镉、铅及其复合污染对小麦种子萌发的影响

为了明确重金属对作物种子萌发的影响,采用水培方法研究了镉(Cd)、铅(Pb)及其复合污染对小麦种子萌发的影响.结果表明,低浓度Cd2+、Pb2+单一处理对小麦种子发芽率、发芽势、发芽指数、活力指数及根长均有一定的促进作用,随着处理浓度的提高其数值逐渐下降.低浓度的Cd2+、Pb2+复合处理对小麦种子发芽势及根长均有一定的促进作用,随着处理浓度的提高其数值逐渐降低.Cd2+、Pb2+复合处理对发芽指数及活力指数具有抑制作用.而Cd2+、Pb2+及其复合污染对芽长产生抑制作用,并且随着处理浓度的增加其抑制作用逐渐上升.Cd2+单一处理对小麦种子萌发的毒性最大,其次是复合处理,最小的是Pb2+单一处理.     

废电池液对大豆种子萌发及贮藏物质变化的影响

以石豆1号为材料,通过水培试验,研究了不同浓度(10%、20%、30%和40%)废电池液对大豆种子萌发及贮藏物质变化的影响。结果表明:随着废电池液浓度的上升,大豆种子发芽率、发芽势、发芽指数、活力指数、根长、下胚轴长、贮藏物质消耗率和运转效率都呈下降趋势,根(下胚轴)长抑制指数逐渐增大,其中当废电池液浓度为10%时,大豆萌发期根长和贮藏物质运转效率明显受到抑制,根长抑制指数显著提高;当废电池液浓度为20%时,大豆萌发期下胚轴长显著减少,下胚轴长抑制指数显著增加;当废电池液浓度为30%,大豆种子的发芽率、发芽势、发芽指数、活力指数及贮藏物质消耗率均显著下降。说明本试验中30%废电池液浓度对大豆种子萌发有显著抑制作用。     

盐胁迫对罗布白麻种子萌发的影响

研究了不同浓度梯度的NaCl溶液、Na_2CO_3溶液以及Na_2SO_4溶液对罗布白麻种子萌发所产生的影响。结果表明,3种盐溶液对种子萌发有明显的抑制作用,种子的发芽率、发芽势、发芽指数、胚根长度、活力指数、耐盐指数都随盐浓度增加呈下降趋势。低浓度(50 mmol/L) NaCl溶液对罗布白麻种子发芽抑制作用高于其他两种盐分,浓度高于50 mmol/L时,Na_2SO_4对罗布白麻种子发芽的抑制作用较其他两种盐分低,高浓度(≥200 mmol/L)时,Na_2CO_3对种子发芽抑制作用最大。3种钠盐对罗布白麻种子萌发的毒性依次为Na_2CO_3 NaCl Na_2SO_4。     

干旱胁迫对圆叶决明种子萌发的影响

通过聚乙二醇（PEG-6000）溶液模拟干旱条件,分别对圆叶决明CPI86134与CPI34721种子进行胁迫处理,测定不同胁迫梯度下,发芽率、发芽势、相对发芽势、胚根/胚芽比值等指标的变化情况,据此综合评定两者的抗旱性。结果表明,不同浓度的PEG胁迫环境对圆叶决明种子萌发有显著影响,随着干旱胁迫程度加大,对种子萌发的抑制作用明显增强,活力指数对PEG胁迫的反应更敏感。CPI34721与CPI86134种子萌发受干旱胁迫抑制的程度不同,其中CPI34721较弱,CPI86134相对较强。萌发初期,CPI34721的发芽率、相对发芽率、发芽势、相对发芽势、发芽指数等指标与CPI86134比较都表现出较高的数值。     

硅对NaCl胁迫下野大豆种子萌发的影响

以野生大豆为材料,研究了外源硅(K2SiO3 )对NaCl胁迫下野大豆种子的发芽率、发芽势、发芽指数及胚生长的影响.结果表明:100 mmol·L-1 NaCl 胁迫浓度可以抑制野大豆种子的萌发,施加0.5和1.0 mmol·L-1 K2SiO3后,可以有效提高野大豆种子的萌发速度和萌发率,增加胚根和胚芽的长度.然而当K2SiO3浓度高于2.0 mmol·L-1时野大豆种子的萌发则受到抑制.外源施加适宜浓度的硅,可以增强野大豆种子在盐分胁迫下的萌发能力.     

低浓度铬对生菜种子萌发及幼苗的影响

[目的]探讨低浓度Cr6+对生菜种子萌发及幼苗生长的影响。[方法]采用0、5、10、20、30、40 mg/L的Cr6+溶液进行生菜种子发芽试验。[结果]Cr6+对生菜种子的发芽势和发芽指数影响不大、对发芽率影响极显著;活力指数随Cr6+浓度的增加而下降,Cr6+为20 mg/L影响显著,为40 mg/L影响极显著;Cr6+显著抑制苗长和根长,浓度越高影响越大;Cr6+≥5 mg/L显著降低生菜种子的成苗率。[结论]在该研究浓度下,不利于生菜种子的萌发和幼苗的生长。     

大气CO2浓度升高对东北主栽作物种子活力的影响

大气CO2浓度升高是全球气候变化的重要特征之一,为揭示未来气候变化对作物种子活力的影响,进行种子发芽对CO2增加的适应性响应研究.2019年在中国科学院海伦农业生态实验站进行开顶式气室(OTC)模拟CO2增加试验,选取东北三大主栽作物大豆、玉米和水稻为供试作物,设置两个CO2处理,分别为aCO2 (400 μmol· mol-1)和eCO2(700 μmol·mol-1).结果 表明:相比于对照(aCO2)处理,CO2浓度升高后,大豆种子的体积、百粒重、24 h吸胀速度、浸出液电导率、发芽率、发芽势和发芽指数分别降低了11.24％、10.53％、2.51％、27.72％、15.85％、19.75％和10.17％;虽然CO2升高未显著影响玉米种子百粒重,但其24 h吸胀速度和浸出液电导率分别降低了3.69％和8.62％,而发芽率、发芽势、发芽指数和活力指数分别提高了81.03％、75.00％、56.14％和81.68％;水稻种子的体积降低了21.35％,而其千粒重、发芽势、发芽指数和活力指数分别提高了5.62％、5.19％、26.11％和32.21％.综合以上结果表明,大气CO2浓度升高对不同作物种子活力的影响存在差异,从发芽指标来看,大气CO2浓度为700 μmol· mol-1时,种子活力表现为玉米＞水稻＞大豆.     

紫斑病对大豆室内发芽特性的影响

通过紫斑病对大豆室内发芽特性的影响研究,结果表明,大豆感染紫斑病后,种子的发芽势、发芽率、活力指数明显降低,不同感染级别种子的发芽势间存在明显差异,因此,大豆种子感染紫斑病后会因播种品质显著降低而不适于大田用种.     

酸雨胁迫对水稻种子萌发的影响及其生理机制研究

采用人工模拟酸雨培养水稻种子的方法,通过测定不同pH酸雨处理下水稻种子的发芽率、发芽势、发芽指数以及萌发过程中淀粉酶活性、贮藏物质消耗率和运转效率等,研究了酸雨抑制水稻种子萌发的机制。结果表明,随着酸雨pH的降低,水稻种子的发芽率、发芽势、发芽指数、种子贮藏物质消耗率和运转效率等均逐渐降低,显著抑制水稻种子萌发和贮藏物质的消耗率以及贮藏物质的运转效率的pH阈值均为5.0,当酸雨pH值降低到2.0时种子基本不萌发。酸雨胁迫使淀粉酶活性峰值提前,致使发芽后期因酶活力不够而最终影响萌发。     

不同水势环境对大豆种子活力的影响

试验用7种浓度的PEG溶液来创造大豆种子吸水的不同水势环境。结果表明:种子在低渗透势溶液中缓慢吸水比在清水中快速吸水,其发芽势、发芽率、发芽指数和活力指数都明显提高,田间出苗率达极显著差异,同时提高幼苗干重、鲜重。大豆种子在-1.1860MPa的PEG溶液中吸水48小时,种子活力提高。     

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.