D Seelenfreund; R Piña; K-Y Ho; S Lobos; Ximena Moncada; A Seelenfreund
Broussonetia papyrifera (L.) Vent. (Magnoliophyta: Urticales), or paper mulberry, is a species of Asian origin dispersed by humans throughout the Pacific. Our aim is to evaluate the genetic variability of this plant in order to determine its potential as a commensal species for studying the mobility and\\/or migratory movements of the people that carried it. For this study, we analysed
Th e embryological processes leading to seed formation in S. nemorosa are comprehensively studied for the fi rst time. A number of embryological specifi cities have been established, typical of the malesterile plants. Th ey show that the investigated species manifests a tendency for transition from hermaphrodite to the evolutionally more advanced unisexual fl owers in Magnoliophyta.
Neimanis, Karina; Staples, James F; Hüner, Norman P A; McDonald, Allison E
Alternative oxidase (AOX) is a terminal ubiquinol oxidase present in the respiratory chain of all angiosperms investigated to date, but AOX distribution in other members of the Viridiplantae is less clear. We assessed the taxonomic distribution of AOX using bioinformatics. Multiple sequence alignments compared AOX proteins and examined amino acid residues involved in AOX catalytic function and post-translational regulation. Novel AOX sequences were found in both Chlorophytes and Streptophytes and we conclude that AOX is widespread in the Viridiplantae. AOX multigene families are common in non-angiosperm plants and the appearance of AOX1 and AOX2 subtypes pre-dates the divergence of the Coniferophyta and Magnoliophyta. Residues involved in AOX catalytic function are highly conserved between Chlorophytes and Streptophytes, while AOX post-translational regulation likely differs in these two lineages. We demonstrate experimentally that an AOX gene is present in the moss Physcomitrella patens and that the gene is transcribed. Our findings suggest that AOX will likely exert an influence on plant respiration and carbon metabolism in non-angiosperms such as green algae, bryophytes, liverworts, lycopods, ferns, gnetophytes, and gymnosperms and that further research in these systems is required. PMID:23664893
Vibrans, Alexander C; Sevegnani, Lúcia; Uhlmann, Alexandre; Schorn, Lauri A; Sobral, Marcos G; de Gasper, André L; Lingner, Débora V; Brogni, Eduardo; Klemz, Guilherme; Godoy, Marcela B; Verdi, Marcio
This study is part of the Floristic and Forest Inventory of Santa Catarina, conceived to evaluate forest resources, species composition and structure of forest remnants, providing information to update forest conservation and land use policy in Southern Brazilian State of Santa Catarina (95 000 km2). In accordance to the Brazilian National Forest Inventory (IFN-BR), the inventory applies systematic sampling, with 440 clusters containing four crosswise 1 000m2 plots (20 x 50m) each, located on a 10 x 10km grid overlaid to land use map based on classification of SPOT-4 images from 2005. Within the sample units, all woody individuals of the main stratum (DBH > or = 10cm) are measured and collected (fertile and sterile), if not undoubtedly identified in field. Regeneration stratum (height > 1.50m; DBH < 10cm) is registered in 100m2 in each sample unit. Floristic sampling includes collection of all fertile trees, shrubs and herbs within the sample unit and in its surroundings. This study performs analysis based on 92 clusters measured in 2008 within an area of 32320km2 of mixed ombrophyllous forests with Araucaria angustifolia located at the state's high plateau (500m to 1 560m above sea level at 26 degrees 00'-28 degrees 30' S and 49 degrees 13'-51 degrees 23' W). Mean density (DBH > or = 10cm) is 578 individuals/ha (ranging from 85/ha to 1 310/ha), mean species richness in measured remnants is 35 (8 to 62), Shannon and Wiener diversity index (H') varies between 1.05 and 3.48. Despite high total species diversity (364 Magnoliophyta, five Coniferophyta and one tree fern) and relatively high mean basal area (25.75m2/ha, varying from 3.87 to 68.85m2/ha), the overwhelming majority of forest fragments are considered highly impacted and impoverished, mostly by logging, burning and extensive cattle farming, turning necessary more efficient protection measures. Basal area was considered an appropriate indicator for stand quality and conservation status. PMID:22017139