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

Nepi, Massimo; Stpiczyńska, Małgorzata

doi:10.1007/s00114-007-0307-2

Cited by 74 publications

(81 citation statements)

References 53 publications

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“…Floral nectar is the most commonly resource produced by orchids (van der Pijl and Dodson 1966;Arditti 1992;Dressler 1993) and its production is costly for plants (Koopowitz and Marchant 1998;Nepi and Stpiczyńska 2008). The flowers of some species can reabsorb nectar (Nicolson 1995;Koopowitz and Marchant 1998;Nepi et al 2001;Luyt and Johnson 2002;Agostini et al 2011;Stpiczyńska et al 2012) and this is seen as part of a resource-recovery strategy and a means of maintaining homesostasis in the nectary.…”

Section: Discussionmentioning

confidence: 99%

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Does Oeceoclades maculata (Orchidaceae) reabsorb nectar?

Aguiar

Pansarin

2013

European Journal of Environmental Sciences

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Nectar is the most common resource offered by orchid flowers. In some cases, flowers reabsorb nectar as part of a resource-recovery strategy. Nectar is present only in the morning in the widespread orchid Oececoclades maculata (Lindl.) Lindl. To determine whether this is due to reabsorption or evaporation of water, the volume of nectar and its concentration in previously bagged flowers were determined throughout the day at two hourly intervals. In addition, the entrance to the nectary of flowers of cultivated plants was obstructed with petroleum jelly in the morning, to prevent the evaporation of water and, in the afternoon, the presence of nectar was recorded. Furthermore, manually self-pollinated flowers, also with the entrance to the nectary obstructed, had their nectary checked 24 hours after pollination to determine whether post-pollination reabsorption occurred. In addition, the period when the pollinators of O. maculata foraged for nectar was determined in order to establish whether it was associated with the period when nectar was available. The volume and concentration of nectar in O. maculata flowers vary from 0.82 µl (25.10%) between 10-12 h and 0.36 µl (33.73%) between 16-18 h and this difference is caused by evaporation of water. Post-pollination reabsorption does not occur in this species. Pollinators forage most actively between 10-12 h. Thus, O. maculata does not reabsorb nectar, but evaporative water loss is a significant factor determining the variation in the volume and concentration of this reward and this is positively correlated with butterfly visitation.

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Section: Discussionmentioning

confidence: 99%

“…In these cases the flowers reabsorb nectar after pollination. A decrease in the volume of nectar accompanied by a decrease in sugar concentration indicates nectar reabsorption (Nepi and Stpiczyńska 2008).…”

Section: Introductionmentioning

confidence: 99%

Does Oeceoclades maculata (Orchidaceae) reabsorb nectar?

Aguiar

Pansarin

2013

European Journal of Environmental Sciences

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“…Nectar resorption is a long-known phenomenon, but has rarely been addressed in studies on nectar secretion (Pedersen et al 1958;Southwick 1984;Pyke 1991;Búrquez and Corbet 1991;Nepi and Stpiczyńska 2008). Resorption of nectar has generally been demonstrated (as in Fritillary) during final stages of anthesis as a postpollination phenomenon (Koopowitz and Marchant 1998;Luyt and Johnson 2002) or following the completion of sexual stages in dichogamous flowers (Langenberger and Davis 2002).…”

Section: Nectar Secretion and Resorptionmentioning

confidence: 99%

Secretion and composition of nectar and the structure of perigonal nectaries in Fritillaria meleagris L. (Liliaceae)

2012

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The structure of perigonal nectaries, nectar production and carbohydrate composition were compared at various stages in the lifespan of the flower of Fritillaria meleagris L. The six nectaries each occupied a groove that is located 2-4 mm above the tepal base. The average nectary measured 11.0 mm long and 1.0-1.2 mm wide. The structure of nectaries situated on both inner and outer tepal whorls was identical, and at anthesis they were equally accessible to potential pollinators. However, secretion from nectaries associated with inner tepals tended to exceed that produced by nectaries located on the outer tepals. On average, regardless of flower stage, one flower secreted 10.87 ± 12.98 mg of nectar (mean and SD; N = 182). The nectar concentration ranged between 3 and 75%, with average concentration of sugars exceeding 50%. Both nectar production and concentration were dependent on the stage of anthesis, with the highest scores being recorded during full anthesis (21.75 ± 16.08 mg; 70.5%, mass and concentration, respectively) and the lowest at the end of anthesis (1.32 ± 2.69 mg; 16.9%, mass and concentration, respectively). A decline in both mass of nectar secreted and nectar concentration during the final stage of anthesis indicates nectar resorption. Nectar was composed of sucrose, glucose and fructose in approx. equal quantities, and its composition did not change significantly during subsequent stages of flowering. The nectaries comprised a single-layered secretory epidermis and several layers of subepidermal parenchyma. The nectariferous cells did not accumulate starch during any of the investigated stages. The nectary was supplied with one large and several smaller vascular bundles comprising xylem and phloem. Transport of assimilates and nectar secretion by protoplasts of secretory cells (and probably also nectar resorption) were facilitated by cell wall ingrowths present on the tangential walls of epidermal cells and subepidermal parenchyma. Epidermal cells lacked stomata. Nectar passed across the cell wall and through the cuticle which was clearly perforated with pores.

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“…Mais cette méthode considère la sécrétion de nectar comme un processus statique. Or, il a été montré que de nombreuses plantes, dont le colza, sécrètent du nectar en continu Pacini et Nepi, 2007), et de surcroît pour certaines d'entre elles, dont le colza encore, un processus de réabsorption se produit également en continu, de façon concomitante au processus de sécrétion (synthèse dans Nepi et Stpiczyńska, 2008). Ce processus de réabsorption est inhibé chez un certain nombre d'espèces lorsque le nectar est régulièrement retiré de la fleur (Luo et al, 2014), et ce notamment chez le colza (Burquez et Corbet, 1991).…”

Section: Taux De Sécrétion Apparentunclassified

“…4.4.1 Âge de la fleur et pollinisation D'autres facteurs sont encore à prendre en compte pour expliquer la variabilité de la sécrétion nectarifère, avec en premier lieu l'âge de la fleur, la sécrétion se réalisant en continu jusqu'au moment de sa sénescence où le nectar est peu à peu réabsorbé (Nepi et Stpiczyńska, 2008). C'est un facteur particulièrement important pour les espèces protogynes ou protandres, comme le tournesol ou la carotte, où la sécrétion peut varier selon la phase sexuelle qui évolue avec l'âge (Langenberger et Davis, 2002 ;Wist et Davis, 2006, 2008Varga et al, 2013).…”

Section: Une Méthode Rigoureuse Pour Comparer La Sécrétion Nectarifèrunclassified

Mesurer la sécrétion nectarifère : exemple d'une lignée hybride F1 et de son parent mâle stérile chez le colza d'hiver (Brassica napusL.)

Chabert¹,

Lemoine²,

Fronteau³

et al. 2017

OCL

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Reçu le 5 octobre 2017 -Accepté le 7 novembre 2017Résumé -Au cours de l'histoire évolutive des plantes à fleurs, l'apparition des nectaires floraux a permis de substituer le pollen par du nectar pour attirer les animaux pollinisateurs, permettant de diminuer les coûts de la pollinisation animale liés à la consommation du pollen. Dans les productions de semence hybride des cultures entomophiles, connaître le niveau de sécrétion nectarifère des lignées en présence, mâle fertile (MF) et mâle stérile (MS), est important si l'on souhaite maximiser les transferts de pollen entre les deux. Dans cet article, nous faisons tout d'abord une revue des méthodes qui existent pour mesurer la sécrétion nectarifère, puis retenons celle qui mesure un taux de sécrétion brut, qui permet d'exprimer une vitesse de sécrétion, pour l'utiliser sur deux lignées de colza d'hiver (Brassica napus L.), la variété hybride F1 Exocet MF et son parent MS. Nous montrons que la sécrétion nectarifère du colza est constante sur un intervalle de temps de 6-8 heures durant les heures du jour, que cette sécrétion admet une température optimale se situant entre 20°C et 30°C, et qu'elle est autour de deux fois moindre chez le parent MS par rapport à la lignée F1. Ces résultats permettent de proposer une méthode de mesure rigoureuse pour comparer la sécrétion nectarifère entre lignées ou variétés. Nous concluons sur les principales autres variables dont il faudrait tenir compte pour notamment pouvoir estimer la quantité totale de nectar sécrétée par une surface donnée de culture.Mots clés : méthode / sécrétion nectarifère / colza / semence hybride / température Abstract -Measuring nectar secretion: the example of an F1 hybrid and its male sterile parent in winter oilseed rape (Brassica napus L.). During the evolutionary history of flowering plants, the appearance of floral nectaries allowed the replacement of pollen by nectar to attract pollinators, allowing lower costs involved in animal pollination by reducing the consumption of pollen. In the hybrid seed productions of entomophilous crops, knowing the levels of nectar secretion of the different lines, the male fertile (MF) and the male sterile (MS) ones, is important to maximize pollen transfers between them. In this study, we start with a review of current methods used to measure nectar secretion, and choose the one that provides a gross secretion rate in order to use it on two winter oilseed rape (Brassica napus L.) lines, the hybrid F1 'Exocet' and its MS parent. We show that oilseed rape has a gross nectar secretion rate that is constant over a period of 6-8 hours during daylight hours, that it has a thermal optimum included between 20°C and 30°C, and that the parental MS line secretes about half as much as the hybrid F1 one. These results enable us to propose a rigorous method to compare nectar secretions between lines and varieties. We conclude with the main other variables that should be taken into account to estimate the total amount of nectar produced by a given area of crop.

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

Cited by 74 publications

References 53 publications

Does Oeceoclades maculata (Orchidaceae) reabsorb nectar?

Does Oeceoclades maculata (Orchidaceae) reabsorb nectar?

Secretion and composition of nectar and the structure of perigonal nectaries in Fritillaria meleagris L. (Liliaceae)

Mesurer la sécrétion nectarifère : exemple d'une lignée hybride F1 et de son parent mâle stérile chez le colza d'hiver (Brassica napusL.)

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