首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
ODAP (N-oxalyl-L-2,3-diaminopropionic acid) is present in the seeds of grass pea. In this study, variation of total ODAP accumulation in leaves throughout the crop growth starting from 40 days after sowing to maturity, and the distribution pattern of ODAP in different plant parts including the seeds at the mature stage was analyzed. Five grass pea accessions were evaluated for two subsequent growing seasons in one location of ICARDA, Aleppo (Syria). The results found that the rate of accumulation of total ODAP varied during plant development. Increased rates of synthesis were noticed in young leaves of grass pea. The highest total ODAP content in leaves was noted in the early growth stage (40–50 days after sowing). Mean total ODAP content in leaves ranged from 0.17 to 0.96 percent during 2010–2011 and from 0.19 to 1.28 percent during 2011–2012. During maturity, the total ODAP content was lowest in the seeds than in leaves, stems, pod cover, seed coat, and cotyledons. The ranges of total ODAP content were 0.13 (seed)–0.34 (stem), 0.20 (seed)–1.01 (leaf), 0.22 (seed)–0.62 (leaf), 0.21 (seed)–0.66 (leaf), and 0.21 (seed)–0.78 (leaf) percent in B387, B222, B390, Bio-520, and B587 accessions, respectively, during maturity. The results indicated that the rate of accumulation and synthesis of total ODAP varied during the plant lifespan. The lowest total ODAP content of leaves was observed after 130 days of sowing. The lower total ODAP content after the early vegetative stage of grass pea plants makes them suitable as a feed.  相似文献   

2.
The lipids of the leaves, stems, and roots ofHibiscus sp. have been studied. Their fatty acid compositions have been determined. The greatest amount of unsaturated fatty acids was present in the glycolipids of the leaves and the stems. More than 25% of low-molecular-mass C10-C12 fatty acids have been found in the neutral lipids of the roots.Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 705–708, September–October, 1996. Original article submitted March 11, 1996.  相似文献   

3.
Nettle is a common plant that offers many health benefits and is grown all over the world. The content of active compounds in roots, stems, and leaves was determined based on the extraction procedure optimized using the Central Composite Design. Flavonols, phenolic acids, trigonelline, nicotinamide, nicotinic acids, and short-chain organic acids were determined with the use of LC–MS/MS and capillary isotachophoresis. Trigonelline, which was not previously reported in the roots and stems of nettle, was found in all parts of the plant and considerable variations in its content were observed (2.8–108 µg g−1). Furthermore, the Principal Component Analysis taking into account more variables demonstrated differences in the content of bioactive components between roots and aerial parts of nettle.  相似文献   

4.
Wastewater treatment (WWT) is a priority around the world; conventional treatments are not widely used in rural areas owing to the high operating and maintenance costs. In Mexico, for instance, only 40% of wastewater is treated. One sustainable option for WWT is through the use of constructed wetlands (CWs) technology, which may remove pollutants using cells filled with porous material and vegetation that works as a natural filter. Knowing the optimal material and density of plants used per square meter in CWs would allow improving their WWT effect. In this study, the effect of material media (plastic/mineral) and plant density on the removal of organic/inorganic pollutants was evaluated. Low (three plants), medium (six plants) and high (nine plants) densities were compared in a surface area of 0.3 m2 of ornamental plants (Alpinia purpurata, Canna hybrids and Hedychium coronarium) used in polycultures at the mesocosm level of household wetlands, planted on the two different substrates. Regarding the removal of contaminants, no significant differences were found between substrates (p ≥ 0.05), indicating the use of plastic residues (reusable) is an economical option compared to typical mineral materials. However, differences (p = 0.001) in removal of pollutants were found between different plant densities. For both substrates, the high density planted CWs were able to remove COD in a range of 86–90%, PO4-P 22–33%, NH4-N in 84–90%, NO3-N 25–28% and NO2-N 38–42%. At medium density, removals of 79–81%, 26–32, 80–82%, 24–26%, and 39–41%, were observed, whereas in CWs with low density, the detected removals were 65–68%, 20–26%, 79–80%, 24–26% and 31–40%, respectively. These results revealed that higher COD and ammonia were removed at high plant density than at medium or low densities. Other pollutants were removed similarly in all plant densities (22–42%), indicating the necessity of hybrid CWs to increase the elimination of PO4-P, NO3-N and NO2-N. Moreover, high density favored 10 to 20% more the removal of pollutants than other plant densities. In addition, in cells with high density of plants and smaller planting distance, the development of new plant shoots was limited. Thus, it is suggested that the appropriate distance for this type of polyculture plants should be from 40 to 50 cm in expansion to real-scale systems in order to take advantage of the harvesting of species in these and allow species of greater foliage, favoring its growth and new shoots with the appropriate distance to compensate, in the short time, the removal of nutrients.  相似文献   

5.
The chemical composition and biological activities of the essential oils from the leaves, stems, and roots of Kadsura coccinea (K. coccinea) were investigated. The essential oils were extracted by hydro distillation and analyzed by gas chromatography mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID). Antioxidant activities of the essential oils were examined with DPPH radical scavenging assay, ABTS cation radical scavenging assay, and ferric reducing antioxidant power assay. Antimicrobial activities were evaluated by determining minimum inhibitory concentrations (MIC) and minimum microbiocidal concentrations (MMC). Acetylcholinesterase and butyrylcholinesterase inhibitory activity of the essential oils were also tested. A total of 46, 44, and 47 components were identified in the leaf, stem, and root oils, representing 95.66%, 97.35%, and 92.72% of total composition, respectively. The major compounds of three essential oils were α-pinene (16.60–42.02%), β-pinene (10.03–18.82%), camphene (1.56–10.95%), borneol (0.50–7.71%), δ-cadinene (1.52–7.06%), and β-elemene (1.86–4.45%). The essential oils were found to have weak antioxidant activities and cholinesterase inhibition activities. The essential oils showed more inhibitory effects against Staphylococcus aureus (S. aureus) than those of other strains. The highest antimicrobial activity was observed in the root oil against S. aureus, with MIC of 0.78 mg/mL. Therefore, K. coccinea essential oils might be considered as a natural antibacterial agent against S. aureus with potential application in food and pharmaceutical industries.  相似文献   

6.
Sceptridium ternatum is a herbaceous plant with significant potential for pharmaceutical and cosmetic applications. In this study, we established a spectrum-effect relationship-based strategy to investigate the bioactive basis and tissue distribution in S. ternatum. First, a phytochemical analysis on the ethanol extracts from roots, stems, and leaves of S. ternatum was performed using the colorimetric method, high-performance liquid chromatography–ultraviolet (HPLC–UV), and high-performance liquid chromatography–electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC–ESI-Q-TOF-MS/MS). Then, radical scavenging assays and the lipopolysaccharide-stimulated RAW 264.7 cell model were used to estimate the antioxidant and anti-inflammatory activities, respectively. Spectrum-effect relationship analysis and molecular docking were further employed to evaluate the correlation between the phytochemical profile and anti-inflammatory activity. Our results demonstrate that S. ternatum leaves contained the most abundant flavonoids and exerted the best biological activities. Their IC50 values for scavenging 2,2ʹ-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) and 1,1-diphenyl-2-picrylhydrazyl radicals were 2.43 ± 0.13 and 5.36 ± 0.54 mg/mL, respectively. In lipopolysaccharide-stimulated RAW 264.7 cells, the leaf extract caused the greatest reduction in nitric oxide production (38.15%) and interleukin-6 release (110.86%). Spectrum-effect relationship analysis and molecular docking indicated that quercetin 3-O-rhamnoside-7-O-glucoside possessed high anti-inflammatory activity by binding with interleukin-6. In conclusion, S. ternatum is a rich source of bioactive flavonoids with potential for exploitation in the prevention and treatment of oxidative stress and inflammation-related pathologies.  相似文献   

7.
In-situ rehabilitation of fly ash at dumping sites has rarely been addressed for crop production due to growth-related constraints, largely of heavy metal (HM) contamination in soils and crops. Current communication deals with a novel approach to identify a suitable management option for rejuvenating the contaminated soils. In this background, a 60-days incubation experiment was conducted with different fly ash-soil mixtures (50 + 50%, A1; 75 + 25%, A2; 100 + 0%, A3) along with four ameliorants, namely, lime (T1), sodium sulphide (T2), di-ammonium phosphate (T3), and humic acid (T4) at 30 ± 2 °C to assess the ability of different fly ash-soil-ameliorant mixtures in reducing bio-availability of HMs. Diethylenetriaminepentaacetic acid (DTPA)-extractable bio-available HM contents for lead (Pb), cadmium (Cd), nickel (Ni), and chromium (Cr) and their respective ratios to total HM contents under the influence of different treatments were estimated at 0, 15, 30, 45, and 60 days of incubation. Further, the eco-toxicological impact of different treatments on soil microbial properties was studied after 60 days of experimentation. A1T1 significantly recorded the lowest bio-availability of HMs (~49–233% lower) followed by A2T1 (~35–133%) among the treatments. The principal component analysis also confirmed the superiority of A1T1 and A2T1 in this regard. Further, A1T1 achieved low contamination factor and ecological risk with substantial microbial biomass carbon load and dehydrogenase activity. Thus, liming to fly ash-soil mixture at 50:50 may be considered as the best management option for ameliorating metal toxicity. This technology may guide thermal power plants to provide the necessary package of practices for the stakeholders to revive their contaminated lands for better environmental sustainability.  相似文献   

8.
Manure is a major source of soil and plant contamination with veterinary drugs residues. The aim of this study was to evaluate the uptake of 14 veterinary pharmaceuticals by parsley from soil fertilized with manure. Pharmaceutical content was determined in roots and leaves. Liquid chromatography coupled with tandem mass spectrometry was used for targeted analysis. Screening analysis was performed to identify transformation products in the parsley tissues. A solid-liquid extraction procedure was developed combined with solid-phase extraction, providing recoveries of 61.9–97.1% for leaves and 51.7–95.6% for roots. Four analytes were detected in parsley: enrofloxacin, tylosin, sulfamethoxazole, and doxycycline. Enrofloxacin was detected at the highest concentrations (13.4–26.3 ng g−1). Doxycycline accumulated mainly in the roots, tylosin in the leaves, and sulfamethoxazole was found in both tissues. 14 transformation products were identified and their distribution were determined. This study provides important data on the uptake and transformation of pharmaceuticals in plant tissues.  相似文献   

9.
Salvia miltiorrhiza is a medicinal plant that synthesises biologically-active tanshinones with numerous therapeutic properties. An important rate-limiting enzyme in the biosynthesis of their precursors is 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR). This study presents the organ-specific expression profile of the S. miltiorrhiza HMGR4 gene and its sensitivity to potential regulators, viz. gibberellic acid (GA3), indole-3-acetic acid (IAA) and salicylic acid (SA). In addition, it demonstrates the importance of the HMGR4 gene, the hormone used, the plant organ, and the culture environment for the biosynthesis of tanshinones. HMGR4 overexpression was found to significantly boost the accumulation of dihydrotanshinone I (DHTI), cryptotanshinone (CT), tanshinone I (TI) and tanshinone IIA (TIIA) in roots by 0.44 to 5.39 mg/g dry weight (DW), as well as TIIA in stems and leaves. S. miltiorrhiza roots cultivated in soil demonstrated higher concentrations of the examined metabolites than those grown in vitro. GA3 caused a considerable increase in the quantity of CT (by 794.2 µg/g DW) and TIIA (by 88.1 µg/g DW) in roots. In turn, IAA significantly inhibited the biosynthesis of the studied tanshinones in root material.  相似文献   

10.
Platycodon grandiflorum (PG) is known as a high-potential material in terms of its biological activity. The objective of this report is to provide chromatographic and mass fragment ion data of 38 simultaneously identified saponins, including novel compounds, by analyzing them through ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QToF/MS). In so doing, we investigated their diverse conditions, including morphological parts (stems, roots, buds, and leaves), peeling (or not), and blanching of PG. The total contents of individual saponins indicated an order of roots (containing peel, 1674.60 mg/100 g, dry weight) > buds (1364.05) > roots (without peel, 1058.83) ≈ blanched roots (without peel, 945.17) ≈ stems (993.71) ≈ leaves (881.16). When considering three types of aglycone, the platycodigenin group (55.04 ~ 68.34%) accounted for the largest proportion of the total content, whereas the platycogenic acid A group accounted for 17.83 ~ 22.61%, and the polygalacic acid group represented 12.06 ~ 22.35%. As they are classified as major compounds, novel saponins might be utilized for their role in healthy food for human consumption. Additionally, during blanching, the core temperature of PG was satisfied with the optimal condition, thus activating the enzymes related to biotransformation. Furthermore, through the use of this comprehensive data, additional studies related to buds, as well as roots or the characterization of individual saponins, can be conducted in a rapid and achievable manner.  相似文献   

11.
The plants of the Moraceae family are producers of a great variety of polyphenolic natural products. Among these, the Diels–Alder type adducts (DAAs) are endowed with a unique cyclohexene scaffold, since they are biosynthesized from [4+2] cycloaddition of different polyphenolic precursors such as chalcones and dehydroprenyl polyphenols. To date, more than 150 DAAs have been isolated and characterized from Moraceous and related plants. The main source of DAAs is the mulberry root bark, also known as “Sang-Bai-Pi” in Traditional Chinese Medicine, but they have also been isolated from root bark, stem barks, roots, stems or twigs, leaves, and callus cultures of Moraceous and other related plants. Since 1980, many biological activities of DAAs have been identified, including anti-HIV, antimicrobial, anti-inflammatory, and anticancer ones. For these reasons, natural DAAs have been intensively investigated, and a lot of efforts have been made to study their biosynthesis and to establish practical synthetic access. In this review, we summarized all the updated knowledge on biosynthesis, chemoenzymatic synthesis, racemic and enantioselective total synthesis, and biological activity of natural DAAs from Moraceous and related plants.  相似文献   

12.
Regulating insulin and leptin levels using a protein tyrosine phosphatase 1B (PTP1B) inhibitor is an attractive strategy to treat diabetes and obesity. Glycyrrhetinic acid (GA), a triterpenoid, may weakly inhibit this enzyme. Nonetheless, semisynthetic derivatives of GA have not been developed as PTP1B inhibitors to date. Herein we describe the synthesis and evaluation of two series of indole- and N-phenylpyrazole-GA derivatives (4a–f and 5a–f). We measured their inhibitory activity and enzyme kinetics against PTP1B using p-nitrophenylphosphate (pNPP) assay. GA derivatives bearing substituted indoles or N-phenylpyrazoles fused to their A-ring showed a 50% inhibitory concentration for PTP1B in a range from 2.5 to 10.1 µM. The trifluoromethyl derivative of indole-GA (4f) exhibited non-competitive inhibition of PTP1B as well as higher potency (IC50 = 2.5 µM) than that of positive controls ursolic acid (IC50 = 5.6 µM), claramine (IC50 = 13.7 µM) and suramin (IC50 = 4.1 µM). Finally, docking and molecular dynamics simulations provided the theoretical basis for the favorable activity of the designed compounds.  相似文献   

13.
Seventeen new carbazole alkaloid derivatives, including a trimeric carbazole racemate, (±)-microphyltrine A (1), 15 dimeric carbazole racemates, (±)-microphyldines A–O (2–16), and a C-6–C-3″-methyl-linked dimeric carbazole, microphyldine P (17), were isolated from the leaves and stems of Murraya microphylla (Merr. et Chun) Swingle. The structures of the new compounds were elucidated on the basis of HRESIMS and NMR data analysis. The optically pure isomers of these isolated carbazole alkaloids were obtained by chiral HPLC separation and their absolute configurations were determined by electronic circular dichroism (ECD) data analysis.  相似文献   

14.
In the process of planting and harvesting of Rehmannia glutinosa, only the underground part is used, and a large number of stems and leaves that are considered non‐medicinal parts are usually discarded. Recent studies have shown that the chemical components in the leaves are similar to those identified in the roots. In this study, we selected leaves and roots from Rehmannia glutinosa at different growth stages and leaves from different cultivation regions to investigate the dynamic accumulation of three kinds of glycosides (catalpol, acteoside, and ajugol), six kinds of carbohydrates (rhamnose, fructose, sucrose, melibiose, stachyose, and verbascose), and acidic and neutral polysaccharides via rapid quantitative analysis technology, including ultra high performance liquid chromatography triple quadrupole tandem mass spectrometry, high‐performance liquid chromatography, and UV spectroscopy. The results showed that the Rehmannia glutinosa leaves also contained higher content of catalpol (3.81~24.51 mg/g), ajugol (0.55~10.23 mg/g), acteoside (1.34~21.16 mg/g), monosaccharide/ oligosaccharides (7.71~120.73 mg/g), and polysaccharides (5.63~15.57%). In this study, we developed a new rapid and simple method for determination to clarify the distribution and dynamic accumulation of nine glycosides and saccharides in Rehmannia glutinosa leaves to provide a scientific basis for the discovery, development, and utilization of the resource value of Rehmannia glutinosa leaves.  相似文献   

15.
Eight extraction agents (water, methanol–water mixtures in various ratios, methanol, a 20 mmol l?1 ammonium phosphate buffer, and a methanol–phosphate buffer) were tested for the extraction of arsenic compounds from fruits, stems + leaves, and roots of pepper plants grown on soil containing 17.2 mg kg?1 of total arsenic. The arsenic compounds in the extracts were determined using high‐performance liquid chromatography–hydride generation inductively coupled plasma mass spectrometry. Whereas pure water was the most effective extraction agent for fruits (87 ± 3.3% extraction yield) and roots (96 ± 0.6% extraction yield), the 20 mM ammonium phosphate buffer at pH 6 extracted about 50% of the arsenic from stems + leaves. Decreasing extractability of the arsenic compounds was observed with increasing methanol concentrations for all parts of the pepper plant. In pepper fruits, arsenic(III), arsenic(V), and dimethylarsinic acid (DMA) were present (25%, 37%, and 39% respectively of the extractable arsenic). Arsenic(V) was the major compound in stems + leaves and roots (63% and 53% respectively), followed by arsenic(III) representing 33% and 42% respectively, and small amounts (not exceeding 5%) of DMA and methylarsonic acid were also detected. Hence, for a quantitative extraction of arsenic compounds from different plant tissues the extractant has to be optimized individually. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

16.
The corrosion inhibition effect of the three extracts from Harmal roots (HRE), leaves (HLE), and flowers (HFE) were studied for carbon steel corrosion inhibition in 0.25 M H2SO4 solution. The electrochemical impedance study indicated that the three types of extracts decreased corrosion effectively through a charge transfer mechanism. Harmal roots and leaf extracts showed inhibition values of 94.1% and 94.2%, while it was 88.7% for Harmal flower extract at the inhibitor concentration of 82.6 ppm. Potentiodynamic polarization data revealed that Harmal extracts acted through predominant cathodic type inhibition. Both the corrosion current density and corrosion rate decreased significantly in the presence of Harmal extracts compared to blank solution. The corrosion rate (mpy) value was 63.3, 86.1, and 180.7 for HRE, HLE, and HFE, respectively. The adsorption-free energy change ΔGads (kJ·mol−1) values calculated from the Langmuir adsorption isotherm plots were for HRE (−35.08), HLE (−33.17), and HFE (−33.12). Thus, corrosion inhibition occurred due to the adsorption of Harmal extract on the carbon steel surface via the chemisorption mechanism. Moreover, a computational investigation using B3LYP/6-311G++(d,p) basis set in both gaseous and aqueous phases was performed for the major alkaloids (1–8) present in the Harmal extract.  相似文献   

17.
In this study, we evaluated bioinspired titanium dioxide nanoparticles (TiO2 NPs) that elicited biochemical and proteome modifications in wheat plants under the biotic stress caused by Puccinia striiformis f. sp. tritici (Pst). Biosynthesis of TiO2 NPs was confirmed using UV–Vis spectrophotometry, energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. We found that the nanoparticles with crystalline nature were smaller than 100 nm. The results of FTIR analysis showed the presence of potential functional groups exhibiting O-H, N-H, C-C, and Ti-O stretching. The TiO2 NPs of different concentrations (20, 40, 60, and 80 mg L−1) were exogenously applied to wheat plants under the biotic stress caused by Pst, which is responsible for yellow stripe rust disease. The results of the assessment of disease incidence and percent disease index displayed time- and dose-dependent responses. The 40 mg L−1 TiO2 NPs were the most effective in decreasing disease severity. The bioinspired TiO2 NPs were also evaluated for enzymatic (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), and nonenzymatic metabolites (total proline, phenolic, and flavonoid contents) in wheat plants under stripe rust stress. The 40 mg L−1 TiO2 NPs were effective in eliciting biochemical modifications to reduce biotic stress. We further evaluated the effects of TiO2 NPs through gel- and label-free liquid chromatography-mass spectrometry (LC-MS) proteome analysis. We performed proteome analysis of infected wheat leaves and leaves treated with 40 mg L−1 TiO2 NPs under stripe rust stress. The functional classification of the proteins showed downregulation of proteins related to protein and carbohydrate metabolism, as well as of photosynthesis in plants under biotic stress. An upregulation of stress-related proteins was observed, including the defense mechanisms and primary metabolic pathways in plants treated with 40 mg L−1 TiO2 NPs under stress. The experimental results showed the potential of applying biogenic TiO2 NPs to combat fungal diseases of wheat plants and provided insight into the protein expression of plants in response to biotic stress.  相似文献   

18.
Soil salinity disrupts the physiological and biochemical processes of crop plants and ultimately leads to compromising future food security. Sodium nitroprusside (SNP), a contributor to nitric oxide (NO), holds the potential to alleviate abiotic stress effects and boost tolerance in plants, whereas less information is available on its role in salt-stressed lentils. We examined the effect of exogenously applied SNP on salt-stressed lentil plants by monitoring plant growth and yield-related attributes, biochemistry of enzymes (superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)) amassing of leaf malondialdehyde (MDA) and hydrogen peroxide (H2O2). Salinity stress was induced by NaCl application at concentrations of 50 mM (moderate salinity) and 100 mM (severe salinity), while it was alleviated by SNP application at concentrations of 50 µM and 100 µM. Salinity stress severely inhibited the length of roots and shoots, the relative water content, and the chlorophyll content of the leaves, the number of branches, pods, seeds, seed yield, and biomass per plant. In addition, MDA, H2O2 as well as SOD, CAT, and POD activities were increased with increasing salinity levels. Plants supplemented with SNP (100 µM) showed a significant improvement in the growth- and yield-contributing parameters, especially in plants grown under moderate salinity (50 mM NaCl). Essentially, the application of 100 µM SNP remained effective to rescue lentil plants under moderate salinity by regulating plant growth and biochemical pathways. Thus, the exogenous application of SNP could be developed as a useful strategy for improving the performance of lentil plants in salinity-prone environments.  相似文献   

19.
Light exposure of white wine can cause a light-struck taste (LST), a fault induced by riboflavin (RF) and methionine (Met) leading to the formation of volatile sulfur compounds (VSCs), including methanethiol (MeSH) and dimethyl disulfide (DMDS). The study aimed to investigate the impact of different antioxidants, i.e., sulfur dioxide (SO2), glutathione (GSH) and chestnut tannins (CT), on preventing LST in model wine (MW) and white wine (WW), both containing RF and Met. Both MW and WW samples were added with the antioxidants, either individually or in different combinations, prior to 2-h light exposure and they were stored in the dark for 24 months. As expected, the light induced the degradation of RF in all the conditions assayed. Met also decreased depending on the antioxidants added. The presence of antioxidants limited the formation of LST as lower concentrations of VSCs were found in both MW and WW samples. In the latter matrix, neither MeSH nor DMDS were detected in the presence of CT, while only DMDS was found in WW+GSH, WW+SO2+GSH and WW+CT+SO2 samples at a concentration lower than the perception thresholds. Considering the antioxidants individually, the order of their effectiveness was CT ≥ GSH > SO2 in WW under the adopted experimental conditions. The results indicate tannins as an effective enological tool for preventing LST in white wine and their use will be further investigated in different white wines under industrial scale.  相似文献   

20.
Cadmium (Cd) is a metal of high toxicity for plants. Resolving its distribution and speciation in plants is essential for understanding the mechanisms involved in Cd tolerance, trafficking and accumulation. The model plant Arabidopsis thaliana was exposed to cadmium under controlled conditions. Elemental distributions in the roots and in the leaves were determined using scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDX), and synchrotron-based micro X-ray fluorescence (μ-XRF), which offers a better sensitivity. The chemical form(s) of cadmium was investigated using Cd LIII-edge (3538 eV) micro X-ray absorption near edge structure (μ-XANES) spectroscopy. Plant μ-XANES spectra were fitted by linear combination of Cd reference spectra. Biological sample preparation and conditioning is a critical point because of possible artifacts. In this work we compared freeze-dried samples analyzed at ambient temperature and frozen hydrated samples analyzed at −170 °C. Our results suggest that in the roots Cd is localized in vascular bundles, and coordinated to S ligands. In the leaves, trichomes (epidermal hairs) represent the main compartment of Cd accumulation. In these specialized cells, μ-XANES results show that the majority of Cd is bound to O/N ligands likely provided by the cell wall, and a minor fraction could be bound to S-containing ligands. No significant difference in Cd speciation was observed between freeze-dried and frozen hydrated samples. This work illustrates the interest and the sensitivity of Cd LIII-edge XANES spectroscopy, which is applied here for the first time to plant samples. Combining μ-XRF and Cd LIII-edge μ-XANES spectroscopy offers promising tools to study Cd storage and trafficking mechanisms in plants and other biological samples.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号