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  • Author or Editor: Z.Y. Chen x
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Abstract  

A procedure for the determination of lead in various biological and environmental samples by203Pb radioisotope dilution substoichiometric method is presented. The accuracy of the method by comparison with the literature values of reference materials appears to be good. The standard deviation of the method is less than 10%, and detection limit is about 0.1 g of lead.

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Abstract  

A method of efficiency calibration for the measurement of 88Kr and 138Xe by HPGe γ-spectrometer is proposed in the present paper. The question for the efficient calibration is, how to achieve homogeneous sources of 88Kr-88Rb and 138Xe-138Cs. The fission product gases were obtained by irradiating a precisely measured amount of U3O8 (90% 235U) filled in a quartz glass ampoule. Source cell was first filled up with stearic acid, and then the fission product gases were charged into it. Xenon and krypton are not adsorbed on stearic acid, therefore, homogeneous sources of 88Kr-88Rb and 138Xe-138Cs can be prepared. The results of the experiment demonstrate that the method is feasible and successful.

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To study the development of starch granules in polyploid wheats, we investigated the expression of starch synthetic genes between the synthetic hexaploid wheat SHW-L1, its parents T. turgidum AS2255 and diploid Ae. tauschii AS60. The synthetic hexaploid wheat SHW-L1 showed significantly higher starch content and grain weight than its parents. Scanning electron microscopy (SEM) showed that SHW-L1 rapidly developed starch granules than AS2255 and AS60. The amount of B-type granule in AS60 was less than that in SHW-L1 and AS2255. RT-qPCR result showed that the starch synthetic genes AGPLSU1, AGPLSU2, AGPSSU1, AGPSSU2, GBSSI, SSIII, PHO1 and PHO2 expressed at earlier stages with larger quantity in SHW-L1 than in its parents during wheat grain development. The expression of the above mentioned genes in AS60 was slower than in SHW-L1 and AS2255. The expression pattern of starch synthase genes was also associated with the grain weight and starch content in all three genotypes. The results suggested that the synthetic hexaploid wheat inherited the pattern of starch granule development and starch synthase gene expression from tetraploid parent. The results suggest that tetraploid wheat could plays more important role for starch quality improvement in hexaploid wheat.

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Abstract  

Thermal behaviour of tri(O,O'-diisopropyldithiophosphate)cobalt(III), Co(dptp)3 and bis (O,O'-diethyldithiophosphate)nickel(II), Ni(detp)2 and its adducts with pyridine, Ni(detp)2(py)2 or 4-methylpyridine, Ni(detp)(mpy)2 in a dynamic nitrogen atmosphere was investigated by TG-DTG and DSC techniques, which showed a medium endothermic peak for the evolution process of pyridine(or 4-methylpyridine) and a strong exothermic peak for that of O,O'-diethyldithiophosphate. The thermal stability and decomposition patterns for these compounds were compared and interpreted in terms of structural features such as bond character and steric effects. The kinetic parameters and mechanisms of every decomposition stage involved for all these complexes were obtained employing the non-isothermal kinetic analysis method suggested by Malek et al., which showed the kinetics mechanism for pyrolysis of pyridine(or 4-methylpyridine) is an S-B empirical model with lower activation energy, while that of O,O'-dialkyldithiophosphate is a diffusion model. These results are in accord with the fact that two ligands are of different type.

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This study aimed to investigate the effects of single local vibration (LV) with and without blood flow restriction (BFR) on muscle activity and hormonal responses. A total of 12 physically inactive males were exposed to 10 sets of intermittent LV (35–40 Hz) on unilateral mid-quadriceps in the supine lying position and LV + BFR (inflated to 140 mmHg) sessions in a repeated-measures randomized crossover design, with a 1-week interval separating the sessions. The results indicated that the electromyography values from the rectus femoris during LV + BFR were greater than those during LV (p < 0.05). LV + BFR caused a minor increase in the lactate (LA) response (p < 0.05); LV with or without BFR failed to elicit change in growth hormone (GH) and testosterone (T) levels (p > 0.05). Cortisol (C) levels were decreased postexercise in both the sessions (p < 0.05). In conclusion, BFR elicited higher increase in muscle activity and metabolic response, but it did not induce hormonal responses. The exposure of LV and LV + BFR may only have a relief effect as detected by the reduction in C levels, probably because the LV did not elicit sufficient stimulus to the muscles.

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Genotypes with various Vp-1B alleles perform different levels of pre-harvest sprouting (PHS) tolerance. In this study, 217 white-grained wheat cultivars, including 75 landraces, 39 historical cultivars, and 103 modern cultivars from five major regions of China, were examined to characterize the diversity of the Viviparous-1B ( Vp-1B ) locus associated with PHS tolerance. Four Vp-1B alleles were identified, three ( Vp-1Ba , Vp-1Bb and Vp-1Bc ) of which were previously reported in Chinese wheat cultivars. A new allele, Vp-1Be , was identified in the PHS tolerant landrace Hongheshangtou. Sequence analysis showed that Vp-1Be had an insertion of a 4-bp fragment, two SNPs, and a deletion of an 83-bp fragment compared with the nucleotide sequence of Vp-1Ba (AJ400713), all located in the third intron. Vp-1Be shared 97.80% similarity with the nucleotide sequence of AJ400713. The frequencies of Vp-1Ba , Vp-1Bb , and Vp-1Bc were 36.0%, 5.3%, and 57.3% in landraces; 23.1%, 7.7%, and 69.2% in historical cultivars; and 52.4%, 0%, and 47.6% in current cultivars, respectively.

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The common wheat line, YW243, developed in our research group, was tested for the resistances of barley yellow dwarf virus (BYDV), powdery mildew (Pm) and stripe rust in field, and was analyzed by molecular markers for convenient trace of the resistant genes in breeding. Genomic in situ hybridization (GISH) analysis and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) assay further demonstrated that YW243 was a homozygous multiple translocation line of Triticum aestivum, Thinopyrum intermedium and Secale cereale (T7DS·7DL-7XL & 1BL·1RS). The disease resistance test and marker analysis showed that YW243 carried seven resistance genes to the three diseases, including Bdv2 to BYDV on 7DL-7XL, Pm4 to powdery mildew on 2AL, Yr2, Yr9, Sr 31 and Lr26 and a new Yr to stripe rust on 7B, 1BL, 1RS and 2BL. Restriction fragment length polymorphism (RFLP) markers Xpsr687 and Xwg380 , sequence tagged site (STS) marker STS 1700 , simple sequence repeat (SSR) markers Xgwmc364 and Xgwm582 , SSR markers Xgwm388 and Xgwm501 can be used as diagnostic tools to track Bdv2, Pm4, Yr2, Yr9 and Yr in YW243 , respectively; and two amplified fragment length polymorphism (AFLP) markers M54E63 - 700 and M54E64 - 699 can also be used to select Yr in YW243 .

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Rht18, derived from Triticum durum (tetraploid) wheat, is classified as a gibberellic acid (GA)-responsive dwarfing gene. Prior to this study, the responses of Rht18 to exogenous GA on agronomic traits in hexaploid wheat were still unknown. The response of Rht18 to exogenous GA3 on coleoptile length, plant height, yield components and other agronomic traits were investigated using F4:5 and F5:6 hexaploid dwarf lines with Rht18 derived from two crosses between the tetraploid donor Icaro and tall Chinese winter wheat cultivars, Xifeng 20 and Jinmai 47. Applications of exogenous GA3 significantly increased coleoptile length in both lines and their tall parents. Plant height was significantly increased by 21.3 and 10.7% in the GA3-treated dwarf lines of Xifeng 20 and Jinmai 47, respectively. Compared to the untreated dwarf lines, the partitioning of dry matter to ears at anthesis was significantly decreased while the partitioning of dry matter to stems was significantly increased in the GA3-treated dwarf lines. There were no obvious changes in plant height and dry matter partitioning in the GA3-treated tall parents. Exogenous GA3 significantly decreased grain number spike–1 while it increased 1000-kernel weight in both the dwarf lines and tall parents. Thus, applications of exogenous GA3 restored plant height and other agronomic traits of Rht18 dwarf lines to the levels of the tall parents. This study indicated that Rht18 dwarf mutants are GA-deficient lines with impaired GA biosynthesis.

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