XVI International Botanical Congess

The nectary structure (e.g. nectary volume, stomata number, stomata size) and nectar features (e.g. concentration, chemical composition, sugar proportions) of ca. 50 Bignoniaceae are analyzed and discussed. In general, all taxa bear a conspicuous nuptial nectary surrounding the ovary base. The secretory tissue is mostly supplied by phloem branches and present stomata which are located in the middle and upper part of the nectary epidermis, with an homogeneous distribution. Most species also present extranuptial nectaries. A wide range of nuptial nectar concentration (wt/wt) is found. Sugars and amino acids are always present in the nectar of all species, while alkaloids, phenols and lipids are rarely detected. When nectar sugar proportions are considered two trends can be pointed out: around half of the species have hexose predominant nectars, while the remainder sucrose predominant ones. A correlation analysis was performed with the data - including some features of the flower structure - and few significant correlations were found. They are useful to better understand animal-plant interactions.