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排序方式: 共有194条查询结果,搜索用时 15 毫秒
1.
建立了同时测定干菊花中5种防腐剂的高效液相色谱分析方法,优化后的色谱条件为采用Waters XTerra C18色谱柱(3.9 mm×150 mm,5μm)分离,流动相为乙酸水溶液(0.1%)/甲醇梯度洗脱,用二极管阵列检测器在波长254 nm处进行检测。结果表明,5种防腐剂在18 min内可获得较好的分离效果,在0.1~20.0 mg/L范围内线性关系良好(r≥0.999 8),检出限为0.001 5~0.059 0 mg/L,定量限为0.005 0~0.196 8 mg/L,加标回收率为85.9%~97.8%,RSD为0.5%~12.5%。该方法操作简单、灵敏度高、重复性好,可用于检测干菊花中防腐剂。 相似文献
2.
Simultaneous selection for seed and forage production in cocksfoot (Dactylis glomerata): application of drought tolerance and susceptibility indices
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An experiment was conducted to estimate drought tolerance of some cocksfoot genotypes based on seed and forage yield and related indices (including tolerance index, mean productivity, geometric mean productivity, reduction percentage index, stress tolerance index and stress susceptibility index) and to identify relationships between measured traits. Twenty‐five genotypes were evaluated in the field under control and drought‐stress environments over 2 years. The results revealed a high variation for seed yield and forage yield and the measured indices under both moisture conditions. No correlation was observed between seed yield and forage yield under the control treatment, but this correlation was positively significant under the water‐stress treatment. Drought‐tolerant and susceptible genotypes were identified based on seed and forage yield performance. Genotypes 2, 4 and 7 had high seed yield, while genotypes 7 and 10 had high forage yield under both stressed and non‐stressed conditions and were identified as the most tolerant genotypes in each category. The results also revealed that genotypes 1, 2, 4, 6, 7, 8 and 24 had relatively high seed and forage yield in both control and drought‐stressed conditions. These genotypes can be used for further studies to improve both seed and forage yields concurrently. 相似文献
3.
Detection of seven phytohormones in peanut tissues by ultra-highperformance liquid chromatography-triple quadrupole tandem mass spectrometry
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Development of highly sensitive and reliable method for detection of phytohormones is of great significance to study plant hormones and agricultural production.In this study,an ultra-high-performance liquid chromatography-mass spectrometry/mass spectrometry method was established for separation and quantification of trans-zeatin,trans-zeatin riboside,gibberellin A_3,indol-3-acetic acid,salicylic acid,abscisic acid,and jasmonic acid(JA) without any label.The sepa ration was performed on an Agilent Explus Plus C18 column by using methanol and water as mobile phases with gradient elution.The target compounds were confirmed and quantified by mass spectrum via positive electrospray ionization for trans-zeatin,transzeatin riboside,indole-3-acetic acid,and via negative electrospray ionization for gibberellin3,salicylic acid,abscisic acid,and JA.The limits of detection ranged from 0.0127 ng L~(-1) for gibberellin A_3(GA_3) to 33.26 ng L~(-1) for JA and were lower than the currently reported values in literature.The proposed method was applied for qualitative and quantitative analyses of phytohormones in peanut gynophores and pods.The recoveries of the spiked phytohormones ranged from 80.20 to102.56%.The contents of seven endogenous hormones varied specifically in different development stages of peanuts.This study provides a highly sensitive and selective detection method for hormones and elucidates the growth and development of the gynophore and peanut fruit,which are controlled by seven endogenous hormones. 相似文献
4.
5.
The quality and safety of agricultural products is the technique focus of the strategy of rural vitaliza⁃tion. Carbamate pesticide residues are seriously threatening the safety of agricultural product and human life and health. Nowadays, the common detection methods are instrument-based for carbamate pesticide residue, which dis⁃ satisfy the request of an on-site rapid, sensitive and simultaneous detection for multiple carbamate pesticide resi⁃ dues. Based on the home-made monoclonal antibodies against carbofuran and carbaryl respectivity, a microarray for rapid and simultaneous detection of multiple carbamate pesticide residues was developed within 30 min. Under the optimized conditions, the limits of detection(LODs)were found to be 0.11 and 0.09 ng/g, while the linear ranges were 0.33-3000 and 0.18-1500 ng/g for carbofuran and carbaryl respectively. By using spiked peanut samples, it recorded recoveries of 88.4%-98.3%, 90.1%-118.8% for carbofuran and carbaryl respectively. The RSD of intraarray were found at 9.0%, 3.5%, while the RSD of inter-array were recorded at 12.3%, 16.3% respectively. The de⁃
tection results of the microarray were highly consistent with that of HPLC-MS/MS. This proposed microarray provid⁃ ed an on-site high-sensitivity, simultaneous and rapid detection of carbofuran and carbaryl, and could be widely used in the fields of agricultural product quality safety, food safety and environmental monitoring. 相似文献
6.
Simultaneous flowering caused a gregarious dieback of umbrella bamboo (Fargesia murielae) all over the world in 1993–2000. Mountain Shennongjia in Central China’s Hubei Province is the only native home of umbrella
bamboo, where it dominates the understorey of the farges fir (Abies fargesii) forest between 2 400 and 3 100 m, covering the ground for more than one century before a periodically flowering death. Data
from 20 quadrats along a vegetation sequence revealed that the density, coverage, and height of umbrella bamboo negatively
affected the species richness, diversity, and evenness of vascular plants in the forest. Local climax community of fir-bamboo
was the poorest in species diversity, while the bamboo-free communities (i.e. shrubs and meadows) were bearing a higher species
diversity. The simultaneous dieback of umbrella bamboo is an ecological release, which can periodically promote the plant
diversity in the fir forest. 相似文献
7.
8.
介绍了四轴WEDM机床的结构和坐标系统,在分析了四轴WEDM机床运动的基础上,提出了一种在等锥度和变锥度情况下均适用的四轴运动控制方法。通过这一方法,由工件下表面加工轨迹和锥度角推导出工作台和上导丝嘴的运动轨迹,并应用于四轴WEDM机床计算机数控系统中。实验证明该方法正确有效。 相似文献
9.
Frew Mekbib 《Euphytica》2003,130(2):147-153
An experiment was undertaken to determine the stability of seed yield in 21 common bean genotypes representing three growth
habits. Seven genotypes in each growth habit (determinate bush, indeterminate bush and indeterminate prostrate) were evaluated
in replicated trials at three locations for three years under rain fed conditions in Ethiopia. A combined analysis of variance,
stability statistics and rank correlations among stability statistics and yield-stability statistic were determined. The genotypes
differed significantly for seed yield and genotype × environment (year by location) interaction (GE). The different stability
statistics namely Type1, Type 2 and Type 3 measured the different aspects of stability. This was substantiated by rank correlation
coefficient. There were strong rank correlations among Si
2d, Wi
2,σi
2 and Si
2, where as there was weak correlation between biand Ri
2, Si
2d, Wi
2, σi
2 and Si
2. R2 was significantly and negatively correlated with Wi
2, σi
2 and Si
2. σi
2 is significantly correlated with Wi
2.Yield is significantly correlated with bi and Ri
2.None of the statistics per se was useful for selecting high yielding and stable genotypes except the YS(yield-stability statistic). Most of the high yielding
genotypes were relatively stable. Of the 21 genotypes, only 11genotypes were selected for their high yielding and stable performance.
Genotypes with growth habit III and I (in determinate prostrate and determinate bush) were generally more stable than in determinate
bush.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
CHEN Mei-xia CHEN Xue-sen WANG Xin-guo CI Zhi-juan LIU Xiao-li HE Tian-ming ZHANG Li-jie 《中国农业科学(英文版)》2006,5(11):879-884
Volatile constituents in fully mature fruits of apricot (Prunus armeniaca L.) cultivar Xinshiji were extracted using headspace solid-phase microextraction (HS-SPME) and simultaneous steam distillation extraction (SSDE) and then analyzed using capillary gas chromatography and gas chromatography-mass spectrometry. A total of 70 components were identified by HSSPME, including 20 esters, 19 hydrocarbons, 5 alcohols, 5 ketones, 4 acids, 4 lactones, 3 aldehydes, and 10 miscellaneous components, with the esters being the dominant constituent. On the basis of the odor unit values, it is believed that the following compounds probably contributed to the fresh apricot odor: hexyl acetate, β-ionone, butyl acetate, (E)-2-hexenal, linalool, limonene, γ-decalactone, and hexanal. A total of 49 components were also detected by SSDE, including 13 hydrocarbons, 9 alcohols, 7 aldehydes, 9 esters, 4 ketones, 4 lactones, 2 acids, and 1 miscellaneous component, of which the monoterpene alcohols were the dominant constituents. It could be judged from the odor unit values that the following compounds were the major contributors to boiled apricot aroma: β-ionone, linalool, hexyl acetate, γ-dodecalactone, γ- decalactone, (E)-2-hexenal, hexanal, γ-octalactone, phenylacetaldehyde, butyl acetate, limonene, α-terpineol, and δ-decalactone. The results show that HS-SPME is a simple, rapid, and solvent-free method, which is an alternative to the classical SSDE. 相似文献