响应面分析法优选大蒜中总黄酮的提取工艺

以大蒜为研究对象,以大蒜中总黄酮的提取率为衡量提取工艺的指标,探讨乙醇体积分数、液料比、超声时间、超声功率4个因素对大蒜中总黄酮提取率的影响。在单因素试验结果的基础上,利用响应面中心组合法设计试验方案,以总黄酮提取率为响应值,建立数学模型并验证得到大蒜总黄酮提取工艺的优化组合为乙醇体积分数58%,超声时间40 min,液料比45∶1,超声功率350 W,此条件下总黄酮的提取率为2.132 mg/g。与有机溶剂提取法相比,超声辅助法提取大蒜总黄酮的提取率较高,响应面中心组合法可以优化提取工艺条件,为大蒜中总黄酮的提取提供一定理论依据。     

响应面法优化牛蒡根总黄酮超声波提取工艺

以新鲜牛蒡根为原料,采用超声波辅助提取牛蒡根中总黄酮,在单因素试验基础上,采用Box-behnken试验设计和响应面分析法,探讨料液比、提取温度、乙醇体积分数和提取时间对牛蒡根总黄酮提取率的影响。结果表明,优化的牛蒡根总黄酮超声波法提取工艺为乙醇体积分数61%,料液比1∶23 (g∶m L),提取温度60℃,提取时间59 min,在此条件下总黄酮提取率为27.96 mg/g。     

全缘叶绿绒蒿总黄酮和总生物碱的提取工艺研究

采用响应面法和正交试验法,优化全缘叶绿绒蒿中总黄酮和总生物碱的提取工艺.结果表明,响应面法优化全缘叶绿绒蒿总黄酮的提取条件:乙醇体积分数60％、液料比25:1(mL:g)、提取时间1.5 h;正交试验法优化总生物碱的提取条件:超声功率120 W、温度40℃、液料比30:1(mL:g).建立的全缘叶绿绒蒿中总黄酮和总生物...     

超声波—乙醇萃取辣椒叶中总黄酮的研究

利用超声波与乙醇提取相结合的方法对辣椒叶中总黄酮的提取工艺进行了研究。在单因素试验的基础上,采用正交试验法确立适宜的提取条件,考察了乙醇体积分数、提取温度、提取时间和料液比,对辣椒叶中总黄酮提取量的影响。超声波法提取辣椒叶的优选工艺条件为:在pH值6.5下,超声波功率为45 kHz,料液比为1∶30,乙醇体积分数为50%,在50℃下萃取30 min,可使总黄酮含量达到最大值13.90 mg/g。     

微波辅助提取山楂叶黄酮的试验研究

利用微波辅助提取山楂叶中总黄酮,并对其提取工艺做出优化。选取微波时间、微波功率、液固比3个影响提取效果的因素进行单因素试验,并以总黄酮提取量为指标,利用Design-Expert 8进行响应面分析试验。结果表明,微波辅助提取山楂叶中总黄酮的最佳工艺条件为微波时间120 s,微波功率400 W,液固比33∶1,在此条件下山楂叶总黄酮提取量为7.49 mg/g。     

紫茉莉籽黄酮响应面法优化提取及其抗氧化活性研究

研究旨在采用响应面法优化紫茉莉籽黄酮的提取工艺条件,并对紫茉莉籽黄酮提取物进行体外抗氧化活性评价。在单因素实验的基础上,采用响应面法中的Box-Behnken设计模块,研究料液比、乙醇体积分数、提取时间3个自变量及其交互作用对总黄酮得率的影响,确定最佳提取工艺。通过紫茉莉籽总黄酮对DPPH自由基的清除作用研究其抗氧化活性。结果表明,紫茉莉籽黄酮最佳提取工艺条件为乙醇体积分数75%、料液比1:35(g:mL)、提取时间2 h,在该条件下,紫茉莉籽总黄酮得率达1.736%。紫茉莉籽黄酮对DPPH自由基具有较强的清除作用。响应面法所获得的分析结果可靠,且该法高效、简单,可用作紫茉莉籽黄酮的提取;紫茉莉籽黄酮具有明显的抗氧化活性。     

利用响应面分析法优化山楂多糖的提取工艺

在山楂多糖提取过程中,选取提取时间、提取温度和料液比3个因素进行单因素试验和正交组合设计试验,利用响应面分析法对其提取工艺参数进行优化,获得的最佳工艺条件为:提取时间143min,温度87℃,料液比1∶27.6。在此条件下,山楂多糖提取量最大,实际最大提取量为14.6mg/g,与预测值相符。     

超声微波协同萃取红豆中总黄酮的工艺研究

确定超声微波协同萃取红豆中总黄酮的最佳提取工艺,测定红豆中总黄酮的含量。研究提取时间、微波功率、提取温度、乙醇体积分数、料液比等因素对总黄酮提取率的影响。在进行单因素试验之后,通过正交试验优化超声微波协同萃取红豆总黄酮类化合物的工艺条件。结果表明,对红豆中总黄酮提取的影响程度为乙醇体积分数料液比提取时间微波功率。超声微波协同法提取总黄酮的最佳工艺条件为提取时间30 min,微波功率400 W,提取温度45℃,乙醇体积分数60%,料液比1∶25;提取3次,总黄酮提取量为1.75 mg/g。     

响应面法优化米口袋总黄酮的超声提取工艺

旨在采用超声波辅助法提取米口袋中总黄酮并对工艺进行优化。在单因素实验的基础上,确定料液比、超声温度、超声功率、超声时间4个因素的Box-benhnken的实验设计。以总黄酮的提取率为响应值,采用响应面法优化米口袋总黄酮的提取工艺,建立并分析各因素与指标值的数学模型。最佳工艺参数为:料液比1:40 g/m L,超声温度45℃,超声功率300 W,超声时间60 min,总黄酮提取率理论值为8.08%,实际值为8.22%,相对标准偏差为0.33%。本实验方法具有操作简便、提取时间短和成本低等优点,可为后期米口袋的研究提供理论依据。     

超声联合酶法提取紫花苜蓿总黄酮及其抗氧化性能研究

采用超声联合酶法提取紫花苜蓿总黄酮,利用响应面法对该提取工艺进行优化,并对其提取物进行体外抗氧化活性研究。结果表明,超声联合酶法提取紫花苜蓿总黄酮的最佳工艺为:液料比40:1,超声时间为55min,超声温度为60℃,在此条件下紫花苜蓿总黄酮的提取率达9.928mg/g,与理论值的相对误差为0.40%,相比于其他传统方法,提取量大大提高;此外,紫花苜蓿总黄酮拥有良好的清除DPPH和·OH自由基的能力,其半数清除浓度(IC50)分别为14.31μg/mL及28.23μg/mL。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

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.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

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.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

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.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.