Floral nectar chemical composition of some species from Patagonia. II

Floral nectar chemical compositions of 28 species native to Argentinian Patagonia are reported. Most data obtained are new reports at the generic and/or the specific level. Nectars of these species show high mean concentrations (42.35 +/- 15.56; %, wt/total wt of solution). Most of the species are hexose dominant (68%) and the remaining are sucrose rich (11%) or sucrose dominant (21%). The hexose ratio shows that in most species (71%) glucose predominates over fructose. The nectars of all species have amino acids. In 32% of them, lipids were detected, whereas phenols were present in around 60%. Most of the species are entomophilous, mainly melittophilous and psychophilous. These data together with those of our previous report include a total of 57 species from 19 families, and suggest three trends in the nectar sugar traits of Patagonian plants, regardless of their systematic relationship or floral syndrome: high concentration, hexose dominance, and predominance of glucose. These results suggest that nectar characteristics are not always as similar for plants pollinated by the same animal taxa as formerly thought. (C) 1999 Elsevier Science Ltd. All rights reserved.