Authors:X. Lu, X. Tian, A. Zhao, J. Cui, and X. Yang
To investigate the effect of Zn fertilization on soil Zn fractions and grain Zn concentration in wheat grown on potentially Zn-deficient soil, a field experiment was carried out. The experimental design was split plot consisted of two varieties of wheat (Zhengmai 9023 and Xinong 889) with five Zn levels (0, 7.5, 15, 30 and 45 kg Zn/ha). Results showed that Zn fertilization had no significant effect on wheat yield and grain Zn concentration, and the recovery of Zn fertilizer was only 0.06% to 0.29%. However, the amount of soil DTPA-Zn was increased by 2.3-9.8-folds as Zn supplementation increases during the whole wheat growth stage as compared to the control (Zn0 treatment). Besides, DTPA-Zn was positively correlated with both Loose organic matter bound Zn (LOM-Zn) and Exchange Zn (Ex-Zn), and their partial correlation coefficients were 0.558 and 0.119, respectively. Moreover, these two fractions also showed positive correlation with grain Zn concentration. The amount of LOM-Zn was firstly increased with increasing Zn fertilizer levels then gradually decreased as it get converted to mineral bound Zn (Min-Zn). Zn fertilization in this potentially Zn deficient soil increased the amount of DTPA-Zn in the whole wheat growth stage; however, grain Zn concentration cannot be significantly increased as Zn levels increase, thus suggesting that there are inhibitory factors for Zn absorption and translocation. Furthermore, the amount of soil DTPA-Zn perhaps cannot exactly reflect the capability of soil to supply Zn.
Trifolium pratense cv. Minshan is a dominant red clover variety for animal feeding and pharmaceutical industry in Alpine Pasture Region of Gansu province, northwest China. In order to achieve the best isoflavone production, a 3-year trial was conducted at three locations to study variations of hay yield, total isoflavone concentration and isoflavone yield at different growth stages under different environmental conditions. Predominant isoflavone compounds and distribution of isoflavones in leaves, stems and inflorescences were also investigated. The results indicated that there were large variations on hay yield and isoflavone concentration among different sites, growth stages, age and parts of the plant. Minshan red clover harvested at the flower bud stage had the highest isoflavone yield (86.30 kg ha−1). The temperate climate region, Guanghe, provided the best growth conditions among three sites for isoflavone production (58.93 kg ha−1). The highest isoflavone production (53.42 kg ha−1) appeared at the second year of crop. In Minshan red clover, isoflavones are mainly distributed in leaves (1.12%). The predominant isoflavone compounds were formononetin (0.27%) and biochanin A (0.25%).
Lycopene content (LC) and soluble solid content (SSC) are important quality indicators for cherry tomatoes. This study attempted simultaneous analysis of inner quality of cherry tomato by Electronic nose (E-nose) using multivariate analysis. E-nose was used for data acquisition, the response signals were regressed by multiple linear regression (MLR) and partial least square regression (PLS) to build predictive models. The performances of the predictive models were tested according to root mean square and correlation coefficient (R2) in the training set and prediction set. The results showed that MLR models were superior to PLS model, with higher value of R2 and lower values of for RMSE firmness, pH, SSC, and LC. Together with MLR, E-nose could be used to obtain firmness, pH, soluble solid and lycopene contents in cherry tomatoes.
Authors:X. Wang, X. Yin, X. Zhang, Z. Li, J. Tian, M. Wu, and X. Sheng
A radioactive multitracer solution obtained from the nuclear reaction of selenium with 25 MeV/nucleon40Ar ions was applied to the investigation of the trace elements behavior in feces and urine of mouse. The excretion rates of
23 elements, Na, K, Rb, Mg, Ca, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Zn, Y, Zr, Mo, Nb, Tc, Ru, Ag and In were simultaneously
detected under strictly identical experimental conditions, in order to clarify the excretion behavior of the elements in mice.
Fecal and urinary excretion rates of the elements in mice reached the highest value separately at 48 and 24 hours. The total
excretion of Mo, Tc and Co within 96 hours were all larger, more than 60%. Accumulative excretion rates of Ca, Nb, Mg, Sr,
V, Sc, Na, Cr, Fe, Ag, Mn and Zr were 60-30%. The total rates of Ru, K, As, Zn, Rb, Y, Ga and In were less than 30%, and low
excretion. The main excretion pathway of Mo, Co, Mg, Fe and Ag was through urine, and Na, K, As and Rb were eliminated from
the body also in urine. But fecal excretion of Tc, Nb, Sr, Y, Ru, and In were larger than urinary excretion, and Ca, Sc, Mn,
Zr, Zn were eliminated from the body in feces.
Authors:X. Yang, X. Tian, W. Gale, Y. Cao, X. Lu, and A. Zhao
Three field experiments were conducted to determine the effect of soil Zn, foliar Zn, and soil N application on Zn and phytic acid concentrations in wheat grain grown on potentially Zn-deficient soil. Results showed significant genotypic variation in grain Zn concentrations among fifteen wheat cultivars commonly grown in northwest China. Soil Zn application had mixed effects, increasing grain Zn concentrations of some cultivars by as much as 21%, but reducing grain Zn concentrations of other cultivars by as much as 14%. In comparison, foliar Zn application increased grain Zn concentrations by 26 to 115%. Grain Zn concentrations were 14% larger in the combined (foliar Zn + soil Zn) treatment compared to the foliar Zn treatment, but the added cost of soil Zn application may not be economically justifiable. Wheat grain phytic acid concentrations and phytic acid: Zn molar ratios were less in the foliar Zn and (foliar Zn + soil Zn) treatments compared to the soil Zn and the unfertilized treatments. This indicated that foliar Zn increased Zn bioavailability. Best results were obtained when foliar Zn was applied at early grain filling. Overall, these findings indicate that foliar Zn application to Zn-efficient cultivars could reduce human Zn deficiency in regions with potentially Zn-deficient soil.
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.
A total reflection X-ray fluorescence (TXRF) analyzer with a special structure is described. Its short X-ray path (about 15 cm) resulted in a high sensitivity, low power consumption and small volume. The structure with double total reflection path is suitable for easy change of exciting source to cover a large element range. The minimum detection limit (MDL) of 6 pg for Co under Cu exciting source and 22 pg for Sr under Mo tube. Some significant works were done, such as the detemination of sulfur content in fuel oils, the non-destructive analysis of an ancient bronze utensil and the regular analysis of tap water.
The transformation equation for the thermokinetics of consecutive first-order reactions has been deduced, and a thermokinetic
research method of irreversible consecutive first-order reactions, which can be used to determine the rate constants of two
steps simultaneously, is proposed. The method was validated and its theoretical basis was verified by the experimental results.
Authors:Y.-Q. Zhang, X.-C. Zeng, Y. Chen, X.-G. Meng, and A.-M. Tian
On the basis of the theory of thermokinetics proposed in the literature, a novel thermokinetic method for determination of the reaction rate, the characteristic parameter method, is proposed in this paper. Mathematical models were established to determine the kinetic parameters and rate constants. In order to test the validity of this method, the saponifications of ethyl benzoate, ethyl acetate and ethyl propionate, and the formation of hexamethylenetetramine were studied with this method. The rate constants calculated with this method are in agreement with those in the literature, and the characteristic parameter method is therefore believed to be correct.In the light of the characteristic parameter method, we have developed further two thermo-kinetic methods, the thermoanalytical single and multi-curve methods, which are convenient for simultaneous determination of the reaction order and the rate constant. The reaction orders and rate constants of the saponifications of ethyl acetate and ethyl butyrate and the ring-opening reaction of epichlorohydrin with hydrobromic acid were determined with these methods, and their validity was verified by the experimental results.
Authors:S.-J. Tian, G.-X. Xi, Q.-T. Cheng, X.-D. Lou, and J.-H. Li
The inclusion complex of benzaldehyde (BA) with β-cyclodextrin (β-CD) was prepared and was studied by thermal analysis and
X-ray diffractometry. The composition of the complex was identified by TG and elemental analysis as β-CDBA9H2O. TG and DSC studies showed that the thermal dissociation of β-CDBA9H2O took place in three stages: dehydration in the range 70-120C; dissociation of β-CDBA in the range 235-270C; and decomposition
of β-CD above 280C. The kinetics of dissociation of β-CDBA in flowing dry nitrogen was studied by means of TG both at constant
temperature and at linearly increasing temperature. The results showed that the dissociation of β-CDBA was dominated by a
one-dimensional random nucleation and subsequent growth process (A2). The activation energy E was 124. 8 kJ mol-1, and the pre-exponential factor A 5.041011 min-1.