Morphological and anatomical development in the Vitaceae. VII. Floral development in Rhoicissus digitata with respect to other genera in the family

Abstract

This study forms part of our series of investigations on genera in the Vitaceae and is the first developmental study for the genus Rhoicissus. Vegetative and reproductive development of shoot apices of Rhoicissus digitata (L.f.) Gilg et Brandt were examined using epi-illumination light microscopy and scanning electron microscopy. Leaf-opposed tendrils or inflorescences, typical of the shoot architecture in the Vitaceae, were present at every node. Macroscopically, the shoot appears to grow either monopodially or sympodially. At the microscopic level, however, shoot development is sympodial; the shoot apical meristem bifurcates unequally, with the larger portion forming an uncommitted primordium, which will become either an inflorescence or a tendril, and the smaller portion (in the position of the axillary bud) forming the new shoot apical meristem. Floral primordia first initiate three sepals followed by a calyx ring on which the last two sepal primordia form. The five petals are initiated in a whorl followed by the five stamens in a petal-opposed position. There is no evidence of a common petal-stamen primordium in this species. The gy noecium is initiated as a ring primordium. Subsequently, the four ovules are initiated at the base of the two septa that grow out from the inner gynoecial wall. The nectary disc forms as an outgrowth of the gynoecium base. Mature flowers have greenish petals and a red nectariferous disc. Flowers are bisexual, and seed germination is approximately 63%. Unlike previous studies in Vitis and Parthenocissus, Rhoicissus appears to have few putatively derived floral developmental characters, which would support its relatively basal position in current phylogenies for the family.Key words: Vitaceae, morphology, development, shoot architecture, flower.

Evolution of the intercontinental disjunctions in six continents in the Ampelopsis clade of the grape family (Vitaceae)

“…But we still have some missing taxa in our sampling scheme, such as Rhoicissus with only 41% species sampled. However, each group is supposed to be monophyletic based on morphological, biogeographic, and molecular evidence [28-30,34,36]. The missing taxa in our sampling should have little effect in the present study that focused on phylogenetic relationships among genera and biogeographic evolution at the intercontinental level.…”

Phylogenetic analysis of the grape family (Vitaceae) based on three chloroplast markers

“…These tendrils are considered to be modified shoots or inflorescences (Tucker and Hoefert, 1968;Gerrath et al, 2001). Nectary morphology is highly variable in Vitaceae and has been emphasized in defining genera (Suessenguth, 1953a;Gerrath et al, 2004). Inflorescences of Vitaceae are typically paniculate systems (Troll, 1969).…”

Phylogeny of Vitaceae based on the nuclearGAI1gene sequencesThis article is one of a selection of papers presented at the symposium onVitisat the XVII International Botanical Congress held in Vienna, Austria, in 2005.

“…Rhoicissus has 5-7-merous flowers, fleshy petals, and a nectary disk originated from the widening of the base of ovary (Gerrath et al 2004;Wen 2007a). Rhoicissus has 5-7-merous flowers, fleshy petals, and a nectary disk originated from the widening of the base of ovary (Gerrath et al 2004;Wen 2007a).…”

“…(Soejima and Wen 2006;Wen 2007a). Vegetative and floral development of Vitaceae has been systematically recorded by Gerrath, Posluszny, and their collaborators (e.g., Gerrath and Posluszny 1988a, 1988b, 1988c1989a, 1989b, 1989cGerrath et al 1998Gerrath et al , 2001Gerrath et al 2004). Morphological synapomorphies of Vitaceae in- clude leaf-opposed tendrils, climbing habit, presence of ''pearl'' glands (small spherical epidermal structures with a short stalk) on leaves, and a suite of specialized seed characters.…”