Delayed differentiation of epidermal cells walls can underlie pedomorphosis in plants: the case of pedomorphic petals in the hummingbird-pollinated Caiophora hibiscifolia (Loasaceae, subfam. Loasoideae) species

Understanding the relationship between macroevolutionary diversity and variation in organism development is an important goal of evolutionary biology. Variation in the morphology of several plant and animal lineages is attributed to pedomorphosis, a case of heterochrony, where an ancestral juvenile shape is retained in an adult descendant. Pedomorphosis facilitated morphological adaptation in different plant lineages, but its cellular and molecular basis needs further exploration. Plant development differs from animal development in that cells are enclosed by cell walls and do not migrate. Moreover, in many plant lineages, the differentiated epidermis of leaves, and leaf-derived structures, such as petals, limits organ growth. We, therefore, proposed that pedomorphosis in leaves, and in leaf-derived structures, results from delayed differentiation of epidermal cells with respect to reproductive maturity. This idea was explored for petal evolution, given the importance of corolla morphology for angiosperm reproductive success

Exploring the ontogenetic scaling hypothesis during the diversification of pollination syndromes in <i>Caiophora</i> (Loasaceae, subfam. Loasoideae)

Phenotypic diversification of flowers is frequently attributed to selection by different functional groups of pollinators. During optimization of floral phenotype, developmental robustness to genetic and non-genetic perturbations is expected to limit the phenotypic space available for future evolutionary changes. Although adaptive divergence can occur without altering the basic developmental programme of the flower (ontogenetic scaling hypothesis), the rarity of reversion to ancestral states following adaptive radiations of pollination syndromes suggests that changes in the ancestral developmental programme of the flower are common during such evolutionary transitions. Evidence suggests that flower diversification into different pollination syndromes in the Loasoideae genus Caiophora took place during a recent adaptive radiation in the central Andes. This involved transitions from bee to hummingbird and small rodent pollination. The aim of this work was to examine if the adaptive radiation of pollination syndromes in Caiophora occurred through ontogenetic scaling or involved a departure from the ontogenetic pattern basal to this genus.Fil: Strelin, Marina Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Benitez-Vieyra, Santiago Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Fornoni, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional Autónoma de México; MéxicoFil: Klingenberg, Christian Peter. University of Manchester; Reino UnidoFil: Cocucci, Andrea Aristides. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

What is the real isotopic signature of dust emitted from Tierra del Fuego?

Fil: Gaiero, D.M. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Gili, S. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Strelin, J. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Strelin, J. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Antártico Argentino; Argentina.Fil: Koestner, E. IG-UFRGS. Laboratório de Geología Isotópica; Brasil.Fil: Chemale Jr, F. IG-UFRGS. Laboratório de Geología Isotópica; Brasil.Sugden et al. (2009) suggested an on/off switch mechanism that could explain the 20 times increase of dust deposition in Antarctica during the Last Glacial Maximum (LGM), as compared to present day. This suggested switch resides in Patagonian pro-glacial lakes; when glaciers retreat sediments are deposited in the lakes and dust emission ceased in opposition to cold periods, when glacial pour out sediments to the outwash plain, then increasing dust emission. The on/off switch mechanism proposed is supported on age analyses and strontium (Sr) and neodymium (Nd) isotope ratios of ancient lacustrine sediment samples from the Magellan Strait (MS) and from the North Patagonian icefield (NPI). The lacustrine sediments were used as representative of sediments that were disgorged to the outwash plain during the LGM. We argue on the type of samples used to characterize the possible Patagonian outwash sediments deflated during the LGM and accordingly, on the interpretation of the source of this dust. Modern sediments are deflated from the Patagonian surface mainly from widespread ephemeral lakes (Gaiero 2007), which are sporadically refilled with sediments supplied from the surrounding areas mainly through water runoff. The aim of this contribution is to discuss about this and contrast data from both set of samples and discuss about their significance for the interpretation of the isotopic signatures recorded on the sedimentary archives of the Southern Hemisphere (e.g., Antarctic ice cores). Fig. 1 shows that the mean isotopic composition of dry lake sediments (collected from the ancient outwash plain in the San Sebastián Bay area) and dust collected at Río Grande are significantly different compared to MS samples and very similar to sediments representing the Fuegian continental shelf (Basile et al. 2007). Similar to modern dust released from continental Patagonia (north of ~52° S), modern data from Tierra del Fuego could also be explained by a mixing between Jurassic rhyolites and Quaternary volcanic rocks (e.g., Gaiero et al. 2007; Fig. 1). On the contrary, the samples used by Sugden et al. (2009) seem to characterize discrete sources. The isotopic composition of most samples from the MS plots mostly within the compositional field corresponding to the Antarctic Jurassic rhyolites and similar rocks that outcrop out close along the Fuegian Cordillera (Gaiero et al. 2007). In the case of NPI samples, their compositions are similar to the local outcropping Paleozoic plutonic and metasedimentary rocks (Killian and Behrmann 2003). Nevertheless, directly to the W of the NPI, the isotopic composition of Pliocene/Pleistocene Chilean trench sediments (mean 87Sr/86Sr = 0.707 and &#948;Nd(0) = -2.1) indicates a variable contribution from other rocks cropping out in the area (e.g., Quaternary volcanic rocks). Why MS and NPI samples are different from modern Patagonian dust?Fil: Gaiero, D.M. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Gili, S. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Strelin, J. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Strelin, J. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Antártico Argentino; Argentina.Fil: Koestner, E. IG-UFRGS. Laboratório de Geología Isotópica; Brasil.Fil: Chemale Jr, F. IG-UFRGS. Laboratório de Geología Isotópica; Brasil.Geoquímica y Geofísic

A case of behavioural diversification in male floral function – the evolution of thigmonastic pollen presentation

The authors gratefully acknowledge funding provided by an Else-Neumann-Stipendium (http://www.fu-berlin.de/sites/promovieren/drs/nachwuchs/nachwuchs/nafoeg.html), Deutscher Akademischer Austausch Dienst (DAAD) and botconsult GmbH at different stages of data acquisition. We thank Tobias Grass, Joana Bergmann and Franziska Weber (Freie Universität Berlin) for help with data collection in the field and in the greenhouse. Nicole Schmandt, Federico Luebert, Juliana Chacón and Dietmar Quant (Universität Bonn) provided help in the molecular laboratory and the edition of the molecular dataset. We furthermore thank Markus Ackermann (Koblenz) for providing photographs, Philipp Klein (Berlin) for editing the video and Katy Jones (Berlin) for helpful comments on an earlier version of the manuscript. Rafael Acuña has been supported by the ALECOSTA scholarship program. Coverage of the article processing charge by the German Research Foundation via the Open Access Publication Fund of the Freie Universität Berlin is gratefully acknowledged.Peer reviewedPublisher PD