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1
Chatt, Elizabeth C., Siti-Nabilla Mahalim, Nur-Aziatull Mohd-Fadzil, Rahul Roy, Peter M. Klinkenberg, Harry T. Horner, Marshall Hampton, Clay J. Carter, and Basil J. Nikolau. "Nectar biosynthesis is conserved among floral and extrafloral nectaries." Plant Physiology 185, no. 4 (January 28, 2021): 1595–616. http://dx.doi.org/10.1093/plphys/kiab018.
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Abstract Nectar is a primary reward mediating plant–animal mutualisms to improve plant fitness and reproductive success. Four distinct trichomatic nectaries develop in cotton (Gossypium hirsutum), one floral and three extrafloral, and the nectars they secrete serve different purposes. Floral nectar attracts bees for promoting pollination, while extrafloral nectar attracts predatory insects as a means of indirect protection from herbivores. Cotton therefore provides an ideal system for contrasting mechanisms of nectar production and nectar composition between different nectary types. Here, we report the transcriptome and ultrastructure of the four cotton nectary types throughout development and compare these with the metabolomes of secreted nectars. Integration of these datasets supports specialization among nectary types to fulfill their ecological niche, while conserving parallel coordination of the merocrine-based and eccrine-based models of nectar biosynthesis. Nectary ultrastructures indicate an abundance of rough endoplasmic reticulum positioned parallel to the cell walls and a profusion of vesicles fusing to the plasma membranes, supporting the merocrine model of nectar biosynthesis. The eccrine-based model of nectar biosynthesis is supported by global transcriptomics data, which indicate a progression from starch biosynthesis to starch degradation and sucrose biosynthesis and secretion. Moreover, our nectary global transcriptomics data provide evidence for novel metabolic processes supporting de novo biosynthesis of amino acids secreted in trace quantities in nectars. Collectively, these data demonstrate the conservation of nectar-producing models among trichomatic and extrafloral nectaries.
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Silva, Fredy A., Elizabeth C. Chatt, Siti-Nabilla Mahalim, Adel Guirgis, Xingche Guo, Daniel S. Nettleton, Basil J. Nikolau, and Robert W. Thornburg. "Metabolomic Profiling of Nicotiana Spp. Nectars Indicate That Pollinator Feeding Preference Is a Stronger Determinant Than Plant Phylogenetics in Shaping Nectar Diversity." Metabolites 10, no. 5 (May 22, 2020): 214. http://dx.doi.org/10.3390/metabo10050214.
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Floral nectar is a rich secretion produced by the nectary gland and is offered as reward to attract pollinators leading to improved seed set. Nectars are composed of a complex mixture of sugars, amino acids, proteins, vitamins, lipids, organic and inorganic acids. This composition is influenced by several factors, including floral morphology, mechanism of nectar secretion, time of flowering, and visitation by pollinators. The objective of this study was to determine the contributions of flowering time, plant phylogeny, and pollinator selection on nectar composition in Nicotiana. The main classes of nectar metabolites (sugars and amino acids) were quantified using gas chromatography/mass spectrometric analytical platforms to identify differences among fifteen Nicotiana species representing day- and night-flowering plants from ten sections of the genus that are visited by five different primary pollinators. The nectar metabolomes of different Nicotiana species can predict the feeding preferences of the target pollinator(s) of each species, and the nectar sugars (i.e., glucose, fructose, and sucrose) are a distinguishing feature of Nicotiana species phylogeny. Moreover, comparative statistical analysis indicate that pollinators are a stronger determinant of nectar composition than plant phylogeny.
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Zambon, Vivian, Kayna Agostini, Massimo Nepi, Mônica Lanzoni Rossi, Adriana Pinheiro Martinelli, and Marlies Sazima. "The role of nectar traits and nectary morphoanatomy in the plant-pollinator interaction between Billbergia distachia (Bromeliaceae) and the hermit Phaethornis eurynome (Trochilidae)." Botanical Journal of the Linnean Society 192, no. 4 (December 9, 2019): 816–27. http://dx.doi.org/10.1093/botlinnean/boz107.
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Abstract Nectar production dynamics can show inter- and intraspecific variation, which can be associated with environmental and ecological factors and with the ultrastructural diversity of the floral nectary. In this context, we recorded nectar production dynamics from a morphofunctional perspective using the hummingbird-pollinated Billbergia distachia (Bromeliaceae). The scale-throated hermit Phaethornis eurynome was the only floral visitor observed, indicating a specialized pollination system. Nectar production showed significant differences between day and night, and the periods of major pollinator activity and nectar secretion were synchronous. The ultrastructural features of the nectary showed some evidence of nectar reabsorption in flowers at night, and it can be inferred that this process may be a key factor in the nocturnal pause in nectar production. In this way, nectary morphoanatomy, nectar traits and an energy-saving mechanism through nectar reabsorption contribute to the well-established relationship between B. distachia and P. eurynome.
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Stolar, Jessica, and Arthur R. Davis. "Floral nectary structure, nectar production, and carbohydrate composition in theLiliumAsiatic hybrid ‘Trésor’." Botany 88, no. 2 (February 2010): 185–205. http://dx.doi.org/10.1139/b09-109.
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Floral nectary structure, nectar production, and carbohydrate composition were compared from petals (“inner tepals”) and sepals (“outer tepals”) of Lilium Asiatic hybrid ‘Trésor’ (Liliaceae). The six nectaries each occupied a narrow furrow bordered by two convergent ridges extending adaxially from the petal and sepal base. Each sepal nectary furrow was shorter and more concealed. In both nectary types, many vascular bundles comprising xylem and phloem supplied 5.5–8 layers of nectariferous parenchyma cells below the epidermis, which lacked stomata. Transmission electron microscopy of sepal nectaries demonstrated that parts of the outer epidermal wall adhered to an intact but uplifted cuticle in nectar-secreting flowers. Both apoplastic and symplastic routes were continuous from the vascular bundles to the nectary epidermis. Starch breakdown from amyloplasts throughout the nectary likely augmented nectar production. Nectar solute concentration from another Asiatic hybrid, ‘Orange Pixie’, was also significantly higher in petals. In ‘Trésor’, significantly more nectar was available from sepals, possibly reflecting reduced evaporation from multiple nectar droplets within the covered nectary furrow. However, for both hybrids, the same quantity of nectar sugar was produced by petals and sepals. Nectar composition from petals and sepals also was alike, in ‘Orange Pixie’ averaging 67/19/14 (= sucrose/fructose/glucose) and 59/25/17, respectively, and in ‘Trésor’ averaging 68/23/10 and 62/27/12, respectively.
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Chwil, Mirosława, and Elżbieta Weryszko-Chmielewska. "Nectary structure and nectar secretion of Echium russicum J. F. Gmel. flowers." Acta Agrobotanica 60, no. 1 (2012): 25–33. http://dx.doi.org/10.5586/aa.2007.003.
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In this study, the micromorphology of nectaries in <i>Echium russicum</i> J. F. Gmel. flowers was determined by using scanning electron microscopy (SEM) and their anatomy by using light microscopy (LM). The rate of nectar production of flowers and sugar concentration in nectar were investigated. The nectary gland is located below the ovary of the pistil. It is composed of 4 parts corresponding to the parts of the ovary. The widest regions of the nectar-producing tissue are situated by the furrows separating the adjacent parts of the ovary. Nectar is secreted through anomocytic stomata, located only in the lower part of the nectary. The stomata were distributed evenly or they formed clusters of 2-3. The average number of stomata on the surface of the whole nectary was 184. At the nectar secretion stage, open and closed, as well as not fully mature stomata were observed. The orientation of most of the stomata was parallel to the nectary base. The cuticle surface of the cells of the upper and lateral part of the nectary was smooth, whereas in the region producing stomata it showed various folds facilitating the retention of nectar. The flowers produced nectar throughout the flowering period. The weight of nectar secreted throughout the lifetime of ten flowers was, on the average, 20 mg, with the concentration of sugars of 58% and their weight reaching 17 mg.
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Al-Tardeh, Sharaf, Thomas Sawidis, Barbara-Evelin Diannelidis, and Stylianos Delivopoulos. "Nectary structure and nectar presentation in the Mediterranean geophyte, Urginea maritima (Hyacinthaceae)." Botany 86, no. 10 (October 2008): 1194–204. http://dx.doi.org/10.1139/b08-075.
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The morphology, anatomy, and ultrastructure of the floral nectary of Urginea maritima (L.) Baker were investigated at three stages of nectary development. The plant possesses a typical gynopleural (septal) nectary with secondary presentation. The nectary consists of one layer of epithelium secretory cells and one to four layers of subsidiary cells subtended by two to six layers of parenchyma (subnectary) cells. The nectary releases the nectar at a point two-thirds towards the summit of the ovary by means of carpellary sutures. Nectar secretion appears to depend largely on the hydrolysis of starch grains stored in amyloplasts at the intermediate stage. The hydrolysis process most likely commences in the epithelium layer followed by the subsidiary tissue and then the parenchyma cells of the ovary wall. A symplastic transfer of the secreted nectar occurs by plasmodesmata connecting the subsidiary cells to the parenchyma and the epithelial secretory cells. However, microchannels in the cell wall of the epithelial cells may facilitate the apoplastic transfer of the nectar into the nectary cavity. The old stage of nectary development is characterized by a crystallized form of nectar, collapse of the parenchyma cells, complete starch hydrolysis, and disappearance of the amyloplasts and endoplasmic reticulum.
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Weryszko-Chmielewska, Elżbieta, and Mirosława Chwil. "Structure of floral nectaries in Aesculus hippocastanum L." Acta Botanica Croatica 76, no. 1 (March 1, 2017): 41–48. http://dx.doi.org/10.1515/botcro-2016-0049.
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Abstract Representatives of the family Sapindaceae exhibit high morphological diversity of the nectary structure. The present paper shows for the first time the results of micromorphological, anatomical, and ultrastructural analyses of floral nectaries in Aesculus hippocastanum. We have also described the forage and signal attractants of these flowers, which are important for the ecology of pollination. Using light, fluorescence, and electron microscopy, we demonstrated that the A. hippocastanum nectary forming a lobed disc is histologically differentiated into the epidermis with stomata, nectariferous parenchyma, subglandular parenchyma, and vascular bundles reaching the basal part of the nectariferous parenchyma. The use of histochemical assays revealed the presence of insoluble polysaccharides, lipids, terpenoids, and polyphenols including coumarins in the nectary tissues. Nectar is exuded onto the nectary surface via stomata and the permeable cuticle. As indicated by the observation of the ultrastructure of the nectary cells, transport of pre-nectar into parenchymal cells may proceed via the symplast and apoplast. We have also demonstrated that nectar transfer outside the protoplasts of parenchymal cells has a character of granulocrine secretion. A. hippocastanum flowers produce nectar abundantly; one flower secreted on average 2.64 mg of nectar and the concentration of sugars in the nectar was 33%.
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Amato, Bianca, Sophie Petit, and Russell Schumann. "Improving floral nectar storage on filter paper for sugar recovery." Australian Journal of Botany 69, no. 8 (2021): 585. http://dx.doi.org/10.1071/bt21006.
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Nectar analysis has been used to understand pollination systems, but nectar storage methods have rarely been considered as potential sources of inaccuracy in the recovery of data. Prompt nectar sugar analysis is not always possible and storage methods can affect results. We aimed to develop an effective method to store nectar on filter paper. Nectars from two subspecies of Eremophila maculata (Scrophulariaceae) and Strelitzia reginae (Strelitziaceae) were spotted on filter papers. Nectars were redissolved and assayed by high-performance liquid chromatography to determine the masses of sugars recovered from the papers from Day 0 to Day 30. We evaluated the effects of the method of elution, paper type and size, and storage treatments on sugar recovery. Liquid nectars were also stored in the refrigerator. Sugars were best eluted from filter papers in 15mL of water and agitated for 1min. Nectar sugars stored on small papers tended to be recovered more successfully than those stored on larger papers (significantly for glucose). Paper performed better than nylon for glucose. Desiccant had a marginal positive effect on nectar sugar recovery, and filter paper performed better than did refrigeration of liquid nectar for storage. If highly accurate measurements are needed, nectars should be eluted with large volumes of water from small filter papers stored with desiccant within a few days of collection.
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Davis, A. R., R. W. Shuel, and R. L. Peterson. "Distribution of carbofuran and dimethoate in flowers and their secretion in nectar as related to nectary vascular supply." Canadian Journal of Botany 66, no. 7 (July 1, 1988): 1248–55. http://dx.doi.org/10.1139/b88-178.
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The distribution of two systemic insecticides (carbofuran, dimethoate) in floral parts and nectar of Ajuga reptans L. (Lamiaceae), Brassica napus L. (Brassicaceae), and Vicia faba L. (Leguminosae), which differ in their types of nectary vascular supply, was determined. Radioactivity was detected in all floral organs when excised flowering plant tops were cultured in sucrose solution containing a combination of 14C-labelled and formulated (unlabelled) insecticide. In A. reptans and B. napus, combined nectary tissue and nectar contained the most radioactivity on a fresh weight basis. Radioactivity was detected in floral nectar of all species, and in extrafloral nectar of V. faba. Estimated concentrations of insecticide were much higher in extrafloral than in floral nectar of V. faba; the presence of xylem in the nectary vasculature to the former may be responsible. However, the presence of xylem is not necessary for the secretion of systemic insecticides by nectaries.
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Bory, Gérarad, and Danielle Clair-Maczulajtys. "Composition du nectar et rôle des nectaires extrafloraux chez l'Ailanthus glandulosa." Canadian Journal of Botany 64, no. 1 (January 1, 1986): 247–53. http://dx.doi.org/10.1139/b86-036.
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The composition of the extrafloral nectar from Ailanthus glandulosa varies according to the type of nectary. When the buds open, those which are located on the cataphylls or the stipules are only supplied by carbohydrate reserves. In this case, a high sucrose content is found in the nectar, and rhamnose is also detected. The floriferous or sterile state of the trees does not modify the sugar composition of the foliar nectar. For amino acids, the predominance of serine, threonine, and proline is constant in all types of nectars. The amount of proline is very important in the nectar of the cataphylls and increases with the age of the leaf. The activity of the foliar nectaries seems to correlate with the occurrence of a requirement for photosynthetic products. The nectaries from trees developing fruits or from those showing only vegetative growth continue to be functional for a long time. The ablation of foliar nectaries leads to a sugar accumulation in the leaf and slows down the reconstitution of starch reserves in the branch. The function of the extrafloral nectaries is interpreted as being the elimination of excess sugars. Thus, the initiation of these nectaries may be due to a carbohydrate accumulation during the ontogeny of foliar organs.
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Weryszko-Chmielewska, Elżbieta, Mirosław Chwil, and Marek Wróbel. "The position and structure of the nectary in spring heath (Erica carnea L.) flowers." Acta Agrobotanica 62, no. 2 (2012): 13–21. http://dx.doi.org/10.5586/aa.2009.022.
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Ecological traits of <i>Erica carnea</i> L. flowers and the morphology of floral nectaries were investigated using stereoscopic, light and scanning electron microscopy. The nectary in the flowers of <i>Erica carnea</i> is located in the basal part of the ovary. It represents the gynoecial nectary type. It has the form of a yellow, ribbed ring with eight outgrowths, pointed towards the base, which alternately adjoin the stamen filaments. The height of the nectary is 400 µm and its thickness 200 - 250 µm. The parenchyma of the nectary is composed of 6 - 8 layers. Nectar secretion occurs through anomocytic stomata with a diameter of 17 µm. Guard cells are only found on the outgrowths of the nectary and they are situated most frequently at the level of other epidermal cells. During nectar secretion, a small degree of pore opening was observed. In the flowers of <i>Erica carnea</i>, secondary nectar presentation was found, with the nectar accumulating at the base of the fused corolla.
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Bernardello, Gabriel, Leonardo Galetto, and Gregory J. Anderson. "Floral nectary structure and nectar chemical composition of some species from Robinson Crusoe Island (Chile)." Canadian Journal of Botany 78, no. 7 (July 1, 2000): 862–71. http://dx.doi.org/10.1139/b00-055.
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Floral nectary structure and nectar composition of 12 species, including 11 endemics, are reported from Robinson Crusoe Island (Juan Fernández Archipelago, Chile). These species are mostly hummingbird pollinated. Nectary morphology follows the general pattern within each of the families, suggesting it is an ancestral feature. The mean nectar concentration (± SD) as a percentage of weight (weight/total weight of solution) was 28.3 ± 20.7. Sucrose, fructose, and glucose were identified in most samples. In Nicotiana cordifolia, an unknown monosaccharide was also detected. When more than one sample per species was examined, there was usually variability in sugar ratios. Statistical tests indicated that population size does not influence this variability. However, there were differences when the pollinator type was compared, with a trend of a higher sucrose proportion and a lower coefficient of variation of sucrose in the species pollinated by hummingbirds. This would indicate a specialization in the nectar composition of the hummingbird-pollinated species. Cuminia eriantha, N. cordifolia, and Rhaphithamnus venustus also possess amino acids in their nectar. In the non-hummingbird-pollinated species, the presence of nectaries and nectar serves as an indication of the ancestral pollination system of the first colonizers rather than the current condition, which is wind pollination or self-compatibility for most of the species. Thus, the presence of nectar in flowers does not necessarily indicate extant biotic pollination.Key words: angiosperms, Robinson Crusoe Island, nectary structure, nectar sugar composition, sugar concentration, hummingbird pollination.
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Nocentini, Daniele, Massimo Guarnieri, and Chiara Soligo. "Nectar defense and hydrogen peroxide in floral nectar of Cucurbita pepo." Acta Agrobotanica 68, no. 2 (2015): 187–93. http://dx.doi.org/10.5586/aa.2015.009.
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This study was carried out to investigate some similarities between the nectaries of <em>Nicotiana</em> sp. and <em>Cucurbita</em> pepo, such as starch accumulation in the nectary parenchyma, changes in nectary color during maturation, and the production of a large quantity of sucrose-dominant nectar. The concentration of hydrogen peroxide in <em>C. pepo</em> floral nectar was determined in order to verify the presence of a defense mechanism similar to that found in <em>Nicotiana</em> sp. which protects nectar from yeast and bacteria proliferation. We also tested the eventual accumulation of antioxidants in the nectary of <em>C. pepo</em> as a protection against oxidative stress caused by hydrogen peroxide. The level of hydrogen peroxide found in the floral nectar of <em>C. pepo</em> was much lower than that found in <em>Nicotiana</em> sp. and the male flowers of <em>Cucurbita</em> had a higher concentration than the female flowers. The low oxidative stress induced by this level of hydrogen peroxide caused the accumulation of a low amount of lutein inside the plastoglobules which were contained in amyloplasts. Plastids of the <em>C. pepo</em> nectary are specialized in the accumulation of starch rather than antioxidants.
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Davis, A. R., R. L. Peterson, and R. W. Shuel. "Vasculature and ultrastructure of the floral and stipular nectaries of Vicia faba (Leguminosae)." Canadian Journal of Botany 66, no. 7 (July 1, 1988): 1435–48. http://dx.doi.org/10.1139/b88-198.
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The floral nectary of Vicia faba L. (faba bean, broad bean, or field bean) consists of a disk which bears a long, basal, tapered projection. Large, open stomata, located at the tip of the projection, probably serve as exits for nectar. Phloem is present in the floral nectary. The extrafloral nectary consists of numerous secretory and nonsecretory trichomes aggregated on the abaxial surface of each stipule. Both xylem and phloem are present in the stipule beneath the extrafloral nectary. In both nectary types, large companion cells accompany the phloem. Epidermal and parenchyma cells of the floral gland, as well as the companion cells, develop wall ingrowths and are therefore transfer cells. Ultrastructural evidence suggests a granulocrine mechanism of nectar secretion in the floral nectary, wherein both apoplastic and symplastic routes for prenectar movement and escape appear feasible. Floral and extrafloral nectar differ in sugar concentration and in the predominance of sucrose, both of which are higher in exudate from floral nectaries.
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Stpiczynska, Malgorzata. "Incorporation of [3H]sucrose after the resorption of nectar from the spur of Platanthera chlorantha (Custer) Rchb." Canadian Journal of Botany 81, no. 9 (September 1, 2003): 927–32. http://dx.doi.org/10.1139/b03-085.
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Platanthera chlorantha (Custer) Rchb., a moth-pollinated orchid, secretes abundant nectar. Sucrose incorporation following the resorption of nectar from the spurs of the pollinated and unpollinated flowers of P. chlorantha was investigated. The study was carried out using 3H-labelled sucrose and microautoradiography. In this orchid species, nectar was secreted and accumulated in the spur. Inside the spur, the epidermis developed numerous unicellular secretory hairs engaged in nectar secretion and resorption. Nectar resorption occurred near the end of anthesis. Following pollination, sucrose from the resorbed nectar was incorporated into starch accumulated in parenchyma cells of developing capsules. Additionally, radioactivity in the cell walls of parenchyma and ovules was also observed. The label was not detected either in the gynoecium of unpollinated flowers or in tuberous roots of all plants investigated. Therefore, the results demonstrate that carbohydrates reclaimed from uncollected nectar in pollinated flowers of P. chlorantha are next utilized inside the adjacent maturing fruits.Key words: Platanthera chlorantha, Orchidaceae, nectar resorption, nectary spur, microautoradiography, pollination.
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Stpiczyńska, Małgorzata, Magdalena Kamińska, and Kevin L. Davies. "Nectar secretion in a dry habitat: structure of the nectary in two endangered Mexican species of Barkeria (Orchidaceae)." PeerJ 9 (August 2, 2021): e11874. http://dx.doi.org/10.7717/peerj.11874.
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Barkeria scandens and B. whartoniana are endangered, endemic taxa from Mexico. They are epiphytes adapted to dry habitats. Since these plants are xerophytic, their flowers were investigated for structural adaptations to nectar secretion. The flowers of both species are structurally similar, and contrary to most claims for the genus, have functional floral nectaries comprising a nectary chamber and a narrow tubular cuniculus. Nectar is present in both these structures, and contains sugars and lipid-like compounds. The nectary tissue is composed of a single-layered epidermis overlying 1–2 layers of subepidermal secretory parenchyma. The outer tangential wall of the epidermal cells is thick and multi-layered, whereas the cuticle, which often shows blistering, is lamellate and possesses micro-channels. Lipid-like material occurs both between the microfibrils of the cell wall and in the micro-channels. Robust secretory tissue, thick cell walls, and lipid-like nectar components limit nectar evaporation. Moreover, the rigidity of the nectary potentially makes it possible for red-flowered B. scandens to switch from entomophily to ornithophily.
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Dmitruk, Marta. "Biology of flowering and nectar production in the flowers of the beauty bush (Kolkwitzia amabilis Graebn.)." Acta Agrobotanica 65, no. 4 (2012): 15–20. http://dx.doi.org/10.5586/aa.2012.017.
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Nectar production and the morphology of the nectary and pollen grains of <em>Kolwitzia amabilis </em>Graebn. were studied during the period 2008–2009 and in 2011. The blooming of beauty bush flowers started in the third decade of May and ended in the middle of June; flowering lasted 22–23 days. The flower life span was 4–5 days. Nectar production began at the bud break stage. The tube of the corolla in beauty bush flowers forms a spur inside which the nectary is located. The secretory surface of the nectary consists of two layers of glandular epidermal outgrowths: unicellular trichomes, with their length ranging 54.6 μm – 70.2 μm, and papillae with a length of 13.0 μm – 20.6 μm. The mean weight of nectar per 10 flowers, determined for the three years of the study, was 8.6 mg, with a sugar concentration of 50.8%. The weight of nectar sugar was on average 4.4 mg. In terms of the size, beauty bush pollen grains are classified as medium-sized. These are tricolporate grains.
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Vesprini, J. L., M. Nepi, and E. Pacini. "Nectary Structure, Nectar Secretion Patterns and Nectar Composition in Two Helleborus Species." Plant Biology 1, no. 5 (September 1999): 560–68. http://dx.doi.org/10.1111/j.1438-8677.1999.tb00784.x.
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Davis, A. R., R. L. Peterson, and R. W. Shuel. "Anatomy and vasculature of the floral nectaries of Brassica napus (Brassicaceae)." Canadian Journal of Botany 64, no. 11 (November 1, 1986): 2508–16. http://dx.doi.org/10.1139/b86-333.
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The floral nectaries of Brassica napus L. (Argentine or Swede rape) consist of two pairs of glands which are supplied by phloem only. The lateral pair has an extensive phloem supply and produces most of the flowers' nectar, whereas the median pair is supplied by limited phloem and produces relatively little nectar. Because both lateral and median nectaries contain cells exhibiting similar structural features, the disparity in phloem supply between them could account for the observed difference in nectar production. Ultrastructural evidence suggests an energy-requiring, eccrine mechanism of nectar secretion in Brassica napus. Both apoplastic and symplastic routes for nectar movement and escape appear feasible. Stomata on the nectary surfaces may serve as exits.
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Müller, Andreas, and Paul Westrich. "Morphological specialisation for primary nectar robbing in a pollen specialist mining bee (Hymenoptera, Andrenidae)." Journal of Hymenoptera Research 95 (February 17, 2023): 215–30. http://dx.doi.org/10.3897/jhr.95.98260.
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The European mining bee species Andrena lathyri (Andrenidae) is a narrow specialist of flowers of Lathyrus and Vicia (Fabaceae), from which both females and males gain nectar by primary nectar robbing. Both sexes are equipped with a unique proboscis, which is much longer and more strongly angled than in most other Andrena bees including the most closely related species. The comparison between the shape of the proboscis and the interior of the host flowers combined with field observations revealed that the specialised mouthparts of A. lathyri precisely correspond to the dimensions of the flower interior and the position of the nectary, representing one of the few known examples of a morphological adaptation to primary nectar robbing in bees. For nectar uptake, the bee’s head is inserted laterally under the standard petal before it is moved towards the flower base, thereby slitting the calyx longitudinally to a depth necessary to reach the nectary from inside the flower with the specialised proboscis. Nectar-robbing individuals of A. lathyri are able to adapt their behaviour to the different calyx lengths of their host flower species by slitting the calyx over varying distances. Except for the slit in the calyx, primary nectar robbing by A. lathyri does not damage any flower parts allowing for normal fruit development.
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Papp, N. "Nectar and nectary studies on sevenEuphorbiaspecies." Acta Botanica Hungarica 46, no. 1-2 (June 2004): 225–34. http://dx.doi.org/10.1556/abot.46.2004.1-2.16.
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Marie Judith Samadoulougou-Kafando, Pingdwinde, Charles Parkouda, Remy Kindanloun Bationo, Donatien Kabore, Inoussa Salambere, Hagretou Sawadogo-Lingani, and Mamoudou H. Dicko. "INFLUENCE DE LA FERMENTATION LACTIQUE SUR LES PROPRIETES ANTIOXYDANTES ET LES TENEURS EN POLYPHENOLS TOTAUX DE NECTARS DE MANGUE." International Journal of Advanced Research 9, no. 01 (January 31, 2021): 22–33. http://dx.doi.org/10.21474/ijar01/12275.
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La presente etude a pour objectif devaluerlaptitude de trois isolats de bacteries lactiques (Lactobacillus plantarumTD1h,Lactobacillus fermentumLOr2j et Pediococcus acidilacticiTE5a) àfermenter du nectar de mangue et àameliorerlactivite antioxydante. Leursaptitudes àsurvivre et àfermenter le nectar de mangue ont dabord ete evaluees àtraversle suivi de leur cinetique de croissance, levolution du pH et de lacidite titrabledans le nectar de cultivar de mangue Valencia. Ces isolats ont ensuite ete utilises pour fermenter des nectarsde trois cultivars de manguepuis, les teneurs en polyphenols totaux et lactivite antioxydanteont ete determinees aucours de la fermentation. Le suivi des paramètres au cours de la fermentation montre que pour chaque isolat, il ya une augmentation du nombre de cellulesdans le nectar de mangue accompagnee dune augmentation de lacidite titrable et dune baisse du pH. Les teneurs en polyphenols totaux ont significativement augmentedans les nectars de mangue fermentes avec L. plantarum TD1h et P. acidilactici TE5a.La meilleure augmentation a ete de 55,36% obtenue lors de la fermentation du nectar de cultivar lippens avec L. plantarum TD1h. Quant àlactivite antioxydante, elle a significativement augmente dans les nectars de cultivars Lippens et Kent. La meilleure reduction de la concentration requise pour provoquer une inhibition de 50% de la DPPH (IC50)a ete de 42,82% obtenu lors de la fermentation du nectar de cultivar lippens avec L.fermentum LOr2j.
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Mione, Thomas, and Isaac Argeo Diaz. "Dracula’s mistress: removal of blood-red floral nectar results in secretion of more nectar." Plant Ecology and Evolution 153, no. 1 (March 26, 2020): 59–66. http://dx.doi.org/10.5091/plecevo.2020.1589.
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Background and aims – Flowers of Jaltomata quipuscoae (Solanaceae) secrete blood-red nectar that serves as an energy reward and possible attractant to pollinators. The purposes of this study were to determine whether simulated pollinator visits (manual removal of nectar) stimulates replenishment of nectar, and report the pattern of nectar presentation during the lifespan of the flower. Methods – For the nectar replenishment experiments flowers were paired: each pair of flowers was selected to be on the same plant and at the same developmental stage. From all 62 flowers nectar was removed and discarded (not measured) at time zero. Then, over a period of eight hours, the nectar of one flower was measured four times, i.e., every two hours, while nectar of the paired control flower was measured only at the end of the eight-hour period. In the nectar dynamics experiment five sets of flowers received different treatments: flowers were unmanipulated for zero, one, two, three or four days and then nectar was removed once every day. The volume of nectar produced and concentration of sugar in the nectar were recorded at each extraction for both studies.Key results – In the nectar replenishment study significantly higher nectar volume and consequently significantly higher total sugar content was present in the experimental nectar-extracted flowers. In the nectar dynamics study, nectar was produced starting on day one or two, continuously through the life of the open flowers until one or two days before the corolla senesced. Delay of nectar removal from different flower sets for zero, one, two, three or four days resulted in a linear increase in nectar volume and total nectar sugar production, and had little or no effect on the cumulative (life of the flower) nectar production. Floral longevity, seven to ten days, was not affected by a single removal of nectar each day.Conclusions – The floral nectary of J. quipuscoae responded to nectar removal by secreting more nectar, and thus more total sugar (not a higher concentration of sugar) than was secreted by control flowers. In flowers from which nectar was not removed, nectar volume and thus total sugar secreted continued to accumulate linearly, suggesting that reabsorption of nectar either does not occur or is slow relative to the rate of secretion. The more we (or pollinators) take, the more the flowers make: the volume of nectar and sugar production increase if nectar is removed frequently but not if nectar is removed infrequently.
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Stpiczyńska, Małgorzata, Kevin L. Davis, and Magdalena Kamińska. "Structure of the cuniculus nectary in Brassavola flagellaris Barb. Rodr. (Laeliinae Benth., Orchidaceae)." Acta Agrobotanica 63, no. 1 (2012): 3–10. http://dx.doi.org/10.5586/aa.2010.001.
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To date, the structure of the cuniculus nectary has not been studied in detail. Furthermore, the secretory mechanism of such nectaries has not been investigated. The present paper describes, for the first time, the structural organization and ultrastructure of the cuniculus nectary in the moth-pollinated orchid <i>Brassavola flagellaris</i> Barb. Rodr. This tubular structure is situated between the perianth tube and ovary and, in its possession of thick, cellulose cell walls, resembles the nectary of ornithophilous taxa. The presence of large secretory vesicles that fuse with the plasmalemma indicate that granulocrine nectar secretion occurs in this species. The lumen of the cuniculus is lined with unicellular hairs. However, the cuticle overlying the whole epidermal surface lining the lumen (both glabrous and pubescent regions) was coated with nectar residues and became distended and cracked, indicating that this entire tissue is probably involved in nectar secretion.
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Swada, Jeffrey G., Jose I. Reyes De Corcuera, and Nicki J. Engeseth. "Impact of Alternative Thermal and Non-Thermal Processing on the Enzymatic Activity of Papaya and Strawberry Nectars and Their Blends." Journal of Food Engineering and Technology 9, no. 1 (June 15, 2020): 1–14. http://dx.doi.org/10.32732/jfet.2020.9.1.1.
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Pectin methylesterase (PME) in papaya nectar results in undesirable gel formation and peroxidase (POD) in strawberry nectar leads to nutrient loss, browning, and off-flavor production. Because of this, the effect of alternative processing techniques including ultra high temperature (UHT, 20-135°C, 1-3 s), high pressure processing (HPP, 20 or 60°C, 200-600 MPa) and irradiation (0-10 kGy) on PME and POD activity in papaya and strawberry nectar and their respective blends were compared to traditional thermal processing (80-130°C, 0-10 min). Traditional thermal (110°C, 5 min, 71.5% reduction) and UHT (110°C, 1-3 s, 98.0% reduction) processing were able to sufficiently reduce PME activity and prevent gel formation in papaya nectar. PME reduction was enhanced by synergistic reductions in nectar blends after UHT at 80°C. HPP was unable to prevent gel formation in papaya nectar, with enhanced activity at 400 MPa. Exposure of a blend 50P:50S to 10 kGy irradiation prevented gel formation. UHT enhanced POD activity at 110°C and synergistic reductions resulted for POD activity in nectar blends after irradiation. These findings highlight the benefits of alternative processing in reducing enzyme activity in fruit nectars and nectar blends.
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Stpiczyńska, Małgorzata, and Massimo Nepi. "Ecophysiological aspects of nectar reabsorption." Acta Agrobotanica 59, no. 1 (2012): 61–69. http://dx.doi.org/10.5586/aa.2006.006.
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A number of approaches, both direct and indirect, have shown that nectar is reabsorbed by numerous plant species, irrespective of the age or sex of the flower. Furthermore, reabsorption occurs regardless of whether or not the flower has been pollinated. Reabsorption helps to maintain concentration of nectar and their viscosity and thereby encourages continued visits by pollinators. Conversely, the capacity to vary concentration of nectar sugars may confer evolutionary advantage by encouraging visits by more than one kind of pollinator and this is particularly important in regions where there is a paucity of pollinators. A further important role of nectar reabsorption is the maintenance of the energy equilibrium of the plant. A number of studies have shown that nectar production involves considerable energy expenditure requiring as much as 37% of the plant's daily production of energy by photosynthesis. The increased metabolic costs incurred by the plant during nectar production and secretion can reduce its growth and reproduction during the following season. Reabsorption of nectar that has not been collected by pollinators enables the plant to conserve at least some of the energy reserved for the secretion of nectar. Sugars reabsorbed from nectar can be re-used for the development of fruit and ovules - processes which demand large quantities of sugar. Despite convincing evidence for the reabsorption of nectar, few detailed studies have addressed the transport and incorporation of reabsorbed sugars. One of the questions that remain to be answered is 'What is the cellular basis for nectar reabsorption by the nectary?'
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Zhu, Ya-Ru, Min Yang, Jana C. Vamosi, W. Scott Armbruster, Tao Wan, and Yan-Bing Gong. "Feeding the enemy: loss of nectar and nectaries to herbivores reduces tepal damage and increases pollinator attraction in Iris bulleyana." Biology Letters 13, no. 8 (August 2017): 20170271. http://dx.doi.org/10.1098/rsbl.2017.0271.
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Floral nectar usually functions as a pollinator reward, yet it may also attract herbivores. However, the effects of herbivore consumption of nectar or nectaries on pollination have rarely been tested. We investigated Iris bulleyana , an alpine plant that has showy tepals and abundant nectar, in the Hengduan Mountains of SW China. In this region, flowers are visited mainly by pollen-collecting pollinators and nectarivorous herbivores. We tested the hypothesis that, in I. bulleyana , sacrificing nectar and nectaries to herbivores protects tepals and thus enhances pollinator attraction. We compared rates of pollination and herbivory on different floral tissues in plants with flowers protected from nectar and nectary consumption with rates in unprotected control plants. We found that nectar and nectaries suffered more herbivore damage than did tepals in natural conditions. However, the amount of tepal damage was significantly greater in the flowers with protected nectaries than in the controls; this resulted in significant differences in pollinator visitation rates. These results provide the first evidence that floral nectar and nectaries may be ‘sacrificed’ to herbivores, leading to reduced damage to other floral tissues that are more important for reproduction.
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Hansen, Dennis M., Karin Beer, and Christine B. Müller. "Mauritian coloured nectar no longer a mystery: a visual signal for lizard pollinators." Biology Letters 2, no. 2 (March 2006): 165–68. http://dx.doi.org/10.1098/rsbl.2006.0458.
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Most floral nectars are clear as water, and the enigmatic coloured nectar in three endemic plant species in Mauritius has puzzled scientists studying it. One hypothesis about the possible ecological function of coloured nectar is that it serves as a visual signal for pollinators. Recent studies have shown that at least two of the three Mauritian plant species with coloured nectar are visited and pollinated by endemic Phelsuma geckos. We here provide experimental evidence for the visual signal hypothesis by showing that Phelsuma ornata geckos prefer coloured over clear nectar in artificial flowers. In flowering plants, coloured nectar could additionally function as an honest signal that allows pollinators to assert the presence and judge the size of a reward prior to flower visitation, and to adjust their behaviour accordingly, leading to increased pollinator efficiency. Our study provides a first step in understanding this rare and intriguing floral trait.
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Anderson, Jay F., Hema S. N. Duddu, Steven J. Shirtliffe, and Arthur R. Davis. "Structure of floral nectaries and comparison of reproductive and vestigial organs in the staminate and pistillate flowers of dioecious Silene latifolia (Caryophyllaceae)." Botany 97, no. 1 (January 2019): 1–21. http://dx.doi.org/10.1139/cjb-2018-0120.
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Silene latifolia Poiret of Eurasia has established in North America, prompting this structural study of its mature unisexual buds and flowers. Floral nectaries, anther and stigma changes, and vestigial reproductive structures were studied using light and scanning electron microscopy. In staminate flowers, anthers dehisced before anthesis and >90% of their pollen was liberated within 36 h. Accumulated in the tubular calyx, nectar descended an anthophore from the stomatal-bearing nectary at the stamen bases. Nectary tissue surrounded the pistillode, a central filamentous organ lacking ovules but tipped by hairs resembling stigmatic papillae. In pistillate flowers, nectar flowed into an inflated calyx. The annular nectary had 10 regularly spaced, stomatal-lined craters and was continuous with the adaxial surfaces of the infertile antisepalous and epipetalous staminodes. Key elements of entomophilous pollination leading to successful sexual reproduction of this invasive species include secondary nectar presentation from disparate floral nectaries that, for pistillate flowers, also incorporate the staminodes; rapid pollen release from anthers; and elongation of papillae by tip growth that enhances each stigma’s receptive surface. Context is also provided for future studies of floral nectary development in this model dioecious species.
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Galetto, Leonardo. "Nectary structure and nectar characteristics in someBignoniaceae." Plant Systematics and Evolution 196, no. 1-2 (1995): 99–121. http://dx.doi.org/10.1007/bf00985338.
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Begot, Laurent, Filip Slavkovic, Myriam Oger, Clement Pichot, Halima Morin, Adnane Boualem, Anne-Laure Favier, and Abdelhafid Bendahmane. "Precision Phenotyping of Nectar-Related Traits Using X-ray Micro Computed Tomography." Cells 11, no. 21 (October 31, 2022): 3452. http://dx.doi.org/10.3390/cells11213452.
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Flower morphologies shape the accessibility to nectar and pollen, two major traits that determine plant–pollinator interactions and reproductive success. Melon is an economically important crop whose reproduction is completely pollinator-dependent and, as such, is a valuable model for studying crop-ecological functions. High-resolution imaging techniques, such as micro-computed tomography (micro-CT), have recently become popular for phenotyping in plant science. Here, we implemented micro-CT to study floral morphology and honey bees in the context of nectar-related traits without a sample preparation to improve the phenotyping precision and quality. We generated high-quality 3D models of melon male and female flowers and compared the geometric measures. Micro-CT allowed for a relatively easy and rapid generation of 3D volumetric data on nectar, nectary, flower, and honey bee body sizes. A comparative analysis of male and female flowers showed a strong positive correlation between the nectar gland volume and the volume of the secreted nectar. We modeled the nectar level inside the flower and reconstructed a 3D model of the accessibility by honey bees. By combining data on flower morphology, the honey bee size and nectar volume, this protocol can be used to assess the flower accessibility to pollinators in a high resolution, and can readily carry out genotypes comparative analysis to identify nectar-pollination-related traits.
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Kostryco, Mikołaj, and Mirosława Chwil. "Nectar Abundance and Nectar Composition in Selected Rubus idaeus L. Varieties." Agriculture 12, no. 8 (July 30, 2022): 1132. http://dx.doi.org/10.3390/agriculture12081132.
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The increasing commercial production of R. idaeus offers insects nectar and pollen rewards, thus increasing the chance of cross-pollination, which enhances fruit yields. The knowledge of nectar characteristics may help farmers/beekeepers to improve the quality of their products. Therefore, we determined and compared nectar weight, sugar concentration and weight, and the qualitative and quantitative composition of sugars and amino acids in the nectar of six raspberry cultivars: three biennial and three repeated fruiting cultivars. The nectary abundance in these cultivars ranged between 20.2 ± 3.84 mg (‘Polka’) and 26.4 ± 7.3 mg (‘Glen Ample’) of nectar per flower with a sugar concentration of 34.6 ± 5.61–47.3 ± 9.33%. The contents of glucose and fructose (g/100 g) were in the range from 42.96 ± 0.71 (‘Glen Ample’) to 46.94 ± 0.55 (‘Laszka’) and from 50.7 ± 1.43 (‘Polka’) to 54.2 ± 0.72 (‘Radziejowa’). Sucrose was detected only in ‘Glen Ample’ (5.6 ± 1.12 g/100 g) and ‘Polka’ (6.2 ± 0.95 g/100 g). Taking into account the increasing sugar weight in the nectar, the cultivars were ranked as follows: ‘Polka’ < ‘Polana’ < ‘Radziejowa’ < ‘Pokusa’ < ‘Laszka’ < ‘Glen Ample’. The nectar of the analyzed raspberry cultivars was classified as a hexose-dominant type. Aspartic acid, glutamic acid, and proline were the most dominant endogenous amino acids, whereas exogenous acids were dominated by lysine and leucine. The present results provide valuable information about the nutritious value of R. idaeus nectar for pollinators.
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Stpiczyńska, Małgorzata, and Jacek Pielecki. "Structure of floral nectaries, nectar production and sugar composition in nectar of 7 species of Vicia L. Fabaceae." Acta Agrobotanica 52, no. 1-2 (2013): 49–57. http://dx.doi.org/10.5586/aa.1999.006.
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Nectaries of investigated species of <em>Vicia</em> were ranked into 3 morphological types: automorphic (<em>V. sepium</em> L.), transitoric (<em>V. angustifolia</em> L., <em>V. sativa</em> L., <em>V. villosa</em> Roth, <em>V. cracca</em> L.) and flat, epimorphic (<em>V. hirsuta</em> (L.) S. F. Gray and <em>V. tetrasperma</em> (L.) Schreb.). The best nectaring was connected with well defined nectary structure, and moreover quantity of nectar was correlated with nectary size but was not depended on number of secretory stomata. Sucrose dominated in the nectar of 6 species of vetches, the exception was balanced nectar of <em>V. tetrasperma</em>.
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Wei, Jiangkun, Zixin Huo, Stanislav N. Gorb, Alejandro Rico-Guevara, Zhigang Wu, and Jianing Wu. "Sucking or lapping: facultative feeding mechanisms in honeybees ( Apis mellifera )." Biology Letters 16, no. 8 (August 2020): 20200449. http://dx.doi.org/10.1098/rsbl.2020.0449.
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Nectarivorous insects generally adopt suction or lapping to extract nectar from flowers and it is believed that each species exhibits one specific feeding pattern. In recent literature, large groups of nectarivores are classified as either ‘suction feeders', imbibing nectar through their proboscis, or ‘lappers', using viscous dipping. Honeybees ( Apis mellifera ) are the well-known lappers by virtue of their hairy tongues. Surprisingly, we found that honeybees also employ active suction when feeding on nectar with low viscosity, defying their classification as lappers. Further experiments showed that suction yielded higher uptake rates when ingesting low-concentration nectar, while lapping resulted in faster uptake when ingesting nectar with higher sugar content. We found that the optimal concentration of suction mode in honeybees coincided with the one calculated for other typical suction feeders. Moreover, we found behavioural flexibility in the drinking mode: a bee is able to switch between lapping and suction when offered different nectar concentrations. Such volitional switching in bees can enhance their feeding capabilities, allowing them to efficiently exploit the variety of concentrations presented in floral nectars, enhancing their adaptability to a wide range of energy sources.
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Zambon, Vivian, Kayna Agostini, Massimo Nepi, Mônica Lanzoni Rossi, Adriana Pinheiro Martinelli, and Marlies Sazima. "Nectar as manipulator: how nectar traits influence changes in pollinator groups of Aechmea vanhoutteana, a bromeliad from the Brazilian Atlantic Forest." Botanical Journal of the Linnean Society 192, no. 4 (December 2, 2019): 803–15. http://dx.doi.org/10.1093/botlinnean/boz086.
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Abstract Nectar is an important floral resource in the establishment of plant-pollinator interactions. Recent studies have shown that nectariferous tissues are independent of the ABC model of floral development and that ecological interactions can modify their expression. In this sense, it would be interesting to study generalist species in relation to nectar production and nectary morpho-anatomy to verify the strategies used to attract different pollinator groups. We recorded nectar production dynamics in Aechmea vanhoutteana (Bromeliaceae) from a morpho-functional and ultrastructural perspective. We observed different species of hummingbirds, bees and butterflies visiting flowers of A.vanhoutteana, and their frequency varied throughout floral anthesis. The nectar volume and quantity of sugar also varied significantly during anthesis, and this spatial and temporal variability seems to be related to an increase in bee visits, representing an important aspect of the reproductive strategy of this species, since bees can fly longer distances than the observed hummingbirds (although both have territorial behaviours). Thus, it can be suggested that anatomical and physiological nectar traits may be related to pollen flow, an important aspect of the reproductive strategy of A. vanhoutteana, suggesting plant resource allocation for optimizing reproduction through nectar production.
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Nicolson, Susan W., Leo de Veer, Angela Köhler, and Christian W. W. Pirk. "Honeybees prefer warmer nectar and less viscous nectar, regardless of sugar concentration." Proceedings of the Royal Society B: Biological Sciences 280, no. 1767 (September 22, 2013): 20131597. http://dx.doi.org/10.1098/rspb.2013.1597.
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The internal temperature of flowers may be higher than air temperature, and warmer nectar could offer energetic advantages for honeybee thermoregulation, as well as being easier to drink owing to its lower viscosity. We investigated the responses of Apis mellifera scutellata (10 colonies) to warmed 10% w/w sucrose solutions, maintained at 20–35°C, independent of low air temperatures, and to 20% w/w sucrose solutions with the viscosity increased by the addition of the inert polysaccharide Tylose (up to the equivalent of 34.5% sucrose). Honeybee crop loads increased with nectar temperature, as did the total consumption of sucrose solutions over 2 h by all bees visiting the feeders. In addition, the preference of marked honeybees shifted towards higher nectar temperatures with successive feeder visits. Crop loads were inversely proportional to the viscosity of the artificial nectar, as was the total consumption of sucrose solutions over 2 h. Marked honeybees avoided higher nectar viscosities with successive feeder visits. Bees thus showed strong preferences for both warmer and less viscous nectar, independent of changes in its sugar concentration. Bees may benefit from foraging on nectars that are warmer than air temperature for two reasons that are not mutually exclusive: reduced thermoregulatory costs and faster ingestion times due to the lower viscosity.
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Plowright, R. C. "Corolla depth and nectar concentration: an experimental study." Canadian Journal of Botany 65, no. 5 (May 1, 1987): 1011–13. http://dx.doi.org/10.1139/b87-139.
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The effect of corolla depth on nectar concentration was examined both by field surveys of nine different species and by experimental manipulation of the spurs of flowers of Aquilegia caerulea. The surveys showed that the relationship between concentration and corolla depth was influenced by present and past environmental conditions. The Aquilegia caerulea experiment demonstrated, as expected, that nectar evaporates much faster in flowers with small effective corolla depths than in those with deep corollas. These results affect the usefulness of arguments about the adaptive significance of nectar concentrations. Here it is suggested that the dilute nectars reported from hummingbird flowers are a secondary consequence of their having evolved deep tubular flowers.
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Falcão, Poliana Figueroa, Gladys Flávia de A. Melo-de-Pinna, Inara R. Leal, and Jarcilene S. Almeida-Cortez. "Morphology and anatomy of extrafloral nectaries in Solanum stramonifolium (Solanaceae)." Canadian Journal of Botany 81, no. 8 (August 1, 2003): 859–64. http://dx.doi.org/10.1139/b03-083.
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Solanum stramonifolium Dunal. (Solanaceae) is a pioneer species very common in the Atlantic forest of northeast Brazil. The plants bear extrafloral nectaries (EFNs) that are frequently visited by ants. Ant exclusion experiments show reduced seed set in plants without ants. This paper describes the morphology and anatomy of the nectary of S. stramonifolium. This species bears structural EFNs, vascularized by both phloem and xylem. The nectary is located around the lower, external surface of the calyx, as a ring of five protuberances. Secretory cells are present only below these protuberances and arranged in several strata. The nectar is secreted by stomata situated on projections above the surface of these protuberances. Nectar secretion begins at the floral bud stage and continues through fruit development. We suggest that production of nectar during the entire reproductive period of S. stramonifolium functions as a mechanism of flower and seed protection.Key words: Solanaceae, Solanum stramonifolium, extrafloral nectaries, ants, plant-ant interactions.
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Żuraw, Beata, Elżbieta Weryszko-Chmielewska, Halina Laskowska, and Elżbieta Pogroszewska. "The structure of septal nectaries and nectar presentation in the flowers of Allium aflatunense B. Fedtsch." Acta Agrobotanica 62, no. 2 (2012): 31–41. http://dx.doi.org/10.5586/aa.2009.024.
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The location and structure of the septal nectaries in the flowers of <i>Allium aflatunense</i> B. Fedtsch. were studied. Light and scanning electron microscopy were used for examination. It has been shown that the septal nectaries are located in the lower part of the ovary and in the gynophore on which the ovary is borne. Nectar is secreted through the single-layered epidermis surrounding three nectary slits and nectar release occurs through three openings located at the base of the gynophore, which are the outlets of the ducts connected to the nectary slits. The expanded and fused bases of the stamen filaments and the tepals participate in secondary nectar presentation. In the flowers of <i>Allium aflatunense</i>, numerous purple elements: tepals, filaments, style and pedicle, perform the role of a colour attractant. On the intensely green ovary, there occur glistening conical outgrowths of epidermal cells, which may also function as signal attractants.
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Vieira, Milene Faria, Maria Regina S. Andrade, Nelson S. Bittencourt, and Rita M. de Carvalho-Okano. "Flowering phenology, nectary structure and breeding system in Corymborkis flava (Spiranthoideae:Tropidieae), a terrestrial orchid from a Neotropical forest." Australian Journal of Botany 55, no. 6 (2007): 635. http://dx.doi.org/10.1071/bt06193.
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Flowering phenology, breeding system and nectary structure of Corymborkis flava (Sw.) Kuntze were studied in a fragment of the Atlantic Forest in south-eastern Brazil. The flowering period extended from March (end of rainy season) to early June and seed dispersal occurred from June to September (dry season). Flowering peak occurred mainly in April, with up to 34 open flowers per plant being observed. The yellow, odourless and tubular flowers lasted ~7.8 days. The flowers present a perigonal nectary located in the basal lateral parts of the labellum; this is the first report on the nectary location and characterisation in the Tropidieae tribe. At the pre-anthesis stage, cells of both secretory parenchyma and epidermis of the nectary are filled with compound amyloplasts. However, starch grains were not observed in these tissues in senescent flowers, indicating that these starch grains are hydrolysed and used as source of sugars for nectar production. The nectar accumulates between the cuticle and the outer periclinal wall of the epidermal cells before flowing out into the nectar chamber. C. flava is a self-compatible species and spontaneous self-pollination does not occur because of hercogamy. The high pollinia removal (0.80) and insertion (0.82) per flower, as well as the high natural fruit-set indicate an efficient natural pollination system. The present study contributes for the knowledge of the diversity of reproductive strategies and nectary structures in Orchidaceae.
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Heil, Martin, Andrea Hilpert, Ralf Krüger, and K. Eduard Linsenmair. "Competition among visitors to extrafloral nectaries as a source of ecological costs of an indirect defence." Journal of Tropical Ecology 20, no. 2 (March 2004): 201–8. http://dx.doi.org/10.1017/s026646740300110x.
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Extrafloral nectar is an indirect, generally ant-mediated, defence mechanism that is particularly common in tropical plants. This study focuses on interactions among different groups of arthropods visiting extrafloral nectaries of the South-East Asian myrmecophilic plant, Macaranga tanarius. The diurnal activity patterns of arthropods on nectaries were recorded on two occasions, each plant being used once in an untreated state and once after chemical induction of extrafloral nectar flow. Ants, widely regarded as the most important consumers of extrafloral nectar, made up only 60% of all nectary-visiting arthropods. Striking negative relations became obvious between ants and ‘non-ants’, among which two (morpho)species of fly (Grammicomya sp. and Mimegralla sp., both Micropezidae) were most important. On most leaves, either ants or ‘non-ants’, but not both groups, were present at one time. Behavioural observations revealed that many flies actively excluded other arthropods, including ants, from the nectaries or leaves. However, the flies had no detectable defensive effect against herbivores. The presence of these ‘thieves’ of extrafloral nectar therefore can cause ecological costs in terms of reduced presence of ants that consume extrafloral nectar and defend plants.
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Kostryco, Mikołaj, and Mirosława Chwil. "Nectar Secretion, Morphology, Anatomy and Ultrastructure of Floral Nectary in Selected Rubus idaeus L. Varieties." Agriculture 12, no. 7 (July 13, 2022): 1017. http://dx.doi.org/10.3390/agriculture12071017.
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The distinctive features of floral nectaries facilitate identification of ecological and phylogenetic links between related taxa. The structure and functioning of nectaries determine the relationships between plants, pollinators, and the environment. The aim of the study was to determine and compare the micromorphology of the epidermis in the floral nectaries of six Rubus idaeus cultivars belonging to biennial (‘Glen Ample’, ‘Laszka’, ‘Radziejowa’) and repeated fruiting (‘Pokusa’, ‘Polana’, ‘Polka’) groups. Another objective was to characterize the cuticle ornamentation and stomatal morphology, the anatomy of the nectary epidermis, parenchyma, and sub-nectary parenchyma in the initial nectar secretion phase, as well as the ultrastructure of the nectary epidermis and parenchyma cells in the initial and full nectar secretion phases. The study was carried out using light, fluorescence, scanning and transmission-electron microscopy techniques. Semi-thin and ultrathin sections were used for the microscopic analyses. The cuticular ornamentation and stomatal morphology may be helpful elements in the identification of relatedness between Rubus species. The interaction of the extensive system of endoplasmic reticulum membranes, mitochondria, and Golgi apparatus indicates high metabolic activity, and the fusion of transport vesicles with the membrane suggests granulocrine nectar secretion. The results bring new data to the biology of plants.
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Tiban, Nela Nedić, Mirela Šimović, Martina Polović, Antonija Šarić, Ivana Tomac, Petra Matić, and Lidija Jakobek. "The Effect of High Voltage Electrical Discharge on the Physicochemical Properties and the Microbiological Safety of Rose Hip Nectars." Foods 11, no. 5 (February 23, 2022): 651. http://dx.doi.org/10.3390/foods11050651.
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Although neglected as an industrial raw material, rose hip has been important for both nutritional and medical purposes for centuries. The main goal of this study was to propose a rapid and inexpensive non-thermal technique such as high voltage electrical discharge (HVED) to preserve valuable rose hip bioactive compounds, towards the development of high-quality products, including low-calorie products. The objective of this work was to evaluate the effects of HVED on the physicochemical properties and the microbiological safety of rose hip nectar formulations and, for comparison, on a pasteurised sample. Physicochemical analysis proved that rose hip pulp and the prepared nectars were valuable sources of polyphenols and ascorbic acid with high antioxidant activity. The HVED technique had minimal effects on the quality characteristics of the nectars under the different process conditions (50, 100 Hz; 10, 15, 20 min). In addition, the pasteurised nectar showed the greatest loss of ascorbic acid (54%) and phenolic compounds (40%). The microbiological quality of nectars was examined immediately after preparation/treatment and after 6 and 12 days of storage at 4 °C. In addition to the pasteurised sample, HVED-treated rose hip nectar prepared from microwave-blanched puree with extended shelf life had satisfactory microbiological safety after storage.
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Mosti, Stefano, Cynthia Ross Friedman, Ettore Pacini, Luigi Brighigna, and Alessio Papini. "Nectary ultrastructure and secretory modes in three species of Tillandsia (Bromeliaceae) that have different pollinators." Botany 91, no. 11 (November 2013): 786–98. http://dx.doi.org/10.1139/cjb-2013-0126.
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The floral nectaries of three Tillandsia L. spp. having different pollinators were investigated with transmission electron microscopy (TEM) to describe the previously unstudied ultrastructure of the nectar-producing tissues (primarily the epidermis) and also to determine if any differences in the ultrastructural features could be correlated to pollination mode. We determined that there were variations in nectaries among the three species, and that these may be linked to pollinator choice. Tillandsia seleriana Mez, which has a strict relationship with ants, had a nectary epithelium characterized by abundant dictyosomes and endoplasmic reticulum (ER), and a final degeneration stage possibly leading to holocrine secretion. The presence of protein crystals in epithelial plastids was correlated to a nectar enriched with amino acids and proteins, likely functioning to provide a protein-enriched diet and possibly defence against pathogens. Epithelial cells of the hummingbird-pollinated Tillandsia juncea (Ruiz et Pav.) Poir. nectary displayed cell wall ingrowths and dictyosomes and also contained cytoplasmic lipid droplets and protein crystals within plastids, both of which would enrich the nectar for hummingbirds. The nectary epithelium and the parenchyma of bat-pollinated Tillandsia grandis Schltdl. possessed a few cubic protein crystals in the plastids and its secretion product appeared electron transparent.
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Pernal, S. F., and R. W. Currie. "Nectar quality in open-pollinated, pol CMS hybrid, and dominant SI hybrid oilseed summer rape." Canadian Journal of Plant Science 78, no. 1 (January 1, 1998): 79–89. http://dx.doi.org/10.4141/p97-071.
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Nectar sugar composition and temporal patterns of nectar sugar production were examined in oilseed summer rape (Brassica napus L. ssp. oleifera (Metzg.)) from six open-pollinated, eight pol cytoplasmic male-sterile (CMS) hybrid and seven dominant self-incompatible (SI) hybrid cultivars at three field plot sites in Manitoba. The total sugar content of nectar samples was measured by the Dreywood anthrone reaction for total carbohydrate, and simple sugar composition was determined using an enzymatic bioanalysis for D-glucose, D-fructose and sucrose. Hybrid and open-pollinated cultivar flowers had similar sugar content. Mean total sugar content per flower also did not vary among hybrid breeding systems when compared within individual weeks of the bloom period or within daily sampling periods. However, for all cultivars, total nectar sugar content per flower was lower during the 08:00 and 11:00 h sampling periods and increased to maximum levels during the 14:00 and 16:00 h sampling periods. Significant differences in nectar sugar content were also found in relation to the bloom phenology of the cultivars. Cultivars produced the greatest amount of sugar per flower during the first 2 wk of the bloom period, then sugar production decreased in the third and fourth weeks. Nectar sugar ratios from all cultivars averaged approximately 1:1 glucose:fructose. Nectar glucose content among cultivars was similar but, among breeding systems, CMS cultivars tended to have lower amounts of glucose than SI or open-pollinated cultivars. Selecting for higher total sugar content may produce nectars more attractive to foraging honeybees (Apis mellifera L.), thereby ensuring adequate pollination of hybrid parental lines and F1 hybrid plants. Selecting for lower nectar glucose will produce honeys with more desirable granulation characteristics. Overall, the production and quality of nectar sugar in oilseed rape hybrids are similar to those of open-pollinated cultivars, and are not likely to adversely affect the pollinating activities of honeybees or their potential for honey production. Key words: oilseed summer rape, Brassica napus, honeybees, Apis mellifera, nectar, simple sugars
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Vezza, Maurizio, Massimo Nepi, Massimo Guarnieri, Daniele Artese, Nicoletta Rascio, and Ettore Pacini. "Ivy (Hedera helixL.) Flower Nectar and Nectary Ecophysiology." International Journal of Plant Sciences 167, no. 3 (May 2006): 519–27. http://dx.doi.org/10.1086/501140.
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Chwil, Mirosława. "The structure of secretory tissue of the stigma and septal nectaries as well as nectar secretion of flowers of Hosta fortunei Baker L. H. Bailey (Funkiaceae)." Acta Agrobotanica 62, no. 1 (2012): 27–36. http://dx.doi.org/10.5586/aa.2009.004.
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A study of <i>Hosta fortunei</i> Baker L. H. Bailey (Funkiaceae) flowers was conducted in the years 2007 - 2008. The flower life span and flowering duration as well as the nectar production rate were determined. The structure of the tissues of the stigma and nectary was investigated using stereoscopic, light and scanning electron microscopy (SEM). The plants flowered over a period of five weeks. Flowers of <i>H. fortunei</i> lived two days, on the average. Developed a pistil with an elongated ovary terminating in a discal stigma. On the surface of the stigma, unicellular glandular trichomes grew densely, composed of a stalk with a length of 113 - 213 µm and a head which was characterised by a large diameter range of 54 - 96 µm. The cuticle on the apical surface of a part of the trichomes was smooth, whereas it was striated on the stalk. Their protoplast was characterised by dense cytoplasm and weak vacuolisation. In the head of the trichomes fatty substances were accumulated. Septal nectaries occurred in the ovary of the superior pistil. Nectar was exuded onto the surface through three openings, situated in the upper part of the ovary of the pistil. At these places, epidermal cells formed a smooth or slightly wrinkled cuticle. The outer walls of the cells of the epidermis covering the duct accumulating nectar were thick. The glandular tissue of the nectary was made up of 2 layers of different-shaped, thin-walled cells and a deeply stained protoplast. They contained dense cytoplasm and a large, frequently lobate nucleus. At the final stage of secretion, fine vacuoles were observed in the cytoplasm of the glandular cells. Nectar secretion was abundant. In its initial stage, secretion droplets, increasing during the activity of the glandular tissue, were observed on the epidermis surface around the nectar openings. The weight of nectar from 10 flowers was 92.41 mg. The sugar concentration in the nectar was within a range of 23% - 30%, with an average value of 26%. Sugar yield was 23.83 mg/from 10 flowers.
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Weryszko-Chmielewska, Elżbieta, and Aneta Sulborska. "Morphological characters of the flowers and the structure of the nectaries of Acer platanoides L." Acta Agrobotanica 64, no. 3 (2012): 19–28. http://dx.doi.org/10.5586/aa.2011.026.
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The micromorphology of the nectaries and of other elements of the flower was examined by scanning electron microscopy (SEM). The anatomy of the nectaries was determined using light microscopy (LM). The inflorescences of <i>A. platanoides</i> comprise flowers included in two categories: functionally male and female. Nectaries of similar structure are found in both types of these flowers. The nectary gland located on the surface of the receptacle belongs to interstaminal nectaries. It has the form of a fleshy ring situated between the petals and the pistil. The bases of the staminal filaments are located in the depressions of the nectary. The outer diameter of the nectary reaches ca. 5 mm, while the thickness of this gland's tissues is 400-700 μm. In the epidermis of the nectary gland, there are numerous, evenly distributed stomata through which nectar release occurs. The stomata function asynchronously. In some stomata, we could observe nectar drops flowing out and a layer of this secretion around the stomata. The secretory parenchyma of the nectary is composed of several layers of thick-walled cells, whereas the ends of the vascular bundles with xylem and phloem elements are situated in the subglandular parenchyma. Chloroplasts are found both in the epidermal cells and in the glandular parenchyma cells and photosynthesis can take place in them due to the nectary's good exposure to light. The presence of starch grains was found in the chloroplasts; they can be energy material for nectar production.
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Nachev, Vladislav, Kai Petra Stich, Clemens Winter, Alan Bond, Alan Kamil, and York Winter. "Cognition-mediated evolution of low-quality floral nectars." Science 355, no. 6320 (January 5, 2017): 75–78. http://dx.doi.org/10.1126/science.aah4219.
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Plants pollinated by hummingbirds or bats produce dilute nectars even though these animals prefer more concentrated sugar solutions. This mismatch is an unsolved evolutionary paradox. Here we show that lower quality, or more dilute, nectars evolve when the strength of preferring larger quantities or higher qualities of nectar diminishes as magnitudes of the physical stimuli increase. In a virtual evolution experiment conducted in the tropical rainforest, bats visited computer-automated flowers with simulated genomes that evolved relatively dilute nectars. Simulations replicated this evolution only when value functions, which relate the physical stimuli to subjective sensations, were nonlinear. Selection also depended on the supply/demand ratio; bats selected for more dilute nectar when competition for food was higher. We predict such a pattern to generally occur when decision-makers consider multiple value dimensions simultaneously, and increases of psychological value are not fully proportional to increases in physical magnitude.
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Essinger, Cathryn. "Nectar." Ecotone 16, no. 1 (2020): 159. http://dx.doi.org/10.1353/ect.2020.0030.
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