Abstract
Elucidating the evolutionary patterns of flower and inflorescence structure is pivotal to understanding the phylogenetic relationships of Angiosperms as a whole. The inflorescence morphology and anatomy of Philodendron subgenus Meconostigma, belonging to the monocot family Araceae, has been widely studied but the evolutionary relationships of subgenus Meconostigma and the evolution of its flower characters have hitherto remained unclear. This study examines gynoecium evolution in subgenus Meconostigma in the context of an estimated molecular phylogeny for all extant species of subgenus Meconostigma and analysis of ancestral character reconstructions of some gynoecial structures. The phylogenetic reconstructions of all extant Meconostigma species were conducted under a maximum likelihood approach based on the sequences of two chloroplast (trnk and matK) and two nuclear (ETS and 18S) markers. This topology was used to reconstruct the ancestral states of seven floral characters and to elucidate their evolutionary pattern in the Meconostigma lineage. Our phylogeny shows that Meconostigma is composed of two major clades, one comprising two Amazonian species and the other all the species from the Atlantic Forest and Cerrado biomes with one Amazonian species. The common ancestor of the species of subgenus Meconostigma probably possessed short stylar lobes, long stylar canals, a stylar body, a vascular plexus in the gynoecium and druses in the stylar parenchyma but it is uncertain whether raphide inclusions were present in the parenchyma. The ancestral lineage also probably possessed up to 10 ovary locules. The evolution of these characters seems to have occurred independently in some lineages. We propose that the morphological and anatomical diversity observed in the gynoecial structures of subgenus Meconostigma is the result of an ongoing process of fusion of floral structures leading to a reduction of energy wastage and increase in stigmatic surface.
Highlights
The highly diverse monocot family Araceae Juss. comprises 3,319 currently recognized species classified into 118 genera [1]
Our findings suggest that the morphological diversity observed in the gynoecium of Meconostigma species is the result of an ongoing process of fusion of its flower structures leading to a reduction of energy wastage and increase in stigmatic surface and, as a consequence, the chances of fertilization
Meconostigma This is the first study to estimate the detailed phylogenetic relationships of Meconostigma with a complete sampling of extant species, and the first to use a well-established phylogeny to suggest the possible evolutionary scenario under which floral structures evolved in this group
Summary
The highly diverse monocot family Araceae Juss. comprises 3,319 currently recognized species classified into 118 genera [1]. Comprises 3,319 currently recognized species classified into 118 genera [1]. The Neotropical genus Philodendron Schott is of special interest as it represents the second most diverse genera of the family, with 489 accepted species [2], and is one of the most conspicuous and wellknown groups of epiphytic and hemiepiphytic plants [3]. The current taxonomy of Philodendron follows Mayo [4], Grayum [5], Croat [6] and Sakuragui et al [7] and comprises three subgenera: Philodendron, Pteromischum and Meconostigma, the latter with 21 species. Philodendron is composed of very showy and horticulturally durable plants. These features are especially notable in subgenus Meconostigma and as a consequence, species of this subgenus are widely used in horticulture as valuable ornamental plants [8]. The roots of some species, such as P. corcovadense [9] and P. williamsii [10] are used by traditional Brazilian populations for making rustic craft products that are widely sold in urban centers
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
