About the morphology and anatomy of pollen cones and the pollen presentation within the genus Fitzroya (Cupressaceae)

2019 ◽  
Vol 130 (2) ◽  
pp. 218-224
Author(s):  
Veit Martin Dörken
Keyword(s):  
Pollen Presentation

Pollen presentation and pollination syndromes, with special reference to Penstemon

2000 ◽  
Vol 15 (1) ◽  
pp. 11-29 ◽  
Author(s):  
James D. Thomson ◽  
Paul Wilson ◽  
Michael Valenzuela ◽  
Maria Malzone
Keyword(s):  
Special Reference ◽  
Pollination Syndromes ◽  
Pollen Presentation

Changes in cytoplasmic carbohydrate content during Helleborus pollen presentation

Grana ◽  
2002 ◽  
Vol 41 (1) ◽  
pp. 16-20 ◽  
Author(s):  
José L. Vesprini ◽  
Massimo Nepi ◽  
Laura Cresti ◽  
Massimo Guarnieri ◽  
Ettore Pacini
Keyword(s):  
Carbohydrate Content ◽  
Pollen Presentation

Solitary bee pollinators adjust pollen foraging to the unpredictable flower opening of a species of Petunia (Solanaceae)

2019 ◽  
Vol 129 (2) ◽  
pp. 273-287
Author(s):  
Fernanda Figueiredo De Araujo ◽  
Reisla Oliveira ◽  
Theo Mota ◽  
João Renato Stehmann ◽  
Clemens Schlindwein
Keyword(s):  
Floral Biology ◽  
Floral Resources ◽  
Pollen Foraging ◽  
Flower Opening ◽  
Foraging Patterns ◽  
Social Species ◽  
Pollen Presentation ◽  
Total Pollen ◽  
Flower Visiting ◽  
Effective Pollinators

Abstract Details of the foraging patterns of solitary bees are much less well known than those of social species, and these patterns are often adjusted to exploit floral resources of one or only a few species. The specialized flower-visiting bees of Petunia are good models for investigating such foraging patterns. Here we analysed the floral biology and pollen presentation schedule of the endangered Petunia mantiqueirensis in mixed Araucaria forests of Serra da Mantiqueira, Brazil. Pollinators and their pollen foraging behaviour and food specialization were determined through analyses of scopa pollen loads. Flowers opened throughout the day and presented all their pollen resources within the first 30 min of anthesis, thus providing their pollen resources in an asynchronous fashion in one-flower packages throughout the day. Females of Pseudagapostemon fluminensis were the most frequent flower visitors, contacting stigmas in 96% of their visits, and were the unique effective pollinators of Petunia mantiqueirensis. These pollinators were responsible for the first three visits to 115 individually monitored flowers at any daylight hour, removing ~86% of a flower’s total pollen supply during the first visit. Although female bees harvest the majority of pollen resources of Petunia mantiqueirensis, analyses of scopa loads revealed that most of them also collect pollen from plants of other families while foraging for pollen in Petunia flowers.

The cost of fidelity: foraging oligolectic bees gather huge amounts of pollen in a highly specialized cactus–pollinator association

2019 ◽  
Vol 128 (1) ◽  
pp. 30-43 ◽  
Author(s):  
Isabelle Cerceau ◽  
Samuel Siriani-Oliveira ◽  
Ana Laura Dutra ◽  
Reisla Oliveira ◽  
Clemens Schlindwein
Keyword(s):  
Male Reproductive Success ◽  
Flower Opening ◽  
Mechanical Filter ◽  
Pollen Presentation ◽  
Oligolectic Bees ◽  
The Cost ◽  
Fruit And Seed Set ◽  
Flower Handling ◽  
Plant Pollinator ◽  
Pollinator Foraging Behaviour

Abstract Plant–pollinator interactions vary along a specialization–generalization continuum. Advances in understanding the evolutionary and ecological consequences of different degrees of specialization depend on precise data on plant–pollinator interdependency. We studied the association of Parodia neohorstii (Cactaceae) and its bee pollinators focusing on pollinator foraging behaviour, flower functioning, female and male reproductive success, and pollen fate. Parodia neohorstii showed synchronized flower opening and pollen presentation but discontinuous blooming. The apparently generalized flowers partition pollen through thigmonastic stamen movements that function as a mechanical filter against generalist bees by restricting access to the major pollen reservoir to bees that show flower handling ‘know-how’, thereby favouring the oligolectic bee Arhysosage cactorum. This pollinator adjusted its pollen foraging to flower opening, removed pollen hurriedly, and promoted maximal fruit and seed set, which was minimal in its absence. Estimates of pollen fate revealed that a huge amount of pollen flows to specialized pollinators (86.5%), and only 0.9% reaches conspecific stigmas. The specialized interaction between P. neohorstii and Arhysosage cactorum, both threatened species, is efficient but fragile. Any environmental modification that causes a mismatch between the partners is likely to result in reproductive failure.

Pollen biodiversity – why are pollen grains different despite having the same function? A review

2020 ◽  
Vol 193 (2) ◽  
pp. 141-164 ◽  
Author(s):  
Ettore Pacini ◽  
Gian Gabriele Franchi
Keyword(s):  
Pollen Dispersal ◽  
Pollen Grains ◽  
Reproductive Function ◽  
Female Competition ◽  
Size Number ◽  
Pollen Presentation ◽  
Dispersal Unit ◽  
Number Of Cells ◽  
Physiological Characters ◽  
Female Counterpart

Abstract The main morphological, cytological and physiological characters of ripe pollen are described, compared, analysed and discussed individually, in multiple combinations and in respect to the female counterpart and the biotic and abiotic components of the environment. This is to try to understand the reasons why pollen grains have the same reproductive function, but at dispersal are morphologically and physiologically different in many respects. The considered characters are: one or more types of grain per species; shape and size; number of cells; types of pollen dispersal unit; sporoderm stratification, furrows, colpori and other kinds of apertures; pollen presentation and array; water content percentage; and mature pollen reserves and osmotics. Some of the pollen features are correlated between themselves, some with the female counterpart or male and female competition, and others with the different components of the environment where the species lives, when it flowers and when pollen presentation occurs.

Secondary Pollen Presentation in Angiosperms and Its Biological Significance

1993 ◽  
Vol 41 (5) ◽  
pp. 417 ◽  
Author(s):  
GJ Howell ◽  
AT Slater ◽  
RB Knox
Keyword(s):  
Close Association ◽  
Biological Significance ◽  
Selective Advantage ◽  
Floral Organ ◽  
Pollinator Behaviour ◽  
Secondary Pollen Presentation ◽  
Male Function ◽  
Increased Risk ◽  
Pollen Presentation ◽  
Male Phase

Secondary pollen presentation is the developmental relocation of pollen from the anthers onto another floral organ which then functions as the pollen presenting organ for pollination. Nine different types have been identified in sixteen angiosperm families according to which organ is used for presentation, whether the pollen is exposed or concealed within a structure and how pollen is loaded onto the presenting surface: (1) Enveloping bloom presenters (Araceae); (2) Perianth presenters with exposed pollen presentation (Epacridaceae); (3) Androecial presenters (Santalaceae); (4) Terminal stylar presenters with passive pollen placement and concealed stigmas (Rubiaceae and Proteaceae); (5) Terminal stylar presenters with passive pollen placement and sub-terminal stigmas (Marantaceae and Polygalaceae); (6) Terminal stylar presenters with active pollen placement (Asteraceae, Calyceraceae and Lobeliaceae); (7) Sub-terminal stylar presenters (Campanulaceae, Cannaceae, Fabaceae and Myrtaceae); (8) Exposed stigmatic presenters (Rubiaceae); (9) Indusial stigmatic presenters (Goodeniaceae and Brunoniaceae). Secondary pollen presentation occurs in three monocotyledon and thirteen dicotyledon families. The presentation types appear to have been independently derived indicating that secondary pollen presentation is a character with a selective advantage. In all but the enveloping bloom type of secondary pollen presentation, developmental relocation of pollen requires simultaneous, introrse anther dehiscence and a close association of the presenting organ to the anthers prior to anthesis. The various secondary pollen presentation systems may be modified to promote xenogamy or autogamy and this can even change during anthesis. Most plants which have secondary pollen presentation, display reduced herkogamy within the flower to facilitate pollination. Increased risk of self-pollination due to this may be overcome through dichogamy, herkogamy within inflorescences, dry stigmas, self-incompatibility systems and passive or active control over pollinator behaviour. Enhanced male function of the flowers of secondary pollen presenting plants is also evident through extension of the male phase by the protection, controlled release and precise placement and receipt of pollen. Plants displaying secondary pollen presentation are almost always protandrous.

Are diel patterns of nectar production and anthesis associated with other floral traits in plants visited by potential bird and mammal pollinators?

2004 ◽  
Vol 52 (1) ◽  
pp. 87 ◽  
Author(s):  
V. M. Saffer
Keyword(s):  
Western Australia ◽  
Visual Cues ◽  
Floral Traits ◽  
Pollination Syndromes ◽  
Nectar Production ◽  
Diel Patterns ◽  
Pollen Presentation ◽  
Pollination Systems

Plants pollinated predominantly by vertebrates are thought to have suites of floral traits (e.g.�colour, conspicuousness, odour) that favour either birds or mammals, with brightly coloured, conspicuous flowers associated with birds and drab, concealed flowers with non-flying mammals. This study examined two other floral traits, diel patterns of nectar production and pollen presentation (anthesis). It would be expected that these would be nocturnal in putatively mammal-pollinated plants and diurnal in bird-pollinated plants. In four Banksia and two Dryandra species, all known to be visited by honeyeater birds and small marsupials at one site in south-western Australia, there was no clear correspondence between visual cues and diel patterns of resource presentation. This lack of correlation between floral traits does not support the idea of specialised pollination syndromes, but rather is consistent with generalised pollination systems.

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