共查询到20条相似文献，搜索用时 583 毫秒
1.
2.
以菊芋叶为原料,以料液比、乙醇浓度、超声时间、超声功率为考察因素,在单因素试验的基础上,通过响应面设计优化菊芋叶多酚的提取工艺,并探究菊芋叶多酚的体外抗氧化活性.结果表明,菊芋叶多酚的最佳提取条件为:料液比1:20(g/mL),乙醇浓度50％,超声时间50 min,超声波功率500 W,在该条件下多酚得率为31.923 mg/g.抗氧化试验表明:菊芋叶多酚具有明显的抗氧化活性,对DPPH自由基(DPPH·)、羟基自由基(·OH)和超氧阴离子自由基(O2·)有较好的清除能力;与VC的抗氧化活性相比,菊芋叶多酚对O2·的清除作用明显高于VC. 相似文献
3.
核桃青皮多酚的抗氧化性研究 总被引：3，自引：0，他引：3
通过体外抗氧化体系对核桃青皮多酚的抗氧化能力进行研究。结果表明,核桃青皮多酚在各体系中均有一定的抗氧化性能,并且其抗氧化能力随着浓度的增加而增强;在所选浓度下,核桃青皮多酚对DPPH自由基和过氧化氢的清除能力、对三价铁离子的还原能力均明显强于VC。当其质量浓度高于10 mg/L时,核桃青皮多酚对羟基自由基的清除作用强于VC对超氧阴离子自由基的清除作用;当其质量浓度低于22.3 mg/L时,核桃青皮多酚对超氧阴离子自由基的清除力强于VC对超氧阴离子自由基的清除作用。 相似文献
4.
《农产品加工．学刊》2016,(3)
采用热水浸提法分别在不同提取温度(40,60,80,100℃)下提取得到4种蛤蒌叶粗多糖,并测定其总多酚和蛋白质的含量。然后测定4种粗多糖对羟基自由基、DPPH自由基和超氧阴离子自由基的清除能力,以及粗多糖的还原能力来评价提取温度对其抗氧化活性的影响。结果显示,蛤蒌叶粗多糖中总多酚和蛋白质的含量随着提取温度的升高而下降。提取温度在40~100℃内,随着提取温度的升高,蛤蒌叶粗多糖对羟基自由基、DPPH自由基和超氧阴离子自由基的清除能力均呈下降趋势,而提取温度对其还原能力的影响没有明显差别。结果表明,提取温度对于蛤篓叶粗多糖的抗氧化活性有显著影响,主要是通过影响粗多糖中的总多酚和蛋白质含量来影响其抗氧化活性。 相似文献
5.
研究了白骨壤叶的水浸提工艺,并采用邻苯三酚自氧化法、水杨酸法、DPPH法,分别测定了白骨壤叶水提液清除超氧阴离子自由基、羟自由基和DPPH自由基的能力。结果表明,水浸提白骨壤叶的最适工艺条件为:料液比1∶25(g∶mL),温度50℃,时间120min,提取率8.14%。白骨壤叶水提液对超氧阴离子(·O2)-、羟基自由基(·OH)及DPPH·自由基均有一定的清除活性,且与其浓度呈正相关,其IC50分别为1.16,1.42,2.27mg/mL,因此白骨壤叶水提液具有一定的体外抗氧化活性。 相似文献
6.
以蓝莓为原料,在单因素试验的基础上,通过正交试验优化果胶酶辅助提取蓝莓多糖工艺,并研究了所提取蓝莓多糖的抗氧化能力。结果表明,正交试验优化蓝莓多糖最佳提取工艺为:果胶酶添加量0.5%,pH 4.0,提取温度60℃,提取时间1.5 h,获得的多糖得率为2.721%;采用果胶酶辅助提取的蓝莓多糖具有抗氧化活性,清除超氧阴离子、羟自由基的能力较强,清除率分别为52.54%和42.60%,对DPPH自由基也有一定的清除力,清除率为13.49%。 相似文献
7.
8.
研究了3种不同溶剂体系提取菜籽饼中植酸粗提液的体外抗氧化性能力。通过Fenton反应体系产生羟自由基(.OH),由连苯三酚在碱性溶液中自氧化反应产生超氧阴离子自由基(O2-.);用分光光度法检测3种植酸粗提液的还原能力及对.OH、O2-.和DPPH.的清除作用。结果表明,3种溶剂提取得到的植酸粗提液都具有还原能力;对羟自由基、超氧阴离子自由基、DPPH自由基也有一定的清除能力。 相似文献
9.
发芽糙米抗氧化性质的研究 总被引：1，自引：0，他引：1
以超声波—微波辅助乙醇提取法和乙醇提取法比较糙米发芽前后总多酚的变化。并对糙米和发芽糙米的多酚提取物进行羟基自由基清除能力、超氧阴离子清除能力、总还原力及油脂的抗氧化性质进行研究。结果表明,超声波—微波辅助乙醇提取法优于单纯的乙醇提取法,总多酚提取率提高了1.43倍。发芽糙米清除羟基自由基效果比糙米原料高40%;超氧阴离子清除能力比糙米原料高24.34%;还原能力比原料糙米高1.84倍,对延缓植物油脂的酸败效果明显好于原料糙米。 相似文献
10.
利用超声波法提取野生薄荷精油,针对总抗氧化能力、超氧阴离子自由基清除能力、羟基自由基清除能力及DPPH自由基清除能力薄荷精油的抗氧化活性进行研究,同时与合成抗氧化剂没食子酸丙酯(PG)的抗氧化性进行比较分析.结果表明,新疆伊犁野生薄荷精油是一种天然的抗氧化剂,并呈现一定的量效关系,其抗氧化能力在各方面均比人工合成的抗氧化剂PG要弱,对清除DPPH自由基的能力远不如人工合成的抗氧化剂PG,而在对清除超氧阴离子自由基能力和清除羟基自由基能力上具有显著的能力与效果. 相似文献
11.
Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts 总被引：7，自引：0，他引：7
Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed. 相似文献
12.
C. J. Spurr D. A. Fulton P. H. Brown R. J. Clark 《Journal of Agronomy and Crop Science》2002,188(4):275-280
Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality. 相似文献
13.
Jens Jensen 《Euphytica》1979,28(1):47-56
Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans. 相似文献
14.
G. H. Kroon 《Euphytica》1994,76(1-2):125-125
Summary
K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes. 相似文献
15.
Hongyan WEI Jian ZHOU Jinguang LU Jingzheng SONG Qiongxi YU Zhihong JIANG 《Medicinal Plant》2019,(6):27-29
[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol... 相似文献
16.
Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed. 相似文献
17.
Summary Reactions of 13 grasses to Meloidogyne naasi varied with species; ryegrasses, fescues and their hybrids were generally susceptible and cocksfoot and timothy resistant. Marked variation in host resistance levels occurred between genotypes within cultivars.Selection of single plants, followed by tests on replicate tillers, identified resistant and susceptible genotypes in both Italian and perennial ryegrass cultivars. Resistant plants had few nematode-induced galls and fewer females and eggs than susceptibles. There was more or less continuous variation, with many genotypes intermediate between extremes of resistance and susceptibility. Selected resistant and susceptible genotypes are of use in assessing variation in nematode populations and as controls for breeding and selection programmes. 相似文献
18.
W. Erskine M. Tufail A. Russell M. C. Tyagi M. M. Rahman M. C. Saxena 《Euphytica》1993,73(1-2):127-135
Lentil production is limited by lack of moisture and unfavorable temperatures throughout its distribution. Waterlogging and salinity are only locally important. Progress has been made in breeding for tolerance to drought through selection for an appropriate phenology and increased water use efficiency and in breeding for winter hardiness through selection for cold tolerance.The diseases rust, vascular wilt, and Ascochyta blight, caused by Uromyces viciae-fabae, Fusarium oxysporum f. sp. lentis, and Ascochyta fabae f. sp. lentis, respectively, are the key fungal pathogens of lentil. Cultivars with resistance to rust and Ascochyta blight have been released in several countries and resistant sources to vascular wilt are being exploited. Sources of resistance to several other fungal and viral diseases of regional importance are known. In contrast, although the pea leaf weevil (Sitona spp.) and the parasitic weed broomrape (Orobanche spp.), and to a lesser extent the cyst nematode (Heterodera ciceri), are significant yield reducers of lentil, no sources of resistance to these biotic stresses have been found. Directions for future research in lentil on both biotic and abiotic stresses are discussed. 相似文献
19.
Mohammed Riyazaddin Polavarapu B. Kavi Kishor Are Ashok Kumar Belum V. S. Reddy Rajendra S. Munghate Hari C. Sharma 《Plant Breeding》2015,134(4):423-436
Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums. 相似文献
20.
Herbage yield trials are necessary to test if candidate varieties are well suited for organic conditions. In order to elucidate
a particular suitability for organic conditions, we run such trials in parallel under both organic and conventional conditions.
Here, we report on second and third year results of the sowings 2004 and 2005. These trials are part of a targeted breeding
programme for organic conditions. Irregular colonisation of pure grass plots with adventitious plants, in particular white
clover, was recognized as a major constraint to the quality of the results obtained under organic conditions. The coefficients
of variance in dry matter yield almost doubled when compared to conventional trials, and significant differences in annual
yield among varieties were rare. However, when herbage yield was corrected for the estimated fraction of adventitious plant
colonization at each cut, the number of instances with statistically significant differences for annual yield among varieties
increased more than fourfold. Dry matter yields under organic and conventional conditions were significantly and positively
correlated. However, analysis of variance showed a significant culture type by variety interaction for annual dry matter yield
in 12 out of 24 trials. When diploid and tetraploid varieties of the same Lolium species were tested in one common trial, only tetraploid varieties were identified as being particularly well suited for organic
conditions, while in these trials, the great majority of apparently poorly suited varieties were diploid. This suggests that
breeding tetraploid Lolium varieties is promising when aiming at a favourable response to organic agriculture. 相似文献