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91.
Changes of antioxidative enzymes and cell membrane osmosis in tomato colonized by arbuscular Mycorrhizae under NaCl stress 总被引:7,自引:0,他引:7
Salinity toxicity is a worldwide agricultural and eco-environmental problem. Many literatures show that arbuscular mycorrhizal fungi (AMF) can enhance salt tolerance of many plants and some physiological changes occurred in AM symbiosis under salt stress. However, the role of ROS-scavenging enzymes in AM tomato is still unknown in continuous salt stress. This study investigated the effect of Glomus mosseae on tomato growth, cell membrane osmosis and examined the antioxidants (superoxide-dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX; peroxidase, POD) responses in roots of mycorrhizal tomato and control under different NaCl stress for 40 days in potted culture. NaCl solution (0, 0.5 and 1%) was added to organic soil in the irrigation water after 45 days inoculated by AMF (Glomus mosseae). (1) AMF inoculation improved tomato growth under salt or saltless condition and reduced cell membrane osmosis, MDA (malonaldehyde) content in salinity. So the salt tolerance of tomato was enhanced by AMF; (2) SOD, APX and POD activity in roots of AM symbiosis were significantly higher than corresponding non-AM plants in salinity or saltless condition. However, CAT activity was transiently induced by AMF and then suppressed to a level similar with non-AM seedlings; (3) higher salinity (1% level) and long stress time suppressed the effect of AMF on SOD, APX, POD and CAT activity; (4) this research suggested that the enhanced salt tolerance in AM symbiosis was mainly related with the elevated SOD, POD and APX activity by AMF which degraded more reactive oxygen species and so alleviated the cell membrane damages under salt stress. Whereas, the elevated SOD, POD and APX activity due to AMF depended on salinity environment. 相似文献
92.
93.
The palladium-catalyzed regio- and diastereo-selective allylic alkylation of allyl acetates with carbon nucleophiles occurred. The stereochemistry was highly controlled by the palladium catalyst with 2-(diphenylphosphino)benzoic acid as the ligand, and vicinal quaternary and tertiary carbon centers were constructed. 相似文献
94.
The structure of ammonium hexafluoroarsenate, NH4AsF6, has been determined by X‐ray diffraction using a single crystal grown from saturated solution in anhydrous HF. NH4AsF6 crystallizes rhombohedral with the KOsF6 structure type, with a = 7.459(3) Å, c = 7.543(3) Å (at 200 K), Z = 3, space group (No. 148). No phase transition was observed in the 100 K–296 K temperature range. The structure is dominated by regular AsF6 octahedra and disordered NH4+ cations. Raman spectrum of a single crystal of NH4AsF6 shows the bands at 372 cm?1, 572 cm?1, 687 cm?1 (AsF6?) and at 3240 cm?1 and 3360 cm?1 (NH4+). 相似文献
95.
采用胶晶模板法制备出具有三维多孔结构的纳米CoFe2O4。利用X射线衍射仪(XRD)、傅里叶变换红外(FT-IR)光谱仪、扫描电镜(SEM)、透射电镜(TEM)和N2吸附-脱附对样品的晶型和形貌结构等进行表征,采用差示扫描量热法(DSC)对比研究多孔纳米CoFe2O4和球形纳米CoFe2O4对高氯酸铵(AP)的热分解性能的影响,并考察这两种催化剂对AP催化热分解的动力学参数。结果显示,制备出的多孔纳米CoFe2O4样品具有典型的尖晶石结构,孔径约200 nm;比表面积明显高于40 nm球形CoFe2O4,达到55.646 m2·g-1。DSC测试结果表明:多孔纳米CoFe2O4的加入促进了AP的热分解,最高使AP的高温分解峰温降低91.46℃,能量释放最高达1120.88 J·g-1,是纯AP分解放热量的2.3倍;多孔纳米CoFe2O4具有较高的比表面积,能提高催化反应的接触面积,使AP的高温分解峰温度更低,反应活化能较小,从而表现出比球形纳米CoFe2O4更高的催化活性。此外,对多孔纳米CoFe2O4催化AP的热分解机理进行初步探索,纳米多孔催化剂对气态中间产物的作用促进了AP的热分解。 相似文献
96.
Márcio Lazzarotto Francine Furtado Nachtigall Eduardo Ernesto Castellano 《Thermochimica Acta》2005,429(1):111-117
Thermo gravimetric analysis of ammonium-p-tert-butylcalix[6]arene salts were carried out to determine the stoichiometry of the inclusion compounds and the temperature of leaving of the ammonium cation, as amine, from the solid phase by a reverse proton transfer reaction to calixarene. The chain length of the amine molecules and their relative basicity order are the main factors which determine the decomplexation temperatures for the ammonium salts of piperidinium, diethylammonium, ethylenediammonium, morpholinium, s-butylammonium, butylammonium, hexylammonium and triethylammonium salts of p-tert-butylcalix[6]arene anion. The solid state structure of bis-diethylammonium-p-tert-butylcalix[6]arene dianion is reported. The calix moiety adopts a 1,2,3 alternate conformation, with one ammonium as exo-calix and other as endo-calix, with an intricate array of hydrogen bonds between phenol, phenolate and ammonium cations. 相似文献
97.
Investigations of the Phase Relations in the Quaternary Systems Bi2O3/Bi2Ch /Bi2Ch (Ch = S, Se, Te) The stability ranges in the pseudobinary systems Bi2O2S/Bi2O2Se, Bi2O2S/Bi2O2Te and Bi2O2Se/Bi2O2Te have been studied by solid state and chemical transport reactions. A complete mixed crystal Bi2O2(TexSe1–x), 0 ≤ x ≤ 1 exists between the ternary compounds Bi2O2Te and Bi2O2Se. The thermal behaviour of the mixed crystal and the coexistence ranges have been determined by x‐ray and thermal analysis. 相似文献
98.
(NH4)2[Mo6Cl14] · H2O ( 1 ) was prepared from reactions of MoCl2 in ethanol with aqueous NH4Cl solution. It crystallizes in the monoclinic space group I2/a (no. 15), Z = 4 with a = 912.3(1), b = 1491.2(2), c = 1724.8(2) pm, β = 92.25(1)°; R1 = 0.023 (based on F values) and wR2 = 0.059 (based on F2 values), for all measured X‐ray reflections. The structure of the cluster anion can be given as [(Mo6Cl)Cl]2– (i = inner, a = outer ligands). Thermal stability studies show that 1 loses crystal water followed by the loss of NH4Cl above 350 °C to yield MoCl2. The water‐free compound (NH4)2[Mo6Cl14] ( 2 ) was synthesized by solid state reaction of MoCl2 and NH4Cl in a sealed quartz ampoule at 270 °C. No single‐crystals could be obtained. Decompositions of 1 and 2 under nitrogen and argon exhibited the loss of NH4Cl at about 350 °C. Decomposition under NH3 resulted in the formation of MoN and Mo2N at 540 °C and 720 °C, respectively. 相似文献
99.
Mokhles M. Abd-Elzaher 《中国化学会会志》1999,46(6):975-982
The reaction between roasted serpentine ore and ammonium sulfate was studied at the range of temperature 250–1000°C using different molar ratios to determine the maximum extraction of magnesia and also to characterize the different reaction products. The maximum extraction of MgO from the roasted ore reached 92.4% at 400°C. It was found from XRD that ammonium magnesium sulfate [(NH4)2Mg2(SO4)3] was produced as the main product at 400°C, which decomposes to magnesium sulfate at 500–600°C. The last compound decomposes to magnesium oxide at 900–1000°C. Thermal analysis of the reaction mixture confirmed the results obtained by XRD. Extraction of magnesia by ammonium chloride at 300–400°C showed low percentage of extraction (7.8%). Comparison was made between using ammonium chloride instead of sulfate taking into consideration the thermal decomposition products of both ammonium salts. Extraction of magnesia from the roasted ore by aqueous ammonium sulfate or ammonium chloride showed good results. 相似文献
100.
Haengsoon Park 《Tetrahedron》2005,61(26):6352-6367
Only a limited number of ligands have been successfully employed for the Ni-catalyzed asymmetric hydrovinylation reaction. Diarylphosphinites, carrying β-acylamino groups prepared from readily available carbohydrates, in conjunction with highly dissociated counteranions {[(3,5-(CF3)2C6H3]4B− or SbF6−}, effect the hydrovinylation of vinylarenes under ambient pressure of ethylene with high enantioselectivity. Nitrogen substituents such as -COCF3 and COPh groups lead to isomerization of the primary products (3-arylbutenes) to Z- and E-2-aryl-2-butenes. In a prototypical synthesis of a 2-arylproionic acid, (S)-3-(4-bromophenyl)-1-butene (89% ee) has be transformed into (R)-ibuprofen by Ni-catalyzed cross-coupling with i-BuMgBr, followed by oxidation of the double bond with NaIO4 and KMnO4. Asymmetric codimerization of norbonene and ethylene using binaphthol-derived phosphoramidites as ligands gives 1:1, 2:1 or polymeric adducts depending on the relative configurations and nature of the BINAP and amine moieties. With one of the phosphoramidite-Ni complexes, counteranions BAr4− [Ar=3,5-(CF3)2C6H3] and SbF6−, which had been used interchangeably in other reactions, give either a 1:1 adduct or a 2:1 adduct, respectively. 相似文献