Nectar production and presentation

Pacini, Ettore; Nepi, Massimo

doi:10.1007/978-1-4020-5937-7_4

Cited by 169 publications

(204 citation statements)

References 130 publications

(192 reference statements)

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“…Owing to the importance of nectaries in pollination, the location of nectar secretion and presentation, combined with nectar quantity and composition, are the main factors in determining potential pollinators among nectar-feeding animals (Simpson and Neff 1983;Pacini et al 2003;Pacini and Nepi 2007).…”

Section: Introductionmentioning

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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Section: Introductionmentioning

confidence: 99%

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

2012

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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

“…Or, il a été montré que la concentration du nectar admet une très grande variabilité, due principalement aux variations d'humidité relative atmosphérique (Pacini et Nepi, 2007). Il est donc préférable, dans la mesure du possible, de mesurer simultanément le volume et la concentration du nectar sécrété par une fleur, puis d'exprimer la quantité de nectar sécrétée en masse de sucres totaux dissous (STD) par l'intermédiaire d'une formule combinant ces deux variables.…”

Section: Convertir Le Volume En Masse De Sucresunclassified

“…La température joue enfin un rôle majeur sur la sécrétion nectarifère, bien que ce rôle n'ait été encore que relativement peu étudié (Pacini et Nepi, 2007 ;Petanidou, 2007).…”

Section: Les Lignées Ms Sont-elles Aussi Nectarifères Que Les Lignéesunclassified

“…Le nectar étant sécrété de façon continue (Pacini et Nepi, 2007), nous avons estimé les pentes, ainsi que les intervalles de confiance à 95 % associés, de la masse de STD en fonction de la durée écoulée entre le prélèvement initial et la mesure effectuée à l'aide de modèles linéaires mécanistes de la forme ŷ= â.x (méthode d'inférence statistique dite des moindres carrés ; Bolker, 2008), pour chacune des deux lignées (F1 et MS) et pour chaque catégorie de température (< 20°C ; entre 20°et 30°C ; > 30°C). Deux moyennes dont les intervalles de confiance à 95 % ne se recouvrent pas ne peuvent être considérées comme statistiquement identiques, avec une chance de 5 % de se tromper (Nakagawa et Cuthill, 2007).…”

Section: Analyses Statistiquesunclassified

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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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Host‐plant sex and phenology of Buddleja cordata Kunth interact to influence arthropod communities

González‐Ramírez,

López‐Gómez,

Cano‐Santana

et al. 2024

Ecology and Evolution

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Intraspecific variation in plants is expected to have profound impacts on the arthropod communities associated with them. Because sexual dimorphism in plants is expected to provide consistent variation among individuals of the same species, researchers have often studied the effect it has on associated arthropods. Nevertheless, most studies have focused on the effect of sexual dimorphism in a single or a few herbivores, thus overlooking the potential effects on the whole arthropod community. Our main objective was to evaluate effects of Buddleja cordata's plant‐sex on its associated arthropod community. We surveyed 13 pairs of male and female plants every 2 months during a year (June 2010 to April 2011). Every sampling date, we measured plant traits (water content and leaf thickness), herbivory, and the arthropod community. We did not find differences in herbivory between plant sex or through time. However, we found differences in water content through time, with leaf water‐content matching the environmental seasonality. For arthropod richness, we found 68 morphospecies associated with female and 72 with male plants, from which 53 were shared by both sexes. We did not observe differences in morphospecies richness; however, we found sex‐associated differences in the diversity of all species and differences on the diversity of the most abundant species with an interesting temporal component. During peak flowering season, male plants showed higher values on both parameters, but during the peak fructification season female plants showed the higher values on both diversity parameters. Our research exemplifies the interaction between plant‐phenology and plant‐sex as drivers of arthropod communities' diversity, even when plant sexual‐dimorphism is inconspicuous, and highlighting the importance of accounting for seasonal variation. We stress the need of conducting more studies that test this time‐dependent framework in other dioecious systems, as it has the potential to reconcile previous contrasting observations reported in the literature.

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Nectar production and presentation

Cited by 169 publications

References 130 publications

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

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.)

Host‐plant sex and phenology of Buddleja cordata Kunth interact to influence arthropod communities

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