Morphological and anatomical development in the Vitaceae. V. Vegetative and floral development in Ampelopsis brevipedunculata

Abstract

The vegetative and floral development of Ampelopsis brevipedunculata was studied using both three-dimensional and histological techniques. An uncommitted primordium (which usually develops into a tendril in young seedlings and a cymose inflorescence in mature plants) is initiated opposite every leaf on the flank of the shoot apical meristem. Flowers are hermaphroditic, pentamerous, and protandrous. The sepals are initiated spirally, and form a calyx unit as the result of subsequent activity of a basal ring primordium. The common petal–stamen primordia are initiated simultaneously, but differentiate into petals and stamens unidirectionally. The gynoecium is initiated as a ring primordium, which produces two septa from the inner gynoecium wall. Two bitegmic, anatropus ovules arise from the base of each septum. At maturity the gynoecium is superior and two-loculed. Pollen is tricolporate. A nectar-secreting disc arises from the base of the ovary. The fruit is a turquoise-blue berry, containing one to four seeds. Axillary buds, present at each node, develop sylleptically and normally abscise at the end of the growing season. A vertical series of as many as six serial axillary buds develop basipetally to form the overwintering buds, which are not externally visible.