甜菜种子萌发中某些生理生化过程的变化

本实验对甜菜种子萌发过程中的贮藏物质以及呼吸强度、过氧化氢酶活性、酯酶同工酶的变化进行了研究。研究结果表明:在种子萌发初期淀粉含量下降,还原糖含量增加,蔗糖在种子萌发24小时之内就消耗殆尽,蛋白质在萌发初期就存在着合成作用;种子萌发初期呼吸强度、过氧化氢酶活性、酯酶同工酶活性明显增强,可作为种子活力的生理生化指标;不同类型品种间的物质转化速度及代谢强度,均表现为高糖型品种大于丰产型品种,因此,这些代谢特点又可作为早期品种选择的参考生理指标。     

甜菜种子活力鉴定指标的研究

对不同种子活力的甜菜种子发芽率、发芽势、活力指数、发芽指数、物质效率、贮藏物质运转率以及种子萌发时期酸性磷酸酯酶、脱氢酶活性进行了比较研究,结果表明,高活力种子的发芽势、发芽率、活力指数、物质效率、贮藏物质运转率均大于低活力种子。种子萌发24h后,高活力种子中酸性磷酸酯酶活性大于低活力种子,萌发初期,胚根中的脱氢酶活性也表现为高活力种子大于低活力种子。依据可重复性和可操作性原则,种子贮藏物质运转率、胚根脱氢酶活性可作为鉴定甜菜种子活力大小的可靠生理指标。     

贮藏时间对油菜种子生理生化性状的影响

本文以贮藏在常温密封干燥条件下的油菜种子为材料,研究与种子活力有关的理化特性。结果表明,油菜种子活力与电导率呈负相关;活力较低的种子可溶性糖和蛋白质的外渗量明显增加,超氧化物岐化酶、过氧化氢酶活性以及维生素C含量明显下降。     

花生种子生活力与呼吸强度及ATP含量的关系

呼吸作用提供植物生命活动所需的大部分能量,是植物代谢的中心。呼吸作用释放出来的能量一部分转变为热能而散失掉,一部分以ATP(三磷酸腺苷)形式贮存着。因此,呼吸作用与ATP含量关系密切。种子中ATP含量水平在调节种子萌发的代谢中起着重要作用。许多植物种子的ATP含量与种子的活力呈正相关。 花生种子生活力与呼吸强度及ATP含量的关系未见报道。探讨种子在劣变过程中生活力     

酸雨对大豆萌发种子能量代谢的影响

为了探索酸雨对大豆种子萌发时能量代谢的影响,采用pH值分别为2.5.4.0的模拟酸雨及宅内培养方法,测定不同酸雨胁迫强度对种子的ATP含量、能荷、过氧化氢酶活性、线粒体活性及呼吸速率的影响.结果表明:随着酸雨胁迫时间的延长,种子萌发ATP含量、能荷含量及过氧化氢酶活性呈先升后降的趋势,线粒体活性呈先升后降再平稳的趋势,呼吸速率呈现降-升-降-升的变化趋势.随着酸雨胁迫强度逐渐减弱,种子的ATI含量、能荷含量、过氧化氧酶活性及线粒体活性均逐渐升高.酸雨伤害增强,大豆种子呼吸作用与能量代谢减弱,酸雨胁迫强度与大豆萌发种子各呼吸指标间呈现剂量-效应关系.     

马铃薯实生种子活力的研究

本试验以贮藏不同年限的马铃薯实生种子为材料,对其活力和反映活力状况的若干生态和生理生化指标进行了研究,从种子活力的角度测定了种子的实用价值。主要结果是:马铃薯实生种子随着贮藏年限的延长,其发芽率、发芽势、发芽指数、活力指数渐趋降低,幼苗生长速度减慢;砂培出苗率和出苗整齐度比普通发芽试验的发芽率和发芽势更能确切地反映种子的活力;随着种子活力的下降,其内部的脂肪酸价升高,种子浸出液的相对电导率增大;活力高的实生种子,其过氧化物酶同工酶酶带较活力低的实生种子数量多,颜色深,酯酶同工酶亦有相似的结果;同薯8号和克疫两品种的实生种子活力下降的速度不同,前者慢、后者快;马铃薯实生种子在一般室内温湿度贮藏条件下,经8年或更长时间贮藏后,仍具有种用价值,可作播种材料;马铃薯实生种子活力的测定,采用活力指数或发芽指数较其它生态指标更具有适用性和可靠性。脂肪酸价和相对电导率作为活力测定的生理生化指标对劣变速度快的实生种子是灵敏而适用的。     

胚乳裂纹对玉米种子萌发过程中保护酶活性的影响

以玉米杂交种种子为试验材料,研究胚乳无裂纹、胚乳单裂纹、胚乳双裂纹和胚乳龟裂文种子在萌发过程中超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）3种保护酶活性以及丙二醛（MDA）含量和细胞膜透性的变化规律。结果表明,随着种子萌发进程推进,其SOD、POD、CAT活性和细胞膜透性均呈逐步上升趋势,保护酶活性升高幅度表现为POD最大、CAT次之、SOD最小;不同胚乳裂纹类型种子在萌发过程中,其保护酶活性均表现为龟裂文种子 <双裂纹种子 <单裂纹种子 <无裂纹种子。种子萌发过程中其MDA含量呈逐步下降的变化趋势,并表现为龟裂文种子中MDA含量最高,双裂纹的种子次之,无裂纹的种子最低。说明胚乳裂纹对种子萌发代谢具有不利影响,在种子生产中应该减少胚乳裂纹产生。     

不同贮藏条件对花生种子活力的影响及其生理机制的研究

研究了花生种子含水量、贮藏温湿度、贮藏容器对花生种子活力的影响及其生理机制。结果表明,温度是影响花生种子活力及寿命的主要因素,花生种子在高温条件下贮藏活力下降快,在２０℃以内种子受环境湿度影响较小,寿命长,贮藏９～１２个月仍具有种用价值。种子含水量低贮藏寿命长,南方花生种子的安全含水量是５％ ～６％ 左右。湿度低种子贮藏寿命长,适宜的环境湿度似在５２％ 左右。研究还阐明了不同贮藏条件和种子水分对种子生理代谢的影响及与种子活力的关系,为春花生种子妥善贮藏提供了依据。     

过氧化氢浸种对大豆种子萌发的生理生化效应

为探明过氧化氢浸种对大豆种子萌发的影响,测定了过氧化氢浸种的大豆种子萌发期POD、SOD、PPO酶活性,电解质外渗率和种子发芽情况,旨在探讨提高种子活力的途径.结果表明,过氧化氢浸种可以提高大豆种子的活力和相关酶的活性.0.1%过氧化氢处理明显提高种子发芽率、活力指数和POD、SOD活性;0.01%处理明显提高种子的电解质外渗率和PPO活性.     

萌发棉子腺苷磷酸含量变化研究

种子在萌发过程中,需要耗费大量的生物能。种胚内含能化合物ATP、ADP、AMP的供给量是种子萌发和幼苗生长的重要因素。国内外曾先后有人用荧光素酶法测定吸胀种子ATP含量,探讨其与种子活力的关系。在棉花种子活力的研究中,光子与毛子     

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.     

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.     

La pourriture fongique des tubercules de pomme de terre en atmosphère contrôlée

Résumé Fusarium culmorum et, dans une moindre mesure,F. avenaceum, F. sambucinum, Colletotrichum coccodes etCylindrocarpon sp. ont été isolés de tubercules entreposés en atmosphère contr?lée (AC) et atteints de pourriture grave. Des expériences d'inoculation de tubercules avec 10 espèces ou variétés fongiques et conservation en AC à 8 et 10°C ont montré que: 1) les champignons non pathogènes en atmosphère normale (ex.:Cylindrocarpon sp.) le devenaient en AC, 2) ceux qui étaient faiblement pathogènes en atmosphère normale étaient nettement plus virulents en AC (ex.:F. culmorum), 3) les espèces ou variétés virulentes en conditions d'air normales (Fusarium sulphureum etPhoma exigua var.foveata) ne provoquaient pas de pourriture plus grave en AC et leur activité pouvait même être légérement freinée.

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Summary The extensive rotting of tubers which occurred during storage trials in controlled atmospheres has led to a mycological and pathological study of the rots. The most frequently isolated species wasFusarium culmorum althoughF. avenaceum, F. Sambucinum, Coletotrichum coccodes and aCylindrocarpon sp. were also present. Tubers of cvs Bintje and Ulla were inoculated with 19 isolates of 10 fungal species or varieties associated with rotting of stored tubers (Table 1). The tubers were incubated at 8 or 10°C in normal or controlled (2% O₂:1% CO₂, 2% O₂:6% CO₂, 2% O₂:12% CO₂, 6% O₂:6% CO₂) atmospheres and the extent of rotting was determined a month later (Tables 2 and 3 and Fig. 2). Species which were weakly virulent in a normal atmosphere (variousFusarium spp. andPhoma exigua var.exigua) were clearly more aggressive in the controlled atmosphere and this was especially evident in the case ofF. culmorum. Species ot pathogenic in a normal atmosphere under experimental conditions (Colletotrichum coccodes, Cylindrocarpon sp.,Phoma eupyrena) caused rotting in the controlled atmosphere. The two species which were virulent in a normal atmosphere (F. sulphureum andP. exigua var.foveata) were also virulent in the controlled atmosphere and in some cases the extent of rotting was even less. As a general rule, rotting caused by weakly virulent fungi was greater in both cultivars in the controlled than in a normal atmosphere.

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Zusammenfassung Eine starke F?ulnis von in Kontrotrollierter Atmosph?re gelagerten Kartoffelknollen veranlasste eine mykologische und pathologische Untersuchung. Der am h?ufigsten isolierte Pilz warFusarium culmorum. F. avenaceum, F. sambucinum, Colletotrichum coccodes undCylindrocarpon sp. wurden ebenfalls bestimmt. Neunzehn St?mme von 10 Pilzsorten oder-Arten welche bei Lagerf?ulnis vorkommen (Tab. 1) wurden auf Knollen der Sorten Bintje und Ulla inokuliert. Die Lagerung wurde bei 8 oder 10°C under Normalbedingungen oder kontrollierter Atmosph?re durchgeführt (2% O₂:1% CO₂, 2% O₂:6% CO₂, 2% O₂:12% CO₂, 6% O₂:6% CO₂). Der F?ulnisgrad (Abb. 1) wurde nach einem Monat bonitiert. Die Ergebnisse sind in den Tabellen 2 und 3 dargestellt und in der Abb. 2 illustriert. Unter in Normalbedingungen nur schwach virulente Arten (verschiedeneFusarien undPhoma exigua var. exigua) waren deutlich aktiver in kontrollierter Atmosph?re. Dies was besonders der Fall fürF. culmorum. Pilze, die im Versuch unter Normalbedingungen nicht pathogen waren (Colletotrichum coccodes, Cylindrocarpon sp., Phoma eupyrena), haben unter kontrollierter Atmosph?re Sch?den verursacht. Hingegen werden die beiden unter Normalbedingungen sehr pathogenen Arten (F. sulphureum undP., exigua var.foveata), durch kontrollierte Atmosph?re wenig beeinflusst. Es wurde sogar in einigen F?llen eine gewisse Verringerung des F?ulnisbefalls beobachtet. Ganz allgemein haben die getesteten kontrollierten Bedingungen die Entwicklung der Pilzf?ulnis an beiden Kartoffelsorten gef?rdert, speziell durch Pilzarten, welche unter Normal-bedingungen wenig Sch?den verursachen.

     

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).     

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.