枣ISSR扩增体系的建立

以冬枣DNA为研究对象,利用单因素试验,分析了Mg2+浓度、dNTP浓度、Taq酶含量、引物浓度、模板DNA含量以及退火温度对ISSR-PCR扩增的影响,经优化建立了枣属植物最适ISSR-PCR反应体系,25μL反应液中包含1×PCR Buffer、2.0 mmol/L Mg2+、0.25 mmol/L dNTP、1.5 UTaq酶、1.25μmol/L引物和50 ng模板,最适退火温度为58℃。PCR反应体系的建立为应用ISSR标记技术开展枣种群遗传变异分析和构建遗传图谱奠定基础。     

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.     

石斛属植物ISSR扩增体系的建立与优化

旨在建立并优化石斛属植物的ISSR-PCR反应体系。通过对ISSR-PCR反应体系中主要影响因子模板DNA、dNTP、10×PCR Buffer、引物以及Taq DNA聚合酶分别进行单因素优化,最终建立一套适用于石斛属植物的扩增多态性高、稳定性强、带型清晰的ISSR最佳反应体系。20μL反应体系的适宜浓度及用量分别为：模板DNA 10 ng/μL 3μL,dNTP 2.5 mmol/L 1.5μL,10×PCR Buffer 3.0μL,引物4μmol/L 3.5μL,TaqDNA聚合酶5 U 0.2μL。这一优化体系适用于石斛ISSR分析,为今后遗传多样性与亲缘关系分析、连锁图谱构建、QTL定位、基因定位与克隆等方面的研究提供了技术支撑。     

日本沼虾SRAP反应体系正交设计及优化

对影响SRAP反应的4个因素(Taq酶、dNTP、Mg2+、引物)4个水平进行正交组合,以建立日本沼虾的SRAP分子标记技术。试验分两步进行:第一步筛选出可有效扩增的引物组合;第二步对筛选出的体系进行优化。结果表明,日本沼虾SRAP反应体系适宜引物组合为Me4Em2,最适条件为在25μL的反应体系中,Mg2+、dNTP、Taq酶、引物浓度分别为2.5 mmol/L、0.25 mmol/L、0.64 U/20μL、0.6μmol/L。本研究结果为SRAP分子标记技术在日本沼虾中的应用奠定了基础。     

大豆SSR技术反应体系的优化

以大豆为材料,研究了PCR反应体系的主要成分模板DNA浓度、dNTP浓度、引物浓度、Taq酶浓度及退火温度对大豆SSR扩增结果的影响,探索影响SSR扩增结果的各因素的最佳用量及引物的退火温度。结果表明:在试验设计范围内,DNA浓度和dNTP浓度对扩增影响较大,引物浓度在0.05~0.2μmol/L范围内对扩增影响较小,Taq酶浓度对扩增有一定影响,引物要有其扩增适宜的退火温度。确立了适合大豆SSR分子标记研究的优化体系。最终确定总反应体系为20μL,模板DNA 20 ng,dNTP 200μmol/L,引物0.15μmol/L,Taq酶0.5 U,10×Taq Buffer 1.5 mmol/L,ddH2O补至20μL。     

橡胶草及其近缘种ISSR反应体系及扩增程序的优化

本研究旨在建立和优化橡胶草及其近缘种ISSR (Inter-simple sequence repeat)反应体系和扩增程序。以橡胶草及其近缘种叶片为供试材料,采用单因素试验方法,正交试验方法 L16(44)和极差分析方法,对橡胶草ISSR-PCR反应中4个主要影响因素(dNTP浓度, DNA浓度,引物浓度和Taq DNA聚合酶浓度)进行优化,并在最优反应体系的基础上进行引物和退火温度的筛选。结果表明:dNTP和DNA对PCR扩增结果有较为显著的影响,引物和Taq酶的浓度变化对扩增结果无显著影响。最后确定橡胶草及其近缘种ISSR-PCR反应体系(20.0μL)为:双蒸水14.2μL,10×Buffer (含Mg2+) 2.0μL,DNA模板50.0 ng,10 mmol/L引物1.2μL,2.5 mmol/L dNTP 1.6μL,5 U Taq DNA聚合酶0.1μL。PCR扩增程序为:94℃5 min,94℃45 s,退火1 min,72℃70 s,45个循环,72℃10 min,4℃保存。本研究为橡胶草及其近缘种的遗传多样性和交配系统等后续研究提供理论参考。     

马蹄金ISSR反应体系的正交优化

以CTAB法提取的马蹄金叶片DNA为模板,应用L16(45)正交表系统分析了DNA、Mg2+、dNTP、Taq酶、引物5种ISSR反应成分浓度变化对扩增结果的影响。量化分析结果表明:Taq酶、dNTP不同水平对PCR反应结果有显著影响,正交设计可以应用于ISSR-PCR反应体系的建立,用这种方法建立的马蹄金IS-SR优化反应体系为:1×buffer,25ng模板DNA,1.75mmol/LMg2+,225μmol/LdNTP,0.9μmol/L引物,1.25UTaqDNA聚合酶,总体积20μl。这一优化系统的建立为今后利用ISSR标记技术,研究马蹄金的地理变异提供一个标准化程序。     

不结球白菜ISSR反应条件的优化

本文通过单因素试验确定了Taq DNA聚合酶、dNTP、引物和Mg2 4种因素在不结球白菜ISSR反应体系中的适宜浓度范围,并在此基础上利用正交试验设计,从4种因素3个水平对不结球白菜ISSR反应体系进行了优化,确立了适合不结球白菜的ISSR反应体系,并在10个不结球白菜品种中进行了验证.在20 μL反应体系中,含Taq DNA聚合酶1 U、dNTP 0.25 mmol/L、引物0.25 μmol/L、1×PCR buffer、Mg2 2.5 mmol/L、模板DNA 30 ng.通过梯度PCR测验和总循环次数梯度处理试验,确定了适宜的退火温度和总循环数.这一体系的建立为今后利用ISSR技术进行不结球白菜种质资源分类、遗传图谱构建和基因定位奠定了技术基础.     

珍稀植物攀枝花苏铁ISSR扩增条件的优化

在利用ISSR技术对攀枝花苏铁（Cycas panzhihuaensis）种质资源遗传多样性进行研究的实验过程中, 对影响PCR扩增效果的一些因素如DNA的提取、模板DNA质量浓度、Taq酶用量、引物用量、dNTP的用量以及退火温度等指标进行筛选和优化。试验结果表明,20μl的反应体系中采用15~25ng 的模板DNA、2.0~2.5mmol/L的Mg2 + 浓度、0.2mmol/L的dNTPs、0.2μmol/L ISSR 引物、0.2U Tag DNA 聚合酶、48 ℃~55 ℃(退火温度随引物不同而定)的复性温度,以及35个循环数为攀枝花苏铁ISSR—PCR 扩增条件的最佳选择。攀枝花苏铁ISSR—PCR 扩增条件的优化为进行攀枝花苏铁种群间遗传分化的研究奠定了基础。     

苎麻ISSR-PCR体系的优化

ISSR分子标记是在SSR标记基础上发展起来的一种新技术,ISSR标记成孟德尔式遗传,在多数物种中是显性的,目前已经广泛应用于植物品种鉴定、遗传作图、基因定位、遗传多样性、进化及分子生态学当中。笔者以苎麻自交系品种为材料,研究了苎麻ISSR分析过程中的影响因素,包括10×PCRBuffer、模板浓度、Mg2 、dNTP、引物、Taq酶、循环次数、退火温度等,建立了适于苎麻ISSR分析的PCR反应体系:即在20ul反应体系中,引物浓度为1.0umol/L;模板DNA的用量为60～100ng;Mg2 浓度为2.0mmol/L;dNTP浓度为0.2mmol/L;Taq酶用量为1U。适宜的扩增程序为先94℃变性5min,再94℃变性30sec、56℃复性45sec、72℃延伸90sec共34个循环,最后72℃延伸7min,4℃保存。     

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.