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Summary

A new mixed C18-SCX SPE column and gas chromatography-mass spectrometry have been used for determination of six β2-agonists residues in pig's liver. After hydrolysis, the six β2-agonists were extracted with 6:4 (v/v) ethyl acetate-isopropanol and then cleaned on a commercial mixed-adsorbent solid-phase extraction column. The eluted solution was analyzed by gas chromatography-mass spectrometry (GC-MS) and quantified by the external standard method. Sample pre-treatment and GC-MS conditions were critically examined. The linear range was 0.005–2.00 mg L–1 and correlation coefficients were 0.9987–1.000. The LOD of mabuterol, clenbuteroland, and salbutamol was 0.2 μg kg–1. Average recoveries of these three compounds from spiked pig's liver ranged from 65.3 to 95.8% and relative standard deviations were between 5.4 and 9.9%. The LOD of cimaterol, bromobuterol, and ractopamine was 0.3 μg kg–1. Average recoveries of these three compounds from spiked pig's liver ranged from 63.8 to 88.1% and relative standard deviations were between 5.0 and 9.7%. These results indicate the method is highly sensitive, simple, inexpensive, and results in good purification. It could also meet requirements for analysis of pig's urine in domestic and import/export inspection work.

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Based on the known GA20-oxidase (GA20ox) cDNAs of barley and wheat, oligonucleotide primers were designed to isolate GA20ox genes from genomic DNA of Dasypyrum villosum. A total of 19 clones were obtained. Each of them contained an open reading frame encoding a putative 40-KDa protein of 359 amino acid residues. Twenty-one SNPs and 4 InDels were found and could divide the 19 sequences into 2 classes, designated as DvGA20ox-1 and DvGA20ox-2, respectively. Q-PCR analyses showed that both DvGA20ox-1 and DvGA20ox-2 were in leaf blade, leaf sheath, stem, eustipes, root and developing spike. Similar expression levels were found between DvGA20ox-1 and DvGA20ox-2 in three stages. The total expression levels of DvGA20ox-1 and DvGA20ox-2 presented downtrend in leaf blade and ascend in stem, eustipes and developing spike along with the development of plants, respectively. However, they were firstly increased and then decreased in root from seeding stage to heading stage. These results revealed that the gene expression profile of DvGA20ox-1 and DvGA20ox-2 closely related to the growth and development of D. villosum.

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Abstract

High-performance liquid chromatography with a hydrophilic-interaction liquid chromatographic (HILIC) column has been successfully used to retain and separate the polar phosphonic herbicides glyphosate and glufosinate. Online electrospray tandem ion-trap mass spectrometric and DAD detection were used. The effects on the separation of mobile phase acetonitrile content, buffer concentration, and flow rate, and of column temperature, were investigated. With UV-visible detection at 195 nm, LOQ were <850 mg kg−1, showing the method is suitable for product quality control of these herbicides alone or in combination. Tandem mass spectrometric conditions were optimized for ion-trap detection. Quantification was by use of selected reaction monitoring transitions m/z 168 → 150 in negative-ion mode for glyphosate and m/z 182 → 136 in positive-ion mode for glufosinate. Limits of detection (LOD; S/N > 3) were 0.20 and 0.16 ng for glyphosate and glufosinate, respectively, and the respective limits of quantification (LOQ; S/N = 10) were 0.02 and 0.05 mg kg−1. Sample derivatization was not necessary to achieve low detection limits in residue analysis in this study. Recovery from watermelon, spinach, potato, tomato, radish-root, and water fortified with the herbicides ranged from 63.6 to 107.3% and relative standard deviations were <15.3%.

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Plant-plant interaction plays a key role in regulating the composition and structure of communities and ecosystems. Studies of plant-plant interactions in forest ecosystems have mainly concentrated on growth effects of neighboring plants on target trees. Physiological effects of neighboring plants on target trees, in particular understorey effects on physiology of overstorey trees, have received less attention. It is still unclear what is the physiological mechanisms underlying positive growth effects of understorey removal, although understorey removal has been applied to improve the wood production for hundreds of years worldwide. Only 17.5% of published works dealt with understorey-overstorey interactions and only a few of those researched the understorey effects on the physiology of overstorey trees. Case studies indicated that overstorey Abies faxoniana trees grown with different understorey shrubs showed significantly different levels of tissue nitrogen and mobile carbohydrates. Removal experiment showed that nitrogen and mobile carbohydrates concentrations in Cunninghamia lanceolata trees grown in the absence of understorey shrubs differed significantly (pure stand > mixture) with those in trees grown in the presence of understorey shrubs, in particular during the dry season. This review highlighted that the neighboring woody plants affect Cand N-physiology in overstorey trees. These effects may be mainly resulted from underground competition for soil water rather than for other resources as the effects were more pronounced during the dry season. The present review suggests that positive effects of neighboring removal (e.g., understorey removal, thinning) on overstorey trees can be expected more rapidly and strongly in stressful area (e.g., low rainfall, nutrient-poor site) than in areas with optimal growth conditions. Hence, ecophysiology-based management strategies for dealing with neighboring plants in forest ecosystems should take into account: 1) site conditions, 2) timing, duration and frequency of management practices, and 3) species-specific properties and other aspects such as biodiversity conservation and soil erosion.

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Summary

Dithiocarbamates fungicides (DTCs) are worldwidely used fungicides. Residue analytical methods on DTCs are usually based on headspace gas chromatography, which are not much stable and precise. In this study, a specific, simple and reliable method for determining DTCs fungicides residues was optimized and validated. The DTCs in foods and soils were extracted with an alkaline solution of EDTA and l-cysteine, followed by pH adjusting and methyl derivatization in methyl iodine solution. The organic layer of the reactants was separated, concentrated under vacuum and reconstructed in acetonitrile. DTCs residues were eluted on a C18 column and detected by HPLC-DAD at 272 nm. The S-alkyl derivatives of thiram, mancozeb and propineb were separated at different retention times. At fortified levels of 0.05 mg/kg to 2 mg/kg (residue expressed as CS2, in mg/kg, the same below), it is found that recoveries for DTCs spiked in apple, cucumber, tomato, rice and soil samples ranged from 70.8% to 105.3%, with relative standard deviations (RSD) from 0.6% to 13.7%. Limits of detection (LODs) and quantification (LOQs) ranged from 0.003 to 0.026 mg/kg and from 0.011 to 0.105 mg/kg for various foods and soils. This method was also applied to real sample tests.

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Abstract  

The iron contents in the hair and blood samples of 37 juvenile athletes who were supplemented with 0, 8 and 16 mg Fe/day, respectively, in the food of ferrous gluconatecontaining chocolate for 3 months were determined before and after the supplementation by INAA, SRXRF and blood analysis. The experimental results showed that after supplementation of the iron-fortified food, the normal ferritin level in the blood of the male athletes was attained and the iron content in the hair was increased with supplementation, but both are not in the positive proportion. Most of the female athletes had similar results. It is suggested that supplementation of 8 mg iron/day to juvenile athletes may be desirable.

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Cereal Research Communications
Authors: N. Zhang, R.Q. Pan, J.J. Liu, X.L. Zhang, Q.N. Su, F. Cui, C.H. Zhao, L.Q. Song, J. Ji, and J.M. Li

Plants with deficiency in Gibberellins (GAs) biosynthesis pathway are sensitive to exogenous GA3, while those with deficiency in GAs signaling pathway are insensitive to exogenous GA3. Thus, exogenous GA3 test is often used to verify whether the reduced height (Rht) gene is involved in GAs biosynthesis or signaling pathway. In the present study, we identified the genetic factors responsive to exogenous GA3 at the seedling stage of common wheat and analyzed the response of the plant height related quantitative trait loci (QTL) to GA3 to understand the GAs pathways the Rht participated in. Recombinant inbred lines derived from a cross between KN9204 and J411 with different response to exogenous GA3 were used to screen QTL for the sensitivity of coleoptile length (SCL) and the sensitivity of seedling plant height (SSPH) to exogenous GA3. Two additive QTL and two pairs of epistatic QTL for SCL were identified, meanwhile, two additive QTL and three pairs of epistatic QTL for SSPH were detected. For the adult plant height (PH) investigated in two environments, six additive QTL were identified. Three QTL qScl-4B, qSsph-4B and qPh-4B were mapped in one cluster near the functional marker Rht-B1b. When PH were conditional on SSPH, the absolute additive effect value of qPh-4B and qPh-6B were reduced, suggesting that the Rhts in both two QTL were insensitive to exogenous GA3, while the additive effect values of qPh-2B, qPh-3A, qPh-3D and qPh-5A were not significantly changed, indicating that the Rhts in these QTL were sensitive to exogenous GA3, or they were not expressed at the seedling stage.

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