Development of the gynoecium of Guettarda pohliana in the context of Rubiaceae evolution

作者：Figueiredo Rogerio da Costa; Vieira Ricardo Cardoso; De Toni Karen L G^*

来源：Botany, 2013, 91(8): 562-567.

DOI：10.1139/cjb-2013-0017

• floral meristem
• intercalary growth
• ovule
• placentation
• carpellary septa

Traditional studies examining the evolution of the gynoecium in Rubiaceae focus on variations in ovule morphology. However, development of the gynoecium is poorly understood. Only a few studies have been conducted to examine the formation of the carpellary septa in the subfamilies Cinchonoideae and Ixoroideae. A trend in reduced ovule structures has been observed. The origin of the carpellary septa is also relevant. Therefore, to provide insight into the evolution of embryological characteristics in Rubiaceae, we investigated the ontogeny of the carpels and ovules in Guettarda pohliana (Cinchonoideae), focusing on the carpellary septa, placenta, nucellus, and integument. Guettarda pohliana has a long basal septum and pendulous ovules. The ovules are anatropous, unitegmic, and tenuinucellate. The nucellus is dome-like, the epidermis contains between seven and eight cells, and there are between four and six subepidermal initials. Based on these observations, we propose a new ovule type in the evolutionary diagram of this group. This new Chomelia type is very similar to the Ixora type, but the pendulous ovules differ and Chomelia has a long basal septum.

• 出版日期2013-8