Composition of the floral nectar of different subgenera of Argentinian Passiflora species.

AMELA GARCÍA, M. T. & GOTTSBERGER, G.

PLANT SYSTEMATICS AND EVOLUTION

SPRINGER WIEN

Lugar: Viena; Año: 2009 vol. 283 p. 133 - 147

0378-2697

The composition of the floral nectar sugars and amino acids of four species of Passiflora (P. foetida, P. caerulea, P. suberosa, and P. misera) included in different infrageneric taxa and with distinct pollination mechanisms has been studied. The effect of weather and floral age on nectar volume, existence, and total and relative amounts of the various compounds was explored. Theproportion of sugars was rather constant within a given species whereas the composition, number, and total quantity of amino acids showed great intraspecific and intraplant variability; these nectar properties were independent of floral stage or meteorological conditions. Species belonging to the same subgenus displayed equivalent sugar ratios and similar total amount of amino acids, so thesecharacteristics might be conservative in the genus. For all species, the amino acid concentration surpassed known values for their respective pollination syndromes, viz. bee and wasp-pollinated flowers. No relationship emerged between pollinators with different glossa length and nectars with distinct sugar ratios. Rather, nectar chemical composition seems to reflect taxonomic relationships.