Nectar Secretion, Reabsorption, and Sugar Composition in Male and Female Flowers of <i>Cucurbita pepo</i>

Nepi, Massimo; Guarnieri, Massimo; Pacini, Ettore

doi:10.1086/319581

Cited by 94 publications

(106 citation statements)

References 25 publications

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“…Probably these factors affect nectar production. However the higher temperatures did not provoke an increase in the sugar concentration of the nectar, as would be expected due to evaporation (Nepi et al 2001), as the lowest values were observed at 13h, when the temperature was highest (tables 1, 2). Similar outcomes were reported by several authors in other species (Southwick 1983, Pleasants 1983, Jakobsen & Kristiansson 1994, Corbet 2003, Karp et al 2004.…”

Section: Discussionsupporting

confidence: 54%

“…Our results demonstrate that sugar concentration in C. pepo flowers was high (35%-45%) compared with these melliferous plants. A relatively high production of nectar (94 µL during the morning) also was observed in C. pepo 'Greyzini' (Nepi et al 2001). Further investigation, comparing C. pepo and melliferous plants should be performed to evaluate whether C. pepo can be considered a melliferous species.…”

Section: Discussionmentioning

confidence: 95%

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Nectar and pollen production in pumpkin (Cucurbita pepo L.)

Vidal¹,

Jong²,

Wien³

et al. 2006

Rev. bras. Bot.

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-(Nectar and pollen production in pumpkin (Cucurbita pepo L.)). Cucurbitaceae species depend on pollination by honey bees for fruit production. The overall objective of this work was to evaluate the potential of C. pepo for pollen and nectar production, that could help maintain colonies placed in the field. Plants of pumpkin were cultivated in field, in 1996 and 1997. Before anthesis, male flowers were covered to prevent visits by bees and other insects. After anthesis the flowers were uncovered and the following parameters were evaluated: 1) nectar production; 2) total sugar concentration in the nectar; 3) nectar replacement; and 4) production of pollen and flowers during the crop cycle. Nectar production varied from 18 to 79 µL flower -1 and increased progressively from 7h to 13h. The sugar concentration, measured at 7h, 9h and 11h, did not vary, averaging 50.5% ± 0.5% in 1996 and 40.5% ± 0.6% in 1997. At 13h the concentration decreased to 42% in 1996 and to 35% in 1997. Total daily nectar production was not influenced by removing nectar several times per day, indicating that nectar secretion is not stimulated or inhibited by frequent removal. The number of pollen grains did not differ in the two years, with an average of 43,669 ± 1,382 grains per flower. The peak rate of male and female flowers occurred from 60 to 66 days after planting (DAP) with 34.6 male flowers and 2.2 female flowers per plant, respectively. Cucurbita pepo has a potential for honey and pollen production of about 105 and 160 kg per hectare per season, respectively, which is enough to sustain, at least, five honeybee colonies.Key words -flower production, honey potential, nectar production, pollen production, sugar concentration RESUMO -(Produção de néctar e pólen em abóbora (Cucurbita pepo L.)). As espécies das cucurbitáceas dependem da polinização por abelhas para produzir frutos. O objetivo geral deste trabalho foi avaliar o potencial da C. Pepo para produzir pólen e néctar, no sentido de ajudar a manter colônias no campo visando a polinização. Plantas de abóbora foram cultivadas no campo, em 1996 e 1997. Antes da antese, flores masculinas foram cobertas para prevenir visitas de abelhas e outros insetos. Depois da antese as flores foram desprotegidas e os seguintes parâmetros foram avaliados: 1) produção de néctar; 2) concentração total de açúcar no néctar; 3) reposição de néctar e 4) produção de pólen e flores durante o ciclo da cultura. A produção de néctar variou de 18 a 79 µL flor -1 e aumentou progressivamente de 7h00 para 13h00. A concentração de açúcares, avaliada às 7h00, 9h00 e 11h00, não variou, apresentando uma média de 50,5% ± 0,5% em 1996 e 40,5% ± 0,6% em 1997. Às 13h00 a concentração decresceu para 42% em 1996 e para 35% em 1997. A produção diária de néctar não foi influenciada pela remoção do néctar em diferentes horas do dia, indicando que a produção de néctar não é estimulada ou inibida pela freqüente remoção. O número de grãos de pólen não variou nos dois anos, com uma média de 43.669 ± 1.382 grãos por flor. O...

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Section: Discussionsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 95%

Nectar and pollen production in pumpkin (Cucurbita pepo L.)

Vidal¹,

Jong²,

Wien³

et al. 2006

Rev. bras. Bot.

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“…As fl ores de Cucurbita sp. abrem-se antes ou logo após o nascer do sol e duram somente um dia (Winsor et al 2000, Nepi et al 2001. Nos locais de estudo as fl ores já estavam abertas às 5:00h da manhã e fechavam-se entre 11:00h e 12:00h.…”

Section: Methodsunclassified

Polinização entomófila de abobrinha, Cucurbita moschata (Cucurbitaceae)

Serra¹,

Campos²

2010

Neotrop. entomol.

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-The objectives of this work were to determine the squash entomofauna in the region of Viçosa, Minas Gerais state, to study their behavior on fl owers and their importance for pollination, verifying the role of each pollinator. The most common species were Trigona spinipes (Fabricius), Trigona hyalinata (Lepeletier), Apis mellifera (L.) and Melipona quadrifasciata (Lepeletier). The visitation behavior of A. mellifera, M. quadrifasciata, and Bombus morio (Swederus) were similar. They visited fl owers for nectar collection, positioning themselves vertically between the corolla and the sexual structures of the fl owers, with the back directed toward the fl oral axis, which permitted the removal of pollen from the anthers of fl owers with stamens and its deposition on the stigma of fl owers with pistils, being considered therefore effective pollinators. Trigona spinipes and T. hyalinata foraged in groups, preventing other species from landing on the fl owers which they occupied. Due to their small body size and only infrequent contact with the sexual structures of the fl owers, these species are considered occasional pollinators. The number of fruits produced differed between freely visited fl owers, those prevented from receiving visits and those visited only a single time by M. quadrifasciata, B. morio, A. mellifera, T. hyalinata or T. spinipes. Flowers prevented from receiving visits or visited only once by T. spinipes did not produce fruits. The remaining pollination systems led to fruitifi cation, with open pollination or a single visit from either M. quadrifasciata or B. morio leading to most fruit production.

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“…Reclamation of nectar components in Fritillary is facilitated by the presence of micro-channels or pores in the cuticle that covers the secretory epidermis, as in Echinacea purpurea L. (Moench) (Wist and Davis 2006), P. chlorantha (Stpiczyńska 2003a) and C. pepo (Nepi et al 2001). Also, in F. meleagris, the efficiency of nectar resorption is improved by the wall ingrowths present in the cells of the nectariferous epidermis and parenchyma, and these were still present at the final stages of anthesis, when nectar resorption occurs.…”

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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Nectar Secretion, Reabsorption, and Sugar Composition in Male and Female Flowers of Cucurbita pepo

Cited by 94 publications

References 25 publications

Nectar and pollen production in pumpkin (Cucurbita pepo L.)

Nectar and pollen production in pumpkin (Cucurbita pepo L.)

Polinização entomófila de abobrinha, Cucurbita moschata (Cucurbitaceae)

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

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