施氮量对春小麦根系生长及产量的影响

为探讨施氮量对春小麦根系生长及产量的影响,选用龙麦26和龙麦33为试验材料,分析了不同施氮水平(45、60、75、90和105 kg·hm-2)下春小麦根系性状和籽粒产量的差异.结果表明,施氮量对春小麦根系生长有影响,但在不同根系性状上表现不同.随着施氮量的增加,根系总长、干重、活力呈先升后降趋势,根面积和体积呈升高趋势,根平均直径和根冠比呈下降趋势.春小麦产量也显著受施氮影响,并随施氮量的增加呈先升后降趋势.两个品种均在75～90 kg·hm-2施氮量下获得较好的根系生长状况和增产效果.说明合理施氮可通过促进春小麦根系生长而提高籽粒产量.     

密度和施氮量对啤酒大麦氮素吸收利用及籽粒蛋白质含量的影响

为了给啤酒大麦优质高产栽培提供参考,选用甘啤4号为供试材料,采用裂区试验设计,主区为种植密度,设325万株·hm-2(D325)、375万株·hm-2(D375)和425万株·hm-2(D425)三个水平;副区为施氮量,设0(N0)、75kg·hm-2(N75)、150kg·hm-2(N150)、225kg·hm-2(N225)和300kg·hm-2(N300)五个水平,研究了密度和施氮量对啤酒大麦氮素积累、利用及籽粒蛋白质含量的影响。结果表明,种植密度仅对氮素利用效率有显著性影响,且随着密度增大氮素利用效率也增大。施氮量对籽粒清蛋白和球蛋白含量影响不显著,对植株氮素浓度、产量及籽粒醇溶蛋白含量等影响均达显著水平;随着施氮量增加,植株氮素浓度和氮素积累量均表现为先增大后减小,且均在N225处理达到最大;产量(y)随施氮量增加而增加,且与施氮量(x)可建立二次方程:y=-0.003x2+5.846 6x+2 748.7(R2=0.966 5);氮素吸收效率、氮素利用效率和氮素收获指数与施氮量均呈极显著的负相关,相关系数分别为-0.97、-0.95和-0.96;氮肥生理利用率、表观利用率和农艺利用率也在不同种植密度和施氮处理下存在差异;籽粒总蛋白、醇溶蛋白和谷蛋白含量与施氮量呈显著正相关,相关系数分别为0.99、0.97和0.99。种植密度和施氮量的互作对氮素利用效率、氮素收获指数和醇溶蛋白含量有显著影响,对其余指标的影响均不显著。     

不同施氮水平对胡麻根系形态和氮素利用的影响

以陇亚杂1号为研究对象,设置4个施氮量(纯N)水平:不施氮(N0,0kg·hm-2)、低氮(N1,78.75kg·hm-2)、中氮(N2,105kg·hm-2)、高氮(N3,131.25kg·hm-2),采用土柱栽培法研究了氮肥运筹对胡麻根系形态和氮素利用率的影响。结果表明:施氮抑制了胡麻枞形期根系的生长,现蕾期后根长、根系直径、根表面积和根体积均随着施氮量增加而增加,当超过一定施氮量(N2)时又呈下降趋势。中氮处理增加了胡麻生育后期根系在40cm以下土层的分布,随着施氮量的增加,根系分布呈现高氮(N3)浅根化趋势。胡麻的根冠比随着生育进程的推进逐渐降低,但中氮处理显著提高了生育后期的根冠比。胡麻成熟期各器官氮素积累量和分配比例表现为:籽粒茎根叶非籽粒生殖器官,籽粒在氮素的分配上占有绝对优势,而且在中氮水平(N2)时籽粒中氮素分配比例最高,显著高于其他处理。与不施氮相比,施氮处理下籽粒产量增加,中氮水平下的氮素籽粒生产效率最高。综合籽粒产量和氮素利用结果表明,在本试验条件下,施氮量105kg·hm-2为有利于实现胡麻高产和高效的最优氮肥运筹模式。     

氮肥运筹对稻茬小麦干物质、氮素转运及氮素平衡的影响

为给稻茬小麦高产、优质栽培中合理施氮提供依据,以低蛋白小麦品种宁麦9号和高蛋白小麦品种豫麦34号为材料,设置不同施氮水平(0、150、225和300 kg·hm-2)及基追比(基肥∶追肥为1∶9、3∶7、5∶5和7∶3),研究氮肥运筹对小麦植株C-N积累与转运规律、产量、蛋白质含量及氮素利用的影响。结果表明,适当增加施氮量及追肥比例可同步提高两小麦品种籽粒产量和蛋白质含量。随施氮量和追肥比例的增加,两品种干物质转运量均呈先增后降的趋势,而干物质转运效率及其对籽粒产量的贡献率则显著降低。营养器官氮素转运量随施氮量增加而增加,随追肥比例增加先增后降;氮素转运率及其对籽粒氮素贡献率则随施氮量和追肥比例增加而下降。相关分析表明,提高花后干物质积累是提高小麦产量的重要途径,而促进花前营养器官贮存氮素向籽粒的转运是提高小麦蛋白质含量的重要措施。增加施氮量和基肥比例显著增加了两品种氮素的表观损失量并降低了氮素利用效率。本试验条件下,增施氮肥至225 kg·hm-2,追肥比例宁麦9号≤50%、豫麦34号为50%～70%可同步提高两品种籽粒产量、品质和氮素利用效率,降低氮素损失。     

拔节期追氮对冬小麦产量、效益及氮素吸收和利用的影响

为探讨豫北地区合理的氮肥施用模式,以周麦18和济麦22为材料,分析了拔节期追氮对冬小麦籽粒产量、经济效益及氮素吸收和利用的影响.结果表明,在底施纯氮120 kg·hm-2的基础上,随拔节期追氮量的增加,籽粒产量呈先增后降趋势,籽粒产量与追氮量之间可用二次曲线方程进行拟合.周麦18和济麦22在追氮140 kg·hm-2(N260)处理下籽粒产量和经济效益较高.随追氮量的增加,植株氮素积累总量增长缓慢且有下降趋势,籽粒氮素收获指数、追施氮素利用效率和氮肥偏生产力显著降低,追施氮肥农学利用效率呈先升后降变化趋势.拔节期追氮促进了营养器官氮素向籽粒中转运.各追氮处理下,周麦18和济麦22籽粒氮素分别有81.53％～88.62％和79.65％～89.10％来自营养器官氮素的转运.综合来看,底施氮肥120kg·hm-2结合拔节期追氮140～180 kg·hm-2是豫北地区小麦高产高效的氮肥施用模式.     

免耕覆盖条件下氮磷配施对旱地小麦氮素积累、分配及产量的影响

为给免耕覆盖条件下旱地小麦高产和氮肥管理提供理论依据,通过大田试验研究了150kg·hm-2和180kg·hm-2两种施氮水平下不同氮磷配比(1∶0.5、1∶0.75、1∶1)对旱地小麦植株氮素积累和转运、氮利用效率及产量的影响。结果表明,在1∶0.5和1∶0.75氮磷配比下,增加施氮量可提高小麦开花和成熟期植株氮素积累量、营养器官花前贮存氮素转运量及其对籽粒氮素的贡献率,并最终提高产量、籽粒蛋白质含量及氮素收获指数;在氮磷比为1∶1时,增加施氮量则表现出相反的结果。在低氮(150kg·hm-2)条件下,增施磷肥可提高开花期和成熟期地上部氮素积累量、营养器官花前贮存氮素转运量及转运效率,并提高产量、籽粒蛋白质含量、氮肥利用率、氮肥偏生产力和氮素收获指数;高氮(180kg·hm-2)条件下,上述指标则随着施磷量的增加呈先升后降的趋势。总体来看,1∶0.75的氮磷比最有利于小麦植株氮素吸收及营养器官花前贮存氮素向籽粒的转运,并最终获得了最高的籽粒产量、氮肥利用率及氮素收获指数。     

施氮对滴灌春小麦干物质积累、转运及产量的影响

为给滴灌春小麦氮素科学管理提供参考,在大田条件下,以新春6号和新春35号为供试材料,研究施氮量(0、75、150、225、300、375kg·hm-2)对滴灌春小麦干物质积累、分配和转运的影响。结果表明,在一定范围内,施氮可促进滴灌春小麦干物质积累和转运,新春6号和新春35号分别以施氮225和300kg·hm-2的效果最佳。新春35号最大干物质积累速率、最大积累量和生育期均大于新春6号。两品种的籽粒产量均随着施氮量的增加呈先增后降的趋势,新春6号和新春35最高产量的施氮量分别为288和335kg·hm-2。新春6号千粒重大于新春35号,而穗粒数小于新春35号。因此,滴灌春小麦应根据品种对氮素的需求特点,合理施氮。     

施氮对冬小麦旗叶蔗糖含量及籽粒淀粉合成的影响

为给小麦高产优质栽培提供依据,在高产田块上,设置三个氮肥用量(90、180、270 kg N·ha-1),研究了施氮对两个冬小麦品种豫麦49和太空6号开花后旗叶蔗糖、籽粒淀粉合成动态及产量的影响.结果表明,施氮对两品种旗叶蔗糖含量及SPS酶活性、籽粒蔗糖含量及SS酶活性、籽粒淀粉积累速率及产量均有显著影响,但影响特点因品种而异.豫麦49在施氮量90～270 kg·ha-1范围内,随施氮量的增加,旗叶和籽粒的蔗糖含量、SPS和SS活性以及籽粒淀粉积累速率均呈增加趋势.太空6号在施氮90～180 kg·ha-1范围内,上述指标在灌浆中后期与施氮量呈正相关;当氮肥用量增加至270 kg·ha-1时,各项指标均下降.相关分析表明,两供试冬小麦品种籽粒蔗糖含量与旗叶蔗糖含量分别呈极显著和显著正相关(豫麦49 r=0.703**,太空6号r=0.530*);豫麦49籽粒淀粉积累速率与其籽粒蔗糖含量和SS活性之间呈显著和极显著正相关(r=0.578*,r=0.701**),太空6号籽粒淀粉积累速率仅与籽粒SS之间呈显著的正相关(r=0.625*),而与籽粒蔗糖含量之间相关性不显著(r=0.121).施氮量270 kg·ha-1时,豫麦49产量最高;太空6号需氮量相对较低,产量达最大值时的施氮量为180 kg·ha-1.     

施氮量对不同粒色小麦花后光合特性及成熟期氮素分配和籽粒蛋白质组分的影响

为给彩色小麦优质高产栽培提供理论依据,在盆栽试验条件下,选用不同粒色小麦品种中麦8号(白粒)、漯珍1号(紫黑粒)和N3688(绿粒)为供试材料,设置施用纯氮210kg·hm-2(N210)、270kg·hm-2(N270)、330kg·hm-2(N330)和0kg·hm-2(N0)四个施氮水平,采用2因素随机区组试验设计,研究了施氮量对不同粒色小麦品种花后旗叶光合特性、成熟期植株氮素分布及籽粒蛋白质及其组分含量的影响。结果表明,施氮能改善小麦花后旗叶光合特性,延长旗叶光合作用功能期,并显著提高不同粒色小麦品种成熟期各器官的氮素含量和籽粒中总蛋白质及其组分含量。在本试验条件下,不同小麦品种花后旗叶光合特性、成熟期植株氮素含量和籽粒蛋白质及其组分含量对施氮量的效应存在差异,中麦8号在N330处理下各项被测指标均优于其他处理,而漯珍1号和N3688在N270处理下各项被测指标综合评价最优。     

施氮对滴灌春小麦干物质、氮素积累和产量的影响

为给北疆地区滴灌春小麦生产中氮素管理提供依据,以新春6号为材料,设置5个施氮水平(施纯氮0、150、300、450和600 kg·hm-2,分别用N0、N1、N2、N3、N4表示),分析了施氮量对滴灌春小麦干物质、氮素积累和产量的影响.结果表明,滴灌春小麦植株干物质和氮素积累特征符合Logistic曲线,施氮能促进其干物质和氮素积累,以N2处理表现最佳,其干物质量和氮素积累量分别达到19 745.03和310.97kg·hm-2,比其他处理分别高4.42％～60.74％和3.68％～79.65％.滴灌春小麦产量和氮肥当季利用率受施氮量影响均显著,且均随施氮量的增加呈先增加后降低的趋势,其中产量以N2最大,比N0增产45.04％.经函数拟合,施氮量为366.83 kg·hm-2时,滴灌春小麦产量最高.     

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).