On the labelled compounds in the nectaries of twoAloe species after exposure to radioactive glucose and on the mechanism of prenectar secretion

Heinrich, Georg

doi:10.1007/bf01567959

Cited by 32 publications

(8 citation statements)

References 26 publications

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“…This absence seems noteworthy considering the thick labyrinth of secondary wall that can develop (i) in a variety of monocot nectaries ranging from the epithelial cells of septal nectaries in Aloe spp. (Heinrich 1975;Schnepf and Pross 1976;Nepi et al 2006), Musa paradisiaca L. (Fahn and Benouaiche 1979), and Strelitzia reginae Banks ex Aiton (Kronestedt and Robards 1987) to the secretory surface of Epipactis atropurpurea Raf. (Pais and Figueiredo 1994) and (ii) elsewhere in flowers of Lilium spp., such as at the outer walls of the concave endothelial cells lining the transmitting tract of the style or placenta (Rosen and Thomas 1970;Hu et al 1982;Gawlik 1984;Walles 1992, 1995;Janson et al 1994;Singh et al 1999), and to a lesser degree along the stigmatic papillae in L. leucanthum (Gawlik 1984).…”

Section: Nectar Passage To the Exteriormentioning

confidence: 99%

Floral nectary structure, nectar production, and carbohydrate composition in theLiliumAsiatic hybrid ‘Trésor’

Stolar

Davis

2010

Botany

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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.Résumé : Les auteurs ont comparé la structure des nectaires floraux, la production de nectar et la composition en glucides à partir des pétales (« tépales internes ») et des sépales (« tépales externes ») du Lilium 'Trésor' (Liliaceae). Chacun des six nectaires occupe un sillon étroit bordé par deux crêtes convergentes s'étendant en position adaxiale par rapport à la base des pétales et des sépales. Chacun des sillons des nectaires des sépales apparaît plus court et plus discret. Chez les deux types de nectaire, plusieurs faisceaux vasculaires de xylème et de phloème irriguent 5.5-8 couches de cellules de parenchymes nectarifères sous un épiderme dépourvu de stomate. La microscopie électronique par transmission des nectaires des sépales démontre que les parties externes des parois épidermiques adhèrent à une cuticule intacte, mais soulevée dans les fleurs secrétant du nectar. On observe à la fois des routes apoplastiques et symplastiques en continuité avec les faisceaux vasculaires de l'épiderme des nectaires. L'hydrolyse de l'amidon des amyloplastes dans l'ensemble du nectaire augmente vraisemblablement la production en nectar. La teneur en solutés des nectaires d'un autre hybride asiatique, 'Orange Pixie', est également plus importante dans les pétales. Chez 'Trésor', il se forme significativement plus de nectar à partir des sépales, ce qui reflète possiblement une évaporation réduite provenant des multiples gouttelettes de nectar couvrant le sillon du nectaire. Cependant, chez les deux hybrides, les pétales et l...

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Section: Nectar Passage To the Exteriormentioning

confidence: 99%

Floral nectary structure, nectar production, and carbohydrate composition in theLiliumAsiatic hybrid ‘Trésor’

Stolar

Davis

2010

Botany

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“…Another method is micro-autoradiography. This technique had also been applied to study the process of nectar secretion (Fahn and Rachmilewitz 1975;Heinrich 1975;Lüttge et al 1985;Sawidis et al 1989). Radiolabeling of nectar constituents is particularly advantageous in studies of nectar resorption, as it makes it possible to follow the detailed rate of movement of radioactive tracer within the nectary and in other plant tissues and incorporation of resorbed labeled metabolites.…”

Section: Introductionmentioning

confidence: 99%

The complexity of nectar: secretion and resorption dynamically regulate nectar features

Nepi

Stpiczyńska²

2007

Naturwissenschaften

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In this paper, we review the phenomenon of nectar resorption, focusing on its physiological and ecological meaning. Nectar resorption is a phenomenon that has long been known but was rarely reported until the1990s. It has more recently been demonstrated in several species by various direct and indirect methodologies. It has generally been demonstrated in senescent flowers as a phenomenon separate in time from, and independent of, nectar secretion. The significance of this type of resorption is generally recognized as a resource-recovery strategy, recycling at least some materials invested in nectar production. Nevertheless, nectar resorption can occur concomitantly with nectar secretion. Nectar production is therefore best considered as a unified process comprising nectar secretion and resorption. The modulation of these two opposite phases allows nectar concentration to be maintained in a range suitable for pollinators (nectar homeostasis). The mechanism of nectar resorption at the cell level has received little attention, and its molecular basis can only be hypothesized on the basis of recent studies concerning sugar sensing.

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“…Resorption of nectar in P. chlorantha has been studied by micro-autoradiography (Stpiczyń ska, 2003 a, b). Autoradiography had previously been used to study the process of nectar secretion (Fahn and Rachmilewitz, 1975;Heinrich, 1975;Sawidis et al, 1989) but rarely to investigate the process of nectar reabsorption. Since Pedersen et al (1958) demonstrated nectar resorption and sugar translocation in alfalfa at macroscopic level, very few studies have been devoted to nectar resorption and autoradiography at the microscopic level (Stpiczyń ska, 2003 a, b).…”

Section: Introductionmentioning

confidence: 99%

Nectar Resorption and Translocation in Cucurbita pepo L. and Platanthera chlorantha Custer (Rchb.)

Nepi

Stpiczyńska²

2007

Plant Biology

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Nectar resorption and sugar translocation were studied in Cucurbita pepo (Cucurbitaceae) and Platanthera chlorantha (Orchidaceae) by micro-autoradiography. In both species, nectar was resorbed in pollinated and unpollinated flowers and ovules developing into seeds were found to be the main sugar sink. In C. pepo, the mobility of resorbed sugars in pollinated female flowers was higher than in unpollinated ones; male flowers showed lower mobility of resorbed sugar. In P. chlorantha, radioactivity was detected in pollinated flowers below and above labelled unpollinated ones: the nearer the flower, the stronger the accumulation of label in developing fruits.

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On the labelled compounds in the nectaries of twoAloe species after exposure to radioactive glucose and on the mechanism of prenectar secretion

Cited by 32 publications

References 26 publications

Floral nectary structure, nectar production, and carbohydrate composition in theLiliumAsiatic hybrid ‘Trésor’

Floral nectary structure, nectar production, and carbohydrate composition in theLiliumAsiatic hybrid ‘Trésor’

The complexity of nectar: secretion and resorption dynamically regulate nectar features

Nectar Resorption and Translocation in Cucurbita pepo L. and Platanthera chlorantha Custer (Rchb.)

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