Ovule ontogeny of Relbunium species in the evolutionary context of Rubiaceae

Abstract

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.

Ovary and ovule anatomy in the nidularioid complex and its taxonomic utility (Bromelioideae: Bromeliaceae)

“…Anatomical features, especially reproductive ones, have been used in recent studies to improve taxonomic delimitation in different groups, as they exhibit low phenotypic plasticity compared with vegetative characters (Taylor & Robinson, ; Palací, Brown & Tuthill, ; Sajo, Prychid & Rudall, ; De Toni & Mariath, ; Fagundes & Mariath, , ). Embryological features can provide >50 characters associated with the development of anthers, ovules and seeds, contributing to a better understanding of the relationships among families and genera (Tobe, ).…”

“…Embryological features can provide >50 characters associated with the development of anthers, ovules and seeds, contributing to a better understanding of the relationships among families and genera (Tobe, ). Studies such as the observations of ovule development have proved to be efficient in differentiating taxonomic groups, not only by confirming phylogenetic relationships but also by revealing evolutionary patterns within the groups (Tobe & Raven, ; Anton & Cocucci, ; Juncosa & Tobe, ; Tobe, ; Moço & Mariath, ; De Toni & Mariath, , ; Fagundes & Mariath, ).…”

Development of carpels and ovules in Dialypetalanthus fuscescens Kuhlm. (Rubiaceae): an enigmatic taxon

“…In the most recent studies, Figueiredo et al (2013a; proposed new embryological characters for analysis, such as placenta position and origin of the carpellary septa. These embryological analyses have corroborated molecular phylogenies of Rubiaceae (De Toni & Mariath 2010). …”

Morphoanatomy of the ovary and ovule in Bromeliaceae subfamily Tillandsioideae and its systematic relevance

“…Maheshwari, 1950;Palser, 1975;Herr, 1984;Tobe, 1989;De Toni & Mariath, 2010). Some characters do not exhibit significant variations in the subfamily, such as ovule orientation, number of integuments, thickness of the parietal tissue and nucellar epidermis.…”

“…The systematic value of ovule characters has long been noted, and authors have usually demonstrated the utility of embryological information in clarifying relationships among taxa (e.g. Maheshwari, 1950;Palser, 1975;Herr, 1984;Tobe, 1989;De Toni & Mariath, 2010).…”