普通小麦内源α—淀粉酶抑制基因的多态体及染色体定位

依照单克隆抗体免疫斑渍原理，采用等电聚焦法研究了小麦一个内源α－淀粉酶抑制剂的多态体。在普通小麦及其野生近缘物中检测到１０个抑制剂的异构体定位于５个同源位点。普通小麦确定了３个α－淀粉酶抑制基因位点。分别位于２Ａ，２Ｂ和２Ｄ染色体的长臂上。在２７个面包小麦，８个硬粒小麦和１２个与１个隋性等位基因；在Ｉｓａ－Ａ１有２个活性等位基因与１个惰性等因基因；在Ｉｓａ－Ｂ１有２个等位基因；在Ｉｓａ－Ｄ１有１个     

大麦α-淀粉酶抑制蛋白的提取及其功能检测

为了提取大麦α-淀粉酶抑制蛋白(BASI)并对其功能进行检测,利用硫酸胺沉淀、离子交换层析及聚丙烯酰胺等电聚焦电泳等方法获得了α-淀粉酶抑制蛋白特征带。过强阴离子交换柱时,在第三个洗脱峰收集的分馏液中提取出BASI。抑制试验结果表明,BASI可与小麦α-淀粉酶形成复合物,降低α-淀粉酶活性。激光扫描结果更加直观地显示加入BASI后α-淀粉酶-1和α-淀粉酶-2的峰面积都有所下降,下降幅度分别为34.51％和35.96％。     

冬小麦抗白粉病基因的定位

以前报道过１０个冬小麦品系抗白粉病的基因数量与遗传模式，但这些基因的同位关系及其定位还没有确定。１０个抗白粉病小麦品系中，有８个相互杂交并与１３个已知抗白粉病基因的不同寄主品系杂交。各杂交组合中，取Ｆ２３００－８００个幼苗在温室内评定了对白粉病１２７号小种的反应，以确定这种同位关系以及８个小麦品系中抗白粉病基因的各个特性。在Ｃ３９、Ａ５５－２、Ｒ１０７、Ａｒｍａｄａ和ＳＩ５中鉴定出Ｐｍ４ｂ这个常见     

小麦后熟α－淀粉酶的遗传

两个成熟期不穗发芽、籽粒α－淀粉酶水平始终保持很高的小麦品种与一个低α－酶的对照品种杂交，其Ｆ１、Ｆ２和ＢＣ１代分别种植，收获后对各群体籽粒分别进行α－淀粉酶活性分析．结果表明，高水平籽粒α－淀粉酶的分离和重组受一个隐性等位基因控制，这种遗传方式使得很难把低活性的α－淀粉酶纯合个体与杂合个体（低活性α－淀粉酶表现型，但带有高活性基因）区分开来，并且这一遗传方式对小麦育种家有着十分重要的意义．这一称之为后熟α－淀粉酶的遗传基因并不与位于６Ｂ染色体长臂上的有芒抑制基因Ｂ２连锁在一起。     

含有赤霉酸敏感基因的小麦中籽粒后熟α－淀粉酶的表达

两个在籽粒发育后期α－淀粉酶（后熟α－淀粉酶）维持高水平的小麦品种Ｓｐｉｃａ和Ｌｅｒｍａ５２，与一组带有高秆（ｒｈｔ）等位基因或矮化基因Ｒｈｔ１、Ｒｈｔ２及Ｒｈｔ３（赤霉素不敏感等位基因）的４个近等位基因品系杂交，种植Ｆ１和Ｆ２群体，并分析其籽粒α－酶和株高的表现．Ｒｈｔ３基因显示出对株高显著的影响，并强烈抑制了籽粒后熟期α－淀粉酶的合成．相比之下，Ｒｈｔ１和Ｒｈｔ２对株高影响不大，但仍显著地降低了后熟期α－淀粉酶活性．这些观察表明，赤霉酸直接或间接地参与了作用．对品种改良、鉴定和控制高α－淀粉酶种质方面矮化基因的效应进行了讨论．     

人α—干扰素2b基因转化番茄,番木瓜的研究（I）：人α—干扰素2b基因？…

以ＰＢＶ８８９（α－ＩＦＮ－２ｂ）为基因供体,利用ＥｃｏＥ Ｉ／Ｐｓｔ Ｉ双酶切分离出基因α－ＩＦＮ－２ｂ,再利用现有的植物表达质粒ＲＯＫ Ⅱ（带ＰＲＶ－ＣＰ基因,３５Ｓｐｒｏｍｏｔｅｒ／ＮＰＴ Ⅱ）,用ＸｂａＩ／ＳａｃＩ双酶切分离出大片段（Ｅ６）作为基因受体,采用定向连接法将α－ＩＦＮ－２ｂ拼接在Ｅ６上,完成植物表达载体构建。采用ＤＡＮ ｄｏｔ ｂｌｏｔ、ＲＮＡ ｄｏｔ ｂｌｏｔ对重组子进行筛选     

大麦对白粉病抗性的分子及细胞表达

在Ｐ－０３和Ｓ－０３大麦品种中，鉴定了５个抗性关联基因的诱导与两个近源的大麦白粉病菌系ＣＣ１４２（Ａａ６）和ＣＣ１４３（Ｖａ６）生长发育的直接关系．大麦品种含有抗白粉病基因Ｍｌａ６，而大麦白粉病两个菌系仅在对Ｍｌａ６毒力上有所不同。两个菌系在两个品种中的发育差异反映在防御基因诱导的方式上．所鉴定的抗性基因反应包括几丁质酶、过氧化物酶和苯丙氨酸解氨酶等．这两个菌系在接种１６ｈ后表现出相似的发育特性。这时，Ｓ－０３对无毒菌系ＣＣ１４２发育的抑制已很明显，但Ｐ－０３对ＣＣ１４２的抑制到接种４８ｈ才能观察到。ＣＣ１４２发育的差异与Ｓ－０３中一个对无毒菌系起作用的早期专化抗性基因有关．按种后１６ｈ，在Ｓ－０３中观察到几丁质酶及过氧化物酶基因较高的转录水平，而在Ｐ－０３中，作用于ＣＣ１４２专化抗性基因在２４ｈ后才能观察到。Ｓ－０３中所观察到的对无毒菌系较早抗性基因反应可归于该品种对ＣＣ１４２发育较早的抑制作用。     

小麦品种BD159籽粒的α－淀粉酶水平

来自澳大利亚Ｖｉｃｔｏｒｉｃ州的优良小麦育种系ＢＤ１５９，于１９９０年在各试验点表现出了变化范围较大的落粒数值。而标准品种的该数值普遍较高。品种ＢＤ１５９的可变和不可预测性状是来自澳大利亚育种方案的一大批优良品系和亲本原种的特点。具有低落粒数的ＢＤ１５９籽粒样本的α－淀粉酶活性水平得到了提高。α－淀粉酶均匀地分布在籽粒的近侧和远侧．这种α－淀粉酶的分布类型同典型的发芽籽粒中α－淀粉酶活性的剧烈倾斜分布是完全不同的；此外，也缺少籽粒发芽的证据。这表明小麦品种ＢＤ１５９的异常表现同Ｓｐｉｃａ和Ｌｅｒｍａ等小麦品种在后熟期α－淀粉酶的综合性状是不同的。在澳大利亚新南威尔士州北部的Ｎａｒｒａｂｒｉ地区，把小麦植株从大田移栽到冷玻璃室中，直至成熟。这样，就产生了高水平的α－淀粉酶。而同时，生长在大田中的植株上的籽粒具有非常低的α－淀粉酶活性。     

小麦穗发芽的研究进展

小麦成熟期稳发芽是一种世界性的灾害，国内外育种家和生物化学家对此都很重视，1975～2001年先后举行了9次国际谷物收获前稳发芽研讨会，促进了该领域研究的深入开展。本文综速了小麦穗发芽发生的原因，详细介绍了影响稳发芽的α-淀粉酶、α-淀粉酶抑制蛋白以及小麦抗稳发芽育种等方面的研究进展。     

大豆热激蛋白与内源激素变化的研究

对６个华北生态型大豆品种热激蛋白与内源激素变化的研究表明;在开花结荚期,高温促进大豆ＨＳＰ７２－７３的合成,内源ＩＡＡ和ＡＢＡ也随之发生变化。不同大豆品种ＨＳＰ７２－７３,ＩＡＡ和ＡＢＡ的变化有显著差异,抗倒伏,抗脱落的品种表现较强的ＨＳＰ７２－７３合成能力。     

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.     

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.     

Evolutionary aspects of the trade-off between seed size and number in crops

Whereas the concept that availability of resources drives seed production is sound in principle, it is incomplete as there are many solutions to the allocation of resources that derive from the trade-off between number and size. This paper examines evolutionary aspects of this trade-off in annual grain crops. The analysis is centred on the working hypotheses that, for a given species and environment, allocation of resources to reproduction involves (H1) high plasticity in seed number, which allows for variable resource availability, and (H2) a relatively narrow range of seed size that results from evolutionary and agronomic selection. Comparisons between crops and fish are used to highlight common evolutionary elements in taxa where parents provide little or no care to their offspring, with the consequence that both number and early survival of offspring, hence fitness of parents, are partially related to embryo size and reserves.

The plasticity of seed number in relation to availability of resources is analysed against the established relationship between offspring number and parent growth rate during critical stages. The notion that seed size is under stabilising selection is analysed against three conditions: (1) mean seed size is conservative for a given species and environment, (2) seed size affects fitness, and (3) seed size is heritable. Databases from published papers were compiled to analyse the relative variability of seed size and number, and the heritability of seed size. Evidence for and against the link between seed size and parental fitness is revised using the Smith–Fretwell model as framework (Am. Nat., 108, 499–506).

The proposal of high plasticity of seed number and narrow variability of seed size resulting from stabilising natural selection is generally consistent with evolutionary and genetic considerations. Agronomic selection may have reinforced natural selection leading to relatively narrow seed size in species such as wheat and soybean, where cultivated types retained high plasticity for seed number. In contrast, selection for one or few inflorescences in crops like sunflower and maize may have morphologically reduced seed number plasticity and increased variability of seed size and its responsiveness to resource availability in relation to their wild ancestors.     

Citrus Flavonoids in Fruit and Traditional Chinese Medicinal Food Ingredients in China

Flavonoids-enriched tissues of citrus such as peel, immature fruit and flower are consumed as culinary seasonings, tea ingredients in China for centuries. This HPLC quantitative study on the five citrus flavonoids, naringin, hesperidin, neohesperidin, sinensetin and nobiletin on a wide range of Chinese citrus fruits and several Traditional Chinese Medicinal food ingredients in East China, revealed a great diversity in flavonoid composition. Huyou peel (C. paradisi cv. Changshanhuyou) was found to be the best naringin (3.25%) and neohesperidin (2.76%) source; C. aurantium, a major ingredient of several citrus-related TCM, is also a suitable source of naringin and neohesperidin, and a good juice source for flavanone glycosides; the peel of Wenzhoumiju (C. unshiu) is one of the richest local species in hesperidin (up to 6.25%); Zaoju (C. subcompressa) has the highest content of nobiletin (0.59%), a polymethoxylated flavone. LC-ES-MS analysis of Zanthoxylum genus for flavonoids revealed for the first time the presence of significant amounts (0.74%) of hesperidin in the root of Liangmianzhen (Z. nitidum (Roxb.) DC), a relative of Sichuan pepper, which is a spice widely used in China.     

Effect of a continuous hot water treatment of potato tubers on seed-borne fungal pathogens

Summary The viability of five pathogens was decreased by treatment with hot water when tested in vitro.Polyscytalum pustulans was most sensitive andRhizoctonia solani least sensitive. Potato tubers were exposed to 55°C for 5 min in a commercial continuous hot water treatment plant using naturally contaminated seed tubers and tubers which had been inoculated by dipping in comminuted cultures. The frequency of eyes colonised byP. pustulans, Helminthosporium solani, andR. solani was reduced to virtually zero and the effect persisted on tubers subsequently stored at 4°C and at 15°C for up to 16 wk. Results withColletotrichum coccodes were inconclusive. Treatment suppressedPenicillium spp. which, however, rapidly recolonised the eyes during storage, leading to higher contamination levels in the treated than in the untreated tubers. With tubers inoculated withPhoma foveata, good control was achieved when the incubation period before treatment was 10 d but not when the period was 42 d.     

Role of Benzoxazinones in Cereals

Summary

Heterocyclic 1,4-benzoxazin-3-ones and related benzox-azolinones are important natural products of the cereal crops maize, wheat and rye. Much research has focused on the role of these compounds as defensive agents against plant diseases and pests. Studies of a wide variety of biological effects on herbivores and nematodes, plant pathogenic fungi and bacteria are reviewed in this article. Phytotoxic activity of the compounds is also considered with respect to allelopathic interaction with higher plants. Recent investigations of molecular aspects of interactions of cyclic hydroxamic acids and related benzoxazo-linones with acceptor organisms have demonstrated different effective detoxification strategies and tolerance mechanisms. This research has greatly advanced our knowledge about the multiple roles that these allelochemicals play in ecological systems.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part I: Influence of ultra-fine grinding

Wheat bran is an undervalued by-product of white flour and has great nutritional potential due to its high content in fibres and bioactive compounds. Micronized bran could be used as a food ingredient to improve the nutritional potential of cereal products, or be used as a starting material for other processes (bioactive compound extraction or bran fractionation). The aim of this work was to find a way to efficiently decrease the particle size of bran. The influence of the grinding temperature (ambient or cryogenic grinding) on the granulometric distribution of particles, their composition, and their microstructure was studied, at lab-scale and pilot-scale. It showed that the intrinsic characteristics of bran (glass transition within intermediate layers at −46 °C) had more influence on its grinding behaviour than the type of grinding device used: the particles size distributions obtained after grinding at lab-scale and pilot-scale were very similar. At both scales, the granulometric curves were narrow for cryogenic grinding, while for ambient grinding they were spread over the whole particle size range. Ultrafine particles were obtained in both ambient and cryogenic conditions. Negative temperatures, by increasing the material’s brittleness, favoured a fast fragmentation of bran: one step of cryogenic grinding allowed a median particle size of nearly 50 μm to be reached, whereas three successive steps of ambient grinding were needed for the same result. On the other hand, ambient temperature favoured the dissociation of the different constituent layers of wheat bran, and produced less composite particles than cryogenic grinding.     

Multiple use of plants: Studies on selenium incorporation in some agricultural species for the production of organic selenium compounds

The technique of spraying plants with inorganic forms of selenium can be employed for phytochemical production of organic selenium compounds. Fractionation of the plant material makes it possible to produce a highly concentrated and well defined selenium supplement with potential use in animal and human nutrition. The fractionation also gives opportunities to combine production of organic selenium compounds with other products, for example plant fibres. Multiple use of plants can contribute to a more efficient utilization of land area (in comparison to monocultures solely adapted to food production). It also gives the opportunity to develop systems suitable for long term fixation of carbon, as long as the plant material is not reoxidised to carbon dioxide. Plant fibres could provide raw material for the production of paper or building materials in combination with the production of organic selenium compounds preferentially accumulated in another fraction of the processed plant.     

Biological factors influencing the transmission of potato leafroll virus by different aphid species

Summary Macrosiphum euphorbiae, collected in the field from potato plants infected with potato leafroll virus (PLRV), transmitted the virus to fewer potato plants in a field trial than did laboratory-rearedMyzus persicae. In the laboratory,M. persicae was the only efficient vector of PLRV fromPhysalis floridana seedlings, potato sprouts or excised leaves toP. floridana. Two clones ofM. euphorbiae and one clone ofAulacorthum solani transmitted PLRV from infected potato plants toNicotiana clevelandii as effeciently asM. persicae but a clone ofAphis gossypii was an inefficient PLRV vector. An isolate of PLRV, whichM. persicae transmitted inefficiently from potato toN. clevelandii, was also transmitted inefficiently byM. euphorbiae andA. solani.