Systematics/Phytogeography / Taxonomie/ Section
Krosnick, Shawn , Kiel, Carrie , McDade, Lucinda .
Sweet Rewards: A Survey of Nectary Diversity in Passifloraceae, Malesherbiaceae, and Turneraceae.
Passifloraceae are comprised of ca. 725 species across 15 genera. Most genera are depauperate, with the majority containing ten or fewer species. However, three genera, Passiflora (550 spp.), Adenia (100 spp.) and Basananthe (25 spp.) are larger and display enormous morphological diversity. Several hypotheses have been proposed to explain the diversification observed in these lineages, including specialized pollination syndromes, and complex ecological interactions with herbivores and the mutualists that prey on these herbivores. The current analysis examines diversity of nectary form and function in the two largest genera, Passiflora and Adenia, and in the closely related Malesherbiaceae and Turneraceae. Floral nectaries (FNs) are present in almost all species of Passiflora and Adenia. FNs are found in both Malesherbia and Turnera, but are dissimilar from one another and from those in Passifloraceae. In T. ulmifolia, nectaries are found along the base of staminal filaments, whereas in M. ardens they are at the base of the androgynophore and derived from hypanthium tissue. All FNs examined release nectar via nectariferous parenchyma cells that move nectar outward through stomatal pores. In contrast, extrafloral nectaries (EFNs) release nectar via epidermal secretory cells that are much more diverse in form. EFNs are present at the base of the leaf in Adenia, whereas in Passiflora they are found on floral bracts, stipules, petioles, leaf teeth, and the abaxial surface of the leaf. Petiolar nectaries appear to release nectar without damage to the cuticle whereas abaxial nectaries generally rupture at the time of dehiscence. Turnera ulmifolia has well-developed EFNs on the petiole that are similar to those in Passiflora, whereas Malesherbia lack EFNs and are instead covered in glandular trichomes. A classification of nectary types observed in Passifloraceae is provided to facilitate homology assessment and the examination of phylogenetic patterns of nectary evolution.
Log in to add this item to your schedule
1 - Rancho Santa Ana Botanic Garden, Research, 1500 North College Avenue, Claremont, CA, 91711, USA
2 - Rancho Santa Ana Botanic Garden, 1500 North College Avenue, Claremont, California, 91711, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, July 30th, 2008
Time: 1:00 PM