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排序方式: 共有191条查询结果,搜索用时 15 毫秒
21.
Necla Pehlivan Abdullah Muhammed Yesilyurt Nuran Durmus Sengul Alpay Karaoglu 《Acta Physiologiae Plantarum》2017,39(3):79
Certain number of commercial products has been developed to grow stress resistant plants for the sustainability of agriculture in current era with full of energy dependency and hunger besides global warming. Given the risk of these products on the microbial environment in the rhizosphere and food security of mankind due to the accumulated chemical pollution through the food web, organic fungal plant growth promoting agents might be used. Hence, effects of Trichoderma lixii ID11D (TXD), our local fungal isolate on Zea mays L. cv. Samada 07 as a seed biopriming agent was investigated under dose dependent NaCl stress in this study. Fungus was characterized based on ITS (internal transcribed spacer) regions via clustering approach after isolated from tea plantation area. The higher the NaCl concentration, the more effective the TXD was observed. Improved electron transport rate (ETR), maximum quantum efficiency of PS II (Fv/Fm), the effective quantum yield of PS2 (ΦPS2), photochemical quenching (qP) and decreased non-photochemical quenching (NPQ) was detected in TXD primed plants after NaCl expose. TXD seed biopriming increased the lengths, fresh and dry weights of root/shoots and decreased the lipid peroxidation (MDA) remarkably. Non-enzymatic pathway was found to be more effective than enzymatic one for seed bioprimed plants proven by higher RWC, soluble protein, proline, chlorophyll, carotenoid, and less H2O2 and MDA levels under each dose of NaCl. Detected phenotypic and biochemical improvements pave the way of the potential usage of the formulated fungus biopreperations as a pre-harvest agent in agriculturally important cereals in the future and going beyond lab-based level. 相似文献
22.
The paper presents a simple box model simulating the temporal variation of atmospheric 13CO2 concentration, atmospheric CO2 mixing ratio and 13C content of plant material. The model is driven by observed meteorological and measured biosphere-atmosphere CO2 exchange data. The model was calibrated and validated using measurements from a Hungarian atmospheric monitoring station.
The simulated atmospheric stable carbon isotope ratio data agreed well with the measured ratios considering both the magnitude
and the seasonal dynamics. Observed deviations between the measured and simulated δ13Cair values were systematically negative in winters, while deviations were random in sign and smaller by an order of magnitude
during periods when the vegetation was photosynthetically active. This difference, supported by a significant correlation
between the deviation and modeled fossil fuel contributions to CO2 concentration, suggests the increased contribution of 13C-depleted fossil fuel CO2 from heating and the lower boundary layer heights during winter. 相似文献
23.
K. Georgieva A. Ivanova S. Doncheva S. Petkova D. Stefanov E. Péli Z. Tuba 《Biologia Plantarum》2011,55(3):581-585
Desiccation of Xerophyta scabrida caused considerable damage of chloroplast ultrastructure together with a complete loss of chlorophyll. Upon rehydration,
the relative water content of the pale-green leaves almost reached that of the dark-green ones, however, the Chl content and
photosynthetic activity remained lower. The process of reconstitution of the photosynthetic apparatus in the re-greening leaves
was accompanied by changes in fatty acid (FA) content. The amount of the FA methyl esters was more than 2-fold higher in the
green leaves as compared to the dry ones and slightly increased after rehydration in the pale-green leaves. Among the three
main fatty acids in the leaves, oleic, palmitic and linoleic acid, the latter increased more than 3-fold during rehydration.
This acid is concentrated mainly in the glycolipids and this was an indirect indication for the restoration of the photosynthetic
apparatus. Our results showed that rehydration of X. scabrida led to a decrease of the saturated FA in parallel with an increase of the unsaturated FA, thus indicating increased membrane
permeability. The observed changes in the lipid content can be considered as a characteristic feature of X. scabrida and most probably of other poikilochlorophyllous species. 相似文献
24.
The combined use of different mass spectrometric ionization methods and MS/MS techniques provide the possibility to differentiate between stereoisomers or epimers. In this paper the mass spectral decomposition of 11alpha- and 11beta-substituted estrans was studied. Distinctive stereochemical effects have been observed in their fast atom bombardment product ion spectra. In the electron ionisation (EI) mode, the 5alpha- and 5beta-hydroxylated compounds showed significant differences in the abundance of water elimination. Mass spectrometry has proved to be an effective tool when stereoisomer steroids are compared. 相似文献
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26.
Insecticidal Metabolites from the Rhizomes of Veratrum album against Adults of Colorado Potato Beetle,Leptinotarsa decemlineata 下载免费PDF全文
Tuba Aydin Ahmet Cakir Cavit Kazaz Neslihan Bayrak Yasin Bayir Yavuz Taşkesenligil 《化学与生物多样性》2014,11(8):1192-1204
The dried rhizomes of Veratrum album were individually extracted with CHCl3, acetone, and NH4OH/benzene to test the toxic effects against the Colorado potato beetle, Leptinotarsa decemlineata, which is an important agricultural pest. Fifteen compounds in various amounts were isolated from the extracts using column and thin‐layer chromatography. The chemical structures of 14 compounds were characterized as octacosan‐1‐ol ( 1 ), β‐sitosterol ( 2 ), stearic acid ( 3 ), diosgenin ( 4 ), resveratrol ( 5 ), wittifuran X ( 6 ), oxyresveratrol ( 7 ), β‐sitosterol 3‐O‐β‐D ‐glucopyranoside ( 8 ), diosgenin 3‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐glucopyronoside ( 9 ), oxyresveratrol 3‐O‐β‐D ‐glucopyranoside ( 10 ), jervine ( 11 ), pseudojervine ( 13 ), 5,6‐dihydro‐1‐hydroxyjervine ( 14 ), and saccharose ( 15 ) using UV, IR, MS, 1H‐ and 13C‐NMR, and 2D‐NMR spectroscopic methods. However, the chemical structure of 12 , an oligosaccharide, has not fully been elucidated. Compounds 4, 6, 9 , and 10 were isolated from V. album rhizomes for the first time in the current study. The toxic effects of three extracts (acetone, CHCl3, and NH4OH/benzene) and six metabolites, 2, 2 + 4, 5, 7, 8 , and 11 , were evaluated against the Colorado potato beetle. The assay revealed that all three extracts, and compounds 7, 8 , and 11 exhibited potent toxic effects against this pest. This is the first report on the evaluation of the toxic effects of the extracts and secondary metabolites of V. album rhizomes against L. decemlineata. Based on these results, it can be concluded that the extracts can be used as natural insecticides. 相似文献
27.
Ceyda Tuba Sengel Turk Umut Can Oz Tugrul Mert Serim Canan Hascicek 《AAPS PharmSciTech》2014,15(1):161-176
This investigation aimed to develop nimesulide (NMS)-loaded poly(lactic-co-glycolic acid) (PLGA)-based nanoparticulate formulations as a biodegradable polymeric drug carrier to treat rheumatoid arthritis. Polymeric nanoparticles (NPs) were prepared with two different nonionic surfactants, vitamin E d-α-tocopheryl polyethylene glycol 1000 succinate (vitamin E TPGS) and poly(vinyl alcohol) (PVA), using an ultrasonication solvent evaporation technique. Nine batches were formulated for each surfactant using a 32 factorial design for optimal concentration of the emulsifying agents, 0.03–0.09% for vitamin E TPGS and 2–4% for PVA. The surfactant percentage and the drug/polymer ratio (1:10, 1:15, 1:20) of the NMS-loaded NPs were investigated based on four responses: encapsulation efficiency, particle size, the polydispersity index, and the surface charge. The response surface plots and linearity curves indicated a relationship between the experiment’s responses and a set of independent variables. The NPs produced with both surfactants exhibited a negative surface charge, and scanning electron micrographs revealed that all of the NPs were spherical in shape. A narrower size distribution and higher drug loadings were achieved in PVA-emulsified PLGA NPs than in the vitamin E TPGS emulsified. Decreasing amounts of both nonionic surfactants resulted in a reduction in the emulsion’s viscosity, which led to a decrease in the particle size of NPs. According to the ANOVA results obtained in this present research, vitamin E TPGS exhibited the best correlation between the independent variables, namely drug/polymer ratio and the surfactant percentage, and the dependent variables (encapsulation efficiency R2 = 0.9603, particle size R2 = 0.9965, size distribution R2 = 0.9899, and surface charge R2 = 0.8969) compared with PVA.KEY WORDS: ANOVA, factorial design, nanoparticles, nimesulide, PLGA, PVA, vitamin E TPGS 相似文献
28.
The small intestinal mucosa exhibits a repetitive architecture organized into two fundamental structures: villi, projecting into the intestinal lumen and composed of mature enterocytes, goblet cells and enteroendocrine cells; and crypts, residing proximal to the submucosa and the muscularis, harboring adult stem and progenitor cells and mature Paneth cells, as well as stromal and immune cells of the crypt microenvironment. Until the last few years, in vitro studies of small intestine was limited to cell lines derived from either benign or malignant tumors, and did not represent the physiology of normal intestinal epithelia and the influence of the microenvironment in which they reside. Here, we demonstrate a method adapted from Sato et al. (2009) for culturing primary mouse intestinal crypt organoids derived from C57BL/6 mice. In addition, we present the use of crypt organoid cultures to assay the crypt metabolic profile in real time by measurement of basal oxygen consumption, glycolytic rate, ATP production and respiratory capacity. Organoids maintain properties defined by their source and retain aspects of their metabolic adaptation reflected by oxygen consumption and extracellular acidification rates. Real time metabolic studies in this crypt organoid culture system are a powerful tool to study crypt organoid energy metabolism, and how it can be modulated by nutritional and pharmacological factors. 相似文献
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30.
Background processes at the population level during succession in grasslands on sand 总被引:1,自引:0,他引:1
Two population characteristics, reproductive allocation (RA) and the intensity of photosynthesis, were investigated in the successional stages of the sandy grassland communities of the Great Hungarian Plain. Most of the species studied changed their allocational response as succession advanced. Compound path schemes, as casual models, were constructed and analysed for describing intra-individual effects (influence of assimilating organs and root mass of the plant sampled) as well as the phytosociological effects on RA. In pioneer stages, the high values of path coefficients show that the effect of assimilating organs is responsible for the variability of RA. It is also shown that annuals and perennials exhibit different behaviour as to the regulation of RA. It seems that-in terms of path analysis-the reproduction of annuals is influenced by internal factors only. In case of perennials, an external (namely phytosociological) regulation was also observed. It is suggested that successional stages play a role in regulating the photosynthetic intensity of both the dominant species and the whole plant assemblage.Abbreviations RA =
Reproductive Allocation 相似文献