Search results for "Petal"

COMMENT TO LEHRMANN ET AL. NEW SECTIONS AND OBSERVATIONS FROM THE NANPANJIANG BASIN, SOUTH CHINA

2016

In the study of Earth-surface environmental processes during the events associated with the Permian–Triassic boundary, a key issue is the nature of the latest Permian pre-extinction surface in shallow marine limestones in numerous sites, principally within the Tethyan realm. Sediments below this surface pre-date the extinction event, so that the limestones comprising these latest Permian facies contain diverse fossil remains of organisms that lived just before the extinction. At all reported sites, this surface is disconformably overlain by post-extinction sediments, which contain microbialites in many places, particularly in Tethys. The nature of the youngest pre-extinction surface remains…

Effects of root hemiparasitic infection on host performance: Reduced flower size and increased flower asymmetry

2001

We conducted two pot experiments to examine the relationship between hemiparasitic plant (Rhinanthus serotinus, Scrophulariaceae) infection and host (Linum usitatissimum, Linaceae and Brassica rapa ssp. oleifera, Brassicaceae) performance. We were especially interested in the effects of hemiparasitism on the size and shape asymmetry of host flowers, since neither subject has been studied before. We also conducted a field experiment to examine the effects of shape asymmetry of B. rapa ssp. oleifera flowers on pollination success. The shape of flowers produced by both L. usitatissimum and B. rapa ssp. oleifera plants grown without parasites was less asymmetric, and for both host species, the …

A new species of Capparis (Capparaceae) from ultramafic substrata in New Caledonia

2017

A new species of Capparis, C. parvifolia, is described and illustrated from New Caledonia, where it is known from a few localities on Mont Kaala on ultramafic substrata. The new species is characterized by the relatively small, linear leaf-blade and by the small size of the sepals, petals, stamens, gynophore and fruit. Its affinities with related taxa are discussed and its conservation status assessed.

Modeling dense inflorescences

2016

Showy inflorescences - clusters of flowers - are a common feature of many plants, greatly contributing to their beauty. The large numbers of individual flowers (florets), arranged in space in a systematic manner, make inflorescences a natural target for procedural modeling. We present a suite of biologically motivated algorithms for modeling and animating the development of inflorescences with closely packed florets. These inflorescences share the following characteristics: (i) in their ensemble, the florets form a relatively smooth, often approximately planar surface; (ii) there are numerous collisions between petals of the same or adjacent florets; and (iii) the developmental stage and ty…

Influence of Two N-Fixing Legumes on Plant Community Properties and Soil Nutrient Levels in an Alpine Ecosystem

2013

Abstract Low nitrogen (N) supply is a limiting factor for plant growth in most terrestrial ecosystems. N-fixing legumes therefore have the potential to facilitate surrounding vegetation by increasing soil N levels. This effect should be especially pronounced in low-productivity habitats where ambient soil N levels are low, such as in alpine areas. We examined whether plant species composition, community diversity measures, and soil N levels differed with and without the presence of two alpine legumes, Oxytropis lapponica (Wahlenb.) Gay and Astragalus alpinus L., in a Dryas octopetala heath at Finse, Norway. Species composition and richness differed between plots with and without Oxytropis i…

The role of heterochrony in Schizanthus flower evolution- a quantitative analysis

2021

Abstract Changes in the timing of development within a lineage (heterochrony) have an enormous impact on floral diversification. However, comparative quantitative studies in a broad range of ontogenetic stages are still needed to identify the role of different heterochronic processes shaping diversification patterns. In this study, changes in petal development were compared across species in the genus Schizanthus showing floral diversification mediated by pollinators. In this genus, transitions from bee- to hummingbird- and moth- pollination are associated with lower lip diversification. Variation in size and shape of petals was quantified at key ontogenetic stages by using a traditional an…

2017

Diversification in flower shape and function is triggered by the high plasticity of flower meristems. Minute changes in space and time can profoundly affect the formation of adult structures. Dipsacoideae provides an excellent model system to investigate the evolutionary aspects of temporal and spatial changes in flower development due to its small size, the resolved phylogenetic framework, and significant diversity of perianth form and merosity. In the present study, we investigated the sequence of floral organ initiation and quantified the interactions between flower meristem expansion and petal primordium size in eight species representing two major clades of Dipsacoideae. Our quantitati…

Côté mauvaises herbes, tir de barrage sur trois envahissantes

2006

National audience; Les plantes envahissantes sont évoquées à la conférence sur les zones non agricoles de l'AFPPà Avignon les 11 et 12octobre 2006. La situation à leur égard en France et en Europe est présentée, notamment les dispositions réglementaires et l'identité des 34 principales espèces. Deux communications traitent de l'ambroisie à feuille d'armoise Ambrosia artemisiifolia. Un point sur les méthodes de lutte mécanique, chimique, etc.) insiste sur l'intérêt de la prévention (enherbement, etc.)et de la concertation entre acteurs agricoles et non agricoles. Des essais de lutte chimique (glyphosate ou glufosinate-ammonium en 2004 et 2005, les montrent équivalents et intéressants en débu…

Ahnfeltiopsis devoniensis (Phyllophoraceae, Rhodophyceae) y Petalonia zosterifolia (Scytosiphonaceae, Phaeophyceae) en las costas de Catalunya

2009

Ancestral Reconstruction and Investigations of Genomic Recombination on some Pentapetalae Chloroplasts

2019

Abstract In this article, we propose a semi-automated method to rebuild genome ancestors of chloroplasts by taking into account gene duplication. Two methods have been used in order to achieve this work: a naked eye investigation using homemade scripts, whose results are considered as a basis of knowledge, and a dynamic programming based approach similar to Needleman-Wunsch. The latter fundamentally uses the Gestalt pattern matching method of sequence matcher to evaluate the occurrences probability of each gene in the last common ancestor of two given genomes. The two approaches have been applied on chloroplastic genomes from Apiales, Asterales, and Fabids orders, the latter belonging to Pe…