四倍体野生棉毛棉体细胞胚胎发生与植株再生研究

通过对培养基激素配比,以及不同浓度的PEG、CuSO4和AgNO3等处理,对棉属四倍体野生棉种毛棉(G.tomentosum Nutt.Watt)进行了体细胞培养,获得了大量体细胞胚状体并实现植株再生。与四倍体陆地棉(G.hirsutum,cv.Coker 201)相比,毛棉体细胞培养难度较大,且体细胞胚畸形严重,萌发困难,但通过培养条件的调控可以得到大量胚状体和少量再生植株。试验结果表明,激素组合0.1 mg.L-1 KT+0.1 mg.L-1 2,4-D诱导的愈伤组织较松脆,分化潜力高;PEG处理不利于毛棉的胚性和非胚性愈伤的诱导,而不同浓度的CuSO4和AgNO3处理对于体细胞胚状体诱导和萌发以及植株再生效果有明显差异。其中3.5 mg.L-1 CuSO4+0.5 mg.L-1IBA+0.2 mg.L-1 KT和3 mg.L-1 AgNO3+0.5 mg.L-1 IBA+0.2 mg.L-1 KT组合利于胚性愈伤的增殖和体细胞胚的萌发。     

低酚陆地棉直接体细胞胚胎发生和植株再生

选用低酚陆地棉无菌苗下胚轴为材料进行全固体组织培养,直接诱导获得了胚性愈伤组织,并进一步分化为再生植株.结果表明,激素是影响棉花直接体细胞胚胎发生的重要因素.MSB培养基中添加2,4-D有利于愈伤组织的形成,却不能直接诱导获得胚性愈伤组织.MSB培养基中添加IBA和BA也不能直接诱导获得胚性愈伤组织.MSB培养基附加适当浓度的IBA和KT能直接诱导出胚性愈伤组织.最适激素组合(1.0 mg/L IBA,0.5 mg/L KT)能使诱导棉花下胚轴产生大量胚性愈伤组织,并且在3个月内就可肉眼观察到不同发育时期的胚.MSB培养基中附加1.0 g/L谷氨酰胺和0.5 g/L天门冬酰胺有利于胚萌发成苗.本研究建立了简便高效的棉花直接体细胞胚胎发生和植株再生培养体系,从胚性愈伤组织诱导到植株再生约需5～6个月时间.     

绿色棉新彩棉7号体细胞胚胎发生及其植株再生

以绿色棉新彩棉7号的子叶、下胚轴为外植体,MSB(MS培养基附加B5维生素)基本培养基附加不同激素组合,诱导愈伤组织及调控分化,通过体细胞胚胎发生方式获得再生植株.结果表明:0.1 mg· L-1 KT(Kinetin,激动素)+ 0.1 mg·L-12,4-D(2,4-dichlorophenoxyacetic,2,4-二氯苯氧乙酸)为诱导愈伤组织的最适植物激素组合,不同外植体处理出愈率均达到100％,但下胚轴纵切面背向培养基放置培养更有利于诱导愈伤组织形成;分化调控阶段的最佳植物激素组合为0.15 mg·L-1 KT+ 0.3 mg·L-1 IBA(Indole-3-butyric acid,吲哚丁酸),胚性愈伤分化率可达23.33％; MSB中去除NH4NO3同时KNO3加倍,附加0.5 g·L-1Asn(Asparagine,天冬酰胺)和lg· L-1 Gln(Glutamine,谷氨酰胺),胚性愈伤可进一步分化获得体细胞胚,将成熟的子叶胚接种于1/2MS获得完整的再生植株. 本研究通过体细胞胚发生途径获得了新彩棉7号的再生植株,为天然彩色棉基因工程研究奠定了一定基础.     

胡萝卜高效再生体系的建立

以胡萝卜下胚轴为外植体,研究其愈伤组织诱导及植株再生各个时期的影响因素。试验结果表明：0．1mg／L2,4-D或0．1mg／L2,4-D 0．2mg／L KT的激素组合有利于胡萝卜下胚轴的愈伤组织诱导;在0．1mg／L2,4-D的培养基上形成的愈伤组织主要以胚状体的形式再生,而在含0．1mg／L2,4-D 0．2mg／L KT激素组合的培养基上形成的愈伤组织主要以发生不定芽的方式再生;再生过程中,B5基本培养基上的苗子不易生根,需要附加0．1mg／L的IBA,而在MS培养基上苗子可直接形成根。     

陆地棉抗病品种中521植株再生的研究

以农艺性状优良且抗枯黄萎病的陆地棉品种中521的下胚轴为外植体,采用固液结合的体细胞培养方法建立细胞悬浮系并进行植株再生的研究。结果表明,愈伤组织的诱导以MS 1.0 mg.L-1IBA 0.05 mg.L-1KT 0.1 mg.L-12,4-D 30g.L-1葡萄糖的固体培养基为最佳;体细胞胚的形成以MS 0.01 mg.L-1IBA 0.01 mg.L-1KT 0.005 mg.L-12,4-D 1.0g.L-1谷氨酰胺的液体培养基为最佳,悬浮30 d后可以发现体细胞胚的形成。之后转接入四种不同的MSB固体培养基上诱导再生植株形成,发现MSB 2 g.L-1谷氨酰胺 0.5 g.L-1天冬酰胺 30g.L-1蔗糖 6.0 g.L-1琼脂为最佳培养基,且发现此方法比全程固体培养缩短了体细胞再生的周期,此品种在本研究建立的再生体系下植株再生周期为6个月左右。     

棉属G染色体组野生棉种的体细胞胚胎发生与植株再生研究

通过培养基激素配比、碳源种类等培养条件的筛选，对2个G染色体组棉种（纳尔逊氏棉，Gossypium nelsonii Fryx.；澳洲棉，Gossypium australe F. Muell.）进行体细胞培养并获得了体细胞胚，其中纳尔逊氏棉获得了再生植株，澳洲棉获得了大量的胚状体。与D染色体组棉种克劳茨基棉（Gossypium klotzschianum Anderss）相比，G染色体组棉种再生时间长，且体细胞胚畸形严重、萌发困难，但通过培养条件的调控可以得到大量胚状体和少量再生植株。激素组合0.1 mg L^-1 KT+0.1 mg L^-1 2, 4-D诱导的愈伤组织较松软，分化潜力高；胚性愈伤组织的增殖使用0.2 mg L^-1 KT+0.5 mg L^-1 IBA的激素组合；组合0.25 mg L^-1 IBA＋0.3 mg L^-1 KT有利于体细胞胚胎发生，而含激素组合MSB5+0.15 mg L^-1 KT+0.5 mg L^-1 NAA的培养基适合体细胞胚胎的萌发和植株再生。此外，愈伤组织诱导宜用葡萄糖作为碳源，而在胚性愈伤组织的增殖及保存和胚状体的萌发过程中用麦芽糖作碳源的效果更佳。     

农杆菌介导外源基因在棉花中的表达

用 5～ 6d的棉花无菌苗下胚轴切段与农杆菌共培养 ,菌株质粒中 Gus基因为标记基因 ,NPT 基因为选择基因。在含 0 .1 mg· L- 12 ,4- D和 0 .1 mg· L- 1KT的 MS培养基上共培 48h,转移到添加头孢霉素 50 0 mg· L- 1、卡那霉素 50 mg· L- 1MS培养基中诱导和筛选抗性愈伤组织 ,70～ 80 d时 ,进行 Gus检测 ,选择 Gus阳性愈伤组织 ,经体细胞分化生成转基因再生植株     

香果树组织培养技术研究

采用香果树幼树叶片作外植体,接种到附加不同浓度的KT和ZT组合的MS培养基上,诱导植株再生.结果表明,最适宜香果树叶片愈伤组织诱导和芽增殖的培养基是MS KT 1.0 ZT 2.0,愈伤组织诱导率达35.6%,芽增殖倍数为2.8倍;比较理想的生根培养基是1/2 MS IAA 0.5和1/2 MS IBA 0.5,生根率分别为65%和75%.试管苗移栽最理想的移栽基质是泥炭与珍珠岩(5∶1)的混合物,移栽成活率达95.2%.     

‘黑珍珠’番茄植株再生体系的研究

为了研究‘黑珍珠’番茄植株再生,以‘黑珍珠’番茄幼嫩叶片为外植体诱导愈伤组织,通过愈伤组织诱导培养、愈伤组织分化培养、不定芽增殖培养、生根培养和试管苗移栽,建立高效快速的‘黑珍珠’番茄再生体系。结果表明：最适宜的诱导叶片愈伤组织的培养基为MS+ 1.0 mg/L 6-BA+ 0.1 mg/L NAA,叶片外植体愈伤组织诱导率最高可达98.2%;诱导出的愈伤组织在MS+ 1.5 mg/L 6-BA+ 0.2 mg/L IBA培养基上能很好的分化出不定芽;MS+4.0 mg/L KT+ 0.01 mg/L IBA 培养基可实现不定芽芽增殖;最适宜的生根培养基为1/2MS+ (0.05~0.08) mg/L NAA,试管苗移栽成活率达92%。     

培养基及植物激素对烟草原生质体再生植株的影响

本文研究了不同基本培养基、培养方法及培养基中不同激素浓度配比对烟草叶肉细胞细胞原生质体再生植株的影响.结果表明,利用MS基本培养基进行琼脂糖固体平板培养,对烟草叶肉原生质体的发育速度、分裂频率及愈伤组织形成效果最佳;培养基(1/2 MS NAA 0.5 mg/L 2,4-D 1.0mg/L 6-BA0.5 mg/L 1.2%LMA) (1/2MS 2,4-D2.5mg/L KT0.5mg/L)的培养效果最好,再生细胞团的数目及愈伤组织最多;用1/2 MS IAA 2.0 mg/L KT 0.5 mg/L和1/2 MS IAA0.5 mg/L KT 2 mg/L两种培养基对愈伤组织诱导分化时出芽率高;在再生芽诱导生根时直接用不含任何激素的MS基本培养基效果最理想.     

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.