RESUMO
BACKGROUND: Orchids have evolved various strategies that aim to ensure their reproduction success. These may include the production of rewards for pollinators, or on the contrary, deception. Specific sets of features such as flower morphology, color, nectar, and odor presence (or lack thereof) are considered to determine suitability for pollination by different groups of animals. Stingless bees are thought to be the primary pollinators of the orchids of the Neotropical subtribe Maxillariinae. However, almost black flowered Brasiliorchis schunkeana at first glance presents floral adaptations that may suggest another pollination syndrome-sapromyophily. RESULTS: A few traces of secretion were noticed on the glabrous lip callus and lip apex built by conical to villiform papillae (SEM analysis). Histochemical studies revealed huge amounts of lipids in the epidermis, subepidermis, and some parenchyma cells (SBB test) with various stages of lipids accumulation between cells. Further TEM analysis showed a heterogeneous (lipoid and phenolic) nature of secretion. The dense osmiophilic cytoplasm contained organelles (RER, free ribosomes, dictyosomes, plastids with plastoglobuli, nucleus) and vesicles migrating to plasmalemma. The vesicles, osmiophilic globules, and flocculent material were visible in periplasmic space. The central vacuole possessed osmiophilic phenolic content and flocculent material. GC-MS analysis revealed in floral extract the presence of 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione (77.06%) and 2,5-di-tert-butyl-1,4-benzoquinone (16.65%). Both compounds are known for their biological activity. CONCLUSIONS: The juxtaposition of results led us to the conclusion that the labellar tissue produces lipoid and phenolic material, which is responsible for the glossiness and rotten herring scent. This type of secretion could be classified as a phenolic resin. The chemical analysis revealed the presence of five semiochemicals that are known to be attractants for some Diptera, which together with the rest of the results constitutes a strong premise that representatives of this order could be potential pollinators of B. schunkeana. Field observations however are still needed to confirm this pollination syndrome.
Assuntos
Anti-Infecciosos , Orchidaceae , Animais , Orchidaceae/anatomia & histologia , Polinização , Flores/anatomia & histologia , Néctar de Plantas/análiseRESUMO
The stereotyped floral morphology of Neotropical Malpighiaceae species-zygomorphic and calyx with oil glands-is correlated with oil-bee pollination. In contrast, the floral trends of the Paleotropical lineages are actinomorphy and lack of calyx glands, probably due to the absence of oil-collecting bees. The Paleotropical genus Acridocarpus is an exception because of its zygomorphic, gland-bearing flowers. Glands throughout Acridocarpus inflorescences were morphoanatomically evaluated to verify the occurrence of patterns related to species and geographic distribution. Herbarium (25 species) and fresh samples of A. longifolius were processed according to standard anatomical techniques. To verify the presence of glucose and protein, strip tests were applied to the exudate. Fresh samples were fixed and submitted to histochemical tests. Based on the occurrence, number and placement of glands, three distribution patterns were recognized on the bracteole and ten on the calyx. Bract, bracteole and sepal glands have a typical nectary structure with a palisade-like epidermis and vascularized parenchyma. Glands were classified as short-stalked, sessile or immersed. Histochemical tests performed on bract and sepal glands of A. longifolius were positive for proteins, polysaccharides and phenolic compounds, and negative for oil compounds. Glucose and protein were detected in the exudate. These results allow us to recognize the glands in Acridocarpus inflorescences as nectaries. This comprehensive morphoanatomical study helps to clarify the correlation between patterns of floral morphology and secretion consumers, as well as to better understand floral evolution in Malpighiaceae across their dispersal events.
Assuntos
Flores/anatomia & histologia , Malpighiaceae/anatomia & histologia , Animais , Abelhas , Evolução Biológica , Néctar de Plantas/análise , Polinização/fisiologiaRESUMO
BACKGROUND: Nectar gain and loss are important flower transitions observed in angiosperms, and are particularly common in orchids. To understand such transitions, the availability of detailed anatomical data and species-level phylogenies are crucial. We investigated the evolution of food deception in Epidendrum, one of the largest orchid genera, using genus phylogeny to map transitions between nectar gain and loss among different clades. Associations between anatomical and histochemical changes and nectar gain and loss were examined using fresh material available from 27 species. The evolution of nectar presence/absence in Epidendrum species was investigated in a phylogenetic framework of 47 species, using one nuclear and five plastid DNA regions available from GenBank and sequenced in this study. RESULTS: The presence or absence of nectar was strongly associated with changes in the inner epidermal tissues of nectaries. Nectar-secreting species have unornamented epidermal tissue, in contrast to the unicellular trichomes found on the epidermis of food deceptive species. Bayesian tests confirmed that transitions occurred preferentially from nectar presence to nectar absence across the Epidendrum phylogeny. In addition, independent nectar loss events were found across the phylogeny, suggesting a lack of constraint for these transitions. CONCLUSIONS: Ornamented nectaries may play an important role in the deceptive pollination strategy by secreting volatile organic compounds and providing tactile stimuli to pollinators. The recurrent and apparently irreversible pattern of nectar loss in Epidendrum suggests that food deception may constitute an alternative evolutionarily stable strategy, as observed in other orchid groups.
Assuntos
Evolução Biológica , Orchidaceae/anatomia & histologia , Orchidaceae/fisiologia , Néctar de Plantas/análise , Polinização , DNA de Cloroplastos/genética , DNA de Plantas/genética , Cadeia Alimentar , Orchidaceae/genética , FilogeniaRESUMO
Onion (Allium cepa L.) is one of the main vegetable crops. Pollinators are required for onion seed production, being honeybees the most used. Around the world, two types of onion varieties are grown: open pollinated (OP) and hybrids. Hybrids offer numerous advantages to growers, but usually have lower seed yields than OP cultivars, which in many cases compromise the success of new hybrids. As pollination is critical for seed set, understanding the role of floral rewards and attractants to pollinator species is the key to improve crop seed yield. In this study, the correlation of nectar-analyzed compounds, floral traits, and seed yield under open field conditions in two experimental sites was determined. Nectar composition was described through the analysis of sugars, phenol, and alkaloid compounds. Length and width of the style and tepals of the flowers were measured to describe floral traits. Floral and nectar traits showed differences among the studied lines. For nectar traits, we found a significant influence of the environment where plants were cultivated. Nonetheless, flower traits were not influenced by the experimental sites. The OP and the male-sterile lines (MSLs) showed differences in nectar chemical composition and floral traits. In addition, there were differences between and within MSLs, some of which were correlated with seed yield, bringing the opportunity to select the most productive MSL, using simple determinations of morphological characters like the length of the style or tepals size.
Assuntos
Abelhas/fisiologia , Flores/anatomia & histologia , Cebolas/crescimento & desenvolvimento , Néctar de Plantas/química , Polinização , Sementes/crescimento & desenvolvimento , Animais , Argentina , Produtos Agrícolas/anatomia & histologia , Produtos Agrícolas/química , Produtos Agrícolas/crescimento & desenvolvimento , Cebolas/anatomia & histologia , Cebolas/química , Néctar de Plantas/análiseRESUMO
Grape, orange, peach and passion fruit nectars were formulated and adulterated by dilution with syrup, apple and cashew juices at 10 levels for each adulterant. Attenuated total reflectance Fourier transform mid infrared (ATR-FTIR) spectra were obtained. Partial least squares (PLS) multivariate calibration models allied to different variable selection methods, such as interval partial least squares (iPLS), ordered predictors selection (OPS) and genetic algorithm (GA), were used to quantify the main fruits. PLS improved by iPLS-OPS variable selection showed the highest predictive capacity to quantify the main fruit contents. The selected variables in the final models varied from 72 to 100; the root mean square errors of prediction were estimated from 0.5 to 2.6%; the correlation coefficients of prediction ranged from 0.948 to 0.990; and, the mean relative errors of prediction varied from 3.0 to 6.7%. All of the developed models were validated.
Assuntos
Contaminação de Alimentos/análise , Néctar de Plantas/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Brasil , Calibragem , Citrus sinensis , Frutas/química , Análise dos Mínimos Quadrados , Néctar de Plantas/química , Prunus persica , Espectrofotometria Infravermelho , Espectroscopia de Infravermelho com Transformada de Fourier/estatística & dados numéricos , VitisRESUMO
Background and Aims: The most widespread form of protective mutualisms is represented by plants bearing extrafloral nectaries (EFNs) that attract ants and other arthropods for indirect defence. Another, but less common, form of sugary secretion for indirect defence occurs in galls induced by cynipid wasps. Until now, such galls have been reported only for cynipid wasps that infest oak trees in the northern hemisphere. This study provides the first evidence of galls that exude sugary secretions in the southern hemisphere and asks whether they can be considered as analogues of plants' EFNs. Methods: The ecology and anatomy of galls and the chemical composition of the secretion were investigated in north-western Argentina, in natural populations of the host trees Prosopis chilensis and P. flexuosa . To examine whether ants protect the galls from natural enemies, ant exclusion experiments were conducted in the field. Key Results: The galls produce large amounts of sucrose-rich, nectar-like secretions. No typical nectary and sub-nectary parenchymatic tissues or secretory trichomes can be observed; instead there is a dense vascularization with phloem elements reaching the gall periphery. At least six species of ants, but also vespid wasps, Diptera and Coleoptera, consumed the gall secretions. The ant exclusion experiment showed that when ants tended galls, no differences were found in the rate of successful emergence of gall wasps or in the rate of parasitism and inquiline infestation compared with ant-excluded galls. Conclusions: The gall sugary secretion is not analogous to extrafloral nectar because no nectar-producing structure is associated with it, but is functionally equivalent to arthropod honeydew because it provides indirect defence to the plant parasite. As in other facultative mutualisms mediated by sugary secretions, the gall secretion triggers a complex multispecies interaction, in which the outcome of individual pair-wise interactions depends on the ecological context in which they take place.
Assuntos
Formigas/fisiologia , Oviposição , Néctar de Plantas/metabolismo , Prosopis/fisiologia , Simbiose , Vespas/fisiologia , Animais , Argentina , Néctar de Plantas/análise , Prosopis/química , Açúcares/metabolismo , Árvores/química , Árvores/fisiologiaRESUMO
El Agraz (Vaccinium meridionale Swartz), es una baya que posee alta capacidad antioxidante debido a su contenido de compuestos polifenólicos como antocianinas, ácidos fenólicos y flavonoides. El objetivo de este estudio fue evaluar la composición proximal inicial y el efecto en las características fisicoquímicas (pH, °Brix, acidez titulable (AT)), actividad antioxidante y antiproliferativa de néctares elaborados a partir de agraz liofilizado, almacenados du- rante 42 días. Se prepararon dos néctares: NA (sacarosa) y NB (aspartame), se evaluó cambio en pH, °Brix y AT cada7días durante el almacenamiento. Se determinó contenido de fenoles y antocianinas totales mediante Folin-Ciocalteau y método diferencial de pH, respectivamente, actividad antioxidante mediante FRAP y ORAC. Se analizó la actividad antiproliferativa con sulforodamina B en células SW480 (adenocarcinoma de colon). Los resultados mostraron que ambos néctares presentaron estabilidad en °Brix, pH yAT y el NB presentó menor aporte calórico. El contenido de fenoles totales aumentó durante el almacenamiento. El contenido de antocianinas y capacidad antioxidante se redujo significativamente (p<0,05). NA presentó mejor actividad antiproliferativa a las 72h, con un porcentaje de inhibición del crecimiento celular a una concentración de 1g/mL de 63,50% (IC50=0,6g/mL). Se puede concluir que NA presentó mayor capacidad antiproliferativa y NB mejor actividad antioxidante, que aunque disminuyó significativamente durante el almacenamiento, continuó siendo alta comparada con estudios reportados en la literatura. Para productos realizados a partir de bayas del género Vaccinium. Se requieren estudios adicionales in vivo que permitan comprobar su eficacia quimiopreventiva y dilucidar mecanismos moleculares de acción para beneficio de la salud humana, demostrando su potencial funcional descrito hasta ahora in vitro(AU)
Effect of storage time on the physicochemical characteristics, antioxidant and antiproliferative nectar of unripe (Vaccinium meridionale Swartz). Agraz (Vaccinium meridionale Swartz) is a berry that has high antioxidant capacity due to its content of polyphenolic compounds as anthocyanins, phenolic acids and flavonoids. The aim of this study was to evaluate the initial proximal composition and the effect on the physicochemical characteristics (pH, ° Brix, titratable and acidity (TA), antioxidant and antiproliferative activity of nectars made from unripe lyophilized and stored for 42 days. Two nectars were prepared: NA (sucrose) and NB (aspartame), was evaluated change in pH, °Brix and AT every 7 days during storage. It was determined and total phenols content by Folin-Ciocalteu anthocyanins and pH differential method, respectively, antioxidant activity by FRAP and ORAC. Antiproliferative activity with sulforhodamine B in SW480 cells (colon adenocarcinoma) were analyzed. The results showed that both were stable nectars ° Brix, pH and changes in AT. The NB has lower calories. The content of total phenols increased during storage. The anthocyanin content and antioxidant capacity was significantly reduced (p <0.05). NA presented better antiproliferative activity at 72 h, with a percentage of inhibition of cell growth at a concentration of 1g / ml of 63.50% (IC50 = 0.6 g/mL). It can be concluded that NA had a higher antiproliferative capacity and NB better antioxidant activity than even decreased significantly during storage, remained high com- pared to studies reported in the literature. Further studies "in vivo" to verify their chemopreventive efficacy and elu- cidate molecular mechanisms of action for the benefit of human health, showing their functional potential described so far "in vitro" are required(AU)
Assuntos
Humanos , Masculino , Feminino , Vaccinium , Néctar de Plantas/análise , Polifenóis , Antioxidantes , Armazenamento de Alimentos , Alimentos, Dieta e Nutrição , Valor NutritivoRESUMO
Members of several genera of mites from the family Melicharidae (Mesostigmata) use hummingbirds as transport host to move from flower to flower, where they feed on pollen and nectar. The factors that influence hummingbird flower mite abundance on host plant flowers are not currently known. Here we tested whether hummingbird flower mite abundance on an artificial nectar source is determined by number of hummingbird visits, nectar energy content or species richness of visiting hummingbirds. We conducted experiments employing hummingbird feeders with sucrose solutions of low, medium, and high energy concentrations, placed in a xeric shrubland. In the first experiment, we recorded the number of visiting hummingbirds and the number of visiting hummingbird species, as well as the abundance of hummingbird flower mites on each feeder. Feeders with the highest sucrose concentration had the most hummingbird visits and the highest flower mite abundances; however, there was no significant effect of hummingbird species richness on mite abundance. In the second experiment, we recorded flower mite abundance on feeders after we standardized the number of hummingbird visits to them. Abundance of flower mites did not differ significantly between feeders when we controlled for hummingbird visits. Our results suggest that nectar energy concentration determines hummingbird visits, which in turn determines flower mite abundance in our feeders. Our results do not support the hypothesis that mites descend from hummingbird nostrils more on richer nectar sources; however, it does not preclude the possibility that flower mites select for nectar concentration at other spatial and temporal scales.
Assuntos
Aves/fisiologia , Comportamento Alimentar , Métodos de Alimentação/instrumentação , Ácaros/fisiologia , Simbiose , Distribuição Animal , Animais , Feminino , Masculino , México , Néctar de Plantas/análise , Densidade DemográficaRESUMO
Este estudo avaliou a capacidade antioxidante e os indicadores físico-químicos de néctares caseiros de laranja, manga e maracujá, mantidos sob refrigeração (5 ± 2 o C) por 24 horas. Os néctares foram preparados em laboratório e mantidos sob refrigeração, simulando as condições domésticas. As análises foram realizadas após o preparo (T0) e durante o acondicionamento sob refrigeração (1 h, 4 h e 24 h). Os sólidos solúveis, pH e cor foram determinados respectivamente por refratometria, potenciometria e colorimetria. Carotenoides e ácido ascórbico foram analisados por cromatografia líquida de alta eficiência; a concentração de compostos fenólicos foi determinada utilizando-se o reagente de Folin Ciocalteau e a atividade antioxidante pelo teste do DPPH. Ácido ascórbico, β-caroteno e compostos fenólicos foram identificados em todos os néctares. Foram encontrados α-caroteno e β-criptoxantina no néctar de laranja e licopeno no néctar de manga. Durante 24 horas de refrigeração, os compostos analisados e a atividade antioxidante mantiveram-se estáveis. De forma geral, os parâmetros físico-químicos também se mantiveram estáveis durante o período avaliado. Em conclusão, sob as condições utilizadas no presente estudo, os néctares não apresentaram alteração da capacidade antioxidante, podendo ser considerados fontes de carotenoides e vitamina C, mesmo se consumidos após 24 horas de preparo.(AU)
The objective of the study was to evaluate the antioxidant capacity and the physical-chemical indicators of homemade nectars of orange, mango and passion fruit, kept under refrigeration (5 ± 2 °C) for 24 hours. The nectars were prepared in laboratory and kept under refrigeration simulating the domestic conditions. The samples analyses were performed after their preparations (T0) and during the refrigerated storage (1 h, 4 h and 24 h). Soluble solids, pH and color were determined by refractometry, colorimetry and potentiometry, respectively. Carotenoids and ascorbic acid were analyzed by high performance liquid chromatography, the concentration of phenolic compounds were determined by using Folin Ciocalteau reagent, and the antioxidant activity by the DPPH test. Ascorbic acid, β-carotene and phenolic compounds were identified in all of the analyzed nectars samples. The α-carotene and β-cryptoxanthin were found in orange nectar and the lycopene in mango nectar samples. During the refrigeration for 24 hours, the analyzed compounds and the antioxidant activity remained stable. In general, the physical-chemicals parameters also remained stable during the storage for 24 hours. In conclusion, under the conditions used in this study, the nectars might be considered as antioxidant sources, even if consumed after being prepared 24 hours before.(AU)
Assuntos
Néctar de Plantas/análise , Néctar de Plantas/química , Antioxidantes , Passiflora/química , Mangifera/química , Citrus sinensis/química , Alimentos Resfriados , Ácido Ascórbico , Carotenoides , Compostos FenólicosRESUMO
Este estudo avaliou a capacidade antioxidante e os indicadores físico-químicos de néctares caseiros de laranja, manga e maracujá, mantidos sob refrigeração (5 ± 2 o C) por 24 horas. Os néctares foram preparados em laboratório e mantidos sob refrigeração, simulando as condições domésticas. As análises foram realizadas após o preparo (T0) e durante o acondicionamento sob refrigeração (1 h, 4 h e 24 h). Os sólidos solúveis, pH e cor foram determinados respectivamente por refratometria, potenciometria e colorimetria. Carotenoides e ácido ascórbico foram analisados por cromatografia líquida de alta eficiência; a concentração de compostos fenólicos foi determinada utilizando-se o reagente de Folin Ciocalteau e a atividade antioxidante pelo teste do DPPH. Ácido ascórbico, β-caroteno e compostos fenólicos foram identificados em todos os néctares. Foram encontrados α-caroteno e β-criptoxantina no néctar de laranja e licopeno no néctar de manga. Durante 24 horas de refrigeração, os compostos analisados e a atividade antioxidante mantiveram-se estáveis. De forma geral, os parâmetros físico-químicos também se mantiveram estáveis durante o período avaliado. Em conclusão, sob as condições utilizadas no presente estudo, os néctares não apresentaram alteração da capacidade antioxidante, podendo ser considerados fontes de carotenoides e vitamina C, mesmo se consumidos após 24 horas de preparo.
The objective of the study was to evaluate the antioxidant capacity and the physical-chemical indicators of homemade nectars of orange, mango and passion fruit, kept under refrigeration (5 ± 2 °C) for 24 hours. The nectars were prepared in laboratory and kept under refrigeration simulating the domestic conditions. The samples analyses were performed after their preparations (T0) and during the refrigerated storage (1 h, 4 h and 24 h). Soluble solids, pH and color were determined by refractometry, colorimetry and potentiometry, respectively. Carotenoids and ascorbic acid were analyzed by high performance liquid chromatography, the concentration of phenolic compounds were determined by using Folin Ciocalteau reagent, and the antioxidant activity by the DPPH test. Ascorbic acid, β-carotene and phenolic compounds were identified in all of the analyzed nectars samples. The α-carotene and β-cryptoxanthin were found in orange nectar and the lycopene in mango nectar samples. During the refrigeration for 24 hours, the analyzed compounds and the antioxidant activity remained stable. In general, the physical-chemicals parameters also remained stable during the storage for 24 hours. In conclusion, under the conditions used in this study, the nectars might be considered as antioxidant sources, even if consumed after being prepared 24 hours before.
Assuntos
Antioxidantes , Citrus sinensis/química , Mangifera/química , Néctar de Plantas/análise , Néctar de Plantas/química , Passiflora/química , Alimentos Resfriados , Carotenoides , Compostos Fenólicos , Ácido AscórbicoRESUMO
Pyrostegia venusta (the orange trumpet or commoly called cipَ-de-Sمo-Joمo in Brazil), a medicinal plant that grows with other plants, has an ecological importance due to the presence of nectaries on the leaves. The aim of this work was to study structural and histochemical aspects and the distribution of extrafloral nectaries (ENFs) in P. venusta leaves. Young leaves were collected, fixed and processed by usual techniques, and studied under light microscopy and scanning electron microscopy. Analyses showed that the extrafloral nectaries are dispersed throughout the leaf, with concentrations mainly in the basal third section. Nectaries lie in epidermal depressions and can be found in abaxial and adaxial leaf blades. Their morphology may be characterized macroscopically by achlorophyllous halos and microscopically as structures consisting of a short pedicel, oval multicellular head, covered by a thin cuticular layer with a secretory pole. Reducing sugars, neutral polysaccharides, proteins, starch and phenolic compounds were detected in extrafloral nectaries.(AU)
. Pyrostegia venusta (cipَ-de-Sمo-Joمo) é uma planta medicinal que cresce junto a outras plantas e que apresenta também importância ecolَgica, pela presença de nectلrios na regiمo dos folيolos. O objetivo deste trabalho foi estudar aspectos estruturais, histoquيmicos e da distribuiçمo de nectلrios extraflorais (NEFs) em folhas de P. venusta. Folhas jovens foram coletadas, fixadas e processadas por técnicas usuais e estudadas sob microscopia de luz e eletrônica de varredura. As anلlises mostraram que os NEFs estمo dispersos por toda a folha, concentrando-se preferencialmente no terço basal. Os nectلrios estمo localizados em depressُes epidérmicas e podem ser encontrados nas faces abaxial e adaxial da lâmina foliar. Macroscopicamente, os NEFs podem ser caracterizados como halos aclorofilados e microscopicamente, como estruturas com pedicelo curto, cabeça ovoide pluricelular, recobertos por uma fina camada cuticular e um polo secretor. Nos nectلrios extraflorais foram detectados açْcares redutores, polissacarيdeos neutros, proteيnas, amido e compostos fenَlicos.(AU)
Assuntos
Néctar de Plantas/análise , Bignoniaceae/anatomia & histologia , Bignoniaceae/crescimento & desenvolvimento , Imuno-HistoquímicaRESUMO
O presente estudo objetivou desenvolver néctares de cagaita (Eugenia dysenterica DC.), caracterizá-los quanto aos parâmetros microbiológicos, sensoriais e químicos e verificar a estabilidade do produto durante o armazenamento. Quatro formulações de néctar contendo 20, 30, 40 e 50% de polpa foram desenvolvidas e avaliadas microbiológica (coliformes totais e termotolerantes, bolores, leveduras e Salmonela spp) e sensorialmente (teste de aceitação). A formulação mais aceita foi avaliada quanto ao conteúdo de sólidos solúveis (SS), pH, acidez titulável (AT), relação SS/AT, umidade, proteínas, lipídios, carboidratos, fibra alimentar total (FAT), cinzas, carotenoides e ácido ascórbico (AA), verificando-se a estabilidade do produto armazenado sob congelamento (-18ºC/90 dias) e refrigeração (5ºC/72 horas). Não foi observada a presença dos micro-organismos pesquisados nas quatro formulações desenvolvidas. As formulações com 40 e 50% de polpa apresentaram maior aceitação para os atributos cor, sabor e impressão global. O néctar contendo 50% de polpa apresentou SS de 11,43 ºBrix, pH de 3,59 e relação SS/AT de 19,37. Verificou-se (em 100 g) AT de 0,59 g de ácido cítrico; 85,75 g de umidade; 0,29 g de proteínas; 0,27 g de lipídios; 12,93 g de carboidratos; 0,68 g de FAT; 0,08 g de cinzas; 55,31 kcal; 0,25 mg de carotenoides e 19,6 mg de AA. Durante o armazenamento não foram observadas alterações estatisticamente significativas nos valores de SS, AT, pH, carotenoides e AA. O néctar de cagaita atendeu as características químicas e os padrões microbiológicos estabelecidos pela legislação brasileira, alcançou boa aceitação dos consumidores e apresentou excelente estabilidade durante o armazenamento.
Assuntos
Técnicas Microbiológicas , Pradaria , Armazenamento de Alimentos , Néctar de Plantas/análise , Análise de Alimentos , Microbiologia de Alimentos , FrutasRESUMO
Plant-pollinator interactions are great model systems to investigate mutualistic relationships. We compared pollinator effectiveness between facultative and obligate nectar-feeding bats to determine how foraging specialization influences mutualistic interactions in a bat-adapted cactus. We predicted that a specialized nectarivorous bat would deliver more pollen than an opportunistic nectar-feeding bat because of specialized adaptations to nectar feeding that indicate close association with their food plants. Counter to our predictions, the opportunistic Antrozous pallidus delivered significantly more pollen grains per visit than the specialized Leptonycteris yerbabuenae. Higher pollinator effectiveness, based on visitation rates and pollen deposition levels, varied between species by site, and although A. pallidus visits flowers much less frequently than L. yerbabuenae over all sites, it is likely an effective and reliable pollinator of Pachycereus pringlei in Baja, Mexico. Our results suggest that morphological adaptations and dietary specialization on nectar do not necessarily confer advantages for pollination over less specialized plant visitors and highlight the reciprocally exploitative nature of mutualisms.
Assuntos
Cactaceae/fisiologia , Quirópteros/fisiologia , Comportamento Alimentar , Polinização , Animais , Quirópteros/anatomia & histologia , Flores/fisiologia , Cadeia Alimentar , México , Néctar de Plantas/análise , Especificidade da EspécieRESUMO
PREMISE OF THE STUDY: While mahogany (Swietenia macrophylla) is one of the most important forest species in the Amazon region, little is known about its reproductive biology. Knowledge about the nectary structure and dynamics of nectar production of this species represent a key step toward understanding its relationship with pollinators. ⢠METHODS: Mahogany tree floral buds and flowers in anthesis were collected, fixed, and processed for study by light and transmission and scanning electron microscopy. The chemical composition of nectar and the nectary pigments was also studied. ⢠KEY RESULTS: Both staminate and pistillate flowers have nectaries, which contain a papillose epidermis and stomata. The nectariferous tissue is parenchymatous, with the cell cytoplasm primarily containing mitochondria and plastids. Secretory activity initiates at the beginning of anthesis, which occurs at nightfall. Flowers undergoing anthesis become structurally modified, with starch grains in the plastids disappearing. The number of plastoglobuli in the plastids also increases when nectaries change color from pale yellow to intense red. Pistillate and staminate flowers produce meager nectar rewards. ⢠CONCLUSIONS: Changes in plastoglobuli number seem to be related to an increase in carotenes and color changes during anthesis. Carotenes can be linked to the protection of the plant against oxidative stress, which results from secretory activities. Nectary color has a limited role as a pollinator attractant. Floral rewards comprise small nectar droplets in both flower types, in addition to a few pollen grains in staminate flowers. These meager rewards are probably adapted to attract small generalist insects.
Assuntos
Meliaceae/anatomia & histologia , Meliaceae/fisiologia , Néctar de Plantas/análise , Néctar de Plantas/metabolismo , Brasil , Cromatografia em Camada Fina , Flores/anatomia & histologia , Flores/crescimento & desenvolvimento , Flores/fisiologia , Flores/ultraestrutura , Meliaceae/crescimento & desenvolvimento , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Pólen/anatomia & histologiaRESUMO
BACKGROUND AND AIMS: Variation in the composition of floral nectar reflects intrinsic plant characteristics as well as the action of extrinsic factors. Micro-organisms, particularly yeasts, represent one extrinsic factor that inhabit the nectar of animal-pollinated flowers worldwide. In this study a 'microbial imprint hypothesis' is formulated and tested, in which it is proposed that natural community-wide variation in nectar sugar composition will partly depend on the presence of yeasts in flowers. METHODS: Occurrence and density of yeasts were studied microscopically in single-flower nectar samples of 22 animal-pollinated species from coastal xeric and sub-humid tropical habitats of the Yucatán Peninsula, Mexico. Nectar sugar concentration and composition were concurrently determined on the same samples using high-performance liquid chromatography (HPLC) methods. KEY RESULTS: Microscopical examination of nectar samples revealed the presence of yeasts in nearly all plant species (21 out of 22 species) and in about half of the samples examined (51·8 % of total, all species combined). Plant species and individuals differed significantly in nectar sugar concentration and composition, and also in the incidence of nectar yeasts. After statistically controlling for differences between plant species and individuals, nectar yeasts still accounted for a significant fraction of community-wide variance in all nectar sugar parameters considered. Significant yeast × species interactions on sugar parameters revealed that plant species differed in the nectar sugar correlates of variation in yeast incidence. CONCLUSIONS: The results support the hypothesis that nectar yeasts impose a detectable imprint on community-wide variation in nectar sugar composition and concentration. Since nectar sugar features influence pollinator attraction and plant reproduction, future nectar studies should control for yeast presence and examine the extent to which microbial signatures on nectar characteristics ultimately have some influence on pollination services in plant communities.
Assuntos
Carboidratos/análise , Flores/microbiologia , Insetos/microbiologia , Néctar de Plantas/metabolismo , Plantas/microbiologia , Leveduras/isolamento & purificação , Animais , Ascomicetos/genética , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/isolamento & purificação , Basidiomycota/genética , Basidiomycota/crescimento & desenvolvimento , Basidiomycota/isolamento & purificação , Contagem de Colônia Microbiana , Flores/química , Flores/metabolismo , Frutose/análise , Glucose/análise , Insetos/fisiologia , México , Néctar de Plantas/análise , Plantas/química , Plantas/metabolismo , Polinização , Análise de Sequência de DNA , Sacarose/análise , Leveduras/genética , Leveduras/crescimento & desenvolvimentoRESUMO
UNLABELLED: This work aimed to evaluate the effect of high-pressure homogenization (HPH) with heat shock on Aspergillus niger, vitamin C, and color of mango nectar. The nectar was processed at 200 MPa followed by heat shock, which was optimized by response surface methodology by using mango nectar ratio (45 to 70), heat time (10 to 20), and temperature (60 to 85 °C) as variables. The color of mango nectar and vitamin C retention were evaluated at the optimized treatments, that is, 200 MPa + 61.5 °C/20 min or 73.5 °C/10 min. The mathematical model indicates that heat shock time and temperature showed a positive effect in the mould inactivation, whereas increasing ratio resulted in a protective effect on A. niger. The optimized treatments did not increase the retention of vitamin C, but had positive effect for the nectar color, in particular for samples treated at 200 MPa + 61.5 °C/20 min. PRACTICAL APPLICATION: The results obtained in this study show that the conidia can be inactivated by applying HPH with heat shock, particularly to apply HPH as an option to pasteurize fruit nectar for industries.
Assuntos
Manipulação de Alimentos/métodos , Conservação de Alimentos/métodos , Mangifera/microbiologia , Néctar de Plantas/análise , Pressão , Ácido Ascórbico/metabolismo , Aspergillus niger/crescimento & desenvolvimento , Bebidas/microbiologia , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Frutas/microbiologia , Temperatura Alta , Oxirredução , Pigmentação , Esporos Fúngicos/crescimento & desenvolvimentoRESUMO
O objetivo deste trabalho foi o de investigar se os diferentes horários de coleta de néctar em áreas apícolas influenciam no volume, concentração de açúcar e açúcar total produzido por suas flores, no momento da antese, bem como verificar possíveis alterações nas características do néctar ao longo do tempo e discutir as conseqüências no potencial apícola das áreas de jitirana-branca (Merremia aegyptia). Também foi avaliada a relação entre esta produção de atrativos florais e o comportamento dos polinizadores potenciais, dentre estes a Apis mellifera L. (abelha africanizada). A pesquisa foi realizada em uma área de preservação de Caatinga, no Campus da FATEC Sertão Central, Quixeramobim, Ceará. Foi constatado que: a densidade floral média foi 33,7 flores/m²; seu volume de néctar variou de acordo com o horário de coleta não há reposição de néctar na flor após as 11:00 horas.
The objective of this study was to investigate whether the different time of collection of nectar in hive areas influence the volume, the concentration of sugar and total amount of sugar produced by all its flowers at the time of anthesis, as well as evaluating possible changes in the characteristics of nectar along the time and discuss the beekeeping potential of areas containing "jitirana-branca" (Merremia aegyptia). It was also evaluated the relationship between the generation of floral attractive and the behavior of potential pollinators, including Apis mellifera L. (Africanized honeybee). The study was conducted in a preservation area of Caatinga, at the campus of FATEC, Quixeramobim, CE, Brazil. It was found that: the mean floral density of M. aegyptia was 33.7 flowers/m²; the volume of nectar was affected by the time of collection and no more nectar is secreted by the flowers after 11:00 AM.
Assuntos
Animais , Abelhas , Comportamento Animal , Convolvulaceae/química , Néctar de Plantas/análiseRESUMO
Helicteres guazumifolia Kunth and Helicteres baruensis Jacq. (Sterculiaceae) are two sympatric species of shrubs common along the North Western tropical dry forest of Costa Rica. i recorded their nectar production within a 24 hour cycle. i also describe the morphology of extrafloral nectaries with scanning electron microscopy. in H. guazumifolia secretion was restricted to the first day of flower life span, shortly after anthesis (0600 hr - 1800 hr). Flowers secreted on average 15.63 ±8.45 µl (N=409). Nectar is composed of three main sugars: sucrose, fructose and glucose (mainly sucrose). A total of 17 free amino acids were identified: mainly proline, arginine, threonine and tyrosine, with a concentration above 70 Ng/µl. values were different for H. baruensis. Nectar secretion was confined to the second day after anthesis, starting at 1600 hr and ending at 0600 hr the following day. Flowers secreted on average 77.03 ±64.99 µl (N=163) of nectar. Nectar is also composed of three main sugars; however, it showed a tendency to be hexose-rich, having more fructose and glucose than sucrose. There were also 17 free amino acids, mainly proline, alanine, tyrosine, arginine and threonine. Patterns of nectar production are different between the two species for timing, and for amount and composition of nectar secretion. Rev. Biol. Trop. 57 (Suppl. 1): 161-177. Epub 2009 November 30.
Helicteres guazumifolia Kunth y Helicteres baruensis Jacq. (Sterculiaceae) son dos especies simpátricas de arbustos comunes en el bosque tropical seco de la zona noroeste de Costa Rica. Registré los patrones de producción de néctar de las dos especies según la hora del día o de la noche cuando hubo secreción de néctar. En H. guazumifolia se limitó al primer día del período de vida floral, desde el inicio de la antesis a las 0600 hr hasta las 1800 hr. Las flores secretaron en promedio 15.63 ±8.45 µl (N=409) de néctar. El néctar está compuesto por tres azúcares principales: sacarosa, fructuosa y glucosa, y es rico en sacarosa. Se identificó un total de 17 aminoácidos diferentes en el néctar floral. Prolina, arginina, treonina y tirosina fueron los aminoácidos más abundantes con una concentración mayor a 70 Ng/µl. En contraste, las flores de su pariente H. baruensis, secretaron néctar en el segundo día de vida de la flor, después de la antesis; se inició a las 1600 hr y cesó a las 0600 hr del día siguiente. Las flores secretaron en promedio 77.03 ±64.99 µl (N=163) de néctar. El néctar también está compuesto por tres azúcares principales; no obstante, tiende a ser rico en hexosas, con más fructuosa y glucosa que sacarosa. También contiene 17 aminoácidos libres, siendo los más concentrados prolina, alanina, tirosina, arginina y treonina. Se observan claramente patrones diferentes de producción de néctar entre las dos especies según la hora, la cantidad y la composición del néctar. También describí la morfología de los nectarios florales usando fotomicrografías tomadas con microscopio electrónico.