桃SRAP-PCR反应体系的建立与优化

建立适宜桃基因组DNA的SRAP-PCR扩增体系,为桃基因图谱的构建和分子标记打下基础。以桃基因组DNA为模板,通过正交试验设计,从dNTPs、Mg2+、Taq酶、引物、模板5种因素4个水平对桃SRAP-PCR反应体系进行优化,所建立的体系为25μL:dNTPs为0.12 mmol/L,Mg2+为4 mmol/L,Taq酶2 U,引物为0.3 mmol/L,模板DNA50ng。PCR反应程序为:94℃预变性5 min;94℃变性l min,35℃复性l min,72℃延伸l min,5个循环;94℃变性l min,50℃复性l min,72℃延伸l min,35个循环,72℃延伸10 min。     

龙眼ISSR反应体系的建立和优化

对影响龙眼ISSR－PCR扩增反应的各个参数进行优化,建立适合龙眼的ISSR反应体系：PCR反应体积为20μl,其中模板DNA 25ng,引物0.2μmol/L,dNTP 100μmol/L,Taq DNA聚合酶0.5U,MgCl2 2.5mmol/L,10×PCR缓冲液2.0μl;扩增程序为94℃预变性5min;94℃变性1min,退火温度1min,72℃延伸90s,40个循环;72℃延伸7min     

烟草RAPD反应体系的建立与优化研究

以烤烟品种为材料,研究了烟草RAPD分析过程中的影响因素,包括模板浓度、Mg2+、dNTP、引物、Taq 酶、循环次数、退火温度等,建立了适于烟草RAPD分析的PCR反应体系：即在25μl反应体系中,模板用量为40ng;引物浓度为0.4μM;Mg2+浓度为2.5mM;dNTP浓度为0.2mM;Taq DNA聚合酶用量为1U。扩增程序为94℃预变性5min;然后94℃变性1min,38℃复性1min,72℃延伸1.5min,39个循环;最后72℃延伸5min。     

胡椒SRAP反应体系的建立和优化

建立并优化胡椒SRAP分子标记体系,为海南胡椒属植物亲缘关系和遗传多态性分析、物种和品种鉴定等打下技术基础。利用单因素随机试验对胡椒SRAP-PCR反应体系中各组分（Taq DNA聚合酶、dNTP、模板DNA、引物和Mg2+）的浓度进行优化,同时筛选SRAP-PCR反应的循环数和最适退火温度。通过实验确定了SRAP-PCR反应体系为：反应总体系为20 μL,其中引物0.35 μmol/L,Taq DNA聚合酶1.0 U,dNTP 0.6 mmol/L,Mg2 + 1.5 mmol/L,模板DNA 25~200 ng,同时通过梯度PCR试验,确定引物最佳退火温度;最佳SRAP-PCR反应程序为：94℃预变性5 min;94℃变性30 s,35℃退火30 s,72℃延伸45 s,5个循环;然后94℃变性30 s,48℃退火30 s,72℃延伸45 s,40个循环;最后72℃延伸7 min,4℃保存。SRAP-PCR体系适为胡椒属植物遗传多样性分析奠定了基础,并成功地应用于海南胡椒属植物亲缘关系和遗传多态性分析。     

山杏RAPD反应体系条件的优化

以山杏新鲜叶片为材料,研究了山杏RAPD分析过程中的影响因素,包括Taq酶、Mg2+、dNTP、引物、模板DNA浓度、变性时间、循环次数等,建立了适合山杏RAPD反应的PCR体系,即20μL反应体系中含有Taq酶1.0U、Mg2+ 2.0mM,四种dNTP各0.1mM,引物0.5μM,模板DNA50ng。扩增程序为：94℃预变性4mins;94℃变性1min,36℃退火1min,72℃延伸1.5mins,10个循环;94℃变性30s,36℃退火40s,72℃延伸60s,30个循环;最后72℃延伸5min     

柑桔SRAP和ISSR分子标记技术体系的建立与优化

通过对PCR反应程序、反应体系(DNA模板量、PCR反应体积、Mg2 浓度、dNTP浓度、Taq酶用量、引物量)、电泳检测方法的系统优化,建立了柑桔SRAP-PCR和ISSR-PCR体系;以此进行大规模引物筛选,从而建立了柑桔SRAP和ISSR分子标记技术体系.SRAP-PCR:25μL体系,模板DNA25ng,Tris-HCl10 mmol/L,KCl50 mmol/L,Mg2 1.2 mmol/L,dNTP 120 μmol/L,Taq酶1.5U,引物0.4μmol/L,反应程序为94℃预变性5min,35个循环(94℃ 30s,47℃ 1min,72℃ 1min),72℃延伸10min;ISSR-PCR:25μL体系,模板DNA25ng,Tris-HCl10mmol/L,KCl50mmol/L,Mg2 1.6 mmol/L,dNTP200μmol/L,Taq酶1 U,引物0.8μmol/L.筛选出稳定性好、多态性高的24对SRAP引物和13条ISSR引物.     

实蝇RAPD反应体系的构建与优化

以几种常见的实蝇为材料，研究了实蝇RAPD分析过程中的影响因素，包括模板DNA浓度、dNTP、引物、Taq酶、变性时间、循环次数、退火温度等，建立了适于实蝇RAPD分析的PCR反应体系：在25μl反应体系中，模板DNA用量为80ng，MgCl 2浓度为2.0mM；四种dNTP浓度各为0.2 mM；Taq引物浓度为0.5μM；酶用量为1U；扩增程序：先94℃预变性3min，再94℃变性45s、36℃退火1min、72℃延伸2min共40个循环，最后延伸10min。     

无核葡萄SRAP-PCR反应体系的建立和优化

以大粒无核葡萄‘皇家秋天’的基因组DNA为模板,对无核葡萄SRAP-PCR反应体系的主要成分及反应退火温度进行优化。获得的最优SRAP-PCR反应程序为94℃预变性5 min,94℃变性1 min,38℃复性1 min,72℃延伸1 min,5个循环;94℃变性1 min,56℃复性1 min,72℃延伸1 min,35个循环;72℃终延伸10 min。25 μL体系中,模板DNA 40 ng,Mg2+ 1.5 mmol/L,dNTPs 0.2 mmol/L,引物0.2 μmol/L,Taq DNA聚合酶0.6 U。实验结果表明,优化后的SRAP-PCR反应体系扩增多态性高,带型清晰,稳定性好。     

黄枝油杉ISSR-PCR反应体系的建立与优化

先运用正交设计进行初步筛选,再用单因素设计逐一优化对ISSR-PCR扩增效果有影响的Mg2+、Taq DNA聚合酶、dNTP、引物、模板DNA、循环次数及退火温度.建立了黄枝油杉的最佳反应体系和程序,即25μL体系中含2.0mmol/L的Mg2+、1.5U Taq DNA聚合酶、0.10mmol/L的dNTP、1.0μmol/L的引物、30ng的模板DNA以及2.5μL10×PCR buffer,其余的用灭菌的ddH2O补够25μL.扩增程序:94℃预变性5min;94℃变性30s,48～56℃(不同的引物,其退火温度不同,根据具体引物而定)退火45s,72℃延伸90s,以上3个步骤循环50次;最后72℃延伸7min;扩增产物放在4℃冰箱中保存.该体系和程序稳定性良好,结果可靠,可用于黄枝油杉遗传多样性分析.     

块根紫金牛ISSR-PCR反应体系的建立与优化

采用正交和单因素试验设计方法,研究Mg2+、dNTP、引物、TaqDNA聚合酶、模板DNA、退火温度及循环次数对ISSR-PCR扩增效果的影响,建立块根紫金牛ISSR-PCR反应体系和扩增程序,即25 ul的体系中含Mg2+ 2.0 mmol/L,dNTP0.15 mmol/L,引物1.0μmol/L,TaqDNA聚合酶1.0U,模板DNA50ng,10×Buffer 2.5μl.适宜的扩增程序是94℃预变性5 min,94℃变性30s,56.6℃退火45s,70℃延伸2.0 min;45个循环;72℃延伸7min,4℃保存.采用正交和单因素试验可快速建立ISSR-PCR反应体系.该体系稳定、可靠,可用于块根紫金牛遗传多样性分析.     

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...     

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.     

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.     

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.