Ovule ontogeny of Relbunium species in the evolutionary context of Rubiaceae

• Published in: Australian journal of botany Vol. 58; no. 1; pp. 70 - 79
• Main Authors: De Toni, Karen L.G, Mariath, Jorge E.A
• Format: Journal Article
• Language: English
• Published: Collingwood, Victoria: CSIRO Publishing 2010
• Subjects: carpels; embryo (plant); embryogenesis; evolution; gametogenesis; gametophytes; gynospores; gynosporium; gynosporogenesis; meristems; ontogeny; ovule primordia; ovules; plant morphology; Relbunium; Rubiaceae; sporulation
• ISSN: 0067-1924; 1444-9862
• DOI: 10.1071/BT09134

Carpel and ovule ontogeny, gynosporogenesis and gynogametogenesis in species of Relbunium were studied in order to provide additional data distinguishing evolutionary embryological characters. No significant differences in either ontogeny or morphology were observed among the species. The following characteristics are common to all species studied: (1) an independent development between the establishment of carpels and placenta meristem; (2) a bi-layered structure of the ovule primordia; and (3) a remnant gynosporium of the ovules, which contains the gynospores and binucleated gametophytes that migrate towards the micropyle where their development is concluded. The embryological characters are explored, and additional data are provided for the analyses of the evolutionary tendencies to Relbunium (Endl.) Benth. & Hook. f. species. In accordance with previous evolutionary proposals, the analysed species can be compared with the Galium type.