Características de grãos e amido de diferentes cultivares de quinoa (Chenopodium quinoa Willd.)

Os grãos de quinoa possuem excelente balanço nutricional além das propriedades funcionais, comparativamente superior à dos cereais. A quinoa é cultivada em diversos países e, devido às suas características, têm aumentado o interesse de pesquisadores e consumidores. A quinoa contém pericarpo branco, no entanto, existem grãos com pericarpo vermelho e preto, e todos os tipos são utilizados como alimento em diferentes preparações. Com o objetivo de avaliar as características de grãos de quinoa, amostras de cor branca, preta e vermelha foram analisadas quanto às propriedades físico-químicas e funcionais dos grãos e do amido extraído das diferentes amostras. O amido, extraído pelo método alcalino, foi submetido as análises de teor de amilose, difração de raios X, microscopia eletrônica de varredura (MEV), propriedades térmicas (por DSC-Differential Scanning Calorimeter) e propriedades de pasta (por RVA- Rapid Visco Analyser), além de suscetibilidade à hidrólise enzimática e cor. A composição físico-química dos grãos de quinoa apresentou como principais diferenças o teor de cinzas, fibras e amido. O teor de amilose variou de 13,6% a 21,3%, entre as amostras de amido; os padrões de cristalinidade dos amidos foram de tipo A, típico dos cereais; e, a cristalinidade relativa variou de 25,4 a 29,6 %; as micrografias obtidas por MEV apresentaram as formas poliédricas dos grânulos de amido. Os viscoamilogramas, obtidos para os diferentes amidos, mostraram um comportamento semelhante entre as amostras brancas e pretas. As propriedades térmicas de retrogradação das amostras de quinoa vermelha apresentaram uma menor taxa de retrogradação que variou de 7,5 a 8,5 %; as cultivares brancas apresentaram as maiores taxas de retrogradação de 19,0 a 25,4 %. A hidrólise enzimática dos grânulos de amido, analisada em equivalentes de maltose, variou de 7,2 a 8,7 mg/mL, com uma velocidade maior para a cultivar BSyB, em 60 minutos. O amido extraído das amostras brancas de quinoa apresentou valor de luminosidade de 99,0 e os amidos extraídos das amostras de cor vermelha e preta apresentaram em torno de 97,0. As análises realizadas neste estudo ampliam o conhecimento das características da quinoa de cor branca, vermelha e preta, além de mostrar que a cultivar brasileira (BSyB) apresenta características diferenciadas em vários parâmetros. Devido as suas propriedades todas as amostras analisadas possuem potencial para futuras aplicações tecnológicas.

Classification of Chenopodium Genus Populations and Species Based on Continuous and Categorical Variables

2000 Mathematics Subject Classification: 62P10, 62H30

Towards a model of spray-canopy interactions : interception, shatter, bounce and retention of droplets on horizontal leaves

Pesticides used in agricultural systems must be applied in economically viable and environmentally sensitive ways, and this often requires expensive field trials on spray deposition and retention by plant foliage. Computational models to describe whether a spray droplet sticks (adheres), bounces or shatters on impact, and if any rebounding parent or shatter daughter droplets are recaptured, would provide an estimate of spray retention and thereby act as a useful guide prior to any field trials. Parameter-driven interactive software has been implemented to enable the end-user to study and visualise droplet interception and impaction on a single, horizontal leaf. Living chenopodium, wheat and cotton leaves have been scanned to capture the surface topography and realistic virtual leaf surface models have been generated. Individual leaf models have then been subjected to virtual spray droplets and predictions made of droplet interception with the virtual plant leaf. Thereafter, the impaction behaviour of the droplets and the subsequent behaviour of any daughter droplets, up until re-capture, are simulated to give the predicted total spray retention by the leaf. A series of critical thresholds for the stick, bounce, and shatter elements in the impaction process have been developed for different combinations of formulation, droplet size and velocity, and leaf surface characteristics to provide this output. The results show that droplet properties, spray formulations and leaf surface characteristics all influence the predicted amount of spray retained on a horizontal leaf surface. Overall the predicted spray retention increases as formulation surface tension, static contact angle, droplet size and velocity decreases. Predicted retention on cotton is much higher than on chenopodium. The average predicted retention on a single horizontal leaf across all droplet size, velocity and formulations scenarios tested, is 18, 30 and 85% for chenopodium, wheat and cotton, respectively.

The development of virtual leaf surface models for interactive agrichemical spray applications

This project constructed virtual plant leaf surfaces from digitised data sets for use in droplet spray models. Digitisation techniques for obtaining data sets for cotton, chenopodium and wheat leaves are discussed and novel algorithms for the reconstruction of the leaves from these three plant species are developed. The reconstructed leaf surfaces are included into agricultural droplet spray models to investigate the effect of the nozzle and spray formulation combination on the proportion of spray retained by the plant. A numerical study of the post-impaction motion of large droplets that have formed on the leaf surface is also considered.

Induction of a Th1 immune response and suppression of IgE via immunotherapy with a recombinant hybrid molecule encapsulated in liposome-protamine-DNA nanoparticles in a model of experimental allergy

Liposome-protamine-DNA nanoparticles (LPD) are safe, effective, and non-toxic adjuvants that induce Th1-like immune responses. We hypothesized that encapsulation of allergens into liposomes could be an appropriate option for immunotherapy. The present study evaluated the immunotherapeutic potential of a recombinant hybrid molecule (rHM) encapsulated in LPD nanoparticles in a murine model of Chenopodium album allergy. BALB/c mice were sensitized with the allergen in alum, and the immunotherapy procedure was performed by subcutaneous injections of LPD-rHM, rHM, or empty LPD at weekly intervals. Sensitized mice developed a Th2-biased immune response characterized by strong specific IgG1 and IgE production, IL-4, and the transcription factor GATA3 in spleen cell cultures. Treatment with the LPD-rHM resulted in a reduction in IgE and a marked increase in IgG2a. The LPD-rHM induced allergen-specific responses with relatively high interferon-gamma production, as well as expression of the transcription factor T-bet in stimulated splenocytes. In addition, lymphoproliferative responses were higher in the LPD-rHM-treated mice than in the other groups. Removal of the nanoparticles from the rHM resulted in a decrease in the allergen's immunogenicity. These results indicate that the rHM complexed with LPD nanoparticles has a marked suppressive effect on the allergic response and caused a shift toward a Th1 pathway.

内蒙古草原凋落物分解对生物多样性变化的响应

生物多样性与生态系统功能紧密相关，而凋落物分解是生态系统主要功能之一，同时凋落物的分解反过来又影响了物种的组成和多样性。本研究在内蒙古草原应用分解网袋法，通过功能群去除产生不同的多样性梯度。研究了草原生态系统的生物多样性变化对凋落物分解过程的影响。实验分为相互补充的三个部分，（一）、分解微环境实验研究了功能群多样性变化引起的分解微环境变化对凋落物分解的影响；（二）、凋落物组成实验研究四个功能群的优势物种羊草（Leymus chinensis）、大针茅（Stipa grandis）、细叶葱（Allium tenuissimum）、刺穗藜（Chenopodium aristatum）的15种不同组合方式的单种或混合凋落物在相同的分解微环境下物种间的相互作用对凋落物分解的影响；（三）、综合分解微环境和凋落物组成两种影响凋落物分解的因素，从15种多样性组合的去除样方中收集的单种或混合凋落物放回原样方分解。研究结果表明，功能群多样性，相应地物种多样性高的样方中，其微环境有利于凋落物的分解，两个生物特性差异较大的物种木地肤（Kochia prostrata）和二裂委陵菜（Potentilla bifurca）在功能群多样性高的样方中与多样性低的样方相比均表现出高的分解速率；混合凋落物的分解具有非加和性效应。混合凋落物的分解速率与其初始碳含量呈负相关关系，与其初始氮、磷含量呈正相关；当混合凋落物在功能群多样性不同的环境中分解时，重量降解速率与环境中的功能群多样性没有显著的相关关系，氮流失与功能多样性成正相关。我们的研究表明，群落中凋落物组成和凋落物多样性相比，前者是影响凋落物分解的决定性因素；与地上存活植株的生物学过程相比，凋落物分解受生物多样性的影响较小；在生物多样性更高的区域，可以显著地增加氮的循环过程，有利于提高群落生产力。

植物根系、根区微生物对大气CO2浓度倍增的反应及其生态学意

预测下世纪中叶，大气CO_2浓度将高到目前的两倍（即达到700μ1•1~(-1)）。CO_2倍增对植物地上部的影响已经有了较多的研究，胆是由于方法学上的困难，至今关于倍增CO_2对植物根及根区微生物的研究仍是非常匮乏。本文应用国际上最新的根研究方法，以根系为中心，研究开顶式CO_2C熏蒸培养室中，CO_2倍增条件下根系与地上部，根系与根区微生物[共生的泡囊－丛枝菌根（VAM）真菌，非共生的土壤微生物]的关系。 1. CO_2倍增对根系的影响目前CO_2倍增对根系影响的研究多集中在根生物量的测定，或根／冠比值的测定，而善于其它参数如根长度则很少涉及，而根表面的反应目前还未见文献报道。本实验以幼苗期小麦“青323”（Triticum aestivum）、水稻“中作 29”(Oryza sativa)、大豆“科农4号”（Glycine max）、玉米“农大3138”（Zea mays）、甜高粱“M－81E”（Sorghum saccharatum）为材料，研究CO_2倍增对植物生物量的影响，发现CO_2倍增使C_3植物水稻、大豆的地上部、根系干重均显著增加，使小麦的根系干重显著增加，地上部无显著差异;C_4植物玉米和甜高粱的地上部和根系均没有显著反应。植物干重反应资料表明在光合产物的分配方面，C_3和C_4植物之间存在巨大的差异。 为了解根系获取土壤资源的能力的变化，我们对根系总长度和总表面积进行了分析。用样格交叉法研究根系长度的变化，结果显示，幼苗期的小麦、大豆的根系长度均被显著促进，尤其值得注意的是，尽管玉米根系干重没有显著改变，但是根长度已发生显著变化。同时应用研究根系表面积的最新方法－Na NO_2吸附法，研究发现幼苗期小麦、水稻和大豆的根系表面积在CO_2倍增条件下均显著增加，C_4植物玉米的根表面积亦有显著增加，但甜高粱的根表面积却没有显著反应，这说明即使在C_4植物类型中，根系表面积的反应在不同物种间仍存在很大差异。由于根长度和根表面积增幅大于根干重的增幅，所以推断在CO_2倍增条件下，植物根系细根比例增加，这有利于植物获取更多的养分。由于不同植物之间根系的反应不同，这将改变群落中原有的根系竞争关系，从而影响群落中物种的组成。 2. CO_2倍增对VAM真菌侵染强度和活力的影响本文应用NBT染色法，并结合浸染强度等级和活力等级标准，首次对CO_2倍增条件下，植物VAM真菌的侵染强度和活力的变化进行了检测。对比常规的酸性品红乳酸甘油法和NBT法，发现两者在显示侵染强度时元显著差异，但后者能同时用于侵染活力等级的研究。对幼苗期大豆以及不同生长期的小麦和玉米根系VAM真菌的侵染强度和活力进行观测，结果显示，倍增CO_2对大豆的侵染强度和活力均没有显著效应;使幼苗期玉米的侵染强度显著增加，但侵染活力无显著差异，但随生长期的推移，侵染强度所受的CO_2倍增效应逐渐减小，与14天苗龄（DAP）和35DAP相比，侵染活力在22DAP时所受效应最大;使10DAP小麦的VAM侵染强度和活力均显著增加，而且这种效应在30DAP小麦中的表现与10DAP小麦的相同。说明C_3、C_4植物中，菌根真菌对CO_2倍增反应不同，这也许是C_3、C_4植物对CO_2倍增反应不同的原因之一。倍增CO_2改善了VAM真菌的发育，所以较之于非菌根侵染植物，菌根侵染植物将因为CO_2倍增而获益更多，另一方面不同种植物中，VAM真菌的发育反应不同，这将使植物群落中，根系获取无机营养的竞争能力发生变化，最终影响植物群落的物种丰度和生物多样性以及群落的演替。 3. CO_2倍增对非共生土壤微生物的影响CO_2倍增使生长70天的小麦、垂柳（Salix babylonica）、藜(Chenopodium album)、繁穗苋（Amaranthus cruentus）品种“红苋K112”的地上部和根系的生物量增加。以这些植物所在土壤为材料，用氯仿熏蒸直接提取法研究土壤微生物生物量C（C_(mic)）和生物量N（N_(mic)）的变化，发现CO_2倍增尽管使各类型植物的C_4植物）土壤中C_(mic)的变化趋势不完全相同（小麦和藜所在土壤的C_(mic)下降，垂柳中C_(mic)升高，而在繁穗苋中无显著差异），但N_(mic)在各物种所在土壤中均有不同程度的上升，在繁穗苋中增幅最大。C_(mic):N_(mic)比值在4个物种所在土壤中均明显下降，这意味着CO_2倍增后在植物生长后期，土壤微生物活性提高，分解植物凋落物和土壤中其它有机质的能力加强，从而改善贫瘠土壤中有机质质量。 4.CO_2倍增对植物呼吸和光合作用及C素积累的影响 1）CO_2倍增对植物暗呼吸的影响：以杜仲（Eucommia ulmoides）、紫花苜蓿(Medicago sativa)和玉米等10种植物的离体成熟叶片或整株为材料，研究不同测定温度（15～35 ℃）下，CO_2倍增对植物暗呼吸的影响。结果表明：在较低温度（15 ℃、20 ℃）下，CO_2倍增对植物暗呼吸没有显著效应;在较高温度（30 ℃、35 ℃）时，多数被测植物的暗呼吸显著增强。由于植物在不同温度时它们的暗咱吸受CO_2倍增的促进幅度不同，这将导致不同地区（环境温度不同）的植物暗呼吸反应有差异，而且由于不同物种的暗呼吸增幅不同，综合光合效应，它们的生物量的反应也会不同。 2）CO_2倍增对整株植物的CO_2气体交换及植物C素积累的影响：利用自行设计的一套CO_2气体测定装置，首次尝试同步测定CO_2倍增条件下幼苗期小麦地下部和地上部的气体交换在昼夜24小时内的变化及C素的积累。发现CO_2倍增不仅使小麦地上部C素的积累增加，也使地下部释放的C素增加，但整株植物的C素收入仍高于对照两倍多，这从植物与环境的CO_2气体交换角度为CO_2倍增促进植物生物量的增加提供了依据。并首次提出：植物的整体性及植物所在的环境条件（主要是温度和光照强度）决定着植物暗呼吸对CO_2倍增的响应方式：被抑制或无效应。

海北站周围3种外来物种入侵状况的初步研究

通过对海北生态系统定位站附近3种植物播娘蒿Descurainia sophia、荠菜Capsella bursa-pastoris、灰绿藜Chenopodium glaucum的分布情况的调查,初步分析了3种植物的扩散策略,并预测了其对高寒草甸生态系统潜在的影响.

青海湖盐碱湿地灰绿藜叶的形态解剖学研究

利用光学显微镜和透射电镜对生长于青海湖湖滨盐碱湿地的先锋植物灰绿藜(Chenopodium glaucum Linn. ) 及生长于甘肃兰州大学校园内中生环境对照灰绿藜叶片的显微、超微结构进行了比较观察研究。结果发现中生环境灰绿藜叶片较薄, 有明显的栅栏与海绵组织分化; 叶绿体呈椭圆形, 基粒片层较发达且普遍含有淀粉粒。与对照相比, 生长于高海拔湖滨盐碱湿地灰绿藜叶为等面叶, 叶片厚, 角质层厚, 栅栏组织发达, 气室明显, 具表皮毛; 线粒体较多, 但嵴不发达, 叶绿体呈扁船型沿着壁的边缘排列, 叶绿体的基粒片层不发达且普遍含有脂质球, 一些细胞中常出现大量的多层膜结构。研究结果表明2 种生态型灰绿藜的形态结构已发生了深刻的变异, 湖滨灰绿藜表现出适应区域的寒旱化的明显特征。

Piaburu: a quinoa brasileira que chegou para diversificar a safrinha.

2001

Logística externa de exportación de Quinua : estudio comparativo entre Perú y Bolivia

En los últimos años la quinua se ha constituido en un alimento de gran demanda por sus bondades nutritivas, con un elevado contenido proteico que fluctúa entre 13 a 20 por ciento el cual supera cualitativamente y cuantitativamente a otros cereales como el arroz, avena, cebada, etc. (7 a 11 por ciento). El ciclo de producción de la quinua se encuentra en un proceso de crecimiento exponencial en el cual, Perú viene posicionándose como principal productor y exportador mundial de quinua (50 por ciento), superando a Bolivia (49 por ciento) e ingresando a más de 45 mercados, con una demanda liderada por Estados Unidos. Cabe resaltar que el precio de comercialización de quinua viene siendo determinado por el mercado internacional por cuanto la quinua ha tendido a convertirse en un `commodity` y no varía de manera substancial, si proviene de Bolivia (US$ 6,64 por Kg.) o Perú (US$ 5,64 por Kg.), por lo cual estos costos serán variables de acuerdo a la eficiencia logística de proceso y distribución que permita generar una diferencia competitiva en el mercado. El objetivo de este trabajo es describir y comparar el sistema logístico de exportación de la Quinua peruana y boliviana, con la finalidad de identificar la diferencia competitiva en el mercado internacional utilizando indicadores logísticos emitidos por el Banco mundial, apoyado del diamante de Porter con énfasis en dos determinantes que son la condición de los factores y de la demanda. De acuerdo a los resultados obtenidos Perú en infraestructura, comercio exterior, idoneidad logística, trazabilidad y justo a tiempo; posee mejor desempeño comparado a Bolivia. Además, en los fletes internos (terrestres) y externos (marítimo) de quinua a mercados como EE.UU (Los Ángeles) y España (Puerto de Barcelona), el Perú tiene menores costos de exportación (US$/contenedor 890) que Bolivia (US$/contenedor 1.440), pero mayores al promedio de Latinoamérica. Uno de los factores que se apalancó para esta competitividad, son sus ventajas comparativas (cercanía de Puerto con zonas productoras), y competitivas (modernización del puerto de Callo). Además la iniciativa que ha tenido el estado peruano en la concesión de sus puertos para la modernización y la reducción de trámite documentario, así como el TLC con EE.UU que permitió a Perú tener mejores relaciones comerciales (52 ranking de 144 países evaluados) comparado con Bolivia (82). Y por último se concluye de manera general que el sistema logístico de quinua de Perú logísticamente es más competitivo que el sistema logístico de quinua de Bolivia, ya que obtuvo 10 por ciento más de ampliación de mercado externo, creando una ventaja diferenciada respecto a Bolivia que al 2014 disminuyo en un 15 por ciento en sus exportaciones con respecto al 2013. Asimismo, cerca del 70 por ciento del valor total exportado de la quinua de Perú representa quinua convencional y el otro 30 por ciento quinua orgánica, siendo esta última en promedio un 10 por ciento mejor pagada que el producto convencional. Y que generalmente la mercancía es despachada y puesta a disposición al importador generalmente dado por precio FOB.

Effect of agricultural management and weeds on feeding groups of nematode in Soybean

p.71-81

Salt removing species

Dissertação de Mestrado, Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2007

Essential oils as anti-nematode agents and their influence on in vitro nematode

Tese de doutoramento, Biologia (Biotecnologia), Universidade de Lisboa, Faculdade de Ciências, 2015

Post-dispersal seed predation of non-target weeds in arable crops

Field experiments were conducted to quantify the natural levels of post-dispersal seed predation of arable weed species in spring barley and to identify the main groups of seed predators. Four arable weed species were investigated that were of high biodiversity value, yet of low to moderate competitive ability with the crop. These were Chenopodium album, Sinapis arvensis, Stellaria media and Polygonum aviculare. Exclusion treatments were used to allow selective access to dishes of seeds by different predator groups. Seed predation was highest early in the season, followed by a gradual decline in predation over the summer for all species. All species were taken by invertebrates. The activity of two phytophagous carabid genera showed significant correlations with seed predation levels. However, in general carabid activity was not related to seed predation and this is discussed in terms of the mainly polyphagous nature of many Carabid species that utilized the seed resource early in the season, but then switched to carnivory as prey populations increased. The potential relevance of post-dispersal seed predation to the development of weed management systems that maximize biological control through conservation and optimize herbicide use, is discussed.