Four o'clock pollination biology: nectaries, nectar and flower visitors in Nyctaginaceae from southern South America

Abstract

Floral nectary structure and nectar sugar composition were investigated in relation to other floral traits and flower visitors in contrasting species of Nyctaginaceae from southern South America, representing four tribes (Bougainvilleeae, Colignonieae, Nyctagineae, Pisoneae). Our comparative data will aid in the understanding of plant–pollinator interactions and in the development of hypotheses on the origin of floral and reproductive characters in this family. The nectaries are located on the inner side of the staminal tube. The nectariferous tissue is composed of an epidermis and three to ten layers of secretory parenchymal cells, supplied indirectly by the filament vascular bundles. Stomata appear to be associated with nectar secretion. For the first time in Nyctaginaceae, nectary ultrastructure is described in Boerhavia diffusa var. leiocarpa. Nectary parenchyma cells are densely cytoplasmic and contain numerous starch grains. Plasmodesmata connect the nectariferous cells. Flowers of Nyctaginaceae secrete a small volume of nectar of variable concentration (10–47%). Nectar is dominated by hexoses, but Mirabilis jalapa showed a balanced proportion of sucrose and hexoses. Hymenoptera are the most common visitors for most species; nocturnal Lepidoptera are the most common visitors for M. jalapa and Bougainvillea stipitata. We found relatively low variation in the nectary characteristics of Nyctaginaceae compared with broad variation in flower structure, shape, colour and nectar traits. © 2013 The Linnean Society of London

Pollination Biology and Seed Production of a Federally Endangered Perennial, Echinacea laevigata (Asteraceae∶Heliantheae)

“…In general, those same groups of floral visitors have been recorded previously for the annual species studied or other species belonging to the same plant families (Zimmerman 1977;Adams et al 1981;Townsend 1993;OsorioBeristain et al 1997;Nores et al 2013;Bizecki 2014;Moore 2014). In addition, we found that abundance, diversity, and composition of the community of floral visitors of annual plants vary through space.…”

Contrasting models of the female reproductive tract in four o'clocks (Nyctaginaceae)

“…The 3–9 stamens (1–3 in Boerhavia diffusa ) are connate at the base, forming a staminal tube (Nores et al, 2013). Filaments are mostly unequal and exserted.…”

“…Future studies will explore the relationships between these models and pollen traits (López et al, 2006) and/or compatibility systems (López and Galetto, 2002; Nores et al, 2013). Allionia , Boerhavia , and Mirabilis produce relatively few large, starchy pollen grains, compared with many small lipidic grains in Bougainvillea (López et al, 2006).…”

“…In total, 17 reproductive characters were scored (Table 2), based on our observations and data from other literature (e.g., Nowicke, 1970; Nowicke and Luikart, 1971; Bittrich and Kühn, 1993; López and Galetto, 2002; López and Anton, 2006; López et al, 2006; Douglas and Manos, 2007; Nores et al, 2013). Two of these characters (7 and 8) were optimized on a tree showing a summary of relationships of Nyctaginaceae, modified from Douglas and Spellenberg (2010), as implemented in the program TNT v.1.1 (Goloboff et al, 2008).…”

Pollinator activity and pollination success of Medicago sativa L. in a natural and a managed population

“…In recent years, plant–pollinator interaction has been the focus of much discussion and debate (Fenster, Armbruster, Willson, Dudash, & Thomson, ; Gómez, Abdelaziz, Lorite, Munõz‐Pajares, & Perfectti, ). Plant species that depend on animal pollinators for their reproduction have developed many different phenotypes traits, such as floral display, flower architecture and nectar (Arias‐Cóyotl, Stoner, & Casas, ; Nores, López, Rudall, Anton, & Galetto, ). Insect mediated pollination, the transfer of pollen within or between flowers via insect vectors, is one such ecosystem service that benefits human populations and agriculture (Fisher, Turner, & Morling, ).…”