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We studied the D3-type cyclin function during gynoecium development in Arabidopsis and how they are related to the hormone cytokinin and the transcription factor SPATULA. Growth throughout the life of plants is sustained by cell division and differentiation processes in meristematic tissues. In Arabidopsis, gynoecium development implies a multiphasic process where the tissues required for pollination, fertilization, and seed development form. The Carpel Margin Meristem (CMM) is a mass of undifferentiated cells that gives rise to the gynoecium internal tissues, such as septum, ovules, placenta, funiculus, transmitting tract, style, and stigma. Different genetic and hormonal factors, including cytokinin, control the CMM function. Cytokinin regulates the cell cycle transitions through the activation of cell cycle regulators as cyclin genes. D3-type cyclins are expressed in proliferative tissues, favoring the mitotic cell cycle over the endoreduplication. Though the role of cytokinin in CMM and gynoecium development is highly studied, its specific role in regulating the cell cycle in this tissue remains unclear. Additionally, despite extensive research on the relationship between CYCD3 genes and cytokinin, the regulatory mechanism that connects them remains elusive. Here, we found that D3-type cyclins are expressed in proliferative medial and lateral tissues. Conversely, the depletion of the three CYCD3 genes showed that they are not essential for gynoecium development. However, the addition of exogenous cytokinin showed that they could control the division/differentiation balance in gynoecium internal tissues and outgrowths. Finally, we found that SPATULA can be a mechanistic link between cytokinin and the D3-type cyclins. The data suggest that the role of D3-type cyclins in gynoecium development is related to the cytokinin response, and they might be activated by the transcription factor SPATULA.

SUMMARY Fruit morphogenesis is determined by the coordination of cell division and expansion, which are fundamental processes required for the development of all plant organs. Here, we show that the regulation of TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) LANCEOLATE (TCP2/LA) by miR319 is crucial for tomato fruit morphology. The loss of miR319 regulation in the semi‐dominant La mutant led to a premature SlTCP2/LA expression during gynoecium patterning, which results in modified cell division during carpel development. As a consequence, La mutants exhibited elongated ovary and fruit shape, and a reduced number of ovules and seeds. Elongated fruit shape in La may be partially due to the SlTCP2/LA‐mediated repression of OVATE activity in young floral buds. Further analysis showed that the de‐repression of SlTCP2/LA decreases auxin responses in young floral buds by directly repressing SlYUCCA4 expression, but SlTCP2/LA also acts in parallel with ENTIRE (E) to orchestrate fruit morphology and seed production. Our study defines a novel miRNA‐based molecular link between the domestication‐associated OVATE gene and auxin responses. Given the striking variation in fruit morphology among members of the Solanaceae family, fine‐tuning regulation of gene expression by miRNA coupled with modulation of auxin dynamics may be a common driver in the evolution of fruit shape diversity. [ABSTRACT FROM AUTHOR]

The new species, Paepalanthus fonsecae (Eriocaulaceae), is described and illustrated. It is placed in P. sect. Conodiscus due to its dimerous flowers, subcylindrical receptacles, and a gynoecium with the nectariferous branches of the style inserted below the level of the short stigmas on the fused portion of the style. The new species is compared with similar congeners, especially P. echinoides, from which it is mainly distinguished by having an elongated aerial stem covered by membranaceous and flat leaves, and the inflorescences consisting of usually fewer but longer scapes, each subtending a wider capitulum with elliptic involucral bracts. Paepalanthus fonsecae is known from two collections from central Brazil in the municipalities of Alto Paraíso de Goiás and Cavalcante and, according to IUCN criterion B, it should be treated as critically endangered (CR). Detailed comments on the species' distribution and morphology, along with new anatomical and palynological data, are provided. [ABSTRACT FROM AUTHOR]

Summary: Fate determination is indispensable for the accurate shaping and specialization of plant organs, a process critical to the structural and functional diversity in plant kingdom. The TEOSINTE BRANCHED 1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) family of transcription factors has been recognized for its significant contributions to plant organogenesis and morphogenesis. Recent research has shed light on the pivotal roles that TCPs play in fate determination. In this review, we delve into the current understanding of TCP functions, emphasizing their critical influence on fate determination from the organelle to the cell and organ levels. We also consolidate the molecular mechanisms through which TCPs exert their regulatory effects on fate determination. Additionally, we highlight intriguing points of TCPs that warrant further exploration in future research endeavors. [ABSTRACT FROM AUTHOR]

SUMMARY: The bilateral‐to‐radial symmetry transition occurring during the development of the Arabidopsis thaliana female reproductive organ (gynoecium) is a crucial biological process linked to plant fertilization and seed production. Despite its significance, the cellular mechanisms governing the establishment and breaking of radial symmetry at the gynoecium apex (style) remain unknown. To fill this gap, we employed quantitative confocal imaging coupled with MorphoGraphX analysis, in vivo and in vitro transcriptional experiments, and genetic analysis encompassing mutants in two bHLH transcription factors necessary and sufficient to promote transition to radial symmetry, SPATULA (SPT) and INDEHISCENT (IND). Here, we show that defects in style morphogenesis correlate with defects in cell‐division orientation and rate. We showed that the SPT‐mediated accumulation of auxin in the medial‐apical cells undergoing symmetry transition is required to maintain cell‐division‐oriented perpendicular to the direction of organ growth (anticlinal, transversal cell division). In addition, SPT and IND promote the expression of specific core cell‐cycle regulators, CYCLIN‐D1;1 (CYC‐D1;1) and CYC‐D3;3, to support progression through the G1 phase of the cell cycle. This transcriptional regulation is repressed by auxin, thus forming an incoherent feed‐forward loop mechanism. We propose that this mechanism fine‐tunes cell division rate and orientation with the morphogenic signal provided by auxin, during patterning of radial symmetry at the style. Significance Statement: Our work reveals the cellular basis underpinning a bilateral‐to‐radial symmetry transition occurring during the development of the Arabidopsis female reproductive organ. To promote the medial‐apical fusion of the developing carpels, two bHLH transcription factors, SPATULA and INDEHISCENT, orchestrate auxin accumulation in specific cells to maintain anticlinal cell‐division orientation and fine‐tune progression through the G1 cell‐cycle phase via an Incoherent type‐I Feed‐Forward Loop (I‐IFFL). [ABSTRACT FROM AUTHOR]

A new species of Magnolia (Magnoliaceae) from Antioquia Province in Colombia is described and illustrated. Magnolia amalfiensis, known only from two small populations at elevations of 1,700–2,400 m in the Central Cordillera, is distinguished in having a gynoecium covered by sericeous pubescence, except at the apex of the stigmas. This species is similar to Magnolia henaoi, but the two species differ in number of bracts, size and number of petals, and number of carpels per fruit. Magnolia amalfiensis is placed in Section Talauma based on its stipules, which are adnate along the full length of the petiole, and its stamens, which lack a long filiform connective appendage. This new species increases the total number of Magnolia species from Colombia to 42, of which 15 occur in Antioquia Province. Information about the ecology and conservation status of the new species and its risk category, according to IUCN criteria, is also provided. [ABSTRACT FROM AUTHOR]

Heterochrony acts as a fundamental process affecting the early development of organisms in creating a subtle shift in the timing of initiation or the duration of a developmental process. In flowers this process is linked with mechanical forces that cause changes in the interaction of neighbouring floral organs by altering the timing and rate of initiation of organs. Heterochrony leads to a delay or acceleration of the development of neighbouring primordia, inducing a change in the morphospace of the flowers. As changes in the timing of development may affect organs differently at different stages of development, these shifts eventually lead to major morphological changes such as altered organ positions, fusions, or organ reductions with profound consequences for floral evolution and the diversification of flowers. By concentrating on early developmental stages in flowers it is possible to understand how heterochrony is responsible for shifts in organ position and the establishment of a novel floral Bauplan. However, it remains difficult to separate heterochrony as a process from pattern, as both are intimately linked. Therefore it is essential to connect different patterns in flowers through the process of developmental change. Examples illustrating the importance of heterochronic shifts affecting different organs of the flower are presented and discussed. These cover the transition from inflorescence to flower through the interaction of bracts and bracteoles, the pressure exercised by the perianth on the androecium and gynoecium, the inversed influence of stamens on petals, and the centrifugal influence of carpels on the androecium. Different processes are explored, including the occurrence of obdiplostemony, the onset of common primordia, variable carpel positions, and organ reduction and loss. [ABSTRACT FROM AUTHOR]

Rhododendron is a traditional ornamental and medicinal plant in China, renowned for its aesthetic appeal and therapeutic properties. Regarding Rhododendron decorum Franch., mainly distributed in Yunnan Province, its corolla is regarded as an edible food by the Bai ethnic group in Yunnan Province. However, it is still unclear why the Bai people choose to use the Rhododendron species in their seasonal diet. Here, we employed comparative metabolomics analysis to explore the variations in the metabolites and the enriched biosynthesis pathways within the different floral organs of R. decorum Franch. from Heqing and Yulong County. The metabolite analysis showed that 1340 metabolites were identified from the floral organs in the two regions. Comparing the different flower organs of the same region, 85 differential accumulated metabolites (DAMs) were found from the androecium/gynoecium and corolla in the same region, and 66 DAMs were identified from the same organ in different regions. The KEGG pathway and network analysis revealed significant disparities in both the metabolite composition and enriched pathways among the different floral organs or when comparing the same floral organs across diverse regions, with geographical variations exerting even stronger influences. From the perspective of resource utilization, it was observed that the R. decorum Franch. populations in Heqing County exhibited the greater accumulation of secondary metabolites within their flowers, rendering them more advantageous for medicinal purposes, albeit potentially more toxic. This study provides novel insights into the utilization of corollaries for potential de novo pharmacy development. [ABSTRACT FROM AUTHOR]

Tetradium, a genus within Rutaceae, comprises nine species found in Eastern and Southeastern Asia, distinguished by their opposite pinnate leaves and apocarpous or subapocarpous gynoecium with follicular fruits. While Hartley's 1981 monograph provided foundational insights, a comprehensive phylogenetic analysis of the genus is lacking. Using next‐generation sequencing (NGS), this study aims to (i) establish an NGS molecular data set for Tetradium, (ii) elucidate interspecific relationships via the hybrid capture method and (iii) investigate the taxonomic status of Euodia meliifolia var. celebica. Our data set comprised 28 samples across nine species, sequenced using Illumina Miseq and Hiseq 4000 platforms, with downstream analyses conducted using the HybPhyloMaker pipeline and ASTRAL. Our findings revealed five main groups supported by both molecular and morphological data, highlighting changes in ovule number and seed functionality. Notably, the hybrid capture method proved invaluable for studying old herbarium specimens. Finally, taxonomic revisions were proposed, including the reclassification of E. meliifolia var. celebica as Tetradium celebicum, the fossil Euodia costata as Tetradium costatum, and the fossil Euodia lignata as Tetradium lignatum. An updated description for T. celebicum, supplemented by a specific identification key, is provided. [ABSTRACT FROM AUTHOR]

The style and stigma at the apical gynoecium are crucial for flowering plant reproduction. However, the mechanisms underlying specification of the apical gynoecium remain unclear. Here, we demonstrate that Class II TEOSINTE BRANCHED 1/CYCLOIDEA/PCF (TCP) transcription factors are critical for apical gynoecium specification in Arabidopsis (Arabidopsis thaliana). The septuple tcp2 tcp3 tcp4 tcp5 tcp10 tcp13 tcp17 (tcpSEP) and duodecuple tcp2 tcp3 tcp4 tcp5 tcp10 tcp13 tcp17 tcp24 tcp1 tcp12 tcp18 tcp16 (tcpDUO) mutants produce narrower and longer styles, while disruption of TCPs and CRABS CLAW (CRC) or NGATHAs (NGAs) in tcpDUO crc or tcpDUO nga1 nga2 nga4 causes the apical gynoecium to be replaced by lamellar structures with indeterminate growth. TCPs are predominantly expressed in the apex of the gynoecium. TCP4 interacts with CRC to synergistically upregulate the expression level of NGAs, and NGAs further form high-order complexes to control the expression of auxin-related genes in the apical gynoecium by directly interacting with TCP4. Our findings demonstrate that TCP4 physically associates with CRC and NGAs to control auxin biosynthesis in forming fine structures of the apical gynoecium. High-order complexes of transcription factors synergistically promote auxin biosynthesis, finely tuning the development of the apical gynoecium in Arabidopsis. [ABSTRACT FROM AUTHOR]

Plants generate their reproductive organs, the stamens and the carpels, de novo within the flowers that form when the plant reaches maturity. The carpels comprise the female reproductive organ, the gynoecium, a complex organ that develops along several axes of polarity and is crucial for plant reproduction, fruit formation, and seed dispersal. The epigenetic trithorax group (trxG) protein ULTRAPETALA1 (ULT1) and the GARP domain transcription factor KANADI1 (KAN1) act cooperatively to regulate Arabidopsis thaliana gynoecium patterning along the apical-basal polarity axis; however, the molecular pathways through which this patterning activity is achieved remain to be explored. In this study, we used transcriptomics to identify genome-wide ULT1 and KAN1 target genes during reproductive development. We discovered 278 genes in developing flowers that are regulated by ULT1, KAN1, or both factors together. Genes involved in developmental and reproductive processes are overrepresented among ULT1 and/or KAN1 target genes, along with genes involved in biotic or abiotic stress responses. Consistent with their function in regulating gynoecium patterning, a number of the downstream target genes are expressed in the developing gynoecium, including a unique subset restricted to the stigmatic tissue. Further, we also uncovered a number of KAN1- and ULT1-induced genes that are transcribed predominantly or exclusively in developing stamens. These findings reveal a potential cooperative role for ULT1 and KAN1 in male as well as female reproductive development that can be investigated with future genetic and molecular experiments.

Introduction. Campanula alpina is a perennial herbaceous bellflower grown in the Eastern Alps, Carpathians, and Balkans. Fruit in Campanula species opens by the hippocrepiform slits in the fruit wall, which are formed by axicorns, elongated structures inside the ovary composed of lignified parenchyma cells. Our objectives were to reveal the fruit structure and dehiscence mode in C. alpina and compare it with C. latifolia, a type species of the genus Campanula. Materials and methods. Flowers and fruits at different stages of morphogenesis of C. alpina subsp. alpina were examined. Plant materials were sampled in two plots in the Chornohora massif of the Ukrainian Carpathians. Results. Contrary to other Campanula species, in C. alpina only the basal part of the ovary is fused with the calyx forming the flattened ovary base. The placentation is axile, the fruit wall and septas are parenchymatous, only axicorns are lignified. Dehiscence of the hanged fruit proceeds by the curving of axicorns outside by drying. In the dehiscent capsule viewed from above, hollow openings in the horizontal ovary base are exposed, and the curved axicorns attached to the crumpled fragments of the ovary wall are visible inside the ovary. Discussion. The dehiscence of the fruit in C. alpina proceeds through septifragal and hippocrepiform slits like in C. latifolia. The main differences are that the ovary is mostly superior, openings are located on the horizontal ovary base, and valves together with axicorns curve inside the ovary. The semi-inferior or nearly superior ovary insertion could be traced in illustrations in digital databases and researches for some taxa of Campanula section Medium. No issues have been made on the evolution of the ovary position in Campanuleae, since only the inferior ovary was referred for this tribe before the present article. The functional implications of shifts in the ovary position in C. alpina could be a result of selection of the pollination mechanism, or dissemination mode. Conclusions. The peculiarity of the fruit in C. alpina is the axicorns curving inside the ovary during the dehiscence. It is expected that deviation from the inferior ovary will be confirmed in other related species of the Campanula with pendent fruits. No argumentation about the evolution of secondary hypogyny in Campanula has been proposed so far.

Flowers are plant structures characteristic of the phylum Angiosperms composed of organs thought to have emerged from homologous structures to leaves in order to specialize in a distinctive function: reproduction. Symmetric shapes, colours, and scents all play important functional roles in flower biology. The evolution of flower symmetry and the morphology of individual flower parts (sepals, petals, stamens, and carpels) has significantly contributed to the diversity of reproductive strategies across flowering plant species. This diversity facilitates attractiveness for pollination, protection of gametes, efficient fertilization, and seed production. Symmetry, the establishment of body axes, and fate determination are tightly linked. The complex genetic networks underlying the establishment of organ, tissue, and cellular identity, as well as the growth regulators acting across the body axes, are steadily being elucidated in the field. In this review, we summarise the wealth of research already at our fingertips to begin weaving together how separate processes involved in specifying organ identity within the flower may interact, providing a functional perspective on how identity determination and axial regulation may be coordinated to inform symmetrical floral organ structures. [ABSTRACT FROM AUTHOR]

Simple Summary: Flowers are attractive to many people mainly due to their colourful and conspicuous perianth, which is closely related to successful insect pollination in extant angiosperms. The Lower Cretaceous Yixian Formation (125 million years ago) in Northeastern China is famous for its great diversity of early angiosperms. However, unlike typical flowers in extant angiosperms, the previously documented fossil flowers are usually famous for their "nakedness", namely, they do not have typical petals (corolla), suggesting a pollination strategy for early angiosperms that is different than that of the extant angiosperms. However, without fossil evidence, whether there are petals (corolla) and whether androecium and gynoecium are protected in early flowers are rarely addressed questions. Here, we document a flower bud fossil, Archaebuda cretaceae sp. nov., from the Yixian Formation, which is the second case in the Formation. While reinforcing the truthful occurrence of fragile flower buds in the Early Cretaceous, new fossil evidence demonstrates the existence of gynoecium and possible androecium within the flower bud, suggestive of the possible bisexuality and the protection function of petals in Archaebuda, just as in extant flowers. In addition, it is very likely that conspicuous petals may have played an important role in attracting insects for successful pollination in early angiosperms. Therefore, the occurrence of petals (corolla) in Archaebuda cretaceae sheds a new light on the reproduction of early angiosperms. The Yixian Formation (Lower Cretaceous) in China is famous worldwide for its fossils of early angiosperms, but there has been only one record of flower buds (Archaebuda lingyuanensis) hitherto, in which only the surface of the flower bud was documented while no internal details were known. Such a partial knowledge of flower buds hinders our understanding of the evolution of flowers, and this knowledge lacuna needs to be filled. Our new specimen was collected from an outcrop of the Yixian Formation (Barremian–Aptian, Lower Cretaceous) near Dawangzhangzi, Lingyuan, Liaoning, China. Our observations reveal a new fossil flower bud, Archaebuda cretaceae sp. nov., from the Lower Cretaceous of China. This new record of Archaebuda in the Yixian Formation not only confirms the truthful existence of the expected gynoecium (plus possible androecium) in a flower bud but also underscores the occurrence of typical flowers in the Early Cretaceous. This new information adds first-hand data to flower sexuality, pollination, and evolution. [ABSTRACT FROM AUTHOR]

Key message: EXPANSIN15 is involved in petal cell morphology and size, the fusion of the medial tissues in the gynoecium and expansion of fruit valve cells. It genetically interacts with SPATULA and FRUITFULL. Cell expansion is fundamental for the formation of plant tissues and organs, contributing to their final shape and size during development. To better understand this process in flower and fruit development, we have studied the EXPANSIN15 (EXPA15) gene, which showed expression in petals and in the gynoecium. By analyzing expa15 mutant alleles, we found that EXPA15 is involved in petal shape and size determination, by affecting cell morphology and number. EXPA15 also has a function in fruit size, by affecting cell size and number. Furthermore, EXPA15 promotes fusion of the medial tissues in the gynoecium. In addition, we observed genetic interactions with the transcription factors SPATULA (SPT) and FRUITFULL (FUL) in gynoecium medial tissue fusion, style and stigma development and fruit development in Arabidopsis. These findings contribute to the importance of EXPANSINS in floral and fruit development in Arabidopsis. [ABSTRACT FROM AUTHOR]

Basal angiosperms is a paraphyletic group of plants before branching eudicots and monocots. This group of angiosperms is of great scientific interest because it is the most ancient representative of the flowering plants retained for today. In Ukraine, both ANA-grade and magnoliids are presented. The species diversity of basal angiosperms is about half a percent of the flora of vascular plants of Ukraine, which caused a low research activity on this subject. The objectives of the present study were to elucidate the morphological diversity of fruits within basal angiosperms inhabiting Ukraine and estimate their evolutionary level and adaptations. The morphological diversity of fruit, according to our concept, comprises the structure of the gynoecium, ovary insertion, placentation, ovule number (pre-anthetic features), as well as principal fruit type and morphological adaptations for dispersal (post-anthetic features). The principal fruit types were distinguished according to the principles established previously for classifying fruits of monocots and rosids of the flora of Ukraine. Within the basal angiosperms of the flora of Ukraine, four principal fruit types were established: aggregate fruit, capsule, berry, and one-seeded fruit. Among them, the aggregate fruits are the most numerous. In Nymphaeaceae and Aristolochiaceae, which belong to the native flora of Ukraine, fruits are syncarpous, multi-seeded and inferior, while in the families cultivated in Ukraine (Annonaceae, Magnoliaceae, Calycanthaceae, Schisandraceae, and Lauraceae) fruits are apocarpous, superior and often have low seed number in a carpel. Each family has peculiar gynoecium and fruit features, which can be advanced as well as ancestral. In this article, the carpological spectrum was created to reveal the distribution of principal fruit types in families, genera, and species of the basal angiosperms of the flora of Ukraine. In these spectra, aggregate fruits are the most numerous; however, they occur in families of cultivated flora only. Most species have adaptation for dispersal by animals (birds or ants). The conclusion was made that in the native flora of Ukraine, the most derived members of basal angiosperms are retained.

Since the 19th century, we have had countless debates, sometimes acrimonious, about the nature of the gynoecium. A pivotal question has been whether all angiosperms possess carpels or if some or all angiosperms are acarpellate. We can resolve these debates if we do not define the carpel as a closed megasporophyll but simply as an appendage that encloses the placenta or a single ovule. This redefinition may, however, lead to confusion because often it may not be clear whether the traditional (classical) definition of the carpel or the redefinition is implied. Therefore, a topographic approach is proposed that is compatible with the redefinition. According to this approach, gynoecia comprise one or more gynoecial appendages and placentas or single ovules that may be formed in different positions. Heterotopy refers to these different positions. In the context of evo-devo, which explores evolutionary changes in development, morpho evo-devo delves into spatial shifts of the placentas and ovules leading to heterotopy. Furthermore, it considers shifts in timing (heterochrony) and other processes leading to heteromorphy. Recognizing spatial shifting of the placentas or a single ovule and other evolutionary processes opens up new vistas in the search for the ancestor(s) of angiosperms and their gynoecia. [ABSTRACT FROM AUTHOR]

The morphologically heterogeneous family Rosaceae is, among others, characterized by differently shaped floral axes through different growth of the same. A central conical proliferation bearing the choricarpous gynoecium (as in Fragaria, Geum, Potentilla or Rubus) may also be missing. Members of tribe Maleae (as Crataegus, Malus, Pyrus) have an inferior ovary, i.e. a gynoecial hypanthium. One character, however, distinguishes all representatives of Rosaceae: a perigynous hypanthium, on which upper rim perianth members and stamens are borne. Its shape varies from discto bowl- to tube- to urn-shaped. Studying the nectary in 19 genera (36 species) covering all presently accepted subfamilies and a large part of the tribes of Rosaceae (for six smaller tribes within Amygdaloideae reliable data were evaluated from the literature) we can conclude that if nectar is present in flowers of Rosaceae, it is secreted from a mesophyllary nectary located in or on the inner side of the perigynous hypanthium (receptacle). The differences of the hypanthial nectaries in the various genera/species lie only in the size of the nectary tissue, its exact location on the perigynous hypanthium, its degree of protrusion (flush or non-flush with the inner hypanthial wall), in the nectary slits (sunken between the epidermal cells or not), hairs around the nectary (present or absent on perigynous hypanthium or on/among carpels) and the striation of the nectary epidermal cells. We found no evidence of involvement of other tissues in the nectary. In many cases, the nectary extends from beneath the filament bases to the gynoecium. In some cases, filament bases interrupt the nectary and cause an undulating upper border of the nectary (e.g. in Crataegus, Fragaria, Geum). In Cydonia and Pyrus, a distinct proliferation of the upper part of the hypanthium bears part of the nectary and surrounds as annular bulge the styles, but stylar or ovarian tissue do not contribute to the nectary. Some genera can be characterized by a unique position of the nectary in correlation with the shape of the perigynous hypanthium. In Geum and Waldsteinia (Colurneae), the nectary is formed as a groove in front of the inner filaments along the upper edge of the perigynous hypanthium. The genus Rosa is characterized by an urn-shaped perigynous hypanthium, whose throat usually is almost closed by a thick proliferation of the floral axis that may be the site of only remnants of a nectary. The urn-shaped perigynous hypanthium of Rosa, unique in Rosaceae, forces the long styles of the individual carpels to "squeeze" through the narrow orifice. This achieves the advantageous close proximity of the stigmata, so that the capitate stigmas an outer compitum, a compensation of the disadvantage of a choricarpous gynoecium. What is the selective advantage of nectar secretion in pollen flowers? Nectar production In Rosaceae may be poor and limited mainly to the female phase of the mostly proterogynous flowers. In this way, the attractiveness of the flower is also assured in the non-pollen presenting phase. In addition, during searching for the sparse nectar the insect may come into contact with several stigmata thus compensating the economic disadvantage of a choricarpous compared to a coenocarpous gynoecium. [ABSTRACT FROM AUTHOR]

Lauraceae have one of the oldest fossil records of angiosperms with the earliest known evidence from the mid-Cretaceous. However, most of these records are based on leaves, especially from the Cenozoic of Asia, which are often challenging to assign to extinct or extant genera or species. In contrast, fossils of reproductive organs are more informative, but remain scarce. We here described the first Cenozoic Lauraceae flower of Asia and confirmed the presence of Cryptocarya in the Miocene Zhangpu flora (Fujian Province, south-eastern China) based on an amber inclusion. We scanned the specimen using synchrotron radiation-based micro-computed tomography (SRμCT) and then compared the fossil with extant flowers of the genus. The present fossil flower is small, bisexual, and polysymmetric, with a whorled and trimerous perianth and androecium along with a hypanthium around the gynoecium. The perianth comprises six undifferentiated tepals, the androecium consists of nine stamens and three innermost staminodes, and the gynoecium of a single carpel with a superior, unilocular (and uniovulate) ovary. Our study also shows that the fossil shares an unusual position of the typical staminal glands and a short androecial tube on the rim of the hypanthium with at least one extant Australian species of Cryptocarya, which have not been reported before. Nowadays, Lauraceae are still present in tropical to subtropical regions, mostly in American and Asian rainforests. The discovery of many Lauraceae leaf fossils in Zhangpu, as well as the amber flower of this study, is consistent with the current reconstruction of the amber source environment as a megathermal seasonal rainforest during the Mid-Miocene. [ABSTRACT FROM AUTHOR]

Species of Cyperoideae exhibit wide morphological variation in their flowers due to reduction processes. Their flowers can be bisexual or unisexual, achlamydeous or not, with tepals and stamens varying from one to six and a trimerous or dimerous gynoecium, the latter dorsiventrally or laterally flattened. We studied the floral anatomy and vasculature of Fuirena robusta , Cyperus sesquiflorus , Rhynchospora panicoides , and Schoenoplectus californicus to understand the reduction processes that resulted in different floral morphologies. The floral development of C. sesquiflorus was also analysed. All these species have spikelets with bisexual flowers, but they vary in relation to the perianth, androecium, and gynoecium. Our results show the loss of the outer abaxial tepal in R. panicoides , the total loss of the outer whorl of tepals in F. robusta , and the loss of abaxial tepals (outer and inner) in S. californicus. The tepals are vascularized in F. robusta and R. panicoides and non-vascularized in S. californicus. In C. sesquiflorus , the perianth is absent. Phenolic compounds present in the epidermal cells of the receptacle mark the boundaries between tepals and stamens, before the individualization of these parts. The three stamens present in F. robusta and R. panicoides correspond to the outer whorl. In S. californicus , there is a loss of the adaxial stamens (outer and inner), whereas in C. sesquiflorus the outer stamen whorl and the inner adaxial stamen are lost. The laterally flattened dimerous gynoecium in C. sesquiflorus may be the result of the pressure exerted by the distichously arranged glumes. The most distal flower of the spikelet in this species is staminate by abortion of the gynoecium. The morphological diversity observed in the flowers of Cyperoideae is the result of distinct reduction processes that probably occurred independently in the different clades of the subfamily during the evolution of Cyperaceae. [ABSTRACT FROM AUTHOR]

Introduction. Rosids is the pivotal clade of eudicots, whose taxonomic composition was significantly changed based on molecular phylogeny. Molecular insight led to the re-evaluation of many phenotypic features, especially in reproductive morpho­logy. Although the floral structure and evolution within the current scope of rosids were actively investigated, the morphological structure of fruit was almost fully neglected. The present study aimed to survey the morphological diversity of fruits in rosids (subclass Rosidae) in the flora of Ukraine to reveal the most common fruit types, analyze the distribution of the basic fruit types among rosids, and survey some comparative-morphological features of gynoecium and fruit. Materials and Methods. Fruit features have been surveyed based on many carpological sources. We also analyzed the gynoecium characteristics crucial for fruit deve­lop­ment, i.e., the type of ovary insertion, placentation, and ovule and locule number. For Rosidae, seven basic fruit types were recognized using the approach previously elaborated for the monocot plants of Ukraine: aggregate fruit, multi-seeded monocarp, capsule, berry, multi-seeded pyrenarium, schizocarp, and one-seeded fruit. Results. As a result, the annotated list of morphological characteristics for each of the 54 families of Rosidae occurring in Ukraine was composed. In this list, the complementary and the most contrasting definitions of fruits from different sources were combined. Discussion. According to our calculations, the subclass Rosidae in the flora of Ukraine is represented by 326 genera and at least 1617 species. Our results demon­strated that the most widespread fruit types at the family level seem to be capsular and one-seeded fruits, while at genus and species level the portion of multi-seeded monocarps and aggregate fruits is also significant. Nine families reveal more than one basic fruit type in the flora of Ukraine. Some fruits are ambiguously classified into one or another fruit type because of their intermediate features. Thus, fuzzy boundaries between most fruit types are evident. Conclusions. The obtained results have been compared with our previously reported results for the monocot clade in the flora of Ukraine. In both cases, the predominance of capsular fruits at the family-level spectrum of basic fruit types was clearly demonstrated. The results of our analysis suggest that the model of basic fruit types has the potential to be applied to the formal treatment of fruit structure in other groups of angiosperms.

Flowers are plant structures characteristic of the phylum Angiosperms composed of organs thought to have emerged from homologous structures to leaves in order to specialize in a distinctive function: reproduction. Symmetric shapes, colours, and scents all play important functional roles in flower biology. The evolution of flower symmetry and the morphology of individual flower parts (sepals, petals, stamens, and carpels) has significantly contributed to the diversity of reproductive strategies across flowering plant species. This diversity facilitates attractiveness for pollination, protection of gametes, efficient fertilization, and seed production. Symmetry, the establishment of body axes, and fate determination are tightly linked. The complex genetic networks underlying the establishment of organ, tissue, and cellular identity, as well as the growth regulators acting across the body axes, are steadily being elucidated in the field. In this review, we summarise the wealth of research already at our fingertips to begin weaving together how separate processes involved in specifying organ identity within the flower may interact, providing a functional perspective on how identity determination and axial regulation may be coordinated to inform symmetrical floral organ structures.

Background and aims: The onion (Allium cepa var. cepa) is an allogamous species in which male-sterile lines have been developed. However, the structure of the flower and floral nectaries have only been briefly described. The objective of this study is to update the floral anatomy data, comparing the gynoecium and androecium of male-fertile and male-sterile lines, and to analyze the three-dimensional structure of the floral nectary. M&M: Conventional optical and scanning electron microscopy techniques were used. Results: Fertile and sterile male flowers have the same structural organization. The septal or gynopleural nectary is organized in three zones: 1) production area formed by the glandular tissue arranged radially in the septa of the ovary, 2) discharge zone: a small channel at the apex connects the nectariferous tissue with the pocket formed between the ovary wall and the overlying ridge, and 3) presentation and harvest zone, where the excreted nectar accumulates, formed between the widened base of the inner staminal filaments opposite the ovary. Conclusions: The only anatomical differences in the flowers sterile male lines are the lack of pollen production and the absence of dehiscence, despite having a normal stomium and anther wall. The floral nectaries of onion are a clear example of secondary presentation of nectar. [ABSTRACT FROM AUTHOR]

The appearance of the flower marks a key event in the evolutionary history of plants. Among the four types of floral organs, the gynoecium represents the major adaptive advantage of the flower. The gynoecium is an enclosing structure that protects and facilitates the fertilization of the ovules, which then mature as seeds. Upon fertilization, in many species, the gynoecium itself eventually becomes the fruit, which contributes to the dispersal of the seeds. However, despite its importance and the recent advances in our understanding of the genetic regulatory network guiding early gynoecium development, many questions remain to be resolved regarding the extent of the conservation of the molecular mechanisms for gynoecium development among different taxa, and how these mechanisms give origin and diversification to the gynoecium. In this review, we compile the existing knowledge about the evolution, development, and molecular mechanisms involved in the origin and evolution of the gynoecium. [ABSTRACT FROM AUTHOR]

The vascular anatomy and morphology structure of the Allium sativum flower were studied. New morphological features were investigated for taxonomy in Amaryllidaceae. 15 flowers of Allium sativum were sectioned using standard methods of Paraplast embedding and serial sectioning at 20 mm thickness. Sections were stained with Safranin and Astra Blau and mounted in Eukitt. We find three vertical zones in the Allium sativum gynoecium: synascidiate, symplicate and hemisymplicate. The micromorphology and vascular flower anatomy were described by using flowers transverse sections. The Allium sativum peduncle contains 6 vascular bundles - three large and three small ones, which branch out and form a circle of vascular bundles - a vascular cylinder, from which at the level of the peduncle they depart six pairs of vascular bundles, traces of tepals, traces of stamens and above - traces of dorsal carpel bundles. Stamens depart from the ovary wall. In the center of the ovary, there remains a circle of small vascular bundles- the roots of the ventral complex, which were reorganized above, with the appearance of locules, into ventral carpel bundles, which supplied ovules and end blindly. In the same way, the dorsal carpel bundles also end blindly. The trace of the ovules was single-bundle. The traces of the dorsal carpel bundles were single-bundled. There were 6 ovules, 2 ovules in each locule. Traces of stamens and traces of inner and outer tepals were single-bundled. The study of new features of vascular anatomy and flower morphology will make a significant contribution to the taxonomy of the Amaryllidaceae family. [ABSTRACT FROM AUTHOR]

Premise: Recent studies of floral disparity in the asterid order Ericales have shown that flowers vary strongly among families and that disparity is unequally distributed between the three flower modules (perianth, androecium, gynoecium). However, it remains unknown whether these patterns are driven by heterogeneous rates of morphological evolution or other factors. Methods: Here, we compiled a data set of 33 floral characters scored for 414 species of Ericales sampled from 346 genera and all 22 families. We conducted ancestral state reconstructions using an equal‐rates Markov model for each character. We estimated rates of morphological evolution for Ericales and for a separate angiosperm‐wide data set of 19 characters and 792 species, creating "rate profiles" for Ericales, angiosperms, and major angiosperm subclades. We compared morphological rates among flower modules within each data set separately and between data sets, and we compared rates among angiosperm subclades using the angiosperm data set. Results: The androecium exhibits the highest evolutionary rates across most characters, whereas most perianth and gynoecium characters evolve more slowly in both Ericales and angiosperms. Both high and low rates of morphological evolution can result in high floral disparity in Ericales. Analyses of an angiosperm‐wide floral data set reveal that this pattern appears to be conserved across most major angiosperm clades. Conclusions: Elevated rates of morphological evolution in the androecium of Ericales may explain the higher disparity reported for this floral module. Comparing rates of morphological evolution through rate profiles proves to be a powerful tool in understanding floral evolution. [ABSTRACT FROM AUTHOR]

Based on the suggestion that flower and fruit are integrally evolving structures, we aimed to reveal the floral traits persisting in the fruit structure in Iris pseudacorus, a widely distributed riparian species in Ukraine. We intended to compare the results with the other Iris species studied previously and reveal the constancy of micromorphological features of fruit interior structure. We revealed exomorphological and micromorphological peculiarities of the fruiting ovary using the model of vertical zonality of the gynoecium, vascular anatomy, and general anatomy of the fruit wall. In the fruiting ovary of I. pseudacorus, we revealed the presence of three vertical zones: short synascidiate zone, long symplicate zone bearing uniseriate seeds, and hemisymplicate zone located in the fruit beak. The vascular system of the ovary is composed of dorsal, septal, and ventral veins. Each of three dorsal veins divides radially into the outer tepal trace, stamen trace, and dorsal carpellary bundle, while each septal vein divides tangentially into three bundles of the inner tepal trace. Paired ventral veins enter the ovary from its bottom and supply ovules and seeds. The exocarp is composed of polygonal cells with thickened cellulose walls. The endocarp is uniseriate, unlignified, and composed of live prosenchymal cells, which are elongated tangentially. In the parenchymatous mesocarp, a great number of secretory canals with tannin-like content occur. The dehiscence of fruit on three valves proceeded by both dorsal and ventral slits. Dorsal slits are formed along dorsal grooves and provided by small-celled tissue surrounding the dorsal veins. The presence of ventral sutures of carpels in the symplicate zone of the ovary provides ventral dehiscence of fruit. Hence, the structure of the fruiting ovary in I. pseudacorus is comparable to that of other Iris species. Our investigation confirmed that the vertical zonality, placentation, and vascular system of the gynoecium in Iris can be appropriately estimated in the fruiting stage because the structural components of the ovary, which developed at the pre-anthetic phase, persist in the fruit. [ABSTRACT FROM AUTHOR]

Background. Monocot plants in the flora of Ukraine embrace about 1000 species. The members of this group have various fruit types and ways of dissemination. In this review, the results of the evolutionary-morphological analysis of fruits in monocot plants of the flora of Ukraine and their structural adaptations to dispersal are presented. Gynoecium structure and morphogenetic fruit types in monocots. The features of the inner gynoecium structure and the relation between gynoecium and fruit structure were analyzed, and the main problems of fruit classification were detected. It was revealed that apocarpous fruits are often polymerous or oligomerous, composed of 3–6 one-seeded fruitlets. The species with inferior ovary often develop capsular fruits. One-seeded fruits represent the most reduced variant of the gynoecium structure and fruit wall anatomy, providing few structural traits for analysis. Ecological and functional features of fruits in monocots. The characteristics of dehiscent and indehiscent fruits, as well as adaptations to various ways of dispersal: myrmeco-, endozoo-, epizoo-, anemo-, hydro- and autochory are presented. Dehiscent fruits (follicle and capsule) reveal ventral, dorsal or double, dorsoventral dehiscence. One-seeded fruits and fruitlets are often adapted to hydrochory or anemochory. Trends of evolutionary changes of fruits in monocots. The most diverse fruits are found in low-species taxa of early monocots. Within the monocots, we can observe certain evolutionary trends: incomplete carpel fusion, the occurrence of superior one-seeded fruits and inferior many-seeded fruits. Each of these trends may be evoked by adaptations for pollination in gynoecium at the flowering stage. Conclusions. The present evolutionary morphological and ecological studies of fruits in monocot plants of the flora of Ukraine are impeded by controversial structural types of the gynoecium in some species and a scarcity of data on ways of dispersal of fruits and seeds. The precise carpological and carpoecological investigations of the monocots are desirable for many plants of the flora of Ukraine.

The structural details of the gynoecium are key to understanding the reproductive systems and successful diversification of flowering plants. However, the gynoecium morpho-anatomy in South American species of Cactaceae that evolved in the Andean region remains largely unknown. Here we selected 18 species, most of them of evolutionarily related genera of Cactaceae tribe Trichocereeae, to conduct a detailed comparative study. Observations were made using light, fluorescence, differential interference contrast and scanning electron microscopy. Most of the characters of the ovary and ovule were typical of the family, except for the nucellar beak in Echinopsis aurea and E. haematantha , here reported for the first time in cacti. We found evidence suggesting that the stigmatic surface covered with multiseriate trichomes, the semi-closed style type and the pollen tube transmitting tract are conserved characters among species of Trichocereeae; this finding may be explained by a phylogenetic conservatism of the investigated genera of the tribe. We integrated the available information about structural and histological characters of the gynoecium in the family, taking into account the current phylogenetic context of the examined genera. Our results reinforce the significance of floral anatomical traits for the systematics of Cactaceae. [ABSTRACT FROM AUTHOR]

Since the 19th century, we have had countless debates, sometimes acrimonious, about the nature of the gynoecium. A pivotal question has been whether all angiosperms possess carpels or if some or all angiosperms are acarpellate. We can resolve these debates if we do not define the carpel as a closed megasporophyll but simply as an appendage that encloses the placenta or a single ovule. This redefinition may, however, lead to confusion because often it may not be clear whether the traditional (classical) definition of the carpel or the redefinition is implied. Therefore, a topographic approach is proposed that is compatible with the redefinition. According to this approach, gynoecia comprise one or more gynoecial appendages and placentas or single ovules that may be formed in different positions. Heterotopy refers to these different positions. In the context of evo-devo, which explores evolutionary changes in development, morpho evo-devo delves into spatial shifts of the placentas and ovules leading to heterotopy. Furthermore, it considers shifts in timing (heterochrony) and other processes leading to heteromorphy. Recognizing spatial shifting of the placentas or a single ovule and other evolutionary processes opens up new vistas in the search for the ancestor(s) of angiosperms and their gynoecia.

Abstract Plants generate their reproductive organs, the stamens and the carpels, de novo within the flowers that form when the plant reaches maturity. The carpels comprise the female reproductive organ, the gynoecium, a complex organ that develops along several axes of polarity and is crucial for plant reproduction, fruit formation, and seed dispersal. The epigenetic trithorax group (trxG) protein ULTRAPETALA1 (ULT1) and the GARP domain transcription factor KANADI1 (KAN1) act cooperatively to regulate Arabidopsis thaliana gynoecium patterning along the apical–basal polarity axis; however, the molecular pathways through which this patterning activity is achieved remain to be explored. In this study, we used transcriptomics to identify genome‐wide ULT1 and KAN1 target genes during reproductive development. We discovered 278 genes in developing flowers that are regulated by ULT1, KAN1, or both factors together. Genes involved in developmental and reproductive processes are overrepresented among ULT1 and/or KAN1 target genes, along with genes involved in biotic or abiotic stress responses. Consistent with their function in regulating gynoecium patterning, a number of the downstream target genes are expressed in the developing gynoecium, including a unique subset restricted to the stigmatic tissue. Further, we also uncovered a number of KAN1‐ and ULT1‐induced genes that are transcribed predominantly or exclusively in developing stamens. These findings reveal a potential cooperative role for ULT1 and KAN1 in male as well as female reproductive development that can be investigated with future genetic and molecular experiments.

Introduction: Although DNA methylation patterns are generally considered to be faithfully inherited in Arabidopsis thaliana (Arabidopsis), there is evidence of reprogramming during both male and female gametogenesis. The gynoecium is the floral reproductive organ from which the ovules develop and generate meiotically derived cells that give rise to the female gametophyte. It is not known whether the gynoecium can condition genomic methylation in the ovule or the developing female gametophyte. Methods: We performed whole genome bisulfite sequencing to characterize the methylation patterns that prevail in the genomic DNA of pre-meiotic gynoecia of wild-type and three mutants defective in genes of the RNA-directed DNA methylation pathway (RdDM): ARGONAUTE4 (AGO4), ARGONAUTE9 (AGO9), and RNA-DEPENDENT RNA POLYMERASE6 (RDR6). Results: By globally analyzing transposable elements (TEs) and genes located across the Arabidopsis genome, we show that DNA methylation levels are similar to those of gametophytic cells rather than those of sporophytic organs such as seedlings and rosette leaves. We show that none of the mutations completely abolishes RdDM, suggesting strong redundancy within the methylation pathways. Among all, ago4 mutation has the strongest effect on RdDM, causing more CHH hypomethylation than ago9 and rdr6. We identify 22 genes whose DNA methylation is significantly reduced in ago4, ago9 and rdr6 mutants, revealing potential targets regulated by the RdDM pathway in premeiotic gyneocia. Discussion: Our results indicate that drastic changes in methylation levels in all three contexts occur in female reproductive organs at the sporophytic level, prior to the alternation of generations within the ovule primordium, offering a possibility to start identifying the function of specific genes acting in the establishment of the female gametophytic phase of the Arabidopsis life cycle. [ABSTRACT FROM AUTHOR]

The mechanism of sex differentiation in androdioecy is of great significance for illuminating the origin and evolution of dioecy. Tapiscia sinensis Oliv. is a functionally androdioecious species with both male and hermaphroditic individuals. Male flowers of T. sinensis lack the ovules of gynoecia compared with hermaphrodites. To identify sex simply and accurately, and further find the potential determinants of sex differentiation in T. sinensis , we found that TsRPL10a′ , a duplicate of TsRPL10a , was a male-linked gene. The promoter (5′ untranslated region and the first intron) of TsRPL10a′ can be used to accurately identify sex in T. sinensis. TsRPL10a is a ribosomal protein that is involved in gynoecium development, and sufficient ribosomal levels are necessary for female gametogenesis. The expression level of TsRPL10a was significantly downregulated in male flower primordia compared with hermaphrodites. The RNA fluorescence in situ hybridization (FISH) assay demonstrated that TsRPL10a was almost undetectable in male gynoecia at the gynoecial ridge stage, which was a key period of ovule formation by scanning electron microscope observation. In male flowers, although the promoter activity of TsRPL10a was significantly higher than TsRPL10a′ verified by transgenic Arabidopsis thaliana , the transcriptional expression ratio of TsRPL10a was obviously lower than TsRPL10a′ and reached its lowest at the gynoecial ridge stage, indicating the existence of a female suppressor. The promoter similarity of TsRPL10a and TsRPL10a′ was only 45.29%; the genomic sequence similarity was 89.8%; four amino acids were altered in TsRPL10a′. The secondary structure of TsRPL10a′ was different from TsRPL10a , and TsRPL10a′ did not exhibit FISH and GUS expression in the gynoecium the way TsRPL10a did. From the perspective of RT-qPCR, its high expression level, followed by the low expression level of TsRPL10a in male flowers, indicates its antagonism function with TsRPL10a. The evolutionary analysis, subcellular localization and flower expression pattern suggested that TsRPL10a might be functionally conserved with AtRPL10aA , AtRPL10aB and AtRPL10aC in A. thaliana. Overall, we speculated that TsRPL10a and its duplicate TsRPL10a′ might be involved in sex differentiation by influencing gynoecium development in T. sinensis. [ABSTRACT FROM AUTHOR]

Detailed anatomical studies of flowers and fruits may render traits of phylogenetic importance, but are still rare in the Boraginales. An Old World clade of Cordia comprises many dioecious species, but the floral anatomy is largely unexplored and, hence, the structural basis for sex separation. Fresh material of buds, functionally unisexual flowers and fruits were studied using a stack shot camera. Fixed such material of Cordia crenata, C. cf. grandicalyx and C. sinensis was sectioned using a microtome and stained with safranin red and astra blue, and the gynoecial surface was studied using SEM. The stamens of the female flowers are largely intact, but do not produce pollen, whereas the gynoecium of the male flowers is highly reduced though develops ovules lacking an embryo sac. The morphologically rather unreduced stamens of the female flower may have undergone a shift of function from producing pollen towards attracting pollinators by optical signals. The outer parenchyma of the gynoecium is strongly stained and after fertilisation, one through three ovules are maturing towards seeds. The presence of more than a single seed enclosed in the undivided endocarp is rare in Cordiaceae. [ABSTRACT FROM AUTHOR]

Leiothrix differs from other genera of Eriocaulaceae by having pistillate flowers with nectariferous and stigmatic branches that diverge at different heights on the style and staminate flowers with free or fused petals. To understand the ontogenetic processes that result in these morphological variations, we studied the development and floral vasculature in six species of the genus. In pistillate flowers, the nectariferous branches, which are in a carinal position, correspond to the apex of the carpels, whereas the stigmatic branches, in a commissural position, are formed by the marginal tissues of the carpels and initiate later than the nectariferous branches. The upper margins of the carpels elongate, forming a tubular structure that raises the stigmatic branches; the greater its development, the greater the distance between the stigmatic and nectariferous branches. In staminate flowers, the fusion of the petals appears to be post-genital in the median and apical portions and congenital in the more basal portion. Despite the differences in floral development, Leiothrix shares the same pattern of floral vasculature with other genera of Eriocaulaceae, exhibiting a central vascular plexus in the receptacle from which a single trace diverges for each sepal, petal and stamen. The staminodes are not vascularized. The dorsal carpellary bundles supply the nectariferous branches, but the ventral carpel bundles are reduced and are not involved in the supply of the ovules and stigmas. The differences in the height of insertion of the nectariferous branches are probably the result of selective pressure exerted by different groups of pollinating insects. Our hypothesis is that species in which the nectariferous branches are inserted below the stigmatic branches, and are therefore less accessible, exhibit a more specialized pollination system. The absence of nectariferous branches in L. angustifolia indicates secondary loss probably associated with spontaneous geitonogamy. [ABSTRACT FROM AUTHOR]

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The floral traits and sexual allocation of plants were malleable to the environment. To explore the adaptation strategies of floral traits and sexual allocation patterns to the altitudinal gradient, we addressed the floral traits, sexual allocation patterns and reproductive output of Clematis tangutica as well as the relationships of these indexs along an elevation gradient on the eastern Qinghai-Tibet Plateau. The calyx length, width, thickness and weight, stamen and pistil length, androecium mass, sexual allocation (A/G) and seed set ratio increased as the elevation rised, but stamen and pistil numbers, gynoecium mass and fruit set decreased. As the elevation increased, the male investment of C. tangutica increased, but the female investment decreased, which showed out a trade-off strategy of the sexual allocation. The stepwise regression analysis suggested that seed set ratio was mainly affected by the attractive traits (calyx length, width and weight), pistil number and fruit set. These results suggested that the floral traits and sex allocation patterns of C. tangutica were significantly affected by changes in altitudinal gradient. Low fruit-set success in high altitude may be compensated by producing more seed-bearing fruits. The enlarged attractive organs and the decreased pistil number, and fruit set may affect reproductive success in C. tangutica by promoting successful pollination and reducing maintenance costs. Therefore, C. tangutica ensures seed-set success in extreme environment at high altitude by changing floral traits. Also, this study supported the theory that the male function could be enhanced at high altitude. [ABSTRACT FROM AUTHOR]

Locules are the seed‐bearing structure of fruits. Multiple locules are associated with increased fruit size and seed set, and therefore, control of locule number is an important agronomic trait. Locule number is controlled in part by the CLAVATA‐WUSCHEL pathway. Disruption of either the CLAVATA1 receptor‐like kinase or its ligand CLAVATA3 can cause larger floral meristems and an increased number of locules. In an EMS mutagenized population of Brassica rapa, we identified a mutant allele that raises the number of locules from four to a range of from six to eight. Linkage mapping and genetic analysis support that the mutant phenotype is due to a missense mutation in a CLAVATA 1 (CLV1) homolog. In addition to increased locule number, additional internal gynoecia are formed in brclv1 individuals, suggesting a failure to terminate floral meristem development, which results in decreased seed production. [ABSTRACT FROM AUTHOR]

In this review, the concept of fruit morphogenesis is treated in the context of implementation of the evo-devo approach in carpology. A new viewpoint on the fruit morphogenesis is proposed and justified, comprising the pre-anthetic, as well as post-anthetic periods of fruit development, id est, development of the gynoecium, and development of the fruit itself. It is proposed to recognize ontogenetical (individual) and evolutionary (historical) aspects of fruit morphogenesis, the first of them we can study directly, while the second aspect can be only hypothesized or treated as a theoretical model of fruit evolution in consequence of some presumed changes in the individual fruit morphogenesis. In this article these aspects are named as "ontomorphogenesis" and "phylomorphogenesis" of the fruit, correspondingly. Our concept of ontomorphogenesis of the fruit involves four components that could not be brought together, such as changes in the morphological structure of the gynoecium, abscission of the extragynecial floral parts and the style, histogenesis of the fruit wall and other fruit parts, and terminal stages of the fruit morphogenesis (dehiscence, splitting, or abscission). The current state of studies of these components in the individual and evolutionary contexts is discussed. By examining the patterns of fruit evolution, we should consider factors acting at both the post-anthetic and pre-anthetic periods of fruit ontomorphogenesis.

Partial or complete floral organ fusion, which occurs in most angiosperm lineages, promotes integration of whorls leading to specialization and complexity. One of the most remarkable floral organ fusions occurs in the gynostemium, a highly specialized structure formed by the congenital fusion of the androecium and the upper portion of the gynoecium. Here we review the gynostemia evolution across flowering plants, the morphological requirements for the synorganization of the two fertile floral whorls, and the molecular basis most likely responsible for such intimate fusion process. [ABSTRACT FROM AUTHOR]

IntroductionAlthough DNA methylation patterns are generally considered to be faithfully inherited in Arabidopsis thaliana (Arabidopsis), there is evidence of reprogramming during both male and female gametogenesis. The gynoecium is the floral reproductive organ from which the ovules develop and generate meiotically derived cells that give rise to the female gametophyte. It is not known whether the gynoecium can condition genomic methylation in the ovule or the developing female gametophyte.MethodsWe performed whole genome bisulfite sequencing to characterize the methylation patterns that prevail in the genomic DNA of pre-meiotic gynoecia of wild-type and three mutants defective in genes of the RNA-directed DNA methylation pathway (RdDM): ARGONAUTE4 (AGO4), ARGONAUTE9 (AGO9), and RNA-DEPENDENT RNA POLYMERASE6 (RDR6). ResultsBy globally analyzing transposable elements (TEs) and genes located across the Arabidopsis genome, we show that DNA methylation levels are similar to those of gametophytic cells rather than those of sporophytic organs such as seedlings and rosette leaves. We show that none of the mutations completely abolishes RdDM, suggesting strong redundancy within the methylation pathways. Among all, ago4 mutation has the strongest effect on RdDM, causing more CHH hypomethylation than ago9 and rdr6. We identify 22 genes whose DNA methylation is significantly reduced in ago4, ago9 and rdr6 mutants, revealing potential targets regulated by the RdDM pathway in premeiotic gyneocia. DiscussionOur results indicate that drastic changes in methylation levels in all three contexts occur in female reproductive organs at the sporophytic level, prior to the alternation of generations within the ovule primordium, offering a possibility to start identifying the function of specific genes acting in the establishment of the female gametophytic phase of the Arabidopsis life cycle.

Abstract Locules are the seed‐bearing structure of fruits. Multiple locules are associated with increased fruit size and seed set, and therefore, control of locule number is an important agronomic trait. Locule number is controlled in part by the CLAVATA‐WUSCHEL pathway. Disruption of either the CLAVATA1 receptor‐like kinase or its ligand CLAVATA3 can cause larger floral meristems and an increased number of locules. In an EMS mutagenized population of Brassica rapa, we identified a mutant allele that raises the number of locules from four to a range of from six to eight. Linkage mapping and genetic analysis support that the mutant phenotype is due to a missense mutation in a CLAVATA 1 (CLV1) homolog. In addition to increased locule number, additional internal gynoecia are formed in brclv1 individuals, suggesting a failure to terminate floral meristem development, which results in decreased seed production.

The stigma is the terminal part of the carpel which receives pollen during the pollination process. Although the role of the stigmas in pollination is the same for all angiosperms, stigmas structures are very diverse. This study aimed to evaluate intraspecific, interspecific and intergeneric stigmas variability and then find differences of the stigma morphology amongst 24 holoparasitic Orobanche and Phelipanche species and provide new insights into its potential taxonomic value. This paper was also focused on selecting the best diagnostic features that would be used for future stigma analysis in other species of Orobanchaceae. These analyses were conducted with fresh, dry and fixed material using stereomicroscopy from different locations from Central Europe. Twenty-one quantitative or qualitative morphological features were analysed. This study highlights the variation of stigma morphology and characters which are useful to improve the taxonomic understanding of problematic taxa. Thus, two main types of stigmas were established, based on tested features: 1–oval, rarely hemispherical in shape, most often one-coloured with lobes separated in Phelipanche stigmas; 2–spherical to hemispherical, rarely oval, multi-coloured with partially fused or separated lobes in Orobanche stigmas. The best diagnostic features of the stigmas for distinguishing the Orobanchaceae are the type and subtype of stigma, the length and area of the stigma, the width of single lobes, the width in the middle part of the stigma, the length of upper and lower separation in the middle part between lobes and the angle between lobes in the upper and lower part. The morphological features of the stigmas are important criteria for distinguishing genera, sections and subsections, as well as related species. In this study, we present the first stigma morphological studies for the most numerous genera from the tribe Orobancheae and this paper may determine features possible to use in solving certain taxonomic problems and evolutionary relationships of the species. [ABSTRACT FROM AUTHOR]

Most species of Urticaceae, the nettle family, have small and inconspicuous, diclinous flowers, in which the perianth, androecium and gynoecium tend to vary in number. Our objective was to study the morphology of the developing flowers of seven species of Urticaceae to understand the pathways that lead to the different patterns of floral reduction and the complex development of pseudomonomerous gynoecia. Buds and flowers were prepared for electron and light microscopy. Vascularization was studied via high resolution X-ray computed tomography micro-CT. Only one whorl of perianth organs is initiated, except for Phenax sonneratii, the flower of which is achlamydeous; variation in perianth merosity results from absence of organs from inception; dicliny results from the absence of stamens from inception (pistillate flowers) and from pistil abortion at intermediate developmental stages (staminate flowers). The gynoecium results from a primordium that divides partially forming two congenitally united primordia (most species) or from a single primordium that apparently does not divide. The gynoecium is served by a single (four species), or two vascular bundles. This second condition is expected for a pseudomonomerous gynoecium. Pistillode or rudimentary carpels occur in staminate flowers. The comparison among species shows that the developmental processes acting in the floral construction in Urticaceae is diverse. [ABSTRACT FROM AUTHOR]

The research was aimed tostudy themorphological and anatomical characteristics as well as habitatand geographical distributionof speciesPeltariaangustifolia DC., This study indicated that the plant specimens are perennial glabrous herbs, distinguished by the presence of distinct basal and cauline leaves, and simple corymb inflorescence. Flowers perianth consists of four obovate sepals, and four spathulate petals, with hexanderiaandroecium characterized by dilated filaments from the bases and gynoecium consists of obovate ovary and sessile stigma, the fruit reticulate silicula, and the seeds are ovate-elliptical with faintly reticulate configuration. As for the anatomical study, it included the study of the dimensions and characteristics of each root, stem, leaf, as well as the nature of the leaf venation, and cuticular study. A study of the geographical distribution showed that the species is very rare in Iraq. It is located in the mountain region and exclusively in Jabal Sinjar district. [ABSTRACT FROM AUTHOR]

For Ledebouria socialis, a superior ovary with interlocular septal nectaries that are confined to both ascidiate and plicate zones of the carpel is typical. It is impossible to describe the gynoecium zonation consistently, since the existing terminology does not allow us to display all its peculiarities. A part of the nectaries located in the gynophore and ascidiate zone is internalized from the very beginning of development and postgenital fusion is not required for their formation. For the formation of the distal part of the nectary confined to the plicate zone of the carpel, postgenital fusion is required to isolate nectar cavities from the center of the gynoecium. The nectary is internalized along the gynoecium periphery through the outgrowth of receptacle tissues. The structure of nectaries, as in Ledebouria, can be found in many Asparagales with a superior ovary. [ABSTRACT FROM AUTHOR]

How do separate sexes originate and evolve? Plants provide many opportunities to address this question as they have diverse mating systems and separate sexes (dioecy) that evolved many times independently. The classic "two-factor" model for evolution of separate sexes proposes that males and females can evolve from hermaphrodites via the spread of male and female sterility mutations that turn hermaphrodites into females and males, respectively. This widely accepted model was inspired by early genetic work in dioecious white campion (Silene latifolia) that revealed the presence of two sex-determining factors on the Y-chromosome, though the actual genes remained unknown. Here, we report identification and functional analysis of the putative sex-determining gene in S. latifolia , corresponding to the gynoecium suppression factor (GSF). We demonstrate that GSF likely corresponds to a Y-linked CLV3 -like gene that is specifically expressed in early male flower buds and encodes the protein that suppresses gynoecium development in S. latifolia. Interestingly, GSFY has a dysfunctional X-linked homolog (GSFX) and their synonymous divergence (d S  = 17.9%) is consistent with the age of sex chromosomes in this species. We propose that female development in S. latifolia is controlled via the WUSCHEL-CLAVATA feedback loop, with the X-linked WUSCHEL -like and Y-linked CLV3 -like genes, respectively. Evolution of dioecy in the S. latifolia ancestor likely involved inclusion of ancestral GSFY into the nonrecombining region on the nascent Y-chromosome and GSFX loss of function, which resulted in disbalance of the WUSCHEL-CLAVATA feedback loop between the sexes and ensured gynoecium suppression in males. [ABSTRACT FROM AUTHOR]

The structure of Agapanthus africanus and A. praecox flowers was studied on permanent cross-sectional and longitudinal sections using a light microscope. The genus Agapanthus belongs to the subfamily Agapanthoideae, the family Amaryllidaceae, which is characterized by the presence of the upper ovary, septal nectaries and fruit – fleshy capsule. Micromorphological studies of the flower are considered as a way for detection of unknown plant features, adjustment of plants to specialized ways of pollination and determining the first stages of morphogenesis of fruit, and further use these features in taxonomy. 10 flowers of A. africanus and A. praecox were sectioned using standard methods of Paraplast embedding and serial sectioning at 20 micron thickness. Sections were stained with Safranin and Astra Blau and mounted in Eukitt. It was found that in the studied species the tepals have single-bundle traces. The vascular system of the superior ovary consists of a three bundle dorsal vein, of the ventral roots complex, which are reorganized into paired ventral bundles of the carpel, which form traces to ovules. For the first time, the following gynoecium zones were detected in A. africanus: a synascidiate structural zone with a height of about 560 μm and a fertile symplicate structural zone with a height of about 380 μm and a hemisymplicate zone of 2580 μm. In A. praecox gynoecium, there is a synascidiate structural zone with a height of 200 μm and a symplicate structural zone of 600 μm and a hemisymplicate zone of 620 μm. Septal nectaries appear in the hemisymplicate zone and open with nectar fissures at the base of the column, with a total septal nectar height of 2880 μm in A. africanus and 820 μm in A. praecox. The ovary roof is 300 µm in A. africanus and 200 µm in A. praecox. Triple dorsal bundles of carpels in A. africanus have been identified, which could be considered as adaptation of different stages of morphogenesis of fruit to dehiscence. The new data obtained by the vascular anatomy of the flower and the presence of different ovary zones significantly add to the information about anatomical and morphological features of the studied species, which can be further used in the taxonomy of the family Amaryllidaceae.

Androdioecy is the crucial transition state in the evolutionary direction of hermaphroditism to dioecy, however, the molecular mechanisms underlying the formation of this sex system remain unclear. While popular in China for its ornamental and cultural value, Osmanthus fragrans has an extremely rare androdioecy breeding system, meaning that there are both male and hermaphroditic plants in a population. To unravel the mechanisms underlying the formation of androdioecy, we performed small RNA sequencing studies on male and hermaphroditic O. fragrans. A total of 334 miRNAs were identified, of which 59 were differentially expressed. Functional categorization revealed that the target genes of differentially expressed miRNAs were mainly involved in the biological processes of reproductive development and the hormone signal transduction pathway. We speculated that the miRNA160, miRNA167, miRNA393 and miRNA396 families may influence the sex differentiation in O. fragrans. Overall, our study is the first exploration of miRNAs in the growth and development process of O. fragrans, and is also the first study of androdioecious plants from the miRNA sequencing perspective. The analysis of miRNAs and target genes that may be involved in the sex differentiation process lay a foundation for the ultimate discovery of the androdioecious molecular mechanism in O. fragrans. [ABSTRACT FROM AUTHOR]