Abstract

PAIARO, Valeria; OLIVA, Gabriel E; COCUCCI, Andrea A  and  SERSIC, Alicia N. Caracterización y variación espacio-temporal del néctar en anarthrophyllum desideratum (Fabaceae): Influencia del clima y los polinizadores. Bol. Soc. Argent. Bot. [online]. 2012, vol.47, n.3-4, pp.375-387. ISSN 1851-2372.

Characterization and spatio-temporal variation of nectar in Anarthrophyllum desideratum (Fabaceae): Influence of climate and pollinators. In this study we characterized the volume, concentration and sugar composition of floral nectar in Anarthrophyllum desideratum (DC) Benth., an endemic shrub from the Patagonian steppe pollinated by Passerine birds, and we evaluated it spatio-temporal variation. We analyzed the differences among ecological areas, populations, plants and years, and the relationships between traits, the temperature, rainfall and visitation rate of populations. Nectar showed an average volume of 8.1 µl, a concentration of 28% and was dominated by hexoses, as in other ornithophilous species. The nectar attributes were correlated at population level, and the differences among populations accounted for most of its spatial variability. Volume and concentration varied among years, whereas sugar composition remained constant. The proportion of glucose decreased with increasing temperature, but the rest of the characters did not associate with climatic variations of the region. Nectar volume decreased with increasing the visitation rate of populations. The results suggest the existence of an important spatio-temporal variation of nectar in A. desideratum that would not respond to simple environmental gradients but to a complex scenario with multiple factors.

Keywords : Anarthrophyllum desideratum; Concentration; Ecological area; Nectar volume; Passeriformes; Population; Sugar composition; Precipitation; Temperature; Visitation rate.

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