大豆种子寄藏真菌病害和寄藏真菌检测技术

大豆种子寄藏真菌通过侵染大豆种子、叶、茎、豆荚和花,寄藏于大豆种子的种皮、胚和胚乳等组织中,直接影响种子萌发或降低幼苗活力,导致大豆品质下降、产量降低,严重影响大豆的生产。文章介绍了大豆寄藏真菌的种类,重要寄藏真菌拟茎点菌属(Phomopsis spp.)、尾孢属(Cercospora spp.)和刺盘孢(Colletotrichum spp.)的研究现状,寄藏真菌的检测方法和防治技术,对于大豆病害的预测、预报和防治具有重要的意义。     

大豆拟茎点种腐病菌和其他拟茎点霉属病菌对大豆的致病性

大豆拟茎点种腐病主要影响大豆种子的品质。该病是由病原真菌Phomopsis longicolla引起。该研究利用大豆品种Williams82对分离自大豆的拟茎点种腐病原菌Phomopsis longicolla和分离自其他寄主植物的拟茎点霉属Phomopsis其他病原菌48个菌株对大豆进行致病性比较,病原菌被接种到生长2周的大豆植株上,以大豆植株的茎长和病斑长度进行比较。试验结果显示,被测的病原菌株间对大豆致病性存在显著性差异（P≤0．0001）。     

土壤扰动对寄生真菌代谢物温室防治大豆胞囊线虫的影响

大豆胞囊线虫是影响大豆产量的主要限制性病原。大豆胞囊线虫的自然抑制性是存在的,并且日益受到关注,然而在胞囊线虫生态抑制方面的研究却很少。研究在温室条件下接种真菌后以扰动(土壤过0.5 cm孔筛)为土壤微环境并与无干扰对比,用厚垣轮枝菌(Pochonia chlamydosporium)、镰孢菌(Fusarium spp.)和淡紫拟青霉(Paecilomyces lilacinus)的混合代谢物分别对大豆胞囊线虫进行处理,探讨其对大豆胞囊线虫温室盆栽防效的影响。在接种二龄幼虫(J2)35 d后,对大豆胞囊线虫密度调查结果表明:土壤扰动条件下,接种混合代谢物与不接种混合代谢物相比,雌虫数量降低20.0%~35.9%,胞囊数量降低18.3%~35.0%,卵量降低21.5%~38.5%,根内J2数量降低14.6%~35.3%,其中以4号混合代谢物扰动对大豆胞囊线虫密度降低作用显著;土壤不扰动下,接种混合代谢物与不接种混合代谢物相比,雌虫密度降低19.5%~32.7%,胞囊密度降低19.5%~35.2%,卵量降低21.1%~37.8%,J2数量降低8.0%~27.6%,仅雌虫和根内J2数量与不接种混合代谢物对照差异显著,菌株之间差异不显著。对大豆植株生长发育调查结果表明:扰动可能会促进植株生长、植株鲜重增加,但与不扰动差异不显著。试验证明:扰动对盆栽大豆胞囊线虫雌虫、胞囊、卵和J2的密度有一定的影响,扰动有增强寄生真菌代谢物对胞囊线虫温室防效效果的趋势,对降低大豆胞囊线虫密度起到积极作用。真菌对大豆胞囊线虫生长发育具有抑制作用,土壤扰动干扰和真菌代谢物的配合应用会降低土壤中胞囊线虫的密度,并影响真菌在土壤中的生防效果。     

一株大豆腐霉菌(PSHH1)rDNA的ITS序列鉴定

大豆腐霉菌是黑龙江省大豆根腐病菌群的重要组成部分,为了明确大豆腐霉菌的种类,从黑龙江省黑河市大豆根系土壤分离获得1株腐霉菌PSHH1,应用r DNA-ITS序列分析法对其进行菌种鉴定。Blast和系统进化树结果表明:PSHH1与Gen Bank上登录号为AB259316.1和AB512973.1等的Pythium sylvaticum亲缘关系最近,r DNA-ITS序列同源性大于99%,因此认定PSHH1为Pythium sylvaticum。为了考察PSHH1的致病性,选取了60份当前大豆主栽品种,应用种子腐烂法和下胚轴接种法进行回接试验,通过计算种子腐烂率和植株茎折率来评价PSHH1的致病性,结果显示,PSHH1仅对13.33%的大豆主栽品种表现出较强的致病力,而对61.67%的大豆主栽品种致病力较弱。     

接种AMF对间作大豆生长及有机磷利用的影响

为了研究接种丛枝菌根真菌(AMF)与间作种植模式对红壤上间作大豆磷素吸收利用及生长的影响,通过三室隔网盆栽模拟试验研究了分室磷[不添加磷(P0)、有机磷(OP50)添加和根室不接种(NM)、根室接种丛枝菌根真菌Glomus mosseae(GM)]对大豆生长及磷素利用的影响。结果表明:在OP50处理下,无论何种种植模式,不接种处理下根长均显著高于接种处理,无论接种与否,单作处理下大豆根长均高于间作处理。在OP50处理下,接种GM处理地上部分生物量均明显高于不接种处理,在P0处理下地上部分生物量具有相同趋势。间作处理下,分室添加磷与不添加磷时,GM处理的植株生物量较NM处理分别提高了27.52%和48.76%。单作处理下,分室添加磷与不添加磷时,GM处理的植株生物量较NM处理分别提高了28.49%和27.65%。大豆植株根系磷含量在单作-GM-OP50组合处理下最高。在接种GM处理下,无论是否添加磷,间作大豆根系磷吸收效率均显著高于单作处理。因此,综合菌根侵染率、生物量、磷含量以及磷吸收效率等指标,接种GM和分室添加50 mg·kg-1有机磷处理能更有效地促进间作大豆的生长及磷素的吸收。     

AMF接种与作物根系分隔方式对紫色土上间作大豆生长及磷素吸收的影响

比较了不同丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)接种状况[不接种(NM)、接种Glomus mosseae(GM)、接种Glomus etunicatum(GE)]和玉米/大豆间作体系不同根系分隔方式(不分隔,隔尼龙网,隔塑料布)对大豆植株生长及磷素吸收累积的影响。结果表明:接种GM和GE处理下的间作大豆根系侵染率在不同根系分隔方式之间无显著差异,接种AMF抑制了间作大豆根系的伸长,其中接种GM处理能使大豆生物量显著提高,并在根系不分隔处理下使大豆对磷素吸收较多而生长较好,接种GE真菌则不能促进大豆对磷素的积累。间作体系不同根系分隔方式对大豆的影响也不同,其中大豆的根系长度在隔塑料布处理下最短,大豆生物量在根系分隔处理下均大于不分隔处理,根系不分隔处理能够较好的促进大豆对磷素的积累。所有复合处理中,以GM-不分隔处理组合对间作大豆的生长及磷素累积的促进作用最好。     

哈茨木霉抗多菌灵突变株对大豆菌核病的诱导抗性生理

通过测定接种菌核病菌后不同时间大豆植株抗逆酶活性的变化,研究了土壤中施用拮抗真菌哈茨木霉菌及其抗多菌灵突变株对植株抗逆生理的影响。结果表明:哈茨木霉突变菌株的处理对SOD酶的诱导出现较早,在接种4 h后酶活开始增强,而接种后36 h相比对照可提高67%以上;接种72 h后POD酶活比对照提高27.3%;而MDA含量与对照相比,却始终处于相对较低水平。表明哈茨木霉菌抗多菌灵突变株的应用具有诱导植株抗逆酶活性提高及增强植株抗病能力的作用。     

大豆菌核病鉴定方法比较及分析

大豆菌核病鉴定方法对于大豆菌核病的研究至关重要,本文比较了子叶接种、离体茎段接种、离体叶片接种和离体茎的草酸反应4种大豆菌核病鉴定方法.结果表明:利用子叶接种法接种5 d后所有植株的子叶全部干枯皱缩,10 d后敏感品种合丰25植株开始萎蔫变黄,接种部位周围开始出现白色菌丝;15 d后植株布满白色菌丝;20 d后发病植株开始死亡;而耐性品种MAPLEARROW出现这些症状的时期较晚,死亡率也较低.离体茎段接种法和离体叶片接种法,基本上体现了大豆菌核病的主要致病特征.在离体茎的草酸接种中,合丰25和MAPLE ARROW对草酸的敏感度明显不同,且受害程度有明显差别,是一种方便快捷而且准确性较高的鉴定方法,对于大量种质资源筛选有着重要意义.     

扁茎大豆的花序形态受光周期的调控研究

以扁茎大豆、正常圆茎大豆、扁茎大豆与正常圆茎大豆杂交选育的高代品系为材料,分别进行短日照(12h)和长日照(16h)处理,观察光周期对扁茎大豆及正常圆茎大豆发育速度和形态特征的影响.结果表明,光周期不仅明显影响大豆的开花期、成熟期,而且调控顶端花序的形态.在长日照下,供试大豆品种生殖发育明显受到抑制,开花期延迟,在北京夏播条件下不能正常成熟;扁茎大豆、扁茎大豆与正常圆茎大豆杂交选育的高代品系植株顶端花序轴伸长,部分材料的花序轴上产生侧生花序,但均未象在原产地一样出现扁平、加宽的花序.在短日照条件下,不论是扁茎大豆还是正常圆茎大豆,发育速度均加快,植株顶端为典型的总状花序,花序轴较短,扁茎大豆也未出现扁茎及顶端花序簇集的现象.本实验的结果说明扁茎大豆植株顶端的茎秆扁化、花荚簇集的性状可因光周期等环境因素的变化而变化,是不稳定的性状.对扁茎性状形成和变化的原因亦进行了分析.     

不同氮素水平下接种根瘤菌对大豆生长的影响

通过田间小区试验,在高氮素(73.80kg N/hm2)和低氮素(32.40kg N/hm2)两个水平下接种大豆根瘤菌,比较不同处理大豆花期植株地上部生物量的积累和籽实的产量及产量构成情况。结果表明,较高氮素水平条件下接种大豆根瘤菌对大豆植株地上部生物量的积累和大豆产量的增加都较为明显,与其他处理相比产量增加在8.4%以上,而低氮素水平下接种根瘤菌增产效果不明显。在不接种根瘤菌的情况下,高氮素水平下的产量低于低氮素水平产量。建议今后大豆生产上在保证适量施用氮肥的情况下应接种大豆根瘤菌,这样才能够起到增产及增加肥料利用率的作用。     

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.     

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.     

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.     

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.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.     

Recent Modifications of Chitosan for Adsorption Applications: A Critical and Systematic Review

Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase).