Investigating seasonal air quality variations consequent to the urban vegetation in the metropolis of Faisalabad, Pakistan.

Urban atmospheric pollution is global problem and and have become increasingly critical in big cities around the world. Issue of toxic emissions has gained significant attention in the scientific community as the release of pollutants into the atmosphere rising continuously. Although, the Pakistani government has started the Pakistan Clean Air Program to control ambient air quality however, the desired air quality levels are yet to be reached. Since the process of mapping the dispersion of atmospheric pollutants in urban areas is intricate due to its dependence on multiple factors, such as urban vegetation and weather conditions. Therefore, present research focuses on two essential items: (1) the relationship between urban vegetation and atmospheric variables (temperature, relative humidity (RH), sound intensity (SI), CO, CO2, and particulate matter (PM0.5, PM1.0, and PM2.5) and (2) the effect of seasonal change on concentration and magnitude of atmospheric variables. A geographic Information System (GIS) was utilized to map urban atmospheric variables dispersion in the residential areas of Faisalabad, Pakistan. Pearson correlation and principal component analyses were performed to establish the relationship between urban atmospheric pollutants, urban vegetation, and seasonal variation. The results showed a positive correlation between urban vegetation, metrological factors, and most of the atmospheric pollutants. Furthermore, PM concentration showed a significant correlation with temperature and urban vegetation cover. GIS distribution maps for PM0.5, PM1.0, PM2.5, and CO2 pollutants showed the highest concentration of pollutants in poorly to the moderated vegetated areas. Therefore, it can be concluded that urban vegetation requires a rigorous design, planning, and cost-benefit analysis to maximize its positive environmental effects.

Photocatalytic and antibacterial activity of graphene oxide/cellulose-doped TiO2 quantum dots: in silico molecular docking studies.

Graphene oxide (GO) and cellulose nanocrystal (CNC)-doped TiO2 quantum dots (QDs) were effectively synthesized by employing the co-precipitation method for the degradation of dyes and antimicrobial applications. A series of characterizations, i.e., XRD, FTIR, UV-visible spectroscopy, EDS, FE-SEM, and HR-TEM, was used to characterize the prepared samples. A reduction in PL intensity was observed, while the band gap energy (E g) decreased from 3.22 to 2.96 eV upon the incorporation of GO/CNC in TiO2. In the Raman spectra, the D and G bands were detected, indicating the presence of graphene oxide in the composites. Upon doping, the crystallinity of TiO2 increased. HR-TEM was employed to estimate the interlayer d-spacing of the nanocomposites, which matched well with the XRD data. The photocatalytic potential of the prepared samples was tested against methylene blue, methylene violet, and ciprofloxacin (MB:MV:CF) when exposed to visible light for a certain period. The antibacterial activity of GO/CNC/TiO2 QDs against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria in vitro was tested to determine their potential for medicinal applications. The molecular docking investigations of CNC-TiO2 and GO/CNC-doped TiO2 against DNA gyrase and FabI from E. coli and S. aureus were found to be consistent with the results of the in vitro bactericidal activity test. We believe that the prepared nanocomposites will be highly efficient for wastewater treatment and antimicrobial activities.

Interspecific Differences in Physiological and Biochemical Traits Drive the Water Stress Tolerance in Young Morus alba L. and Conocarpus erectus L. Saplings.

Mitigating climate change requires the identification of tree species that can tolerate water stress with fewer negative impacts on plant productivity. Therefore, the study aimed to evaluate the water stress tolerance of young saplings of C. erectus and M. alba under three soil water deficit treatments (control, CK, 90% field capacity, FC, medium stress MS, 60% FC and high stress, HS, 30% FC) under controlled conditions. Results showed that leaf and stem dry weight decreased significantly in both species under MS and HS. However, root dry weight and root/shoot ratio increased, and total dry weight remained similar to CK under MS in C. erectus saplings. Stomatal conductance, CO2 assimilation rate decreased, and intrinsic water use efficiency increased significantly in both species under MS and HS treatments. The concentration of hydrogen peroxide, superoxide radical, malondialdehyde and electrolyte leakage increased in both the species under soil water deficit but was highest in M. alba. The concentration of antioxidative enzymes like superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase also increased in both species under MS and HS but was highest in C. erectus. Therefore, results suggest that C. erectus saplings depicted a better tolerance to MS due to an effective antioxidative enzyme system.

Foliar Application of Salicylic Acid Improves Water Stress Tolerance in Conocarpus erectus L. and Populus deltoides L. Saplings: Evidence from Morphological, Physiological, and Biochemical Changes.

Reforestation efforts are being challenged as water stress is hampering the sapling growth and survival in arid to semiarid regions. A controlled experiment was conducted to evaluate the effect of foliar application of salicylic acid (SA) on water stress tolerance of Conocarpus erectus and Populus deltoides. Saplings were watered at 90%, 60%, and 30% of field capacity (FC), and half of the saplings under 60% and 30% FC were sprayed with 1.0 mM SA. Results indicated that dry weight production decreased significantly in Populus deltoides under both water deficit conditions, and leaf gas exchange parameters decreased significantly in both the species under both soil water deficit conditions. Foliar application of SA resulted in a significant increase in leaf gas exchange parameters, and compatible solutes, thereby increasing the dry weight production in both of the species under soil water deficit. Oxidative stress (hydrogen peroxide and superoxide anions) increased under soil water deficit and decreased after the foliar application of SA and was parallel to the increased antioxidant enzymes activity (superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase). Therefore, it can be concluded that foliar application of 1.0 mM SA can significantly improve the water stress tolerance in both species, however, positive impacts of SA application were higher in Conocarpus erectus due to improved photosynthetic capacity and increased antioxidant enzyme activity.

Increased antioxidative enzyme activity mediates the phytoaccumulation potential of Pb in four agroforestry tree species: a case study under municipal and industrial wastewater irrigation.

Wastewater used as irrigation water is causing heavy metal accumulation in the agro-ecosystems. A greenhouse study was conducted to compare the phytoaccumulation ability of four agroforestry tree species under different wastewater treatments. Three-month-old potted seedlings of Morus alba, Acacia nilotica, Acacia ampliceps, and Azadirachta indica were irrigation with tap water (C), municipal wastewater (MWW), and industrial wastewater (IWW). Results showed that MWW had a positive and IWW had a negative impact on biomass production in all the species. Acacia ampliceps showed the highest increment (65%) and showed the lowest decrease (5%) in total biomass under both MWW and IWW treatment. Pb concentration was also found highest in the leaves, stem and roots of Azadirachta indica (108.5, 46.2, 180.5 mg kg-1, respectively) under IWW. Production of H2O2 was highest in IWW treatment with almost 148% increase observed in Azadirachta indica. Similarly, the production of antioxidative enzymes (Superoxide dismutase, Catalase and Peroxidase) was also highest in Azadirachta indica under IWW. Therefore, results suggest that along with high increment in total biomass, both Acacia ampliceps and Azadirachta indica showed high Pb concentration and an effective antioxidative defense mechanism and thus, can be used for planting in soils irrigated with MWW and IWW.

Assessment of European and hybrid aspen clones efficiency based on height growth and removal percentage of petroleum hydrocarbons-a field trial.

Soils polluted by organic or inorganic pollutants are an emerging global environmental issue due to their toxic effects. A phytoremediation experiment was conducted to evaluate the extraction potential of three European aspen clones (R2, R3, and R4) and seven hybrid aspen clones (14, 27, 34, 134, 172, 191, and 291) grown in soils polluted with hydrocarbons (includes polycyclic aromatic hydrocarbons (PAH) and total petroleum hydrocarbons (TPH)). Height growth, plant survival rates, and .hydrocarbon removal efficiencies were investigated over a 4-year period at a site in Somerharju, Luumaki Finland, to assess the remediation potential of the clones. Hydrocarbon content in the soil was determined by gas chromatography and mass spectrometry. The results revealed that hybrid aspen clones 14 and 34 and European aspen clone R3 achieved greater height growth (171, 171, and 114 cm, respectively) than the other clones in the study. Further, the greatest removals of PAH (90% at depth 10-50 cm) and (86% at depth 5-10 cm) were observed in plot G15 planted with clone R2. Furthermore, the greatest TPH removal rate at 5-10 cm depth (C22-C40, 97%; C10-C40, 96%; and C10-C21, 90%) was observed in plot 117 with clone 134. However, other clones demonstrated an ability to grow in soils with elevated levels of TPH and PAH, which indicates their tolerance to hydrocarbons and their potential capacity for phytoremediation of hydrocarbon-polluted soils. Our study suggests that European aspen and hybrid aspen clones could be used for the remediation of soils polluted with PAH and TPH.

Bacillus firmus strain FSS2C ameliorated oxidative stress in wheat plants induced by azo dye (reactive black-5).

This study was conducted to determine the ability of a bacterial strain FSS2C to ameliorate growth of wheat plants grown under induced stress of reactive black-5 (RB-5). The strain was taxonomically identified as Bacillus firmus on the basis of its 16S rRNA gene sequence analysis. The B. firmus FSS2C was found physiologically potent in phosphate solubilization, indole-3-acetic acid production and ammonia synthesis in the presence of varying concentrations of azo dye RB-5. Moreover, it decolorized RB-5 in vitro with the maximum decolorization (%) found at pH 7 and 30 °C. Inoculation of wheat plants, growing under stress induced by RB-5 dye, with rifampicin-resistant derivatives of the strain FSS2C substantially reduced the cellular oxidative stress, thereby resulting in higher plant biomass as compared to non-inoculated plants. Similarly, the inoculated plants revealed higher nutrient content in shoots as compared to non-inoculated ones. It was concluded that B. firmus strain FSS2C alleviated the oxidative stress impairment caused by reactive black-5 in wheat plants. Therefore, the strain can be used as bio-inoculant in wastewater irrigated soils.

Phytoaccumulation of Zn, Pb, and Cd in Conocarpus lancifolius irrigated with wastewater: does physiological response influence heavy metal uptake?

Conocarpus lancifolius is a fast-growing and drought tolerant tree species with phytoremediation potential in arid environments. The present study was conducted to evaluate the phytoaccumulation potential under wastewater treatment. The experiment was performed in a greenhouse where 3-month-old seedlings were irrigated with industrial wastewater and growth, biomass and physiological parameters were measured. Concentrations of zinc (Zn), lead (Pb), and cadmium (Cd) in leaves, shoots, and roots along with translocation and tolerance index were also determined. The results showed that under wastewater treatment total biomass increased from 24.2 to 31.5 g, net CO2 assimilation rate increased from 9.93 to 13.3 µmol m-2 s-1, and water use efficiency increased from 1.7 to 2.42. Similarly, heavy metals (Zn, Pb, and Cd) accumulation in stem, leaves, and roots increased significantly under wastewater treatment where the highest concentration of Zn, Pb and Cd was found in roots followed by leaves and stem, respectively. Tolerance index was found >1, and translocation factor of all heavy metals was found >1. The study revealed that phytoaccumulation potential of C. lancifolius was mainly driven by improved net CO2 assimilation rate and water use efficiency.

Acclimation of Betula alleghaniensis Britton to moderate soil water deficit: small morphological changes make for important consequences in crown display.

In the context of the predicted increasing frequency of summer droughts in the northeastern deciduous forest of North America due to climate change, we investigated the acclimation capacity of yellow birch, an economically important native tree species, to soil water deficit. We carried out an integrated examination of allocation of biomass, leaf physiology, branching pattern and in situ 3D crown display. Potted seedlings were subjected to moderate soil water deficit for four consecutive months during their second growing season. Individuals under soil water deficit showed a 40% decrease in biomass accumulation but no change in the relative allocation of biomass to the different plant compartments. Net CO2 assimilation rates at leaf level decreased under water deficit (~15%) but could not alone explain the total reduction in growth, excluding the carbon starvation hypothesis. The observed reduction in net CO2 assimilation rates was related to a decrease in stomatal conductance and chlorophyll content. STARzen (in situ silhouette to total leaf area ratio; a proxy for light interception efficiency) decreased under soil water deficit due to shifts in biomass allocation within the branch compartment from long upper axes to short bottom axes. Despite the fact that the understanding of the processes involved in growth reduction and branching pattern alteration will need more attention in future research, we conclude that under water deficit yellow birch at young stages will: (i) experience a substantial loss of growth and biomass; and (ii) acclimate through architectural plasticity rather than through changes in the relative allocation of root biomass to enhance its water management.

Immunostimulant activities of the aqueous methanolic extract of Leptadenia pyrotechnica, a plant from Cholistan desert.

ETHNOPHARMACOLOGICAL RELEVANCE: Leptadenia pyrotechnica (Forssk.) Decne (Asclepiadaceae) is a well-renowned medicinal shrub, used by herbal practitioners for various ailments including allergic rhinitis, productive cough, abortion, diabetes, stomach disorders, fever, kidney disorders, stones and cancer AIM OF THE STUDY: On the basis of folkloric uses, L. pyrotechnica was selected from the wide medicinal flora of the Cholistan desert of Pakistan, for the exploration of immunomodulatory potential. MATERIALS AND METHODS: Aqueous methanolic (30:70) extract of aerial parts of L. pyrotechnica (Lp. Cr) was prepared by 3 days thrice maceration and subsequent evaporation under reduced pressure. In-vivo experiments were performed in Wistar albino rats including neutrophil adhesion test, haemagglutinating antibody (HA) titre, delayed-type hypersensitivity response, phagocytic activity and cyclophosphamide-induced myelosuppression. RESULTS: Lp. Cr produced a significant increase in phagocytic index in dose-dependent fashion (3.56, 4.18 and 5.42 at 30, 100 and 300mg/kg, respectively) as well as an augmented response in the delayed-type hypersensitivity reaction and HA titre induced by sheep erythrocytes. Lp. Cr also showed improved adhesion of neutrophils with nylon pellets (15.28, 27.85 and 38.42% at the doses of 30, 100 and 300mg/kg) and prevented myelosuppression in cyclophosphamide-treated rats as evidenced from the hematological parameters. The results of treatment were compared with normal and standard control groups throughout the study and the effects by Lp. Cr (300mg/kg) were found to be comparable with Levamisole. CONCLUSIONS: The results indicated that L. pyrotechnica possesses immunostimulatory activity and justify its traditional use for the control and management of diseases in which the immune system needs to be stimulated like infectious diseases.

Vapour pressure deficit during growth has little impact on genotypic differences of transpiration efficiency at leaf and whole-plant level: an example from Populus nigra†L.

Poplar genotypes differ in transpiration efficiency (TE) at leaf and whole-plant level under similar conditions. We tested whether atmospheric vapour pressure deficit (VPD) affected TE to the same extent across genotypes. Six Populus nigra genotypes were grown under two VPD. We recorded (1) (13)C content in soluble sugars; (2) (18)O enrichment in leaf water; (3) leaf-level gas exchange; and (4) whole-plant biomass accumulation and water use. Whole-plant and intrinsic leaf TE and (13)C content in soluble sugars differed significantly among genotypes. Stomatal conductance contributed more to these differences than net CO2 assimilation rate. VPD increased water use and reduced whole-plant TE. It increased intrinsic leaf-level TE due to a decline in stomatal conductance. It also promoted higher (18)O enrichment in leaf water. VPD had no genotype-specific effect. We detected a deviation in the relationship between (13)C in leaf sugars and (13)C predicted from gas exchange and the standard discrimination model. This may be partly due to genotypic differences in mesophyll conductance, and to its lack of sensitivity to VPD. Leaf-level (13)C discrimination was a powerful predictor of the genetic variability of whole-plant TE irrespective of VPD during growth.

Genotype differences in 13C discrimination between atmosphere and leaf matter match differences in transpiration efficiency at leaf and whole-plant levels in hybrid Populus deltoides x nigra.

(13) C discrimination between atmosphere and bulk leaf matter (Δ(13) C(lb) ) is frequently used as a proxy for transpiration efficiency (TE). Nevertheless, its relevance is challenged due to: (1) potential deviations from the theoretical discrimination model, and (2) complex time integration and upscaling from leaf to whole plant. Six hybrid genotypes of Populus deltoides×nigra genotypes were grown in climate chambers and tested for whole-plant TE (i.e. accumulated biomass/water transpired). Net CO(2) assimilation rates (A) and stomatal conductance (g(s) ) were recorded in parallel to: (1) (13) C in leaf bulk material (δ(13) C(lb) ) and in soluble sugars (δ(13) C(ss) ) and (2) (18) O in leaf water and bulk leaf material. Genotypic means of δ(13) C(lb) and δ(13) C(ss) were tightly correlated. Discrimination between atmosphere and soluble sugars was correlated with daily intrinsic TE at leaf level (daily mean A/g(s) ), and with whole-plant TE. Finally, g(s) was positively correlated to (18) O enrichment of bulk matter or water of leaves at individual level, but not at genotype level. We conclude that Δ(13) C(lb) captures efficiently the genetic variability of whole-plant TE in poplar. Nevertheless, scaling from leaf level to whole-plant TE requires to take into account water losses and respiration independent of photosynthesis, which remain poorly documented.

Time course of δ1¹³C in poplar wood: genotype ranking remains stable over the life cycle in plantations despite some differences between cellulose and bulk wood.

Genetic differences in δ¹³C (isotopic composition of dry matter carbon) have been evidenced among poplar genotypes at juvenile stages. To check whether such differences were maintained with age in trees growing in plantations, we investigated the time course of δ¹³C as recorded in annual tree rings from different genotypes growing at three sites in southwestern France and felled at ∼15-17 years. Wood cores were cut from tree discs to record the time course of annual basal area increment (BAI). The isotopic ratio δ¹³C was recorded in bulk wood and in extracted cellulose from the annual rings corresponding to the period 1996-2005. Discrimination against ¹³C between atmosphere and tissues (Δ¹³C) was computed by taking into account the inter-annual time course of δ¹³C in the atmosphere. Annual BAI increased steadily and stabilized at about 8 years. An offset in δ¹³C of ∼1‰ was recorded between extracted cellulose and bulk wood. It was relatively stable among genotypes within sites but varied among sites and increased slightly with age. Site effects as well as genotype differences were detected in Δ¹³C recorded from the cellulose fraction. Absolute values as well as the genotype ranking of Δ¹³C remained stable with age in the three sites. Genotype means of Δ¹³C were not correlated to annual BAI. We conclude that genotypic differences of Δ¹³C occur in older poplar trees in plantations, and that the differences as well as the genotype ranking remain stable while trees age until harvest.