Floral nectar, nectary structure and pollinators in some Argentinean Bromeliaceae
1991
Bernardello, L.M. | Galetto, L. | Juliani, H.R.
The floral nectar chemical composition and nectary structure of some Argentinean Bromeliaceae were studied, including field observations on pollinators. Twenty species belonging to eight genera from the three subfamilies were analysed. The nectar components report is mostly new since no comprehensive study has been carried out on the family previously. Sugars were always present, while alkaloids, lipids. phenols, and proteins were not detected in any sample. Reducing acids were found in three species. Amino acids were detected in a very low concentration in only about half the samples. Pitcairnioideae species show a mean balanced disaccharide/monosaccharide nectar sugar composition, Bromelioideae had hexose-rich nectars and Tillandsioideae saccharose-dominant ones. Nectar concentration ranged from 16 to 48%. All taxa bear septal nectaries with many common features. Pitcairnioideae and Tillandsioideae members have half-inferior ovaries, a feature mostly overlooked in previous studies. Three types of nectary architecture were recognized in both subfamilies. Bromelioideae have inferior ovaries and possess comparable nectaries. Hummingbirds constitute the main flower pollinators of many species but butterflies and bees were occasionally seen in two species, cropping nectar and pollen, respectively.
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