硝酸根在油菜基因转化的影响作用

以芥菜型油菜DB3的下胚轴和子叶为外植体研究了不同浓度的AgNO3在油菜转化体系中的作用。结果表明AgNO3对于油菜下胚轴和子叶芽的分化是必须的，但是当AgNO3浓度超过某一临界值时又抑制愈伤组织的形成和外植体芽的分化。结果还发现未被农杆菌处理的外植体芽的分化所需的AgNO3最适宜的浓度为20μmol/L，而被农村菌处理过的外植体其分化所需的最适宜浓度增加为30μmol/L。     

硝酸银在油菜基因转化中的影响作用

以芥菜型油菜DB3的下胚轴和子叶为外植体研究了不同浓度的AgNO3在油菜转化体系中的作用.结果表明AgNO3对于油菜下胚轴和子叶芽的分化是必须的,但是当AgNO3浓度超过某一临界值时又抑制愈伤组织的形成和外植体芽的分化.结果还发现未被农杆菌处理的外植体芽的分化所需的AgNO3最适宜的浓度为20 μmol/L,而被农杆菌处理过的外植体其分化所需的最适宜浓度增加为30 μmol/L.     

花生不定芽分化及植株再生的研究

为进一步探索和完善高频植株再生体系并扩大基因型的研究,以8个花生品种为材料,对幼叶不同部位（叶片顶端、中间切段、叶片基部）的切段、子叶、上胚轴和下胚轴外植体,接种到添加1 mg/L NAA和6 mg/L BAP的MSB5培养基上,10天后将形成的愈伤组织转移至添加10 mg/L BAP或添加3 mg/L BAP和1 mg/L ABA的再分化培养基上进行培养,诱导不定芽分化。结果表明,6天叶龄叶片中间切段不定芽分化频率达到了91.4%,上胚轴26.7%,下胚轴12.5%和子叶0%;花生品种8823幼叶外植体获得了的91.4%不定芽分化率,生根植株经驯化后移至砂土中,正常开花结果。因此,幼叶外植体分化不定芽频率明显高于子叶、上胚轴和下胚轴;6天叶龄的叶片中间切段为最佳;不同基因型不定芽分化率存在明显差异。     

番茄遗传转化体系的建立及LC和GFP标记基因的表达

本研究以小型番茄(miniature Lycopersicon esculentum Mill.)Micro-Tom为试材,建立其以子叶、下胚轴为外植体的高效、稳定再生体系及遗传转化体系。结果表明,以子叶、下胚轴为外植体时,诱导愈伤组织和芽分化的适宜培养基均为MS 6-BA2.0mg/L IAA0.2mg/L,芽分化率均可高达92%。两种外植体适宜的生根培养基均为MS NAA0.1mg/L。同时,通过根癌农杆菌介导法,建立了Micro-Tom的遗传转化体系。而乙酰丁香酮能大大提高根癌农杆菌转化番茄的效率,当AS=180μm/L时,芽分化率为52.8%;OD600=0.14是转化的最佳菌液浓度;子叶外植体与农杆菌共培养后,经过诱导,根的再生,获得了抗性苗,利用绿色荧光蛋白(GFP)检测和整株表型为紫色(Lc)基因的表达,初步证明外源基因已经整合到Micro-Tom中,为番茄激活标签体系的建立奠定了基础。     

大豆体细胞胚胎发生再生体系的建立与优化

以耐干旱、增产潜力大、抗病毒病、品质优良的晋豆19号大豆为材料,以子叶节、下胚轴、上胚轴、子叶、真叶为外植体,研究外植体类型、激素配比、接种方式等对再生频率的影响。结果显示:无菌苗刚转绿的下胚轴是诱导愈伤组织的最适外植体;诱导愈伤的最适培养基为MS+0.2 mg/L 6-BA+1.0 mg/L 2,4-D;诱导芽分化的最适培养基为MS+1.0 mg/L 6-BA+0.05 mg/L NAA;诱导根分化的最适培养基为MS+0.25 mg/L NAA。各种外植体中,诱导频率高低依次为下胚轴、上胚轴、子叶节、子叶、真叶。     

油菜下胚轴农杆菌介导法转化影响因素探讨

利用甘蓝型油菜下胚轴为外植体，对油菜农杆菌介导转化中的主要因素进行了研究，并由此建立了油菜下胚轴农杆菌介导的遗传转化体系。研究发现，在农杆菌介导的油菜下胚轴转化中，较好的转化体系是：外植体在农杆菌侵染前进行3d的预培养。农杆菌的浸染浓度为OD600=0．2～0．4。共培养时的pH值为5．2。在转化后的分化培养基中附加30μmol／LAgNO3。     

影响白三叶草高频率植株再生因素的研究

以白三叶草子叶和下胚轴为外植体,进行直接再生系统中不同基本培养基成分和激素浓度的研究发现：白三叶草下胚轴顶端细胞的分化能力最强,分化率在65％以上,子叶次之,下胚轴其他部位几乎不分化。高维生素和微量元素可有效提高子叶的再生频率15％,而对下胚轴顶端细胞的分化影响不大。在6-BA 3mg／L NAA0．08ms／L的浓度下,下胚轴上段的再生频率最高,达80％以上。     

甘蓝型油菜下胚轴一步不定芽再生培养及遗传转化应用

本研究建立了以甘蓝型油菜下胚轴为外植体的一步不定芽再生培养和遗传转化体系。首先,以甘蓝型油菜中双11号含部分子叶节的下胚轴为外植体,从6-BA和NAA配比、Ag NO3以及无菌苗苗龄等方面对影响油菜组织培养的因素进行了研究,建立了甘蓝型油菜快速高频一步不定芽再生培养技术体系。该技术体系为,切取5 d苗龄含部分子叶节的下胚轴置于添加4 mg/L 6-BA的MS基本培养基中培养,5 d再生出不定芽,再生频率为100%。在此基础上,进行了甘蓝型油菜的遗传转化,成功地将用p FGC5941双元载体构建的Bn TFL1基因干扰载体转入中双11号中。整个转化过程中,芽的诱导生成只需5 d,接着完成抗性芽的PPT筛选需要30 d,整个转化周期从播种到得到生根抗性苗仅需大约70 d,而传统转化方法抗性芽的诱导筛选需要90 d,整个转化周期需要130 d左右,大大缩短了转化周期,简化了转化过程,提高了转化效率。     

番茄子叶和下胚轴离体再生体系建立

以番茄无菌苗子叶和下胚轴为外植体,研究其在MS附加不同浓度6－BA和NAA的培养基上的分化情况。结果表明：在不同培养基上,番茄子叶和下胚轴均能诱导出淡绿色的愈伤组织和分化形成不定芽,但在不同的培养基上,番茄子叶和下胚轴的出愈率和不定芽诱导存在明显差别。诱导番茄愈伤组织形成和芽分化的最佳培养基分别为：MS+6-BA 2 mg/L+IAA 0.2 mg/L和MS+6-BA 2 mg/L+IAA 0.02 mg/L,番茄不定芽生根培养基为：MS+IAA0.2 mg/L。     

红茄子叶和下胚轴离体再生体系研究

本研究以红茄的子叶和下胚轴为外植体,研究其子叶和下胚轴在不同激素的浓度和组合下分化率及再生频率的变化。在诱导愈伤组织时,低浓度的NAA和高浓度的6-BA会导致下胚轴的诱导能力略低于子叶;IAA和ZT的浓度升高时,红茄下胚轴的分化率随之增加,红茄子叶的分化率随之降低。在IAA浓度为0.3 mg/L时,不定芽分化率达到最高;诱导愈伤组织的最佳培养基为MS+0.2 mg/L NAA+1.0 mg/L 6-BA;不定芽诱导最佳培养基为MS+0.3 mg/L IAA+2.0 mg/L 6-BA;不定芽生根最佳培养基为1/2MS。本研究建立的红茄再生体系,为红茄遗传转化研究奠定了基础。     

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.