水稻双胚苗的发现及其研究进展

著名杂交水稻育种专家袁隆平提出了杂交水稻育种分为三个发展阶段的战略设想,即:三系法品种间杂种优势利用,两系法亚种间杂种优势利用和一系法远缘杂种优势利用。“一系法”即利用无融合生殖法固定水稻品种间及更远缘的强大的杂种优势。这既是人们愿望,也是杂种优势育种发展的最高阶段。利用无融合生殖特性来固定杂种优势,成功的关键在于获得水稻的二倍体无融合生殖材料。早在1979年袁老师就对我们提出了固定杂种优势的途径和寻找无融合生殖材料的方法。其中不定胚就是二倍体无融合生殖的方式之一。它的主要表现形式是多胚现象。因此从大量…     

我国水稻育种技术又获重大突破

<正> 一项采用固定杂种优势育种方式,以实现优质超高产为目标、具有世界意义的重大科研项目——水稻兼性无融合生殖固定杂种优势育种新技术,最近在江苏连云港市研究成功,并获得国家专利。     

高梁无融合生殖基因转移到水稻上的可能性

无融合生殖能用来固定杂交水稻的杂种优势,可是还未发现以无融合方式进行繁殖的栽培稻或野生稻种。高粱是目前已发现具有高频率兼性无融合生殖(80%)的唯一禾谷类作物。我们试图利用原生质体融合的方法进行无融合生殖基因的属间转移。 在诺丁汉大学,我们用水稻品种T309的胚细胞悬浮培养LB-1-作原生质体融合的有效受体,而供体高粱原生质体则由叶片分离。按照常规标准程序,从T309的LB- l悬浮培养分离水稻原生质体,从具无融合生殖基因的高粱系R478分离出叶原生质体。水稻原生质体用乙二酸荧光素(FDA)活体染色容易鉴定。 用电融合液把原生质…     

我国高粱品种改良的育种方法

随着高粱生产和市场需求的变化导致育种目标发生变化，结果所采用的育种方法（技术）也不尽相同。我国高粱品种改良主要运用的育种方法（技术）有：传统育种方法、杂种优势利用法、群体改良法、诱变育种法、倍性育种法、无融合生殖法、转基因育种法。     

对我国水稻无融合生殖研究的思考

论述了无融合生殖固定水稻远缘杂种优势是水稻育种、生产与人民生活发展的必然趋势；明确了无融合生殖固定杂种优势的含义；对我国水稻无融合生殖研究的策略与现状进行了分析；总结了禾本科中无融合生殖的种类与分布；根据与水稻亲缘关系远近与转移方法的不同，把无融合生殖种属归入４个基因库，在此基础上提出了在稻亚科寻找、利用无融合生殖材料及转移远缘禾本科无融合生殖基因入水稻的研究策略。     

小麦无融合生殖研究进展及策略

本文简述了小麦无融合生殖的研究进展，并就我国小麦无融合生殖育种研究策略做了讨论，旨在促进小麦无融合生殖固定杂种优势利用研究的深入发展。     

小麦无融合生殖研究进展及策略

本文简述了小麦无融合生殖的研究进展，并就我国小麦无融合生殖育种研究策略做了讨论，旨在促进小麦无融合生殖固定杂种优势利用研究的深入发展。     

高浓度激素喷穗对多胚水稻胚胎发育的影响

用无融合生殖“固定”水稻杂种优势是水稻遗传和育种中一个十分活跃的研究领域。近年来,我国一些研究,不仅已证实了水稻具有无融合生殖特性,而且获得一批低频率发生的水稻无融合生殖材料(即水稻多胚苗和单性生殖材料等)。但是,已发现的水稻无融合生殖材料最为突出的问题是可用于“固定”杂种优势的无融合生殖方式(即不定胚)的频率太低,通常只有百分之零点儿,难以直接应用。所以,如何提高不定胚的频率成为关键所在。鉴于水稻多胚苗中的不定胚发育与合子胚发育存在竞争关系,通常是后者抑制前者的     

高粱无叶舌类型利用的可能性

1976～1985年研究了在高粱作物育种工作中利用无叶舌特征的前景。全面分析了无叶舌苏丹草уДСТ-1系,高粱×苏丹草杂交种уДСС-1(矮80c×ЛС_m-1系)和高梁уДС-1的主要育种遗传参数。在杂种优势的     

一系法杂交水稻研究的技术策略探讨

通过一系法利用和固定水稻的远缘杂种优势是一项具有极大诱惑力但难度颇大的科研难题。我国水稻无融合生殖研究尚处在探索性阶段,还没有筛选到具有实用价值的无融合生殖种质。由于多倍体水稻的有性生殖能力明显变弱,在多倍性水平筛选和创造水稻无融合生殖种质有可能成为一系法杂交稻研究的突破口。     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Redox Status and Neuro Inflammation Indexes in Cerebellum and Motor Cortex of Wistar Rats Supplemented with Natural Sources of Omega-3 Fatty Acids and Astaxanthin: Fish Oil,Krill Oil,and Algal Biomass

Health authorities worldwide have consistently recommended the regular consumption of marine fishes and seafood to preserve memory, sustain cognitive functions, and prevent neurodegenerative processes in humans. Shrimp, crabs, lobster, and salmon are of particular interest in the human diet due to their substantial provision of omega-3 fatty acids (n-3/PUFAs) and the antioxidant carotenoid astaxanthin (ASTA). However, the optimal ratio between these nutraceuticals in natural sources is apparently the key factor for maximum protection against most neuro-motor disorders. Therefore, we aimed here to investigate the effects of a long-term supplementation with (n-3)/PUFAs-rich fish oil, ASTA-rich algal biomass, the combination of them, or krill oil (a natural combination of both nutrients) on baseline redox balance and neuro-inflammation indexes in cerebellum and motor cortex of Wistar rats. Significant changes in redox metabolism were only observed upon ASTA supplementation, which reinforce its antioxidant properties with a putative mitochondrial-centered action in rat brain. Krill oil imposed mild astrocyte activation in motor cortex of Wistar rats, although no redox or inflammatory index was concomitantly altered. In summary, there is no experimental evidence that krill oil, fish oil, oralgal biomass (minor variation), drastically change the baseline oxidative conditions or the neuro-inflammatory scenario in neuromotor-associated rat brain regions.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part II: Electrostatic separation of particles

Wheat bran is a composite material made of several layers, such as pericarp, testa and aleurone. It could be fractionated into purified fractions, which might either be used as food ingredients, or serve as a starting material for extraction of bioactive compounds. The aim of this work was to evaluate the potential of using electrostatic separation as a way to obtain purified fractions from wheat bran. Ultrafine-ground bran obtained either by cryogenic grinding or by grinding at ambient temperature was used as starting material. The ultrafine bran was then charged by tribo-electrification and introduced in a chamber containing two high voltage electrodes, where bran particles were separated depending on their acquired charge, allowing positively and negatively charged fractions to be collected separately. The particle size distribution, microstructure and biochemical composition of the obtained fractions were studied. The charge of the particles was influenced by their biochemical composition: particles rich in highly branched and cross-linked arabinoxylans (pericarp) were separated from particles rich in β-glucan, ferulic acid and para-coumaric acid (aleurone cell walls). The testa and the intracellular compounds from aleurone were not highly charged, neither positively nor negatively. The most positively charged fraction represented 34% of the initial bran, and contained 62% of the ferulic acid present in the initial bran. The yield of the separation process was good (5.4% loss), and could be further increased.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Pharmacokinetics of Marine-Derived Drugs

Marine organisms represent an excellent source of innovative compounds that have the potential for the development of new drugs. The pharmacokinetics of marine drugs has attracted increasing interest in recent decades due to its effective and potential contribution to the selection of rational dosage recommendations and the optimal use of the therapeutic arsenal. In general, pharmacokinetics studies how drugs change after administration via the processes of absorption, distribution, metabolism, and excretion (ADME). This review provides a summary of the pharmacokinetics studies of marine-derived active compounds, with a particular focus on their ADME. The pharmacokinetics of compounds derived from algae, crustaceans, sea cucumber, fungus, sea urchins, sponges, mollusks, tunicate, and bryozoan is discussed, and the pharmacokinetics data in human experiments are analyzed. In-depth characterization using pharmacokinetics is useful for obtaining information for understanding the molecular basis of pharmacological activity, for correct doses and treatment schemes selection, and for more effective drug application. Thus, an increase in pharmacokinetic research on marine-derived compounds is expected in the near future.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.