Authors:R. Liu, Q.N. Zhang, J. Lu, C.H. Zhang, L. Zhang, and Y. Wu
Salt stress is one of the major abiotic stress which severely limits plant growth and reduces crop productivity across the world. In the present study, the effects of exogenous pyridoxal-5-phosphate (vitamin B6, VB6) on seedling growth and development of wheat under salt stress were investigated. The results showed that exogenous application of pyridoxal-5-phosphate (VB6) significantly increased the RWC, biomass, the concentration of photosynthetic pigments, proline, the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), together with decreasing the content of Malondiadehyde (MDA) and hydrogen peroxide (H2O2) in wheat leaves under salt stress. Meanwhile, the transcript level of P5CR, P5CS, SOD, TaSOS1 and TaSOS4 were also up-regulated after treatment with pyridoxal-5-phosphate. VB6 acts as a signal in regulating the activities of plant antioxidant enzymes and SOS pathway to improve resistance to salt stress. The current study results may give an insight into the regulatory roles of VB6 in improving salt stress and VB6 could be an easily and effective method to improve salt-stress tolerance to wheat in the field condition. It is urgency to understand the molecular mechanism of VB6 to enhance the salt tolerance of wheat in the next work.
Authors:J. L. Zeng, L. X. Sun, F. Xu, Z. C. Tan, Z. H. Zhang, J. Zhang, and T. Zhang
In this paper, organic phase change materials (PCM)/Ag nanoparticles composite materials were prepared and characterized for the first time. The effect of Ag nanoparticles on the thermal conductivity of PCM was investigated. 1-tetradecanol (TD) was selected as a PCM. A series of nano-Ag-TD composite materials in aqueous solution were in-situ synthesized and characterized by means of thermal conductivity evaluation method, TG-DSC, IR, XRD and TEM. The results showed that the thermal conductivity of the composite material was enhanced as the loading of Ag nanoparticles increased. The composite materials still had relatively large phase change enthalpy. Their phase change enthalpy could be correlated linearly with the loading of TD, but their phase change temperature was a little bite lower than that of pure TD. The thermal stability of the composite materials was close to that of pure TD. It appeared that there was no strong interaction between the Ag nanoparticles and the TD. Furthermore, the experiment results indicated that the Ag nanoparticles dispersed uniformly in the materials, occurred in the forms of pure metal.
Authors:L. Zhao, J. Ge, C. Qiao, H. Zhang, and S. Jiang
A high-performance liquid chromatographic (HPLC) method has been developed for separation and quantitative analysis of flavonoid aglycones in Rhododendron anthropogonosides Maxim. Flavonoids in their bound forms were hydrolyzed with acid before HPLC analysis. Analytical samples were pretreated by solid-phase extraction on C18 reversed-phase cartridges. Optimum separation on a 4.6 mm × 250 mm i.d. C18 column was achieved by use of a 52:48 (v/v) mixture of methanol and an aqueous solution of 10 mm citric acid and 1 mm sodium dodecyl sulfate as mobile phase. The flow rate was 1.0 mL min–1 and the detection wavelength 360 nm. Five flavonoids, myricetin, quercetin, luteolin, kaempferol, and isorhamnetin, were separated with high resolution without use of gradient elution. The method was successfully used for efficient quality-control analysis by quantifying flavonoids in R. anthopogonosides. Repeatability tests showed that intra-day and inter-day RSD was <10%. LOD of the five flavonoids were <0.85 μg mL–1. Recovery ranged from 90.2 to 112.5%, with RSD <11.1%.
Authors:L. Yu, S. Wang, X. Jiang, N. Wang, and C. Zhang
Combustion experiments of three typical seaweeds (Gracilaria cacalia, Enteromorpha clathrata and Laminaria japonica) have been studied using a DTA-60H Thermal Analyzer and the combustion processes and characteristics are studied. Thermogravimetric
experiments are carried out on the samples with 0.18 mm particle size at the heating rate of 20°C min−1.
The results indicate that the ignition mode of seaweed is homogeneous and the combustion process is composed of dehydration,
the pyrolysis and combustion of volatile, transition stage, the combustion of char as well as the reaction at high temperature.
And the combustion characteristic parameters are obtained such as ignition temperature, maximum rate of combustion, burnout
temperature etc. The combustion models of these seaweeds are also analyzed. The combustion characteristics and model differences
between the seaweed and woody biomass are caused by the differences of volatile components. The combustibility indexes of
seaweeds calculated are better than that of woody biomass, and the index of Gracilaria cacalia is the best. At last, activation energies are determined using Arrhenius model that is solved by binary linear regression
Authors:J. Zhao, L. Zhong, L. Zou, C. Zhang, L. Peng, W. Xiao, and G. Zhao
The purpose of this study was to investigate the effects of endophytic fungi from tartary buckwheat on the host sprout growth and functional metabolite production. Without obvious changes in the appearance of the sprouts, the exogenous fungal mycelia elicitors notably stimulated the sprout growth and rutin accumulation, and the stimulation effect was mainly depended on the mycelia elicitor species along with its treatment dose. Three endophytic fungi Fat6 (Bionectria pityrodes), Fat9 (Fusarium oxysporum) and Fat15 (Alternaria sp.) were screened to be the most effective candidates for promoting F. tataricum sprout growth and rutin production. With application of polysaccharide (PS, 150 mg/l) of endophyte Fat6, PS (200 mg/l) of endophyte Fat9, and PS (150 mg/l) of endophyte Fat15, the rutin yield was effectively increased to 47.89 mg/(100 sprouts), 45.85 mg/(100 sprouts) and 46.83 mg/(100 sprouts), respectively. That was about 1.5- to 1.6-fold compared to the control culture of 29.37 mg/(100 sprouts). Furthermore, the present study revealed that the biosynthesis of the functional flavonoid resulted from the stimulation of the phenylpropanoid pathway by mycelia polysaccharide treatments. Application of specific fungal elicitors could be an efficient strategy for improving the nutritional and functional quality of tartary buckwheat sprouts.
Authors:L.J. Wu, Y. Shang, T. Liu, W.J. Chen, B.L. Liu, L.Q. Zhang, D.C. Liu, B. Zhang, and H.G. Zhang
In this study, the cDNA of homocysteine S-methyltransferase was isolated from Aegilops tauschii Coss., with the gene accordingly designated as AetHMT1. Similar to other methyltransferases, AetHMT1 contains a GGCCR consensus sequence for a possible zinc-binding motif near the C-terminal and a conserved cysteine residue upstream of the zinc-binding motif. Analysis of AetHMT1 uncovered no obvious chloroplast or mitochondrial targeting sequences. We functionally expressed AetHMT1 in Escherichia coli and confirmed its biological activity, as evidenced by a positive HMT enzyme activity of 164.516 ± 17.378 nmol min−1 mg−1 protein when catalyzing the transformation of L-homocysteine. Compared with the bacterium containing the empty vector, E. coli harboring the recombinant AetHMT1 plasmid showed much higher tolerance to selenate and selenite. AetHMT1 transcript amounts in different organs were increased by Na2SeO4 treatment, with roots accumulating higher amounts than stems, old leaves and new leaves. We have therefore successfully isolated HMT1 from Ae. tauschii and characterized the biochemical and physiological functions of the corresponding protein.
Authors:Y. Zhang, W. Zheng, Q.C. Ying, L.-E. Shi, Z.-L. Zhang, M.-Z. Shi, and Z.-X. Tang
The sub-acute toxicity of E. faecalis HZNU P2 was investigated in rats fed with different doses for 14 days. To evaluate the acute oral toxicity of E. faecalis HZNU P2, rats were fed with E. faecalis HZNU P2 at a high dose of 2×1011 CFU kg−1 for 10 days. Results showed that there were no abnormal clinical signs in any of the groups during the experiment. There were no significant differences in live weight gain among rats fed with E. faecalis HZNU P2, compared to those in control group. Macroscopic or microscopic examinations of organs revealed no abnormalities, indicating that E. faecalis HZNU P2 did not adversely affect the health of rats. Results of this study demonstrated that digestion of E. faecalis HZNU P2 in rats did not show any obvious signs of toxicity.
Authors:Y. Li, Y. Wang, C. Liu, J. Zhang, L. Jian, and C. He
Systematically complicated technique used for preparing high-intensity (more than 8.0 GBq/cm2)241Am -source by a new enamel technique is presented. High intensity241Am -sources with activities ranging from 3.7 to 37 GBq have been made by this new technique. The activity and photon output have been measured. The results were compared with the data reported by the Radiochemical Centre Amersham in their specification. The photon output of241Am -source produced by us meets the technical specification of241Am -sources produced by Amersham. Moreover, the highest intensity can reach 1789 mCi/cm2. The overall utilization ratio of241Am activity (59.5 keV) is 31.2%.
Authors:X.G. Hu, J. Liu, L. Zhang, B.H. Wu, J.L. Hu, D.C. Liu, and Y.L. Zheng
Grains of 12 accessions of Triticum timopheevii (Zhuk.) Zhuk. ssp. timopheevii (AAGG, 2n = 4x = 28) and one bread wheat cultivar Chinese Spring (CS) and one durum wheat cultivar Langdon (LDN) grown across two years were analyzed for grain iron (Fe) and zinc (Zn) concentrations. All the 12 tested T. timopheevii ssp. timopheevii genotypes showed significantly higher concentration of grain Fe and Zn than CS and LDN. Aboundant genetic variability of both the Fe and Zn concentrations was observed among the T. timopheevii ssp. timopheevii accessions, averagely varied from 47.06 to 90.26 mg kg−1 and from 30.05 to 65.91 mg kg−1, respectively. Their grain Fe and Zn concentrations between years exhibited a significantly positive correlation with the correlation coefficients r = 0.895 and r = 0.891, respectively, indicating the highly genetic stability. Flag leaf possessed twice or three times higher concentrations for both Fe and Zn than grain, and a significantly high positive correlation appeared between the two organs with r = 0.648 for Fe and r = 0.957 for Zn concentrations, respectively, suggesting flag leaves might be indirectly used for evaluating grain Zn and Fe contents. Significant correlations occurred between grain Fe and Zn concentrations, and between grain Zn concentration and the two agronomic traits of plant height and number of spikelets per spike. Both the concentrations were not related to seed size or weight as well as NAM-G1 gene, implying the higher grain Fe and Zn concentrations of T. timopheevii ssp. timopheevii species are not ascribed to concentration effects of seed and the genetic control of NAM-G1 gene. There might be some other biological factors impacting the grain’s Zn and Fe concentrations. These results indicated T. timopheevii ssp. timopheevii species might be a promising genetic resource with high Fe and Zn concentrations for the biofortification of current wheat cultivars.
Two lines, L-19-613 and L-19-626, were produced from the common wheat cultivar Longmai 19 (L-19) by six consecutive backcrosses using biochemical marker-assisted selection. L-19 (Glu-D1a, Glu-A3c/Gli-A1?; Gli-A1? is a gene coding for unnamed gliadin) and L-19-613 (Glu-D1d, Glu-A3c/Gli-A1?) formed a set of near-isogenic lines (NILs) for HMW-GS, while L-19-613 and L-19-626 (Glu-D1d, Glu-A3e/Gli-A1m) constituted another set of NILs for the LMW-GS/gliadins. The three L-19 NILs were grown in the wheat breeding nursery in 2007 and 2008. The field experiments were designed using the three-column contrast arrangement method with four replicates. The three lines were ranked as follows for measurements of gluten strength, which was determined by the gluten index, Zeleny sedimentation, the stability and breakdown time of the farinogram, the maximum resistance and area of the extensogram, and the P andWvalues of the alveogram: L-19-613 > L-19-626 > L-19. The parameters listed above were significantly different between lines at the 0.05 or 0.01 level. The Glu-D1 and Glu-A3/Gli-A1 loci had additive effects on the gluten index, Zeleny sedimentation, stability, breakdown time, maximum resistance, area, P and W values. Although genetic variation at the Glu-A3/Gli-A1 locus had a great influence on wheat quality, the genetic difference between Glu-D1d and Glu-D1a at the Glu-D1 locus was much larger than that of Glu-A3c/Gli-A1? and Glu-A3e/Gli-A1m at the Glu-A3/Gli-A1 locus. Glu-D1d had negative effects on the extensibility and the L value compared with Glu-D1a. In contrast, Glu-A3c/Gli-A1? had a positive effect on these traits compared with Glu-A3e/Gli-A1m.