西番莲科龙珠果ISSR-PCR体系的建立和优化

为了获得适于龙珠果ISSR-PCR的反应体系,本研究以龙珠果叶片为试验材料,提取基因组DNA,采用L16(45)正交设计试验,对影响龙珠果ISSR-PCR扩增结果的Mg²⁺浓度、dNTPs浓度、Taq DNA聚合酶用量、引物浓度和模板DNA量进行优化,并筛选了最适退火温度。试验结果分析表明,各因素影响显著性为dNTPs浓度>Taq DNA聚合酶用量>Mg²⁺浓度>模板DNA量>引物浓度。在20μL反应体系中,dNTPs浓度0.2 mmol/L、Taq DNA聚合酶0.5 U、Mg²⁺浓度2.0 mmol/L、模板DNA 25 ng、引物浓度0.4μmol/L为最佳用量。实验从100条UBC引物中筛选得到22条多态性较好的引物。本研究为龙珠果ISSR标记开发、种质资源鉴定、遗传多样性分析和分子标记辅助选择育种等提供科学依据。     

新疆野生欧洲李ISSR-PCR反应体系的建立与优化

为建立适合新疆野生欧洲李的ISSR-PCR反应体系,本研究以野生欧洲李为供试材料,采用L₁₆(4⁵)正交试验设计和单因素试验设计相结合的方法,对影响野生欧洲李ISSR-PCR反应体系的5个因素(DNA模板,Taq酶,dNTPs,引物,Mg²⁺)进行筛选与优化,对16条引物的退火温度进行筛选。结果表明,Taq酶对PCR扩增反应的影响最大,野生欧洲李ISSR-PCR最佳反应体系为:总体积20μL,5 U Taq酶0.10μL,10 mmol/L引物1.00μL,2.5 mmol/L dNTPs 1.50μL,10×Buffer(含Mg²⁺)2.00μL,50 ng/μL DNA模板1.00μL,双蒸水14.40μL。建立的ISSR-PCR反应体系经过22份野生欧洲李样品验证,表明反应体系稳定可靠,可用于后续遗传多样性研究,为野生欧洲李种质资源的保护和利用提供理论参考。     

金莲花ISSR-PCR反应体系的建立与优化

为了建立金莲花ISSR-PCR最佳反应体系,本研究以内蒙古自治区境内野生金莲花为试验材料,采用L₁₆(4⁵)正交实验设计,对影响ISSR-PCR扩增结果的dNTPs、Taq DNA聚合酶、DNA模板、Mg²⁺、引物5个因素进行优化筛选,对反应程序进行优化。结果显示,每个因素都具有极显著差异,影响最大的为dNTPs,其余依次为Taq DNA聚合酶、DNA模板、引物,影响最小的为Mg²⁺浓度。最佳反应体系为:DNA模板30 ng,引物0.2μmol/L,Taq DNA聚合酶0.075 U/20μL,dNTPs 0.15 mmol/L,Mg²⁺1.0 mmol/L,反应总体积20μL。最佳扩增程序为:94℃预变性5 min,94℃变性30 s,52℃退火1 min,72℃延伸100 s,最后72℃延伸7 min,共38个循环,4℃保存。采用优化后的体系对金莲花不同居群进行验证,证明优化后体系扩增出明亮清晰的条带且重复性好,可用于后续金莲花遗传多样性分析。     

食用向日葵SSR-PCR反应体系的优化

为建立食用向日葵分子标记反应体系,以食用向日葵四叶期叶片为DNA模板提取材料,采用单因素试验和正交试验设计,对SSR-PCR反应体系中的6因素(10×PCR Buffer、Mg2+、d NTPs、引物、Taq DNA聚合酶和DNA模板)在5水平上进行正交优化试验,并比较了不同浓度Mg2+、Taq DNA聚合酶、模板DNA对扩增效果的影响,结果表明,各因素水平变化对反应体系的影响为Mg2+Taq DNA聚合酶(引物)DNA模板10×PCR Bufferd NTPs。最终建立食用向日葵SSR-PCR最佳反应体系为:在总体系为20μL的SSR-PCR反应体系中包括10×PCR Buffer 0.2mmol/L、Mg2+2.0 mmol/L、d NTPs 1.8 mmol/L、Taq DNA聚合酶0.2 U、DNA 50 ng、引物1.5 mmol/L。     

酥瓜(Cucumis melo var. conomon Group)ISSR-PCR反应体系建立与优化

利用正交设计L_(16)(4~5),对酥瓜ISSR-PCR反应体系的5个影响因素(引物,d NTPs,Taq DNA聚合酶,Mg2+和模板DNA)在4个水平上进行优化试验,并在36℃~56℃范围内摸索退火温度,建立适合酥瓜ISSR-PCR反应体系,结果表明,在20μL反应体系中,含有引物0.2μmol/L、d NTPs 0.3 mmol/L、Taq DNA聚合酶1.2 U、Mg2+1.0 mmol/L、DNA模板70 ng、10×Buffer 2.0μL为最佳反应体系,ISSR-PCR扩增程序中最佳退火温度为52.5℃。该体系为酥瓜种质资源的遗传多样性分析评价提供了帮助。     

刺槐EST-SSR标记PCR反应体系的优化

为建立一套适用于刺槐EST-SSR标记的PCR反应体系,采用L₁₆(4⁵)正交试验设计结合单因素试验,对刺槐EST-SSR PCR反应体系中的5个主要因素：引物、DNA模板、dNTPs、Mg²⁺和Taq DNA聚合酶进行优化试验。结果表明：在20μL反应体系中,各反应因素的最佳水平为0.5μmol/L引物、30 ng模板DNA、0.15 mmol/L dNTP、0.5 mmol/L Mg²⁺、1.0 U Taq DNA聚合酶。利用随机挑选的3个刺槐优良无性系品种和7对EST-SSR引物对优化体系进行验证,结果均能获得稳定、清晰的条带,证明该体系稳定可靠。此优化体系的建立为刺槐EST-SSR标记的开发以及利用EST-SSR标记深入研究和利用中国刺槐种质资源奠定基础。     

广东紫珠ISSR-PCR反应体系建立及引物筛选

为建立稳定性、重复性好的广东紫珠ISSR-PCR反应体系,以广东紫珠总DNA为试验材料,通过单因子结合正交试验对模板DNA浓度、dNTPs浓度、Mg²⁺浓度、引物浓度和Taq酶用量进行优化,确立了适用于广东紫珠的最佳ISSR-PCR反应体系：0.25 mmol/LdNTPs、1.00 U Taq DNA聚合酶、0.75μmol/L引物、2.0 mmol/L Mg²⁺、100 ng模板DNA,总反应体积为25μL。同时建立重复性和稳定性均较好的ISSR-PCR扩增程序：预变性94℃,5 min;变性94℃,30 s;退火温度与每个引物相对应,退火45 s;72℃延伸90 s;34个循环;后72℃延伸10 min;4℃保存,扩增结束。用来自不同居群4个个体,以100个ISSR引物进行PCR扩增,筛选出扩增效果较好的20个引物。     

山羽藓ISSR-PCR反应体系优化及引物筛选

本研究采用L16(45)正交试验设计法对山羽藓ISSR-PCR反应进行优化试验。研究结果表明,山羽藓ISSR-PCR最佳反应体系(25μL)为:Taq DNA聚合酶0.8 U,Mg2+1.5 mmol/L,d NTPs 0.4 mmol/L,引物0.6μmol/L和模板DNA 40 ng,对该反应体系的影响顺序为:Taq DNA聚合酶引物d NTPs模板DNAMg2+。同时筛选出12条适合山羽藓的ISSR引物,并确定了每条引物的最适退火温度。所建立的体系稳定可靠,条带清晰且多态性丰富,可为后续开展山羽藓种植资源、遗传多样性及分子亲缘地理学研究奠定基础。     

白芥ISSR-PCR反应体系的建立与优化

本实验以产于四川、安徽、广东和青海的白芥农家品种为材料,采用单因素筛选和L16(45)正交设计相结合的方法,对白芥ISSR-PCR反应体系的Mg2+浓度、d NTPs浓度、引物浓度、Taq酶和模板DNA用量进行优化,建立最佳的白芥ISSR-PCR反应体系。结果表明:在20μL的PCR反应体系中,Mg2+浓度2.0 mmol/L、d NTPs浓度0.5 mmol/L、Taq DNA聚合酶0.2 U、引物浓度0.4μmol/L、模板DNA 60 ng为最佳用量。用4个白芥农家品种对建立的ISSR-PCR反应体系进行验证,表明该反应体系稳定性高、可重复性好,同时筛选出条带清晰、多态性较好的18条引物。该反应体系的建立为白芥ISSR标记开发、种质资源鉴定与筛选、遗传多样性分析和分子标记辅助育种等提供了帮助。     

文冠果ISSR反应体系的建立及优化

为了建立文冠果ISSR-PCR最佳反应体系,从而为文冠果遗传多样性研究提供理论依据,从定西巉口林场文冠果人工林内选取健康嫩叶为试验材料,通过单因子试验研究了影响ISSR-PCR反应各因素的浓度,分析因子包括模板DNA用量、退火温度、dNTP浓度、Mg2+浓度、引物浓度及TaqDNA聚合酶用量等。通过研究,找出了各因子合适的条件,建立并优化了文冠果ISSR反应体系,即20μL总反应体系含模板DNA约30 ng,Mg²⁺2.5 mmol/L,引物0.2μmol/L,dNTP 0.20 mmol/L,Taq聚合酶1 U。试验结果表明,在此反应体系下可得到多样性好、条带清晰的图谱。     

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.