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.     

广西特有植物小花异裂菊ISSR-PCR反应体系的建立

以小花异裂菊的叶片为材料,采用正交和单因素试验研究Mg2+、dNTP、TaqDNA聚合酶、引物、模板DNA浓度对ISSR-PCR扩增效果的影响。建立了适宜于小花异裂菊的ISSR-PCR反应体系,即25μL的体系中含Mg2+1.5 mmol/L,dNTP 0.20 mmol/L,TaqDNA聚合酶1.5 U,引物0.8μmol/L,模板DNA 50 ng,10×Buffer 2.5μL。该体系稳定、可靠,为利用ISSR分析小花异裂菊遗传多样性等工作奠定了良好的基础。     

两种方法对广玉兰ISSR-PCR反应体系的优化比较

采用单因子和正交设计2种方法,对影响广玉兰ISSR-PCR反应体系的5个因素（Taq酶、Mg^2＋、dNTP、引模板DNA）进行优化。结果表明：正交设计采用直观分析法获得影响因素最佳反应水平与单因子试验找出影响因素最佳反应水平有一定差异,通过综合比较分析,最终建立了广玉兰ISSR．PCR的最佳反应体系：在20μl的反应体系中,TaqDNA聚合酶1．0U、Mg^2＋1．2—1．5mmoL／L、dNTP1．80mmoL／L、引物0．5—0．6μmoL／L、30ng模板DNA、10×PCR buffer。同时,通过PCR比较,确定延伸时间为2min,循环次数为35个较为合适,确定了引物最佳退火温度,得到了广玉兰ISSR—PCR反应的最佳扩增程序。     

战骨ISSR-PCR反应条件的筛选与优化

采用正交和单因素试验设计方法,研究Mg2+、dNTP、Taq DNA聚合酶、引物、模板DNA、退火温度及循环次数对ISSR-PCR扩增效果的影响,建立并优化战骨ISSR-PCR反应体系和程序,即25μl的体系中合Mg2+ 2.0 mmol/L,dNTP 0.2 mmol/L,TaqDNA聚合酶1.0U,引物0.8μmol/L,模板DNA 50 ng,10×Buffer 2.5μl.退火温度、循环次数分别为52℃、45次.结论:结合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,可用于战骨遗传多样性分析.     

毛竹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浓度及退火温度对毛竹ISSR-PCR扩增效果的影响。毛竹ISSR-PCR反应体系为:25μL的体系中含Mg²⁺1.5 mmol/L,dNTP 0.25 mmol/L,引物1.0μmol/L,TaqDNA聚合酶1.0 U,模板DNA 30 ng,10×Buffer2.5μL。扩增程序为94℃预变性5 min,94℃变性45 s,54℃退火60 s,72℃延伸1.5 min,40个循环;72℃延伸7 min,4℃保存。该体系稳定、可靠,可用于毛竹遗传多样性分析。     

水葫芦苗ISSR-PCR体系的优化与引物筛选

以改良CTAB法提取水葫芦苗基因组DNA为模板,利用正交设计试验对影响ISSR-PCR反应体系的5个因素(TaqDNA聚合酶,dNTP,引物,模板及Mg~(2+))进行了优化筛选。经极差分析和方差分析,最终建立了水葫芦苗ISSR-PCR的最佳反应体系。结果表明,总体积20μL的反应体系中各因素浓度分别为:TaqDNA聚合酶0.025 U/μL、Mg~(2+)1.5 mmol/L、dNTP 1.0 mmol/L、引物0.5μmol/L、模板DNA 1.5 ng/μL。通过筛选得到10条扩增条带清晰的ISSR引物,并通过梯度PCR确定了各引物的最适退火温度。在此基础上对循环次数进行优化,最终确定最佳循环次数为40次。     

新疆贝母DNA提取及ISSR-PCR体系的建立与优化

目的:从新疆贝母干叶片中提取高质量的DNA,建立ISSR-PCR体系并进行优化。方法:通过改进的CTAB法提取基因组DNA;综合利用单因素实验和L9(34)正交实验2种方法,对镁离子、dNTP、模板DNA含量、TaqDNA聚合酶量、引物浓度等因素进行优化,并采用温度梯度筛选引物的退火温度。结果:新疆贝母20μL ISSR-PCR最适反应体系dNTP为0.3 mmol/L,Mg2+为2.0 mmol/L,模板浓度为40～100 ng/(20μL),引物为1.2 mmol/L,Taq DNA聚合酶为1.0 U/20μL,引物UBC 859的最适退火温度为50.7℃。结论:此提取方法得到的DNA纯度高,ISSR-PCR扩增效果显著,为新疆贝母种质资源鉴定、遗传多样性分析奠定研究基础。     

百合属RAPD反应条件优化的研究

以百合DNA为材料,对影响其RAPD反应体系中的6个主要因素(模板DNA、Mg2+、TaqDNA聚合酶、引物、dNTPs、退火温度)进行优化,最终确定了百合RAPD反应的最佳体系(25μL)为:40 ng模板DNA,1.5 mmol/L Mg2+,1.0 U TaqDNA聚合酶,1.0μmol/L引物,200μmol/L dNTPs,引物E 13的最适退火温度为37.3℃.该体系的建立为今后应用RAPD技术鉴定百合属植物的种质资源和遗传多样性研究奠定了基础.     

蓖麻RAPD-PCR反应体系的正交优化

以东北蓖麻为材料建立蓖麻RAPD反应优化体系,用于蓖麻遗传多样性分析.用CTAB提取蓖麻基因组DNA,采用正交试验对影响蓖麻RAPD-PCR扩增的反应组分浓度进行优化.结果表明最佳的蓖麻RAPD-PCR反应体系(25μ1)中含10xbuffer 2.5μ1,模板DNA 4ng/μ1,dNTP 0.4mmol/L,引物0.321μmol/L及Taq酶0.1U/μ1.扩增程序为94℃预变性2min;94℃变性30s,35℃退火30s,72℃延伸1min20s;40个循环;72℃延伸5min.通过正交体系优化,获得了较优的蓖麻凡RAPD-PCR反应体系,为蓖麻RAPD分子标记提供了理论基础.     

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。     

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.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

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...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

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.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

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.     

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.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.