首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
运用高效液相色谱法测定福建参薯类山药资源的尿囊素含量,以检测比较不同参薯类山药资源的尿囊素含量。结果表明:在相同栽培条件下,不同产地山药的尿囊素含量存在一定的差异;采用YMC ODS-AQ色谱柱,尿囊素在0.3~2.1 μg间线性关系良好,回收率为96.4%(RSD=2.4%),精密度良好(RSD=1.2%),样品提取液在10 h内稳定(RSD=2.0%)。该方法简便可靠,可作为山药质量控制的检测手段之一。  相似文献   

2.
为了准确高效地检测土壤交换性铝含量,探寻适宜的检测方法。比较分析了氯化钾交换-中和滴定法、铝试剂法和羊毛铬花青R比色法所测交换性铝的差异性、精密度、准确性和适用性。结果表明,3种方法所测交换性铝无显著性差异。但羊毛铬花青R比色法的精密度优于氯化钾交换-中和滴定法和铝试剂法,羊毛铬花青R比色法平均回收率达99.28%,准确性高于另2种方法。羊毛铬花青R比色法的线性范围在0~0.32 mg/L,对应吸光值范围在0~0.778;铝试剂法的线性范围在0~0.8 mg/L,对应吸光值范围在0.006~0.157;与铝试剂法相比,羊毛铬花青R比色法的线性范围小于铝试剂法,但其吸光值范围大于铝试剂法。羊毛铬花青R比色法显色剂与显色物质吸收峰间隔较远,测定背景干扰小,方法灵敏度较高。羊毛铬花青R比色法检测单个样品的平均用时为4.2 min,检测效率高于另2种方法,且操作简捷,适用性较高。因此,推荐羊毛铬花青R比色法为土壤交换性铝的测定方法。  相似文献   

3.
采用电感耦合等离子体质谱仪(ICP-MS),同时测定了甜菜中12种微量元素的含量.测定结果回收率为91.0%~117.0%,变异系数RSD值为0.29%~2.59%,结果可信度较高.该法精密度高、准确性好、干扰较少、快速简单,可用于质量控制,为食用甜菜中多种元素含量测定提供了方法,为进一步开发和利用红甜菜提供了科学依据.  相似文献   

4.
吉林省普通大豆品种(系)异黄酮含量分析   总被引:2,自引:0,他引:2  
利用超声波法对吉林省26份普通大豆品种(系)大豆异黄酮含量进行HPLC测定.建立了一种HPLC测定大豆籽粒中异黄酮含量的方法.结果表明:异黄酮各异构体在50~1000μmol·L~(-1)范围内线性系数良好,相关系数为0.9998~0.9999;检出限为1.09~2.06 mg·L~(-1),定量限为3.25~6.46 mg·L~(-1);异黄酮各异构体同收率为97.11%~103.31%;相对标准偏差(RSD,n=7)分别为2.03%~4.32%.该方法线性范围广,线性关系好,灵敏度和准确度高,适合于大豆及大豆制品中异黄酮含量的测定.测得吉林省261份普通大豆品种(系)中的异黄酮含量范围1.46~4.97 mg·g~(-1),超过4 mg·g~(-1)的品种(系)有23个,占测定品种(系)总数的8.81%.  相似文献   

5.
建立了高效液相色谱法同时测定鼠曲草中6种黄酮类成分:槲皮素,木犀草素,芹菜素,山奈酚,金丝桃苷,木犀草素-4’-O-β-D-葡萄糖苷含量的方法。样品用80%甲醇超声提取,采用HPLC法检测,色谱柱:Agilent Eclipse XDB C18Column (250×4.6 mm I.D.,5μm);流动相:乙腈-0.1%甲酸梯度洗脱;流速:1.0 mL/min;柱温:30℃;检测波长:360 nm。结果表明,在一定的浓度范围内6种黄酮的浓度与峰面积线性关系良好,相关系数R~2为0. 9997~0. 9999,样品的加样回收率为95. 20%~108. 5%,RSD均≤2. 8%。本方法简便、快捷、精密度高、重现性好,可用于鼠曲草中黄酮类成分的含量测定。研究结果为明确鼠曲草作用的物质基础以及制定质量标准提供很好的依据。  相似文献   

6.
目的建立测定不同年生野山参中人参单体皂苷含量的方法。方法采用高效液相色谱法(HPLC)进行测定,色谱柱为Thermo BDS HypersiL C_(18)柱(250 mm×4.6 mm,5μm),流动相为乙腈-水,梯度洗脱,流速为1.0mL/min,检测波长为203 nm,柱温为40℃,进样量为5μL。结果不同年生野山参中人参单体皂苷的含量为0.1449~6.9259 mg/g,该方法线性良好,r均大于0.9995,具有较高的精密度、稳定性和重复性,平均加样回收率为96.29~98.95%,RSD均小于2%(n=6)。结论本文所建立的含量测定方法简便易行、专属性强、准确可靠,为野山参的基础成分研究提供了参考依据,为野山参的质量控制奠定了基础。  相似文献   

7.
用HPLC法测定菌株S 15发酵液中Zygosporin D(乙酰基细胞松弛素D)的含量。色谱条件为:Kromasil -C18柱(4.6 mm×150 mm, 5 m),柱温25 ℃,流动相乙腈-水(体积比40:60),流速(1.0 mL/min),检测波长(216 nm)。标准曲线回归方程:Y=0.409 03X+1.547 7,r=0.999 8,Zygosporin D回收率为100.5%。实验证明该方法稳定可靠,精密度高,重现性好,简单可行,适用于Zygosporin D的分析检测。  相似文献   

8.
目的建立电感耦合等离子体发射光谱法(inductively coupled plasma atomic emission spectrometry,ICP-AES)同时测定功能农业农产品中钾、钙、铁、镁、锌的方法。方法样品前处理分别采用湿法消解和微波消解,消解液采用电感耦合等离子体发射光谱法进行测定。结果在0.100-10.0 mg/L浓度范围之间呈现良好线性,相关系数r达到0.9999,方法检出限为0.017~0.305mg/L,相对标准偏差RSD为2.5%左右,回收率为97.5%~101.4%之间。结论此方法具有精密度高、稳定性好、回收率高,同时精准测定多个元素等特点,有较好的应用前景。  相似文献   

9.
采用苯酚-硫酸法,测定蛋黄果中水溶性多糖的含量。结果表明:蛋黄果水溶性多糖含量较高,且在5~95 μg/mL的范围内,样品的浓度与吸光度有良好的线性关系,线性回归方程Y=0.009X-0.007 8(r=0.999 3),加标回收率101.8% (n=5,相对标准偏差=1.59% ),蛋黄果水溶性多糖的平均含量为8.66%。  相似文献   

10.
本文报道了气相色谱法测定紫苏油中α—亚麻酸的含量.采用皂化及三氟化硼一甲醇试剂将紫苏油中的脂肪酸甲酯化,以丁二酸二乙二醇聚酯(DEGS)为固定相进行气相色谱分析,用峰面积归一化法定量.结果表明该法快速准确,重现性好,精密度0.08%,平均加样回收率101.31%.  相似文献   

11.
12.
Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.  相似文献   

13.
Marine organisms represent an excellent source of innovative compounds that have the potential for the development of new drugs. The pharmacokinetics of marine drugs has attracted increasing interest in recent decades due to its effective and potential contribution to the selection of rational dosage recommendations and the optimal use of the therapeutic arsenal. In general, pharmacokinetics studies how drugs change after administration via the processes of absorption, distribution, metabolism, and excretion (ADME). This review provides a summary of the pharmacokinetics studies of marine-derived active compounds, with a particular focus on their ADME. The pharmacokinetics of compounds derived from algae, crustaceans, sea cucumber, fungus, sea urchins, sponges, mollusks, tunicate, and bryozoan is discussed, and the pharmacokinetics data in human experiments are analyzed. In-depth characterization using pharmacokinetics is useful for obtaining information for understanding the molecular basis of pharmacological activity, for correct doses and treatment schemes selection, and for more effective drug application. Thus, an increase in pharmacokinetic research on marine-derived compounds is expected in the near future.  相似文献   

14.
Novel food and non-food uses for sorghum and millets   总被引:4,自引:3,他引:4  
Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.  相似文献   

15.
Résumé Fusarium culmorum et, dans une moindre mesure,F. avenaceum, F. sambucinum, Colletotrichum coccodes etCylindrocarpon sp. ont été isolés de tubercules entreposés en atmosphère contr?lée (AC) et atteints de pourriture grave. Des expériences d'inoculation de tubercules avec 10 espèces ou variétés fongiques et conservation en AC à 8 et 10°C ont montré que: 1) les champignons non pathogènes en atmosphère normale (ex.:Cylindrocarpon sp.) le devenaient en AC, 2) ceux qui étaient faiblement pathogènes en atmosphère normale étaient nettement plus virulents en AC (ex.:F. culmorum), 3) les espèces ou variétés virulentes en conditions d'air normales (Fusarium sulphureum etPhoma exigua var.foveata) ne provoquaient pas de pourriture plus grave en AC et leur activité pouvait même être légérement freinée.
Summary The extensive rotting of tubers which occurred during storage trials in controlled atmospheres has led to a mycological and pathological study of the rots. The most frequently isolated species wasFusarium culmorum althoughF. avenaceum, F. Sambucinum, Coletotrichum coccodes and aCylindrocarpon sp. were also present. Tubers of cvs Bintje and Ulla were inoculated with 19 isolates of 10 fungal species or varieties associated with rotting of stored tubers (Table 1). The tubers were incubated at 8 or 10°C in normal or controlled (2% O2:1% CO2, 2% O2:6% CO2, 2% O2:12% CO2, 6% O2:6% CO2) atmospheres and the extent of rotting was determined a month later (Tables 2 and 3 and Fig. 2). Species which were weakly virulent in a normal atmosphere (variousFusarium spp. andPhoma exigua var.exigua) were clearly more aggressive in the controlled atmosphere and this was especially evident in the case ofF. culmorum. Species ot pathogenic in a normal atmosphere under experimental conditions (Colletotrichum coccodes, Cylindrocarpon sp.,Phoma eupyrena) caused rotting in the controlled atmosphere. The two species which were virulent in a normal atmosphere (F. sulphureum andP. exigua var.foveata) were also virulent in the controlled atmosphere and in some cases the extent of rotting was even less. As a general rule, rotting caused by weakly virulent fungi was greater in both cultivars in the controlled than in a normal atmosphere.

Zusammenfassung Eine starke F?ulnis von in Kontrotrollierter Atmosph?re gelagerten Kartoffelknollen veranlasste eine mykologische und pathologische Untersuchung. Der am h?ufigsten isolierte Pilz warFusarium culmorum. F. avenaceum, F. sambucinum, Colletotrichum coccodes undCylindrocarpon sp. wurden ebenfalls bestimmt. Neunzehn St?mme von 10 Pilzsorten oder-Arten welche bei Lagerf?ulnis vorkommen (Tab. 1) wurden auf Knollen der Sorten Bintje und Ulla inokuliert. Die Lagerung wurde bei 8 oder 10°C under Normalbedingungen oder kontrollierter Atmosph?re durchgeführt (2% O2:1% CO2, 2% O2:6% CO2, 2% O2:12% CO2, 6% O2:6% CO2). Der F?ulnisgrad (Abb. 1) wurde nach einem Monat bonitiert. Die Ergebnisse sind in den Tabellen 2 und 3 dargestellt und in der Abb. 2 illustriert. Unter in Normalbedingungen nur schwach virulente Arten (verschiedeneFusarien undPhoma exigua var. exigua) waren deutlich aktiver in kontrollierter Atmosph?re. Dies was besonders der Fall fürF. culmorum. Pilze, die im Versuch unter Normalbedingungen nicht pathogen waren (Colletotrichum coccodes, Cylindrocarpon sp., Phoma eupyrena), haben unter kontrollierter Atmosph?re Sch?den verursacht. Hingegen werden die beiden unter Normalbedingungen sehr pathogenen Arten (F. sulphureum undP., exigua var.foveata), durch kontrollierte Atmosph?re wenig beeinflusst. Es wurde sogar in einigen F?llen eine gewisse Verringerung des F?ulnisbefalls beobachtet. Ganz allgemein haben die getesteten kontrollierten Bedingungen die Entwicklung der Pilzf?ulnis an beiden Kartoffelsorten gef?rdert, speziell durch Pilzarten, welche unter Normal-bedingungen wenig Sch?den verursachen.
  相似文献   

16.
The review of the 2016–2017 marine pharmacology literature was prepared in a manner similar as the 10 prior reviews of this series. Preclinical marine pharmacology research during 2016–2017 assessed 313 marine compounds with novel pharmacology reported by a growing number of investigators from 54 countries. The peer-reviewed literature reported antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral activities for 123 marine natural products, 111 marine compounds with antidiabetic and anti-inflammatory activities as well as affecting the immune and nervous system, while in contrast 79 marine compounds displayed miscellaneous mechanisms of action which upon further investigation may contribute to several pharmacological classes. Therefore, in 2016–2017, the preclinical marine natural product pharmacology pipeline generated both novel pharmacology as well as potentially new lead compounds for the growing clinical marine pharmaceutical pipeline, and thus sustained with its contributions the global research for novel and effective therapeutic strategies for multiple disease categories.  相似文献   

17.
SUMMARY

Vitamin A, iodine, and iron deficiencies affect large numbers of people worldwide. A deficiency of one or more of these micronutrients adversely affects the physical and mental abilities of humans. South Asia contains a high percentage of these individuals, not just because of its large population, but also the prevalence of deficiency is higher there than in many other parts of the world. The reasons for the high rates of deficiency in South Asia are many, but they include inadequate availability of micronutrient-rich foods, sub-optimal dietary habits, and high rates of infection. Across the region, national plans vary from (a) increasing availability of appropriate foods, (b) introducing new dietary behaviors, (c) improving health status, and (d) directly addressing deficiency through intervention programs. The extent to which each of the countries is making progress toward the goals of these plans can help in understanding the priorities for future efforts to address micronutrient malnutrition. This article discusses the adverse effects of micronutrient deficiencies in humans with special reference to South Asia.  相似文献   

18.
Flavonoids-enriched tissues of citrus such as peel, immature fruit and flower are consumed as culinary seasonings, tea ingredients in China for centuries. This HPLC quantitative study on the five citrus flavonoids, naringin, hesperidin, neohesperidin, sinensetin and nobiletin on a wide range of Chinese citrus fruits and several Traditional Chinese Medicinal food ingredients in East China, revealed a great diversity in flavonoid composition. Huyou peel (C. paradisi cv. Changshanhuyou) was found to be the best naringin (3.25%) and neohesperidin (2.76%) source; C. aurantium, a major ingredient of several citrus-related TCM, is also a suitable source of naringin and neohesperidin, and a good juice source for flavanone glycosides; the peel of Wenzhoumiju (C. unshiu) is one of the richest local species in hesperidin (up to 6.25%); Zaoju (C. subcompressa) has the highest content of nobiletin (0.59%), a polymethoxylated flavone. LC-ES-MS analysis of Zanthoxylum genus for flavonoids revealed for the first time the presence of significant amounts (0.74%) of hesperidin in the root of Liangmianzhen (Z. nitidum (Roxb.) DC), a relative of Sichuan pepper, which is a spice widely used in China.  相似文献   

19.
Evolutionary aspects of the trade-off between seed size and number in crops   总被引:1,自引:0,他引:1  
Victor O. Sadras   《Field Crops Research》2007,100(2-3):125-138
Whereas the concept that availability of resources drives seed production is sound in principle, it is incomplete as there are many solutions to the allocation of resources that derive from the trade-off between number and size. This paper examines evolutionary aspects of this trade-off in annual grain crops. The analysis is centred on the working hypotheses that, for a given species and environment, allocation of resources to reproduction involves (H1) high plasticity in seed number, which allows for variable resource availability, and (H2) a relatively narrow range of seed size that results from evolutionary and agronomic selection. Comparisons between crops and fish are used to highlight common evolutionary elements in taxa where parents provide little or no care to their offspring, with the consequence that both number and early survival of offspring, hence fitness of parents, are partially related to embryo size and reserves.

The plasticity of seed number in relation to availability of resources is analysed against the established relationship between offspring number and parent growth rate during critical stages. The notion that seed size is under stabilising selection is analysed against three conditions: (1) mean seed size is conservative for a given species and environment, (2) seed size affects fitness, and (3) seed size is heritable. Databases from published papers were compiled to analyse the relative variability of seed size and number, and the heritability of seed size. Evidence for and against the link between seed size and parental fitness is revised using the Smith–Fretwell model as framework (Am. Nat., 108, 499–506).

The proposal of high plasticity of seed number and narrow variability of seed size resulting from stabilising natural selection is generally consistent with evolutionary and genetic considerations. Agronomic selection may have reinforced natural selection leading to relatively narrow seed size in species such as wheat and soybean, where cultivated types retained high plasticity for seed number. In contrast, selection for one or few inflorescences in crops like sunflower and maize may have morphologically reduced seed number plasticity and increased variability of seed size and its responsiveness to resource availability in relation to their wild ancestors.  相似文献   


20.
Summary

Within the last three decades, the rice-wheat cropping system has triggered, and with time, aggravated soil micronutrient deficiencies in the Indo-Gangetic Plains (IGP). This has largely been due to the shift from an earlier rice and wheat monoculture with low yielding, long duration indigenous varieties, to an intensive rice-wheat rotation cropping system with short duration modern high yielding varieties on the same piece of land. The problems related to micronutrient deficiency in the IGP are more due to the size of its available pools in the soil rather than its total contents and are greatly influenced by crop management, or rather its mismanagement. Deficiency of zinc is widespread in the IGP, but with the extensive use of zinc sulfate, zinc deficiency has reduced in some areas of the region. Meanwhile, the deficiency of Fe, Mn and B has increased in the IGP. Deficiency of Cu and Mo is location specific and can limit rice and wheat yields. The adoption and spread of the rice-wheat system in permeable coarse textured soils, particularly in the western IGP, not only caused iron deficiency in rice but also resulted in the emergence of manganese deficiency in wheat. In highly calcareous and acidic soils, boron is the next limiting micronutrient in crop production after zinc. Bumper rice and wheat harvests in the past decade, the declining use of organic manures in the region and except for the widespread use of zinc sulfate, a general lack of awareness amongst farmers on micronutrient deficiency problems has contributed to micronutrients limiting rice and wheat yields in the IGP. Approaches to alleviating micronutrient deficiencies include matching the crop removals of the micronutrients with its replenishments through their respective external carriers, supplementation through organic sources and mobilization/utilization through cultivation of micronutrient efficient crop cultivars. Identification of efficient micronutrient carriers and finding the optimum rate, mode and time of its application is important in ameliorating the micronutrient deficiencies. This article reviews the extent of micronutrient deficiency and discusses various management options available to reduce micronutrient deficiency induced crop yield reduction for rice and wheat in the Indo-Gangetic Plains.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号