Effects of cadmium exposure on growth and metabolic profile of bermudagrass [Cynodon dactylon (L.) Pers].

Metabolic responses to cadmium (Cd) may be associated with variations in Cd tolerance in plants. The objectives of this study were to examine changes in metabolic profiles in bermudagrass in response to Cd stress and to identify predominant metabolites associated with differential Cd tolerance using gas chromatography-mass spectrometry. Two genotypes of bermudagrass with contrasting Cd tolerance were exposed to 0 and 1.5 mM CdSO4 for 14 days in hydroponics. Physiological responses to Cd were evaluated by determining turf quality, growth rate, chlorophyll content and normalized relative transpiration. All these parameters exhibited higher tolerance in WB242 than in WB144. Cd treated WB144 transported more Cd to the shoot than in WB242. The metabolite analysis of leaf polar extracts revealed 39 Cd responsive metabolites in both genotypes, mainly consisting of amino acids, organic acids, sugars, fatty acids and others. A difference in the metabolic profiles was observed between the two bermudagrass genotypes exposed to Cd stress. Seven amino acids (norvaline, glycine, proline, serine, threonine, glutamic acid and gulonic acid), four organic acids (glyceric acid, oxoglutaric acid, citric acid and malic acid,) and three sugars (xylulose, galactose and talose) accumulated more in WB242 than WB144. However, compared to the control, WB144 accumulated higher quantities of sugars than WB242 in the Cd regime. The differential accumulation of these metabolites could be associated with the differential Cd tolerance in bermudagrass

Mechanisms of Environmental Stress Tolerance in Turfgrass

Turfgrasses constitute a vital part of the landscape ecological systems for sports fields, golf courses, home lawns and parks. However, turfgrass species are affected by numerous abiotic stresses include salinity, heat, cold, drought, waterlogging and heavy metals and biotic stresses such as diseases and pests. Harsh environmental conditions may result in growth inhibition, damage in cell structure and metabolic dysfunction. Hence, to survive the capricious environment, turfgrass species have evolved various adaptive strategies. For example, they can expel phytotoxic matters; increase activities of stress response related enzymes and regulate expression of the genes. Simultaneously, some phytohormones and signal molecules can be exploited to improve the stress tolerance in turfgrass. Generally, the mechanisms of the adaptive strategies are integrated but not necessarily the same. Recently, metabolomic, proteomic and transcriptomic analyses have revealed plenty of stress response related metabolites, proteins and genes in turfgrass. Therefore, the regulation mechanism of turfgrass’s response to abiotic and biotic stresses was further understood. However, the specific or broad-spectrum related genes that may improve stress tolerance remain to be further identified. Understanding stress response in turfgrass species will contribute to improve stress tolerance of turfgrass

Simultaneous determination of chlorinated aromatic hydrocarbons in fly ashes discharged from industrial thermal processes

Chlorinated aromatic hydrocarbons (CAHs) have received increasing attention because of their environmental persistence, bioaccumulation potential and high toxicity. In this study, an analytical methodology based on high-resolution gas chromatography/high-resolution mass spectrometry for the simultaneous determination of four typical kinds of CAHs including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and chlorinated polycyclic aromatic hydrocarbons (ClPAHs) in fly ash was developed. Highly effective cleanup and separation procedures combined with optimum instrumental conditions provided a reliable method for the detection and quantification of CAHs. Meanwhile, the spike of C-13-labeled standards and deuterated phenanthrene achieved more accurate measurement. The method detection limits were determined to be in the ranges of 0.1-13.4 pg g(-1) for tetra-to octa-CDD/F congeners, 0.04-11.1 pg g(-1) for tri-to hepta-CB congeners, 0.2-48.5 pg g(-1) for mono-to octa-CN congeners and 3.5-9.5 pg g(-1) for mono-and di-chlorinated aromatic hydrocarbons. Good recoveries of CAHs (62-136%) were achieved, except for PCN-2 and PCN-6. The developed analytical methodology was validated and then used to determine the levels of CAHs in fly ashes collected from industrial thermal processes. All the target compounds were detected and the CAH congener concentrations showed a wide variation in different fly ashes

Hyperbranched mixed-mode anion-exchange polymeric sorbent for highly selective extraction of nine acidic non-steroidal anti-inflammatory drugs from human urine

This paper describes the poly(divinylbenzene) (PDVB) supported synthesis of quaternized hyperbranched macromolecules (QHMs) and its use as a highly selective, high-capacity mixed-mode anion-exchange (MAX) sorbent. In detail, the aminated PDVB support was firstly synthesized by copolymerization of divinylbenzene and 2-(diethylamino)ethyl methacrylate via Pickering emulsion polymerization. The QHMs were then grafted on PDVB by a divergent synthesis involving consecutive reactions of resorcinol diglycidyl ether with methylamine (N, N-dimethylethanolamine for terminal epoxides), which brought in a high density of quaternary ammonium functionalities. The changes of specific surface area (SBET), pore volume and ion exchange capacity (IEC) with generation number reveal that the QHMs have been grown successfully within the large meso-channels of the porous aminated PDVB. The best compromise between the SBET, pore volume and IEC was obtained at the 4th generation (G4). Due to the highest IEC (0.47 meq/g), the G4-QHMs was successfully applied for mixed-mode solid phase extraction (SPE) of acidic non-steroidal anti-inflammatory drugs (NSAIDs). An efficient approach based on the mixed-mode SPE coupled with HPLC-UV was developed for highly selective extraction and cleanup of nine NSAIDs (tolmetin, TLM; ketoprofen, KEP; naproxen, NAP; flurbiprofen, FLB; diclofenac, DIC; indomethacin, INM; ibuprofen, IBP; mefenamic acid, MFA; tolfenamic acid, TFA) in human urine samples. Under the optimized conditions, the method exhibited satisfactory recoveries ranging from 81.9% to 104.0% with relative standard deviation (RSD) values below 8.5%, good sensitivity (0.004-0.009 mu g mL(-1) limit of detection) and good linearity (coefficient of determination, R-2 > 0.997, 0.01-0.2 mu g mL(-1) for NAP, 0.05-1.0 mu g mL(-1) for FLB, DIC, INM, MFA, TFA, 0.1-2.0 mu g mL(-1) for TLM, KEP, IBP). The hyperbranched MAX sorbent is superior to Oasis HLB and comparable to Oasis MAX in obtaining clean chromatographic profiles. Our results demonstrate the potential application of the hyperbranched MAX for complex sample analysis

Chlorophyll content in bermudagrass exposed to Cd stress (0, 1.5 mM).

<p>Means followed by the same lower-case letter in a column and followed by the same upper-case letter in a row for a given chlorophyll were not significantly different based on Tukey's test (<i>P</i><0.05).</p><p>Chlorophyll content in bermudagrass exposed to Cd stress (0, 1.5 mM).</p

Metabolite levels in leaves of bermudagrass exposed for 14 d to different concentrations of Cd (0, 1.5 mM).

<p>Means followed by the different letter in a row for each metabolite was not significantly different based on Tukey's test (<i>P</i><0.05). UD, undeterminable.</p><p>Metabolite levels in leaves of bermudagrass exposed for 14 d to different concentrations of Cd (0, 1.5 mM).</p

Principal Component analysis of the metabolites profiles in bermudagrass under Cd stress.

<p>Principal Component analysis of the metabolites profiles in bermudagrass under Cd stress.</p

Normalized relative transpiration (NRT) of two genotypes in response to Cd stress.

<p>Normalized relative transpiration (NRT) of two genotypes in response to Cd stress.</p

Hierarchical clustering analysis of metabolites affected by Cd treatment in bermudagrass.

<p>Hierarchical clustering analysis of metabolites affected by Cd treatment in bermudagrass.</p