大气CO2浓度升高对大豆根瘤量及其固氮活性的影响

通过开顶式气室控制CO2浓度，对盆栽大豆进行试验测定，研究了大气CO2浓度升高对大豆根系，重点是根瘤量和根瘤活性的影响。结果表明，大气CO2浓度升高，促进了大豆根系生长，大豆根体积、主根长、根鲜重均呈增长趋势，根冠比增加。CO2浓度为450、550、650和750μmol／mol时，与大气CO2背景浓度相比，在初花期，大豆根瘤数分别增加6．1％、15．9％、19．2％和26．5％，其中主根根瘤数增加较为显著，至鼓粒期，根瘤数增加幅度为7．8％～48．0％，增幅较初花期大，其中侧根根瘤量增加更多。同时，高CO2水平下，根瘤鲜重的变化与根瘤数基本一致。4种高CO2浓度下，初花期根瘤比固氮活性提高10．1％～24．0％，大于鼓粒期的6．0％～13．4％的增加幅度；单株根瘤固氮活性初花期增加10．6％～55．7％，鼓粒期则提高了20．0％～73．9％。     

CO_2浓度倍增对大豆生长及光合作用的影响

以‘齐黄27’大豆为材料,研究人工气候室模拟大气CO2浓度倍增(700μmol.mol-1)的环境条件下大豆植株在生长、色素含量及光合作用相关指标的变化。结果表明:CO2倍增显著增加株高、干鲜重和根瘤数,显著降低根冠比;CO2浓度倍增处理增加了叶绿素、花青素和类胡萝卜素含量,使光合速率、Rubsico的活性、气孔导度和PSⅡ的功能都有所增加。CO2浓度倍增处理对大豆植株的生长具有促进作用,主要是由于高浓度CO2增加了根瘤的数量,增加了叶片叶绿素和类胡萝卜素含量,提高了Rubsico活性,增强了PSⅡ功能并且提高了气孔导度,最终使光合速率增加所致。     

铝胁迫对龙眼幼苗光合作用的影响

以苗龄7个月的乌龙岭龙眼品种实生苗为材料，研究铝胁迫下龙眼光合作用变化规律。结果表明，铝胁迫影响龙眼幼苗光合作用，导致光合效率降低，非气孔因子成为限制光合作用的主要因子。铝胁迫下，龙眼幼苗叶片叶绿素、类胡萝卜素含量，叶绿素a与叶绿素b的比值、净光合速率（Pn）、CO2饱和点均下降，叶绿素a下降了1．79％～79．73％，叶绿素b下降了1．28％～77．98％，类胡萝卜素下降了3．43％～77．25％：暗呼吸速率（Dr）（PAR=0时的Pn），光补偿点（LCP）提高，光饱和点和表观量子产量降低，CO2补偿点升高，羧化效率降低；光呼吸加强，乙醇酸氧化酶活性提高了7．52％～67．82％；光合磷酸化受到抑制，叶绿体光合磷酸化活性下降了24．46％～77．99％。     

大气CO2浓度升高对茶树光合生理特性的影响

通过对不同大气CO2浓度水平下的茶树观测试验,研究了大气CO2增长对茶树新梢叶片净光合速率、蒸腾气孔导度、水分利用效率、叶绿素含量和营养元素含量等光合生理特性的影响。结果表明,在大气CO2浓度为550、750μmol·mol-1时,比正常大气CO2水平下茶树叶片日平均净光合速率提高17.9%和25.8%,并缓解和消除了光合午休现象;茶树叶片气孔导度降低7.6%和13.0%,蒸腾速度稍有下降,水分利用效率提高21.6%和35.8%;同时使茶树新梢叶绿素a、叶绿素b、叶绿素总量和类胡萝卜素含量分别提高12.8%～18.4%、14.0%～22.0%、13.1%～19.4%和17.2%～20.1%,但叶绿素a与叶绿素b的比值有所降低。大气CO2浓度的升高使新梢营养元素N、K、Ca含量有不同程度降低,而Mg、Fe、Zn、Mn、Cu含量有所增加。     

钾肥对菜用大豆生殖生长期叶片叶绿素含量的影响

以2个菜用大豆为材料,在正常氮磷肥基础上,设置4个水平钾肥施用量作为种肥,并分别在大豆开花期和结荚期喷施30 kg·hm-2 K2SO4,研究了钾肥对菜用大豆叶片叶绿素含量的影响.结果表明:钾肥作种肥能显著增加生殖生长期菜用大豆叶片叶绿素含量,2个品种叶绿素总含量均在钾肥施用量120 kg·hm-2时最高.与不施钾肥处理相比,在盛花期、结荚期和鼓粒期,中科毛豆1号叶绿素总含量分别增加9.1％、22.7％和13.0％,品系121分别增加33.3％、17.4％和13.0％.钾肥施用量120 kg·hm-2时,结荚期叶绿素a含量明显增加,并显著提高了叶绿素a/b比值.叶面喷施K2SO4能显著提高菜用大豆叶绿素总量.相同种肥水平下,叶喷钾肥总体上明显增加开花期和结荚期的叶绿素含量,叶绿素a含量,但对鼓粒期叶绿素含量无显著影响.     

PEG-8000模拟干旱胁迫对马铃薯组培苗叶绿素和类胡萝卜素含量的影响

为了明确聚乙二醇(PEG-8000)模拟干旱胁迫对彩色和常规马铃薯组培苗叶绿素和类胡萝卜素含量的影响,以6个马铃薯品种(系)的脱毒组培苗为试验材料,研究比较了在固体培养基中分别添加5%,10%,15%和20%PEG-8000模拟干旱胁迫和对照处理下(不含PEG-8000)培养50 d后组培苗生长生理指标(叶绿素a、叶绿素b、类胡萝卜素)的变化。结果表明,在0～20%PEG浓度下,马铃薯茎叶中色素含量变化复杂,彩色马铃薯品种色素相关指标较常规品种对干旱更敏感。叶绿素a较叶绿素b对干旱的反应更为敏感,类胡萝卜素含量对干旱胁迫的反应较叶绿素更敏感。叶绿素b/a值较其他指标在干旱胁迫下更稳定。在轻度干旱胁迫下,叶绿素a、b,总叶绿素含量及类胡萝卜素含量降低,在中度干旱胁迫下,叶绿素a、b,总叶绿素含量及类胡萝卜素含量增加,彩色马铃薯较常规马铃薯增幅更大,因此在进行抗旱评价时不宜单采用色素指标。干旱影响导致的色素变化由强到弱为‘D613’>‘东农303’>‘200902’>‘渭薯1号’>‘春薯2号’>‘青薯9号’。     

CO2浓度升高对玉米叶片光合生理特性的影响

以沈糯3号为研究材料,利用开顶式气室(OTCs)法研究了二氧化碳(CO2)浓度升高处理下,玉米叶片叶绿素含量、光合生理特性及其子粒产量的变化,揭示CO2浓度升高对玉米光合生理特性及子粒产量的影响机理.结果表明,在整个生育期内,与对照相比,高浓度CO2处理下,玉米叶片叶绿素a、叶绿素b及叶绿素(a+b)的含量增加,而叶绿素a/b的值则先升高后降低;在整个处理期间,净光合速率均高于对照(p＞0.05),升高幅度为12.6%～71.1%,气孔导度低于对照(p＞0.05),其降低幅度为2.9%～18.8%.处理至抽雄期和灌浆期,胞间CO2浓度分别增加152%和161%,均极显著高于对照(p＜0.01);蒸腾速率的变化较小.高浓度CO2处理下,玉米穗粒数和穗粒重均明显高于对照(p＜0.05).CO2浓度升高在一定程度上促进了玉米的光合作用,从而使玉米子粒产量增加.     

感染大豆灰斑病菌后不同抗性的大豆品种叶绿素动态变化的研究

本文采用了抗性不同的大豆品种，在3～4叶期接种，并于接种后1～10天内连续取样，然后测定其接种后内叶绿素的含量。试验结果表明：无论是抗病品种，还是感病品种，在病菌侵入的初期，叶绿素a、b的含量都有所下降：在病菌侵染后7～10天时，感病品种叶片内叶绿素a、b含量比未接种对照低，而抗病品种叶片内叶绿素a、b含量均明显高于未接种对照；另外，致病力不同的生理小种对叶绿素a、b含量变化的影响不同，7号生理小种对叶绿体的破坏能力最强，其次为6号生理小种，而4号生理小种则最弱，其中1号，2号生理小种居中。抗病品种叶片内叶绿素a/b的比值明显高于感病品种，初步认为叶绿素a/b的比值可作为大豆品种对灰斑病抗性鉴定的一种生化指标。     

大气CO_2升高对大豆生理指标及产量影响的研究进展

在全球气候变化过程中,大气CO2浓度不断升高,已从工业革命前的270μmol·L-1升高到2013年的390μmol·L-1,预计到本世纪末将达到700μmol·L-1,CO2浓度的快速升高将对大豆生产产生重要影响。本文从光合速率、叶面积、叶绿素含量、共生固氮、内源激素、以及干物质积累和大豆产量等方面综述了大气CO2浓度升高产生的影响。大多数研究发现,随着大气CO2浓度升高,大豆光合速率随之升高,但少数研究发现,随大气CO2浓度升高,光合速率反而降低,这可能与植物对CO2浓度升高的光合适应反应有关;叶绿素含量随CO2浓度升高呈现增加趋势,但对一些夏大豆研究发现,叶绿素含量无明显变化;叶面积、共生固氮、干物质积累和产量也都对CO2升高产生不同程度的响应,但响应程度因CO2升高幅度、大豆品种、生育时期和其他试验条件而有所差异;有关于CO2升高对内源激素影响的研究报导较少。针对未来所需要开展的研究,我们提出与光合作用相关酶学生理、内源激素以及碳氮代谢角度对CO2影响大豆产量机制进行深入解析,而且在不同品种之间对CO2浓度升高的响应进行分析,明确品种之间是否存在差异。这将对未来大豆高产育种,提高大豆生长的环境适应性有重要的理论价值;并提出了今后的研究方向。     

开放式空气中CO_2浓度和温度增高对水稻叶片叶绿素含量和SPAD值的动态影响

【目的】针对不断增高的大气二氧化碳(CO_2)浓度和温度,研究这两个重要环境因子及其互作对大田生长水稻叶片叶绿素含量和SPAD值的动态影响。【方法】利用农田T-FACE(Temperature-Free Air CO_2 Enrichment)系统,以高产优质粳稻武运粳23为供试材料,设置两个CO_2浓度(环境CO_2浓度和高CO_2浓度)和两个温度处理(环境温度和高温),测定自然生长环境下水稻不同生育期叶片的叶绿素含量及SPAD值。【结果】550μmol/mol CO_2浓度使水稻移栽后41、77、94 d叶绿素a,b和a+b含量均增加(最大增幅为6.4%),但移栽110、119 d后均减少(最大降幅为5.4%)。由于叶绿素b含量对CO_2较叶绿素a含量更敏感,故高CO_2浓度使移栽后41、77和94 d叶绿素a/b值均下降,降幅分别为4.7%、2.3%和0.9%,但移栽110和119 d后分别增加1.9%和5.3%;以上对CO_2的响应多达显著水平。对叶片SPAD值而言,高CO_2浓度对水稻生长前、中期的影响较小,但移栽110和119 d后分别下降3.5%(P=0.1)和19.1%(P0.01)。大田生长期增温1℃,各期叶绿素a、b以及a+b含量多呈增加趋势,叶绿素a/b值表现相反,但总体上变幅小于CO_2效应;高温对水稻前、中期叶片SPAD的影响较小,但移栽110和119d后SPAD值平均下降7.1%和14.8%,均达极显著水平。CO_2与温度处理对上述测定参数多无显著互作效应,但CO_2浓度、温度处理与生育期之间多存在明显的互作效应。【结论】大气CO_2浓度增高有利于水稻生长前中期叶片叶绿素的形成,但生长后期叶绿素含量和SPAD值均明显下降且伴随叶绿素a/b值的显著升高,这种早衰现象在不同生长温度下趋势一致。     

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.     

<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.     

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.