, we have evaluated the effects of O 3 on growth, biomass, and yield of four Indian wheat cultivars by exposure-linked as well as through flux-effect relationship-based analysis using two years of empirical data. Early and late sown cultivars were exposed to ambient O 3 (AO 3) and elevated O 3 i.e., ambient+20 ppb (EO 3). The POD 6 SPEC (species-specific phytotoxic O 3 dose above a threshold of 6 nmol m−2 PLA s-1) on flag leaves for each cultivar and treatment was derived by using DO 3 SE (Deposition of Ozone for Stomatal Exchange) model. Above-ground biomass was reduced more in early sown cultivars (26.1 %) than late sown (21.3 %) because of the larger negative impacts on plant growth under EO 3 treatment. Loss of grain yield under EO 3 exposure was high in early sown cultivars (30.5 %) compared to late sown (23 %) due to high stomatal O 3 uptake during the O 3 exposure period. Based on model outputs, early sown cultivars showed higher accumulated POD 6 SPEC (1.6–3.75 mmol O 3 m−2) compared to late sown cultivar (0.65 to 1.97 mmol m−2). A negative linear relationship was obtained in above-ground biomass and grain yield concerning POD 6 SPEC. The relationship showed that 0.284 mmol O 3 m−2 accumulated POD 6 SPEC is responsible for a 5% reduction of grain yield in early sown cultivars, while 0.393 mmol O 3 m-2 accumulation is required for a 5% reduction in yield of late sown cultivars. The results also suggest that O 3 flux-effect relationship could be a valuable tool for assessing and predicting the risk of O 3 on wheat cultivars in India and for crop productivity models for predicting climate change impacts. [ABSTRACT FROM AUTHOR]