Abstract Detail

Developmental and Structural Section

Dong, Deanna [1], Miller, Paige [1], Hayden, W [2].

Floral anatomy and corolla nectar tubes in Physalis (Solanaceae).

We studied the floral anatomy of five species found in eastern North America: Physalis angulata L., P. heterophylla Nees, P. longifolia Nuttall, P. philadelphica Lamarck, and P. pubescens L. Material studied ranged from small buds to newly open flowers and isolated whole corollas verging on abscission late in the second day of anthesis. Tissues were fixed in FAA and prepared for light and scanning electron microscopy using standard techniques. Though differing in size, orientation, and degree of corolla opening, all species studied possess flowers with five fused sepals that are retained and become accrescent in fruit, five fused yellow petals often with dense pubescence within the throat, and five epipetalous stamens. Flowers have a ring-like nectary below a two- or three-carpellate superior ovary and dark spots near the throat. Notable anther features include sterile placentoids and stomium cells bearing crystal sand. Axile placentas bear numerous unitegmic anatropous ovules. Floral organs initiate in acropetal order on the flanks of the floral meristem as separate elements. Sepal connation occurs early and fused sepals rapidly overarch the other floral organs. Before petal-petal connation, petal to stamen adnation initiates as contact below tips of stamen primordia and proceeds basipetally; separate stamen primordium tips elongate, forming anthers. Petal-petal connation is next, followed by carpel-carpel connation. Corollas of all species studied possess capillary nectary "tubes," anatomical grooves adaxial to petal midveins, that extend distally from petal bases (adjacent to the nectary disk) to points on the corolla limb just beyond the level of filament divergence. Nectar tubes develop by division of petal mesophyll cells laterally adjacent to midveins, comparable to adaxial meristems of leaf ontogeny. Since nectar tubes end in darkly pigmented spots on the corolla, it is inferred that these markings serve as nectar guides for pollinators; a hypothesis that should be tested via observation in the field. Similar multiradial corolla nectar tubes for proximal-to-distal secretion have been reported in Jaltomata and Capsicum; as such, solanaceous nectar tubes differ from examples known in other plant families. Systematic distribution of corolla nectar tubes should be explored among other solanaceous genera.

Broader Impacts:

1 - University of Richmond, Department of Biology, 28 Westhampton Way, Richmond, VA, 23173, USA
2 - UNIVERSITY OF RICHMOND, DEPT OF BIOLOGY, 28 WESTHAMPTON WAY, RICHMOND, VA, 23173, USA

Keywords:
Physalis
Solanaceae
floral anatomy
nectar tubes.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PDS006
Abstract ID:177
Candidate for Awards:Developmental and Structural Section best poster