外源Zn对冬小麦生育后期Zn吸收积累的影响

为探讨外源Zn对小麦植株生育后期Zn吸收积累的影响,以河南省主要推广品种周麦18和矮抗58为材料,于2009-2010年进行网室盆栽试验,测定了不同浓度的Zn（0、200、400和800mg.kg-1干土,分别以Zn0、Zn2、Zn4、Zn8表示）处理下,小麦灌浆初期及成熟期植株叶片、茎鞘、穗部、籽粒及根等部位的Zn含量和干物质积累量,分析了各部位的Zn积累量和分配比例。结果表明,外源Zn处理下,灌浆初期至成熟期,小麦植株各部位Zn含量为4.22～174.98μg.g-1,以叶片Zn含量最高。Zn含量的变异主要是外源Zn所导致,品种及品种×外源Zn的互作对各部位Zn含量亦有不同程度的影响。随外源Zn水平的增加,植株干物质积累量呈现先升后降趋势,在200mg.kg-1处理时,植株干物质积累量最高。植株Zn积累总量亦随外源Zn处理浓度的增加而升高,表现为Zn8〉Zn4〉Zn2〉Zn0,周麦18植株Zn积累量高于矮抗58。灌浆初期,植株Zn的主要积累部位是叶片,至成熟期,籽粒和根是Zn的主要积累部位,植株Zn有50%左右分配至籽粒中。在Zn2处理下,籽粒Zn的分配比例最高。土壤中施加适量Zn肥,有利于植株干物质的积累和Zn的吸收积累。     

小麦籽粒灌浆期铁、锌、锰、铜积累动态的研究

为了解小麦籽粒灌浆期Fe、Zn、Mn、Cu四种微量矿质营养元素的积累规律,以黄淮麦区的小麦品种长5864、郑麦366、济麦20、新麦18为试验材料,选取同一天抽穗及开花的植株进行标记,于花后10～35 d每5 d取各品种籽粒用原子吸收分光光度计法测定了籽粒中Fe、Zn、Mn、Cu的含量,分析其含量和积累量的动态变化.结果表明,四种矿质元素在小麦籽粒中的含量和积累量均表现为Fe＞Zn＞Mn＞Cu.随籽粒灌浆的进行,各元素的含量呈下降趋势.籽粒Fe、Zn含量在花后10～30 d下降,其中花后10～20 d下降迅速,花后20～30 d下降平缓,花后30～35 d含量有所增加;籽粒Mn含量在花后10～35 d持续下降,其中花后10～25 d下降迅速,花后25～35 d下降缓慢;籽粒Cu含量在花后10～20 d下降迅速,花后20～30 d稳中略升,花后30～35 d含量下降.灌浆期籽粒各元素的积累量呈递增趋势,其日积累量在灌浆初期较高.籽粒Fe日积累量最高值出现在花后30～35 d,Zn、Mn、Cu日积累量最高值出现在花后10～15 d.在供试的四个品种中,长5864和郑麦366籽粒Fe、Cu的积累量较高,新麦18籽粒Mn、Zn的积累量较高.     

播期对不同习性小麦品种籽粒灌浆特性的影响

为了给小麦高产栽培提供理论依据,2002～2003年对河南省不同习性的小麦品种在不同播期下的籽粒灌浆速率进行了研究。结果表明,不同播期下小麦品种的籽粒灌浆规律均符合Logistic曲线,灌浆过程中平均灌浆速率、渐增期灌浆速率、快增期灌浆速率对粒重影响较大。因此选择适宜播期、提高渐增期灌浆速率、快增期灌浆速率和平均灌浆速率对提高粒重有重要意义;播期对不同习性品种灌浆高峰出现的日期影响基本一致,但早播时冬性小麦洛旱2号灌浆高峰出现较早,灌浆速率大,晚播时春性品种豫麦18灌浆高峰出现较早,灌浆速率大。因此,在河南生态条件下,春性品种适宜播期为10月中下旬,半冬性品种适宜播期为10月中旬,冬性品种的适宜播期为10月上旬至4中旬。     

小麦 玉米轮作区西农979不同器官氮素转运及对籽粒贡献率的影响

为了解华北地区小麦玉米轮作模式下小麦不同器官氮素吸收、分配及转运的差异,采用田间试验方法,以西农979为供试品种,于小麦的分蘖期、越冬期、返青期、拔节期、抽穗期、灌浆期和成熟期采集植株样品,对其叶、叶鞘、茎、穗轴、颖壳和籽粒的干物重及氮含量进行了测定和分析。结果表明,小麦成熟时,不同器官氮含量从大到小依次为：籽粒＞叶＞叶鞘＞颖壳＞茎＞穗轴,氮积累量从大到小依次为：籽粒>叶鞘>叶>茎>颖壳>穗轴,即氮在籽粒中分配和积累量最大,叶是最大的氮素“源器官”。在不同生育阶段,拔节至抽穗期的氮吸收量和吸收速率最大。在华北小麦玉米轮作区,籽粒氮收获指数达到68.48%,而叶对籽粒的氮转运贡献率达到54.52%;拔节至抽穗期氮素吸收比例占全生育期的48.07%,故而底施氮肥与拔节期追氮的比例控制在5∶5为好。     

Zn~(2 )对小麦幼苗干物质及Zn积累的影响

为了探明Zn在小麦植株中的吸收、分配和积累规律,以小麦品种长5864为供试材料,采用室内水培方法,于培养4~13 d后取幼芽和幼根,用原子吸收分光光度计法测定样品中Zn的含量,研究了不同Zn2 供应水平(0、306、0 mg.L-1,分别用Zn0、Zn30、Zn60表示)对小麦幼苗干物质积累及幼苗Zn含量和积累的影响,分析了小麦幼苗中Zn的积累规律。结果表明,外源Zn2 供应可显著提高幼苗根和芽的干重,对小麦幼苗根的影响大于对芽的影响,根对Zn2 更为敏感。外源Zn2 供应能明显提高小麦幼苗根和芽中Zn的含量和积累量。Zn30处理有利于根的生长,能显著提高根中Zn的含量并促进Zn在根中的积累;Zn60处理有利于芽的生长,能显著提高芽中的Zn含量并促进Zn在芽中的积累。     

杂种小麦干物质积累及其杂种优势的研究

对6个澳大利亚杂种小麦在不同生育期植株及各器官的干物质积累、分配及干物质积累的杂种优势进行了研究。结果表明,植株总干物质积累在籽粒灌浆末期达到最大值,茎秆和叶片干物质积累均在开花期达到最大值。挑旗期茎秆、叶片各占植株总干物质的50％;从孕穗王灌浆末期,茎秆为干物质的主要贮存器官,占植株总干物质的 39.87％～66.67％;在成熟期,籽粒成为干物质贮存的最主要部位,占37.65％,茎秆占35.23％。从6个杂交种平均值来看,干物质积累多表现为正向杂种优势,尤其在营养生长期优势最明显。相关分析表明,营养生长期植株总干物质积累量较大且主要分配在茎秆部位的杂交品种,一般具有较高的籽粒产量和较强的产量优势。     

甘蔗钾素吸收、累积和分配的动态变化特征

以国内当前甘蔗主栽品种ROC22为材料,通过田间实验分析了甘蔗主要器官钾素含量、累积、分配和吸收的动态变化特征。结果表明:在相同生育期,上部茎和青叶鞘始终是钾素含量较高的器官,青叶和中、下部茎次之,根系、枯叶和枯叶鞘则始终相对较低。钾素主要累积于青叶(鞘)和蔗茎中。拔节前青叶(鞘)中的钾素占植株总累积量的95%以上,拔节后其钾素分配比例持续下降,而蔗茎中则持续上升,在工艺成熟期分配至蔗茎的钾素占整个植株的83.3%。甘蔗钾素阶段吸收量和吸收速率则呈现了先上升后下降的趋势,分蘖期至茎伸长4期为甘蔗主要钾素吸收积累阶段,占生育期总吸收的86.8%,其中分蘖期至拔节期的钾素阶段吸收量(4 791.3 mg/plant)和吸收速率(159.7 mg/plant·d)最高,为甘蔗钾素吸收的最大效率期。     

水旱轮作制下蚕豆/小麦间作对小麦锰吸收的影响

为给水旱轮作制下小麦缺锰问题的解决提供依据,采用田间和盆栽试验研究了蚕豆/小麦间作对小麦锰吸收的影响。结果表明,在拔节期,蚕豆/小麦间作显著提高了小麦根际土壤中交换性锰的含量,其中,田间试验间作第1行、第3行小麦比单作分别增加了21.09%、7.78%,盆栽试验间作比单作增加了37.63%,但小麦锰的吸收却没有表现出间作优势。抽穗后,田间试验蚕豆/小麦间作显著促进了小麦对锰的吸收,其中,间作第1行、第3行小麦地上部锰的累积量比单作在抽穗期分别增加了39.30%、29.06%,灌浆期分别增加了51.50%、65.30%,成熟期分别增加了36.17%、13.86%;盆栽试验间作小麦地上部锰的累积量在分蘖期、拔节期、灌浆期和成熟期分别增加了107.46%、36.07%、26.67%、20.92%,但间作小麦根际土壤中交换性锰的含量处于劣势。总之,通过蚕豆/小麦间作在抽穗前提高了小麦根际土壤中交换性锰的含量,从而促进了在灌浆过程小麦地上部,尤其是叶和穗对锰的吸收。     

喷施铁肥对不同基因型小麦产量和铁吸收的影响

为研究小麦的最佳喷施铁肥时期并筛选高铁基因型小麦,采用盆栽方法,以14个不同基因型小麦为材料,通过不同时期喷施铁肥,比较其对小麦产量和铁吸收的影响。结果表明,小麦拔节期叶面喷施铁肥可以增加籽粒产量、籽粒铁含量、籽粒铁累积量及占植株总铁积累量的比例。拔节期喷施铁肥提高了小麦根系的铁含量、累积量及根系铁占植株总铁累积量的比例。不同基因型小麦喷施铁肥时茎中的铁含量、铁累积量及占植株总铁累积量的比例均显著降低。小麦体内的铁主要储存在根系中,地上部的铁主要分布在叶片等营养器官中。与低铁基因型相比,高铁基因型小麦具有较低的籽粒产量和生物量,但籽粒产量占全株总生物量的比例却高于低铁基因型。无论是否喷施铁肥,高铁基因型小麦籽粒铁含量、铁累积量及占植株总铁累积量的比例均显著高于低铁基因型小麦。无论是否喷施铁肥,高铁基因型的根系生物量显著低于低铁基因型,但根系铁含量则显著高于低铁基因型,铁累积量则没有显著差异。拔节期喷施铁肥是促进不同基因型小麦生长、改善小麦铁营养状况的有效途径。     

拔节期追氮对小麦植株地上部Zn吸收和积累的影响

为明确拔节期追氮对小麦植株地上部Zn吸收积累的影响,于2011-2012年以周麦18和济麦22为材料,研究了拔节期不同追氮量处理下,小麦植株开花期和成熟期叶片、茎鞘、穗部、籽粒的Zn含量,分析了各部位Zn的积累量.结果表明,周麦18植株地上部Zn含量和积累量高于济麦22;从空间分布来看,植株地上各部位Zn含量和积累量均随空间位置下移而降低;随拔节期追氮量的增加,两个小麦品种植株地上部Zn积累量在开花期呈先升后降趋势,成熟期则规律不明显,说明拔节期追氮能够调控小麦花后地上各部位Zn的积累和转运.小麦籽粒Zn含量与拔节期追氮量之间的关系可用二次曲线函数进行模拟.小麦植株Zn积累量对氮肥的响应存在品种间差异,周麦18在N3(底施纯氮120 kg·hm-2,追氮100 kg· hm-2)处理下植株Zn积累量和籽粒Zn含量最高,济麦22在N4(底施纯氮120 kg· hm-2,追氮140 kg·hm-2)处理下植株Zn积累量和籽粒Zn含量最高.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

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.     

Redox Status and Neuro Inflammation Indexes in Cerebellum and Motor Cortex of Wistar Rats Supplemented with Natural Sources of Omega-3 Fatty Acids and Astaxanthin: Fish Oil,Krill Oil,and Algal Biomass

Health authorities worldwide have consistently recommended the regular consumption of marine fishes and seafood to preserve memory, sustain cognitive functions, and prevent neurodegenerative processes in humans. Shrimp, crabs, lobster, and salmon are of particular interest in the human diet due to their substantial provision of omega-3 fatty acids (n-3/PUFAs) and the antioxidant carotenoid astaxanthin (ASTA). However, the optimal ratio between these nutraceuticals in natural sources is apparently the key factor for maximum protection against most neuro-motor disorders. Therefore, we aimed here to investigate the effects of a long-term supplementation with (n-3)/PUFAs-rich fish oil, ASTA-rich algal biomass, the combination of them, or krill oil (a natural combination of both nutrients) on baseline redox balance and neuro-inflammation indexes in cerebellum and motor cortex of Wistar rats. Significant changes in redox metabolism were only observed upon ASTA supplementation, which reinforce its antioxidant properties with a putative mitochondrial-centered action in rat brain. Krill oil imposed mild astrocyte activation in motor cortex of Wistar rats, although no redox or inflammatory index was concomitantly altered. In summary, there is no experimental evidence that krill oil, fish oil, oralgal biomass (minor variation), drastically change the baseline oxidative conditions or the neuro-inflammatory scenario in neuromotor-associated rat brain regions.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part II: Electrostatic separation of particles

Wheat bran is a composite material made of several layers, such as pericarp, testa and aleurone. It could be fractionated into purified fractions, which might either be used as food ingredients, or serve as a starting material for extraction of bioactive compounds. The aim of this work was to evaluate the potential of using electrostatic separation as a way to obtain purified fractions from wheat bran. Ultrafine-ground bran obtained either by cryogenic grinding or by grinding at ambient temperature was used as starting material. The ultrafine bran was then charged by tribo-electrification and introduced in a chamber containing two high voltage electrodes, where bran particles were separated depending on their acquired charge, allowing positively and negatively charged fractions to be collected separately. The particle size distribution, microstructure and biochemical composition of the obtained fractions were studied. The charge of the particles was influenced by their biochemical composition: particles rich in highly branched and cross-linked arabinoxylans (pericarp) were separated from particles rich in β-glucan, ferulic acid and para-coumaric acid (aleurone cell walls). The testa and the intracellular compounds from aleurone were not highly charged, neither positively nor negatively. The most positively charged fraction represented 34% of the initial bran, and contained 62% of the ferulic acid present in the initial bran. The yield of the separation process was good (5.4% loss), and could be further increased.     

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.     

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.     

<Emphasis Type="Italic">Pulque</Emphasis>, An Alcoholic Drink from Rural Mexico,Contains Phytase. Its <Emphasis Type="Italic">in vitro</Emphasis> Effects on Corn Tortilla

Pulque is made by fermenting the agave sap or aguamiel of Agave atrovirens with a whole array of microorganisms present in the environment including several lactic acid bacteria and yeasts such as Saccharomyces cerevisiae. Ascorbic acid was determined in pulque and aguamiel, respectively. Phytase activity in lees, liquid and freeze-dried pulque was assayed by measuring the appearance of phosphate from phytate by a colorimetric method likewise phosphate from phytate present in fresh corn tortilla was measured after in vitro incubation with pulque. Iron, zinc, calcium, magnesium and selenium contents were measured in pulque and corn tortilla as well as in nixtamalized corn flour (NCF), the latter is used to make instant tortilla, since corn provides most of the energy as well as most of the phytate in the Mexican rural diet. Pulque showed phytase activity but much less ascorbic acid and iron than previously reported; additionally, phytase in pulque hydrolyzed most of phytate’s corn tortilla. Lees, which is mostly made of pulque’s microbiota, significantly accumulated iron and zinc but no selenium. NCF was fortified with iron by the manufacturers but poorly blended. There were significant differences on selenium content between tortillas samples, apparently some soils in central Mexico are selenium deficient. Moderate pulque intake appears to increase the bioavailability of iron and zinc bound by phytate in corn.