Development of pollen and anatomy of the mature anther in Argentinian species of the three subfamilies of Rubiaceae

NUÑEZ FLORENTIN, M.; ROMERO, M. F.; JUDKEVICH, M. D.; SALAS, R. M.; GONZALEZ, A. M.

Congreso; VII International Rubiaceae and Gentianales Conference; 2017

Rubiaceae is a cosmopolitan family that includes about 1300 species distributed in threesubfamilies: Cinchonoideae, Ixoroideae, and Rubioideae. The microsporogenesis,microgametogenesis, and the structure of the mature anther were described in Argentinianspecies of the three subfamilies for comparative purposes. The study includes two perfectspecies: Cephalanthus glabratus (Cinchonoideae) and Oldenlandia salzmannii (Rubioideae)and a structurally perfect but functionally imperfect species: Randia ferox (Ixoroideae). Wefollowed conventional techniques of optic microscopy. In the two perfect species and in thefunctionally staminate flowers of Randia the development of the pollen follows a normalpattern: the meiosis of the microspore mother cells originates tetrahedral and decussatetetrads. In C. glabratus and O. salzmannii, tetrads are separated in free microspores and thepollen is released in monads, while in Randia the pollen in permanent tetrads. The perfectflowers of Cephalanthus and Oldenlandia, and the staminate flowers of Randia present theanther wall only with remains of exothecium and endothecium with fibrous thickenings andshow a normal dehiscence; the pollen grains are dispersed in bicellular state. In thefunctionally pistillate flowers of Randia, the microspore mother cells collapse and there is aprogressive deterioration of the parietal strata and tapetum; the mature anther is onlyconstituted by exothecium and endothecium without thickenings, and there is not pollengrain development. This work is a contribution to studies of reproductive anatomy, which arecurrently performed in Argentinian Rubiaceae species.