What keeps the style under tension? Experimental tests to understand the biomechanics of the explosive style movement in Marantaceae.

Pollination in Marantaceae is mediated by an explosive style movement. Before release, style tension is held by the hooded staminode. When a pollinator touches the trigger appendage of the hooded staminode the latter deforms and the style rapidly curls upwards.

Dark-centred umbels in Apiaceae: diversity, development and evolution.

The wild carrot () is famous for its dark flowers in the umbel centre. Several studies have been conducted to figure out their functional significance, but the evolution of the dark centre remains an enigma. In the present paper, we consider all known apioid species with dark-centred umbels to get a deeper understanding of their biology and evolution.

Pseudanthia in angiosperms: a review.

Background: Pseudanthia or 'false flowers' are multiflowered units that resemble solitary flowers in form and function. Over the last century the term 'pseudanthium' has been applied to a wide array of morphologically divergent blossoms, ranging from those with easily noticeable florets to derived, reduced units in which individual flowers become almost indistinguishable. Although initially admired mostly by botanists, the diversity and widespread distribution of pseudanthia across angiosperms has already made them a fascinating topic for evolutionary and developmental comparative studies.

Rhizome architecture, development and vascularization in the water lily Nymphaea alba.

Background And Aims: Water lilies are of particular interest with regard to the evolution of angiosperms. They live in an aquatic environment and have been regarded as links to the monocots by some authors. Vascular bundles are sometimes described as scattered or atactostelar as in monocots.

Flower-like meristem conditions and spatial constraints shape architecture of floral pseudanthia in Apioideae.

Background: Pseudanthia are multiflowered units that resemble single flowers, frequently by association with pseudocorollas formed by enlarged peripheral florets (ray flowers). Such resemblance is not only superficial, because numerous pseudanthia originate from peculiar reproductive meristems with flower-like characteristics, i.e.

The 'Male Flower' of (Euphorbiaceae) Interpreted as a Multi-Flowered Unit.

One of the most exciting questions in botany refers to the nature of the angiosperm flower. While most flowering structures are easily identified as flowers, there are few examples lying in-between flowers and inflorescences. Such an example is the staminate unit ('male flower') in (Euphorbiaceae) famous for its branched 'staminal trees.

Sex-differential reproduction success and selection on floral traits in gynodioecious Salvia pratensis.

Background: Gynodioecy, a sexual system with hermaphrodite and female individuals in a population, raises the question how the two sexual morphs are maintained. Salvia pratensis is a gynodioecious species featured by its modified stamens that act as a lever mechanism in pollination. Given sexual dimorphism in floral traits of the species, it is predictable that two sexual morphs differ in their interplay with pollinators and thus in their fitness.

The Search for Common Origin: Homology Revisited.

Understanding the evolution of biodiversity on Earth is a central aim in biology. Currently, various disciplines of science contribute to unravel evolution at all levels of life, from individual organisms to species and higher ranks, using different approaches and specific terminologies. The search for common origin, traditionally called homology, is a connecting paradigm of all studies related to evolution.

Insights Into the Inside - A Quantitative Histological Study of the Explosively Moving Style in Marantaceae.

This study aims to identify the histological basis for the extraordinary, fast movement of the style in Marantaceae. Although this explosive pollination mechanism was subject of many studies, quantitative measurements to document volumetric changes have never been conducted. Based on physical parameters and limitations (poroelastic time), the movement itself is by far too fast to be explained by turgor changes solely.

Flower-like heads from flower-like meristems: pseudanthium development in Davidia involucrata (Nyssaceae).

Flower-like inflorescences (pseudanthia) have fascinated botanists for a long time. They are explained as condensed inflorescences implying that the pseudanthium develops from an inflorescence meristem (IM). However, recent developmental studies identified a new form of reproductive meristem, the floral unit meristem (FUM).

Developmental Changes in Time and Space Promote Evolutionary Diversification of Flowers: A Case Study in Dipsacoideae.

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.

Correction: Understanding the unique flowering sequence in Dipsacus fullonum: Evidence from geometrical changes during head development.

[This corrects the article DOI: 10.1371/journal.pone.

Understanding the unique flowering sequence in Dipsacus fullonum: Evidence from geometrical changes during head development.

The genus Dipsacus is characterized by a remarkable bidirectional flowering sequence and a rare phyllotactic pattern. Considering that flower initiation and flowering sequence may be interconnected, we document the development of the head meristem in Dipsacus fullonum. Our results indicate a gradual change in the geometry of the head meristem beginning with a dome shaped stage, continuing with a remarkable widening in the middle part of the head meristem and ending in a spindle-like form.

Time to split Salvia s.l. (Lamiaceae) - New insights from Old World Salvia phylogeny.

Aims: Salvia L. is widely known as the largest genus in the mint family. A morphological modification of the androecium (lever-like stamens) was used to support this genus.

Space matters: meristem expansion triggers corona formation in Passiflora.

Background And Aims: Flower meristems differ from vegetative meristems in various aspects. One characteristic is the capacity for ongoing meristem expansion providing space for new structures. Here, corona formation in four species of Passiflora is investigated to understand the spatio-temporal conditions of its formation and to clarify homology of the corona elements.

Electrical signals in prayer plants (marantaceae)? Insights into the trigger mechanism of the explosive style movement.

The explosive pollination mechanism of the prayer plants (Marantaceae) is unique among plants. After a tactile stimulus by a pollinator, the style curls up rapidly and mediates pollen exchange. It is still under discussion whether this explosive movement is released electrophysiologically, i.

Flies as pollinators of melittophilous Salvia species (Lamiaceae).

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Premise Of The Study: Floral adaptation to a functional pollinator group does not necessarily mean close specialization to a few pollinator species. For the more than 950 species of Salvia, only bee and bird pollinations are known. Restriction to these pollinators is mainly due to the specific flower construction (lever mechanism).

Live imaging of developmental processes in a living meristem of Davidia involucrata (Nyssaceae).

Morphogenesis in plants is usually reconstructed by scanning electron microscopy and histology of meristematic structures. These techniques are destructive and require many samples to obtain a consecutive series of states. Unfortunately, using this methodology the absolute timing of growth and complete relative initiation of organs remain obscure.

Why Africa matters: evolution of Old World Salvia (Lamiaceae) in Africa.

Background And Aims: Salvia is the largest genus in Lamiaceae and it has recently been found to be non-monophyletic. Molecular data on Old World Salvia are largely lacking. In this study, we present data concerning Salvia in Africa.

Inflorescences: concepts, function, development and evolution.

Background: Inflorescences are complex structures with many functions. At anthesis they present the flowers in ways that allow for the transfer of pollen and optimization of the plant's reproductive success. During flower and fruit development they provide nutrients to the developing flowers and fruits.

Andromonoecy and developmental plasticity in Chaerophyllum bulbosum (Apiaceae-Apioideae).

Background And Aims: Andromonoecy, the presence of hermaphrodite and male flowers in the same individual, is genetically fixed or induced, e.g. by fruit set.

The unique pseudanthium of Actinodium (Myrtaceae) - morphological reinvestigation and possible regulation by CYCLOIDEA-like genes.

Background: Genes encoding TCP transcription factors, such as CYCLOIDEA-like (CYC-like) genes, are well known actors in the control of plant morphological development, particularly regarding the control of floral symmetry. Despite recent understanding that these genes play a role in establishing the architecture of inflorescences in the sunflower family (Asteraceae), where hundreds of finely organized flowers are arranged to mimic an individual flower, little is known about their function in the development of flower-like inflorescences across diverse phylogenetic groups. Here, we studied the head-like pseudanthium of the Australian swamp daisy Actinodium cunninghamii Schau.

Towards an ontogenetic understanding of inflorescence diversity.

Backgrounds And Aims: Conceptual and terminological conflicts in inflorescence morphology indicate a lack of understanding of the phenotypic diversity of inflorescences. In this study, an ontogeny-based inflorescence concept is presented considering different meristem types and developmental pathways. By going back to the ontogenetic origin, diversity is reduced to a limited number of types and terms.

Testing the ontogenetic base for the transient model of inflorescence development.

Backgrounds And Aims: Current research in plant science has concentrated on revealing ontogenetic processes of key attributes in plant evolution. One recently discussed model is the 'transient model' successful in explaining some types of inflorescence architectures based on two main principles: the decline of the so called 'vegetativeness' (veg) factor and the transient nature of apical meristems in developing inflorescences. This study examines whether both principles find a concrete ontogenetic correlate in inflorescence development.