Search Results

You are looking at 1 - 10 of 74 items for

  • Author or Editor: X.L. Li x
  • Refine by Access: All Content x
Clear All Modify Search

Youzimai is a widespread wheat landrace and has been used extensively in breeding programs in China. In order to assess the genetic variation between and within Youzimai accessions, samples of 31 landrace accessions of wheat, all called ‘Youzimai’, were collected from 6 geographic regions in China and evaluated using morphological traits, seedling resistance to powdery mildew, gliadin and microsatellite markers. Typical differences among accessions were observed in morphological characteristics. Forty-five (58.4%) of 77 assayed SSR markers showed polymorphism over the entire collection and total 226 alleles were identified with an average of 5.02 alleles per locus. SSR data indicated that the accessions from Hebei province were the most diverse, as evidenced by greatest number of region-specific alleles and highest diversity index. These accessions, therefore, probably experienced the most substantial morphological and molecular evolution as a result of various natural and anthropomorphic influences. On the other hand, differentiation in gliadin phenotypes was found among seeds within 80.6% of total accessions and average 61.5% of entire collections showed heterogeneous and comprised resistant plants in reaction to powdery mildew, suggesting the presence of a wide diversity within the wheat landrace. By developing an intimate knowledge of the available wheat genotypes, appropriate selections can be made for commercial application in order to conserve and exploit the diversity of the wheat landraces.

Restricted access

A reborn interest has occurred during the last decade toward wheat landraces for broadening genetic basis of modern wheat cultivars. The investigation of molecular traits within and between existing landraces of wheat can help scientists to develop appropriate strategies for their efficient maintenance and exploitation. The present study dealt with the gliadin characterization of forty-seven wheat landraces collected from wheat mainly planted areas of China, each of which was represented by a sample of at least 43 individuals. Twelve accessions selected on the basis of gliadin analysis were investigated further using 21 SSR markers. The results proved that landraces of wheat are a mixture of variable individuals genetically distinguishable from each other. Twelve of the analyzed 47 accessions were observed to be homogeneous, while 35 (74.5%) of them were heterogeneous in their gliadin composition. In total, 122 gliadin pattern were observed. On average, 10.1% (Gst) of the total variation arose from differentiation among regions, and 89.9% was attributed to within-region variation. Furthermore, nineteen of the 21 SSR markers were polymorphic across all the populations. The total number of the amplified DNA products was 110, with a mean of 6.11 alleles per locus. The values of genetic diversity within each landrace population varied from 0.006 to 0.351. Implications for the management of this valuable genetic resource are discussed.

Restricted access

Maize seeds from inbred line Mo17, susceptible to Sugarcane mosaic virus (SCMV), were investigated for SCMV seed transmission. The seed quality significantly influenced the seed transmission rate. There were more infected seedlings derived from larger seeds than smaller seeds in both golden (G) and buff (B) seed groups, the proportion of infected seedlings in G1 was similar to G2 and B1, and significantly higher than the others (P < 0.05 or P < 0.01). While the proportion of SCMV seed transmission was higher in golden (3.9%) than buff seeds groups (2.3%), and there were significantly difference (P < 0.05) between the both colors seeds. However the percentage of infected seedlings was closely related to the location of seeds on ears, most infected seedlings were derived from seeds of the middle (Part III) and mid-base regions (Part IV), and the both parts (Parts III and IV) were significantly higher than that of Part I (P < 0.05). Fisher’s exact test indicated that the seed quality was associated significantly with the efficiency of SCMV seed transmission.

Restricted access

Abstract  

The molar heat capacity C p,m of 1,2-cyclohexane dicarboxylic anhydride was measured in the temperature range from T=80 to 390 K with a small sample automated adiabatic calorimeter. The melting point T m, the molar enthalpy Δfus H m and the entropy Δfus S m of fusion for the compound were determined to be 303.80 K, 14.71 kJ mol−1 and 48.43 J K−1 mol−1, respectively. The thermodynamic functions [H T-H 273.15] and [S T-S 273.15] were derived in the temperature range from T=80 to 385 K with temperature interval of 5 K. The thermal stability of the compound was investigated by differential scanning calorimeter (DSC) and thermogravimetry (TG), when the process of the mass-loss was due to the evaporation, instead of its thermal decomposition.

Restricted access

Hydrated goethite nanorodS

Vibration spectral properties, thermal stability, and their potential application in removing cadmium ions

Journal of Thermal Analysis and Calorimetry
Authors: X. Qiu, L. Lv, G. Li, W. Han, X. Wang, and L. Li

Abstract  

Vibration spectral properties and dehydration behaviors of goethite nanorods with diameters ranging from 13 to 32 nm were investigated using infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. All goethite nanorods were highly hydrated with physisorbed and chemisorbed water. As the diameters of goethite nanorods increased, the hydroxyl deformation vibration in the a-b plane showed a significant blue shift, while the Fe-O vibration in the a-b plane shifted to lower frequencies, indicating an enhancement of O-H bond and the ionicity of Fe-O in a-b plane. The hydrated goethite nanorods are also proved to be useful in environmental remedy because of their excellent removal ability of heavy metal ions.

Restricted access

A rapid and sensitive ultraperformance liquid chromatography-multiple reaction monitoring-multi-stage/mass spectrometry (UPLC-MRM-MS/MS) method has been developed for simultaneous quantification of salvianolic acid B and tanshinone IIA of salvia tropolone tablets in dog plasma. This was achieved by performing quantification using the MRM acquisition with two channels of MRM-MS/MS and MS full scan for more accuracy qualitative results, and the fragmentation transitions of m/z 295→249, 191 for tanshinone IIA and m/z 297→279, 251 for IS in positive mode, m/z 717→519, 321 for salvianolic acid B and m/z 295→267, 239 for IS in negative mode were selected. The UPLC separation was achieved within 3 min in a single UPLC run. Linear calibration curves were obtained over the concentration range of 10 pg/mL−1 ng/mL for tanshinone IIA and 100 pg/mL−1 for salvianolic acid B. Lower limit of quantitation (LLOQ) was 10 pg/mL and 100 pg/mL for tanshinone IIA and salvianolic acid B, respectively. The inter-day and intra-day precision (relative standard deviation, RSD) in all samples were less than 8.21%, and the recoveries were over 85.9% for both tanshinone IIA and salvianolic acid B. The two channels of MRM with MS full scan approach could provide both qualitative and quantitative results without the need for repetitive analyses and resulted in the reduction of further confirmation experiments and analytical time. The pharmacokinetic study of the two active components of salvia tropolone tablets following oral gavage administration of dogs was thus explored with this method.

Full access

Abstract  

The dilution enthalpies of D-mannitol and D-sorbitol in aqueous sodium chloride solution at various concentrations have been determined by isothermal microcalorimetry at 298.15 K. The homogeneous enthalpic interaction coefficients over a quite large range of concentration of aqueous sodium chloride solutions have been calculated according to the excess enthalpy concept. The results show that enthalpic pairwise interaction coefficients (h 2) of D-mannitol and D-sorbitol are positive in aqueous sodium chloride solution and become more positive with increase of the concentration of sodium chloride. The results are interpreted in terms of the different conformations of the two polyols, solute-solute and solute-solvent interactions involved by solvent effects.

Restricted access

Summary  

Adsorption microcalorimetry has been employed to study the interaction of ethylene with the reduced and oxidized Pt-Ag/SiO2catalysts with different Ag contents to elucidate the modified effect of Ag towards the hydrocarbon processing on platinum catalysts. In addition, microcalorimetric adsorption of H2, O2, CO and FTIR of CO adsorption were conducted to investigate the influence of Ag on the surface structure of Pt catalyst. It is found from the microcalorimetric results of H2and O2adsorption that the addition of Ag to Pt/SiO2leads to the enrichment of Ag on the catalyst surface which decreases the size of Pt surface ensembles of Pt-Ag/SiO2catalysts. The microcalorimetry and FTIR of CO adsorption indicates that there still exist sites for linear and bridged CO adsorption on the surface of platinum catalysts simultaneously although Ag was incorporated into Pt/SiO2. The ethylene microcalorimetric results show that the decrease of ensemble size of Pt surface sites suppresses the formation of dissociative species (ethylidyne) upon the chemisorption of C2H4on Pt-Ag/SiO2. The differential heat vs. uptake plots for C2H4adsorption on the oxygen-preadsorbed Pt/SiO2and Pt-Ag/SiO2catalysts suggest that the incorporation of Ag to Pt/SiO2could decrease the ability for the oxidation of C2H4.

Restricted access

A two-year field experiment with a split-split plot design was conducted to investigate the effects of soil N(0, 120 and 240 kg N·ha−1) and foliar Zn applications at different growth stages (jointing, flowering, early grain filling, and late grain filling) on Zn translocation and utilization efficiency in winter wheat grown on potentially Zn-deficient soil. Our results showed that foliar Zn application at the early grain filling stage significantly increased the Zn concentration in the grain (by 82.9% compared to control) and the Zn utilization efficiency (by 49% compared to jointing). The Zn concentration in the straw consistently increased with the timing of the foliar Zn application and was highest at late grain filling. However, the timing of the Zn application had little effect on Zn uptake in the grain and straw. A high N supply significantly increased the Zn concentration in and uptake by grain and straw, but it had little effect on the efficiency of Zn utilization. Consequently, a foliar Zn application at early grain filling causes Zn to re-translocate into grain from vegetative tissues, resulting in highly nutritional wheat grain. Finally, these practices improved the efficiency of Zn utilization in winter wheat and led to Zn-enriched straw, which may contribute to Zn recycling if it is returned to the field. The results also indicated that N nutrition is a critical factor in both the concentration and translocation of Zn in wheat.

Restricted access

Abstract  

The enthalpies of dilution of aqueous solutions for pyridine and methylpyridine isomers have been determined with a 2277-Thermal Activity Monitor at 298.15 K. The results have been treated using the excess function concept and homotactic interaction coefficients have been obtained. The homotactic enthalpic pairwise interaction coefficients are discussed qualitatively in terms of substitution effects of methyl group introduced into the pyridine ring.

Restricted access