黑土层厚度及心土培肥对大豆产量的影响

在盆栽试验条件下,以典型岗地白浆土土层结构为基础,通过改变黑土层的厚度研究了心土层对大豆产量的贡献;并通过混施磷肥和钙肥,研究了心土培肥的效果。结果表明:随着黑土厚度的增加,大豆株高和产量显著增加,白浆土心土对大豆产量的贡献很低,仅为4.7%;各心土培肥处理比心土混层增产9.7%～18.1%,比白浆土原状土壤增产16.0%～34.1%,土壤施磷后增加了Ca2-P、Ca8-P和Al-P的含量。因此,白浆土心混施钙磷肥对大豆有显著的增产效果。     

黑土肥力与大豆产量及品质的通径分析

为解析黑土肥力变化对大豆产量及品质的影响,从而有针对性地调节大豆产量与品质,以黑土坡耕地为研究基础,以单施化肥(不施用有机物料)为对照,分别配施有机肥、秸秆、生物炭3种有机物料对土壤进行培肥研究.采用相关分析、多元逐步回归和通径分析法,分析了不同培肥措施下坡耕黑土肥力变化及其对大豆品质与产量的影响.结果表明,有机培肥处...     

硼素对甜菜产质量效应及施用技术的研究

试验结果表明,不同土壤类型,硼素施用效果不同.黑土区在NP基础上施硼平均增产块根11％,含糖提高0.3～0.9度,产糖量平均提高15％.在碳酸盐黑钙土区,施硼效果不明显.硼与氮、磷、钾的最佳配比为:N:P_2O_5:KaO:B=1:1.6:1:0.07.要素总用量为11.2kg/亩.土壤中有效硼的临界值为0.5ppm。试验还看出,施硼有明显提高叶绿素含量和促进生长发育作用,     

砂壤质潮土夏玉米适宜的化肥种类研究

采用田间试验研究Agro Services International Inc（ASI）推荐施肥、缓/控释肥、保水型复混肥和普通复混肥对夏玉米产量、SPAD值及养分吸收积累的影响。结果表明,夏玉米施用缓/控释肥和ASI推荐施肥增产效果较好,分别比农户习惯施肥处理增产11.0%和9.8%,保水型复混肥没有显著增产效果。夏玉米专用缓/控释肥养分缓慢释放可弥补砂壤质潮土保肥性差的缺点,能维持夏玉米各生育时期较高的叶片叶绿素含量,促进夏玉米对氮、磷、钾养分的吸收利用,提高干物质积累量,具有显著增产效果,是砂壤质潮土区夏玉米适宜的化肥品种。     

高产玉米施硫增产效应与机制研究

对11250kg/ha产量水平的高产玉米施硫肥有显著的增产效果，增产幅度可达14.6%。施硫肥玉米根层数和根条数增加，根系活力提高，叶片叶绿素含量增加．硫肥还促进植株对氮、磷、钾的吸收并使籽粒灌浆速度加快。     

淮北平原大豆施氮磷钾肥的初步研究

砂姜黑土是淮北平原的主要土壤类型,多为麦豆两熟制,其中大豆单产较低,长期徘徊在100多斤。为了迅速提高大豆产量,改进品质,我们于1981—1982年初步研究了氮、磷、钾肥的增产效应,土壤供肥及植株养分含量与产量的关系。     

夏大豆的干物质积累和氮磷钾吸收分配动态的研究

夏大豆产量的高低与各生育期的生长发育状况,养分吸收代谢有密切关系。夏大豆在亩产182kg的产量水平下,每生产100kg籽粒,需要N7.7kg,P_2O_5 2.3kg,K_2O 4.9kg。夏大豆干物质积累的特点是,结荚至鼓粒期积累最快,积累率为35.3％,每株日增重21.7g。夏大豆吸收氮磷钾的数量随生育阶段而不同。植株氮磷钾含量是生育前期高于生育后期。而吸收量以结荚至鼓粒期吸收最多,氮、磷、钾吸收量分别占总吸收量的26.9％,30.9％,38.9％。鼓粒期以后,植株中氮、钾含量明显下降,唯有磷素还在继续吸收。     

不同磷源对橡胶树幼苗生长及土壤磷素组分特征的影响

通过盆栽试验及Hedley土壤磷素分组法研究了海南省玄武岩发育砖红壤上施用不同磷源对橡胶树幼苗生长的影响及土壤磷素组分变化。磷肥处理分别为不施磷处理、施用昆阳磷矿粉100 mg/kg(以全P计,下同)、施用昆阳磷矿粉250 mg/kg和施用普通过磷酸钙100 mg/kg。结果表明:施用磷矿粉和普通过磷酸钙均显著增加了橡胶树幼苗干物重、株高、茎粗和吸磷总量,但高磷矿粉处理和普通过磷酸钙处理橡胶树幼苗叶片磷含量显著降低;高磷矿粉处理取得了与普通过磷酸钙相当的肥效;磷矿粉施用后,土壤树脂提取态磷(Resin-P)、碳酸氢钠提取态无机磷(NaHCO_3-Pi)、氢氧化钠提取态无机磷(NaOH-Pi)、盐酸提取态磷(HCl-P)和残余态磷(Residual-P)等组分含量均显著增加,但碳酸氢钠提取态有机磷(NaHCO_3-Po)和氢氧化钠提取态有机磷(NaOH-Po)不受施磷影响;干物质重和吸磷总量均与土壤Resin-P、NaHCO_3-Pi和Na OH-Pi呈显著的正相关关系;磷矿粉施用11个月后,平均33.1%磷矿粉溶解在土壤中,平均43.5%的磷矿粉残留在土壤Residual-P组分中。为改善玄武岩发育砖红壤上有效磷及橡胶树磷素营养状况,应选择施用高活性磷矿粉以降低磷矿粉颗粒被大量包被的风险。     

玉米秸秆还田对土壤肥力的影响

利用田间微区方法连续3年在沈阳地区草甸土研究玉米秸秆粉碎后直接还田对土壤基本理化性质的影响。结果表明,施用有机物料不仅能够改善土壤的理化性质、培肥地力,还能增加玉米产量,增产效果没有无机肥的增产效果显著。与单施无机肥相比,无机肥配施有机物料能够增加土壤有机质含量,降低土壤容重,提高土壤田间持水量和土壤孔隙度,同时改善土壤的氮、磷、钾养分状况。在等碳量的条件下,玉米秸秆对保持和提高土壤有机质含量的效果好于猪粪肥。     

追肥方式对连作大豆生长发育和产量的影响

采取适当农艺措施可降低连作大豆产量损失,为明确黑土平原区不同追肥方式对连作大豆的效果,在生育后期喷施叶面肥或沟施氮肥,调查大豆根瘤鲜重、植株地上地下干重、叶面积指数和产量.结果显示:后期增施肥能增加根瘤鲜重,是对照的1.3～1.6倍,大豆地上地下干重都明显高于对照,叶面积指数增大.在黑土平原区后期追肥较对照大豆增产11%以上,病虫粒率降低,提高商品品质.喷施叶面肥和土壤追肥的大豆生长发育指标和产量差异不显著(P<0.05).     

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).