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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]

Various regulatory genes encoding transcription factors and miRNAs regulate carpel number. Multicarpelly is normally associated with increased size of the floral meristem, and several genetic factors have been discovered that influence this characteristic. A fundamental understanding of the regulatory genes affecting carpel number can facilitate strategies for agricultural yield improvement, which is crucial, given that the global population is growing rapidly. A multicarpellate plant may provide a significantly higher yield than a plant bearing fewer carpels. Higher yields can be achieved via various means; in this review, we provide an overview of the current knowledge of the various regulatory factors that contribute to multicarpelly and the potential of increasing carpel number to achieve an increased yield. [ABSTRACT FROM AUTHOR]

Different breeding systems occur in the Gardenieae complex (Rubiaceae), from homoecy to dioecy which is present in two tribes, Gardenieae and Cordiereae. As part of a broad project focused on the reproductive anatomy of the species of these two tribes, we described the structural and functional differences of the gynoecium in the different floral morphs and determined the degree of gynoecium development in the staminate flowers. We conducted a comparative anatomical study focused on the gynoecium of one homoecious species (Tocoyena formosa, with perfect flowers) and three dioecious species (Genipa americana, Randia calycina, and Randia heteromera) of Gardenieae and one dioecious species (Cordiera concolor) of Cordiereae. The dioecious species have flowers that are morphologically perfect and functionally unisexual. Flowers in successive stages of development were collected, photographed, and fixed in formalin-acetic acid-alcohol. The material was examined using light microscopy and scanning electron microscopy. The anatomy of the ovary, style, and stigma was analyzed, and megasporogenesis and megagametogenesis were studied. The results achieved in this study, together with previously obtained data of the androecium, show that dioecy originated from homoecy in these species, since the unisexual flowers conserve some characteristics of the perfect flowers. In addition, a new type of ovule for the Rubiaceae family is described. [ABSTRACT FROM AUTHOR]

The grass family (Poaceae) includes cereal crops that provide a key food source for the human population. The food industry uses the starch deposited in the cereal grain, which develops directly from the gynoecium. Morphological interpretation of the grass gynoecium remains controversial. We re-examine earlier hypotheses and studies of morphology and development in the context of more recent analyses of grass phylogenetics and developmental genetics. Taken in isolation, data on gynoecium development in bistigmatic grasses do not contradict its interpretation as a solitary ascidiate carpel. Nevertheless, in the context of other data, this interpretation is untenable. Broad comparative analysis in a modern phylogenetic context clearly demonstrates that the grass gynoecium is pseudomonomerous. A bistigmatic grass gynoecium has two sterile carpels, each producing a stigma, and a fertile carpel that lacks a stigma. To date, studies of grass developmental genetics and developmental morphology have failed to fully demonstrate the composite nature of the grass gynoecium be-cause its complex evolutionary history is hidden by extreme organ integration. It is problematic to interpret the gynoecium of grasses in terms of normal angiosperm gynoecium typology. Even the concept of a carpel becomes misleading in grasses; instead, we recommend the term pistil for descriptive purposes. [ABSTRACT FROM AUTHOR]

• Extrafloral nectary converts to a phylloid flower during phyllody disease in sesame. • Affected extrafloral nectaries depict several morphological variations. • Nectary epidermal cells show differential patterning, abundant stomata and trichomes. • Study indicates that extrafloral nectary of sesame evolved from a suppressed flower. Plant pathogens are known to cause diverse symptoms in plants. Candidatus Phytoplasma (Class: Mollicutes), a phloem inhabiting bacterial pathogen is transmitted by sap sucking insects and is becoming a serious concern in sesame crops grown for oilseed, especially in the Asiatic region. Sesame (Sesamum indicum L.), a member of family Pedaliaceae, bears prominent extrafloral nectaries (EFN) at each node. Our aim was to investigate the morphological and micromorphological changes in EFN development in phytoplasma infected sesame plants with phyllody disease. Scanning electron microscopy was used to study the micromorphological changes from freshly collected EFNs from healthy and phyllody diseased sesame plants. Observations revealed that the extrafloral nectary in sesame gets converted into flower (green in color) on phytoplasma infection. In diseased plants, this reversion was also seen in early stages of developing EFN primordia. Apart from the reversion, different variants were observed in EFN such as developed EFN showing indeterminacy but retaining the EFN structure or instead occasional morphological alterations were observed such as elongation or splitting of EFN tissue into halves, that often showed conversion to spatula shaped structures with leafy characters. In a few instances, inflated gynoecium like-structure emerged from the center of a split EFN. Rarely, deformed stalked flowers were also observed in place of EFN, with positional and structural abnormalities in stamens, gynoecium defects, leafiness of reduced petals and sepal narrowing cum elongation. Phytoplasma infection in sesame caused development of each EFN into a flower indicating that the EFN gland is a suppressed flower in sesame, the suppression of which is released on infection of the plant pathogen. Instead of solitary nature seen in most Sesamum indicum varieties, the cymose nature of inflorescence is thereby resumed. Phytoplasma-induced EFN conversion is a unique symptom among plant pathogens. In addition, EFNs from affected plant also showed indeterminacy and transition organs show leaf-like features indicating a shift of reproductive to vegetative developmental program on phytoplasma infection. Bushiness on affected sesame is mainly due to conversion of EFN to phylloid flowers, especially those with indeterminate nature. In addition, loss of EFN is suggestive of increased susceptibility of phyllody affected sesame to insect infestation. Further studies on anatomy of symptomatic parts will provide a deeper understanding of the conclusions derived from micromorphological data of phytoplasma associated sesame EFN reversion, presented in the current study. [ABSTRACT FROM AUTHOR]

Crop male sterility has great value in theoretical research and breeding application. HTS-1, whose stamens transformed into pistils or pistil-like structures, is an important male sterility material selecting from Chinese Spring three-pistil (CSTP) wheat. However the molecular mechanism of pistillody development in HTS-1 remains a mystery. RNA-seq data of 11 wheat tissues were obtained from the National Center for Biotechnology Information (NCBI), including the stamens of CSTP and the pistils and pistillodic stamen of HTS-1. The Salmon program was utilized to quantify the gene expression levels of the 11 wheat tissues; and gene quantification results were normal-ized by transcripts per million (TPM). In total, 58,576 genes were used to construct block-wise network by co-expression networks analysis (WGCNA) R package. We obtained all of modules significantly associated with the 11 wheat tissues. AgriGO V2.0 was used to do Gene Ontology (GO) enrichment analysis; and genes and transcription factors (TFs) in these significant modules about wheat pistillody development were identified from GO enrichment results. Basic local alignment search tool (BLAST) was used to align HTS-1 proteins with the published pistillody-related proteins and TFs. Genes about wheat pistillody development were analyzed and validated by qRT-PCR. The MEturquoise, MEsaddlebrown, MEplum, MEcoral1, MElightsteelblue1, and MEdarkslateblue modules were significantly corelated to pistillodic stamen (correlation p < 0:05). Moreover, 206 genes related to carpel development (GO:0048440) or gynoecium development (GO:0048467) were identified only in the MEturquoise module by Gene Ontology (GO) analysis, and 42 of 206 genes were hub genes in MEturquoise module. qRT-PCR results showed that 38 of the 42 hub genes had highly expressed in pistils and pistillodic stamens than in stamens. A total of 15 pistillody development-related proteins were validated by BLAST. Transcription factors (TFs) were also analyzed in the MEturquoise module, and 618 TFs were identified. In total, 56 TFs from 11 families were considered to regulate the development of pistillodic stamen. The co-expression network showed that six of HB and three of BES1 genes were identified in 42 hub genes. This indicated that TFs played important roles in wheat pistillody development. In addition, there were 11 of ethylene-related genes connected with TFs or hub genes, suggesting the important roles of ethylene-related genes in pistillody development. These results provide important insights into the molecular interactions underlying pistillody development. [ABSTRACT FROM AUTHOR]

Coffee plants contain well-known xanthines as caffeine. Three Coffea species grown in a controlled greenhouse environment were the focus of this research. Coffea arabica and C. canephora are two first principal commercial species and commonly known as arabica and robusta, respectively. Originating in Central Africa, C. anthonyi is a novel species with small leaves. The xanthine metabolites in flower, fruit and leaf extracts were compared using both targeted and untargeted metabolomics approaches. We evaluated how the xanthine derivatives and FQA isomers relate to the expression of biosynthetic genes encoding N - and O -methyltransferases. Theobromine built up in leaves of C. anthonyi because caffeine biosynthesis was hindered in the absence of synthase gene expression. Despite this, green fruits expressed these genes and they produced caffeine. Given that C. anthonyi evolved successfully over time, these findings put into question the defensive role of caffeine in leaves. An overview of the histolocalisation of xanthines in the different flower parts of Coffea arabica was also provided. The gynoecium contained more theobromine than the flower buds or petals. This could be attributed to increased caffeine biosynthesis before fructification. The presence of theophylline and the absence of theobromine in the petals indicate that caffeine is catabolized more in the petals than in the gynoecium. [Display omitted] • Xanthine biosynthesis of the recently identified Coffea anthonyi species is compared to that of C. arabica and C. canephora. • Caffeine biosynthesis is disrupted in leaves but active in fruits of C. anthonyi. • Data from C. arabica indicate that caffeine synthesis begins in the gynoecium. • C. anthonyi does not express the DXMT genes in leaves, although these are conserved across the majority of Coffea species. [ABSTRACT FROM AUTHOR]

Premise of research. Hydrophyllaceae are characterized by simple floral organization contrasting with a peculiar floral architecture resulting from complex compartments formed by stamen–corolla tube modifications. Additionally, the internal ovary architecture of Hydrophyllaceae shows significant variation, while the developmental trajectory of the gynoecium is relatively conserved. Despite insights from recent studies of the flower and fruit evolution of the family, there are only a few ontogenetic studies of Hydrophyllaceae, and a complete understanding of the underlying processes has not yet been achieved. Methodology. Here, we use scanning electron microscopy and micro–computed tomography to investigate the flower and fruit ontogeny of two genera of Hydrophylleae, Emmenanthe and Pholistoma , with a particular focus on the gynoecium and modifications of the stamen–corolla tube. Pivotal results. Our results complement two previously published data sets, broadening our understanding of Hydrophylleae evolution. Hydrophylleae comprise only a few monotypic or small genera, but their floral evolution appears to be remarkably complex, in terms of both gynoecial structure and perianth modifications. We find 10 stamen–corolla tube modifications, although these may be rudimentary in species previously considered as lacking them altogether (e.g., Emmenanthe). The relative conservation of perianth architecture contrasts with the highly variable internal ovary architecture of Hydrophylleae. There is considerable divergence in ovule/seed number, as well as in the details of (parietal) placentation and septation, and we propose a hypothetical evolutionary series for the internal ovary architectural diversity of Hydrophyllaceae. Conclusions. We propose that—starting from a fairly conserved floral organization—minor heterochronous shifts in both perianth and ovary development can explain most of the morphological diversity found in the flowers and fruits of Hydrophylleae. [ABSTRACT FROM AUTHOR]

Pod shattering causes severe yield loss in rapeseed (Brassica napus L.) under modern agricultural practice. Identification of highly shatter-resistant germplasm is desirable for the development of rapeseed cultivars for mechanical harvesting. In the present study, an elite line OR88 with strong shatter resistance and a lignified-layer bridge (LLB) structure was identified. The LLB structure was unique to OR88 and co-segregated with high pod-shatter resistance. The LLB structure is differentiated at stage 12 of gynoecium development without any gynoecium defects. Genetic analysis showed that LLB is controlled by a single recessive gene. By BSA-Seq and map-based cloning, the resistance gene location was delimited to a 0.688 Mb region on chromosome C09. Transcriptome analysis suggested BnTCP8.C09 as the gene responsible for LLB. The expression of BnTCP.C09 was strongly downregulated in OR88, suppressing cell proliferation in the pod valve margin. KASP markers linked to the candidate gene were developed. This pod shatter-resistant line could be used in rapeseed breeding programs by direct transfer of the gene with the assistance of the DNA markers. [ABSTRACT FROM AUTHOR]

Dioecious plants possess diverse sex determination systems and unique mechanisms of reproductive organ development; however, little is known about how sex-linked genes shape the expression of regulatory cascades that lead to developmental differences between sexes. In Silene latifolia , a dioecious plant with stable dimorphism in floral traits, early experiments suggested that female-regulator genes act on the factors that determine the boundaries of the flower whorls. To identify these regulators, we sequenced the transcriptome of male flowers with fully developed gynoecia, induced by rapid demethylation in the parental generation. Eight candidates were found to have a positive role in gynoecium promotion, floral organ size, and whorl boundary, and affect the expression of class B MADS-box flower genes. To complement our transcriptome analysis, we closely examined the floral organs in their native state using field emission environmental scanning electron microscopy, and examined the differences between females and androhermaphrodites in their placenta and ovule organization. Our results reveal the regulatory pathways potentially involved in sex-specific flower development in the classical model of dioecy, S. latifolia. These pathways include previously hypothesized and unknown female-regulator genes that act on the factors that determine the flower boundaries, and a negative regulator of anther development, SUPERMAN - like (SlSUP). [ABSTRACT FROM AUTHOR]

Representatives of three genera of Livistoninae (Johannesteijsmannia , Licuala and Pholidocarpus) develop corky-warted fruits in contrast to fruit with smooth surfaces in most other representatives of the 'apocarpous clade' of Arecaceae subfamily Coryphoideae. The present developmental study is focused on revealing the anatomical peculiarities of the fruit structure of corky-warted species of Livistoninae and tracing the development of their pericarp. Our study shows that the fruits of Johannesteijsmannia, Licuala bintulensis and Pholidocarpus macrocarpus are drupes of the Rhapis type and that the warts on their fruit surface originate soon after gynoecium pollination as the result of two or three developmental events: (1) suberinization of the exocarp cells; (2) progressive multiplication and growth of the outer zone of the mesocarp; and (3) cracking of the peripheral zone of the pericarp. The warts of taxa of Livistoninae develop at the mid stages of fruit organogenesis and are referred to as either alive, composed of parenchymatous cells and sclereids (species of Licuala and Pholidocarpus), or dead, consisting of cells with suberized walls and sclereids (Johannesteijsmannia). The nests of sclereids comprising the stone of Johannesteijsmannia spp. remain disunited during pericarp development until late developmental stages when the formation of a continuous sclerenchymatous layer occurs, which differs from other representatives of the 'apocarpous clade' of Coryphoideae with a continuous layer of sclereids persisting during fruit development (as in L. bintulensis). It is shown that the development of the stone within the drupes of the Rhapis type can be different even in closely related taxa. The recognition of the fruits of studied taxa of Livistoninae as drupes of the Rhapis type like the fruit of many other taxa of Trachycarpeae and the 'apocarpous clade' of Coryphoideae suggest this character as a synapomorphy for this tribe and the whole clade. [ABSTRACT FROM AUTHOR]

Nectar robbing has multiple effects on plants and pollinators, depending on the traits of a plant and its reproductive system, the behaviour of its pollinators, and the identity of the robber. We aimed to evaluate temporal variation in morphological traits of robbed and intact flowers of the ornithophilous Asian basket plant, Aeschynanthus speciosus (Gesneriaceae). We measured the length of the style and corolla, and the width of the stigma of the flowers of potted A. speciosus plants on three different days. We also recorded whether nectar robbing influenced the position of the androecium in relation to the gynoecium between robbed and intact flowers. Nectar robbing by the bananaquit, Coereba flaveola, had a negative effect on the development of floral traits of A.speciosus, resulting in flowers with smaller styles and stigmas, and reduced herkogamy. We discuss these findings from the perspective of plant-nectar robber interactions, offering insights into the strategies adopted by plants to counteract the negative effects of nectar robbing. [ABSTRACT FROM AUTHOR]

Species of the genus Burmannia possess distinctive and highly elaborated flowers with prominent floral tubes that often bear large longitudinal wings. Complicated floral structure of Burmannia hampers understanding its floral evolutionary morphology and biology of the genus. In addition, information on structural features believed to be taxonomically important is lacking for some species. Here we provide an investigation of flowers and inflorescences of Burmannia based on a comprehensive sampling that included eight species with various lifestyles (autotrophic, partially mycoheterotrophic and mycoheterotrophic). We describe the diversity of inflorescence architecture in the genus: a basic (most likely, ancestral) inflorescence type is a thyrsoid comprising two cincinni, which is transformed into a botryoid in some species via reduction of the lateral cymes to single flowers. Burmannia oblonga differs from all the other studied species in having an adaxial (vs. transversal) floral prophyll. For the first time, we describe in detail early floral development in Burmannia. We report presence of the inner tepal lobes in B. oblonga , a species with reportedly absent inner tepals; the growth of the inner tepal lobes is arrested after the middle stage of floral development of this species, and therefore they are undetectable in a mature flower. Floral vasculature in Burmannia varies to reflect the variation of the size of the inner tepal lobes; in B. oblonga with the most reduced inner tepals their vascular supply is completely lost. The gynoecium consists of synascidiate, symplicate, and asymplicate zones. The symplicate zone is secondarily trilocular (except for its distal portion in some of the species) without visible traces of postgenital fusion, which prevented earlier researchers to correctly identify the zones within a definitive ovary. The placentas occupy the entire symplicate zone and a short distal portion of the synascidiate zone. Finally, we revealed an unexpected diversity of stamen-style interactions in Burmannia. In all species studied, the stamens are tightly arranged around the common style to occlude the flower entrance. However, in some species the stamens are free from the common style, whereas in the others the stamen connectives are postgenitally fused with the common style, which results in formation of a gynostegium. [ABSTRACT FROM AUTHOR]

Flowering plants produce flowers and one of the most complex floral structures is the pistil or the gynoecium. All the floral organs differentiate from the floral meristem. Various reviews exist on molecular mechanisms controlling reproductive development, but most focus on a short time window and there has been no recent review on the complete developmental time frame of gynoecium and fruit formation. Here, we highlight recent discoveries, including the players, interactions and mechanisms that govern gynoecium and fruit development in Arabidopsis. We also present the currently known gene regulatory networks from gynoecium initiation until fruit maturation. [ABSTRACT FROM AUTHOR]

Pseudomonomerous gynoecia with three (or four) carpels are unknown in the species-rich core group of Apiales, but this condition is shared by three species-poor families (Pennantiaceae, Torricelliaceae, Griseliniaceae) that form the basal grade of the order. Testing a hypothesis on the ancestral nature of carpel dimorphism in Apiales requires comparative data for all three lineages in this grade. We provide the first detailed description of flowers, including floral vasculature and gynoecium development, in a member of Pennantiaceae (Pennantia corymbosa). In contrast to many other Apiales, the inflorescence of Pennantia is paniculate and therefore has an unstable number of phyllomes in axes terminated by flowers. All phyllomes in the inflorescence are shifted onto lateral branches they subtend exhibiting recaulescence, a pattern that has not been reported elsewhere in Apiales. Plants are dioecious with functionally unisexual flowers. There are normally five stamens alternating with five petals. Anthers are present and produce pollen in stamens of male as well as female flowers, but ventral microsporangia are reduced in some anthers of female flowers. Anther morphology sometimes varies even among stamens of the same flower. Two types of synthecal anthers are recorded. Pollen dimorphism is confirmed: inaperturate pollen produced by stamens of female flowers supposedly acts as the only reward for pollinators in the absence of nectaries. The gynoecium of the female flower is syncarpous and pseudomonomerous: only one of three carpels is fertile. The gynoecium is initiated as three carpel primordia (future stigmas). One of them is smaller than the other two and occupies an alternistaminal (and antepetalous) position. The two large carpel primordia are located in the radii of stamens that are generally smaller (early in development) than the three other stamens. The carpel dimorphism is maintained at anthesis. The carpel with the smaller stigma is fertile, and those with larger stigmas are sterile. The carpels are congenitally united below the stigmas. The ovary is superior, unilocular (vs. inferior and plurilocular in Torricelliaceae and Griseliniaceae) and usually uniovulate with pendent ovule(s) inserted at the cross-zone level of the fertile carpel. As in most other Apiales, the short symplicate zone is sealed by postgenital fusion at anthesis and forms an internal compitum. The fertile carpel of the members of the basal grade of Apiales investigated so far is uniformly arranged in a petal radius. This is consistent with the idea that pseudomonomery is associated with stable patterns of flower groundplan in Apiales. Our data do not provide any clear structural or developmental evidence of independent origins of carpel dimorphism in Pennantiaceae, Torricelliaceae and Griseliniaceae. [ABSTRACT FROM AUTHOR]

In order to determine an easy leaf age(LA)diagnostic method of panicle differentiation stage of sorghum, the panicle differentiation of sorghum and the relationship between differentiation stage and LA and leaf age index(LAI)were investigated. Hybrid cultivar ‘Jinyunuo 3' and conventional cultivar ‘Guojiaohong 1' were used as materials planted in three sowing dates, the panicle differentiation stage and corresponding LA were recorded. The results were as follows:(1)The panicle differentiation could be divided into five stages, i. e. vegetative stage, elongation stage, panicle branch differentiation stage, spikelet and floret differentiation stage, gynoecium and stamen formation stage. The sterile spikelet with stalk could develop to gynoecium and stamen formation stage.(2)With the detention of sowing date, the starting date of panicle differentiation was advanced, and the growth duration shorted, and LA and LAI of each stage of panicle differentiation were decreased, but there were differences among varieties.(3)The relationship between the panicle differentiation stage and LAI conformed to linear regression correlation, with a formula of panicle differentiation stage(Yi)to LAI(Xi) of Yi=bXi+a.(4)With the detention of sowing date, the parameter b and |a| in formula of ‘Jinyunuo 3' were increased, while those of ‘Guojiaohong 1' were decreased. To sum up, it is viable to infer panicle differentiation stage applying LAI, and the results provide theoretical basis for sorghum cultivation index management. [ABSTRACT FROM AUTHOR]

The family Rapateaceae represents an early-divergent lineage of Poales with biotically pollinated showy flowers. We investigate developmental morphology and anatomy in all three subfamilies and five tribes of Rapateaceae to distinguish between contrasting hypotheses on spikelet morphology and to address questions on the presence of nectaries and gynoecium structure. We support an interpretation of the partial inflorescence (commonly termed spikelet), as a uniaxial system composed of a terminal flower and numerous empty phyllomes. A terminal flower in an inflorescence unit is an autapomorphic feature of Rapateaceae. The gynoecium consists of synascidiate, symplicate, and usually asymplicate zones, with gynoecium formation encompassing congenital and often also postgenital fusions between carpels. Species of Rapateaceae differ in the relative lengths of the gynoecial zones, the presence or absence of postgenital fusion between the carpels and placentation in the ascidiate or plicate carpel zones. In contrast with previous reports, septal nectaries are lacking in all species. The bird-pollinated tribe Schoenocephalieae is characterized by congenital syncarpy; it displays an unusual type of gynoecial (non-septal) nectary represented by a secretory epidermis at the gynoecium base. [ABSTRACT FROM AUTHOR]

Abstract Background In Aristolochia (Aristolochiaceae) flowers, the congenital fusion of the anthers and the commissural, stigmatic lobes forms a gynostemium. Although the molecular bases associated to the apical–basal gynoecium patterning have been described in eudicots, comparative expression studies of the style and stigma regulatory genes have never been performed in early divergent angiosperms possessing a gynostemium. Results In this study, we assess the expression of five genes typically involved in gynoecium development in Aristolochia fimbriata. We found that all five genes (AfimCRC, AfimSPT, AfimNGA, AfimHEC1 and AfimHEC3) are expressed in the ovary, the placenta, the ovules and the transmitting tract. In addition, only AfimHEC3, AfimNGA and AfimSPT are temporarily expressed during the initiation of the stigma, while none of the genes studied is maintained during the elaboration of the stigmatic surfaces in the gynostemium. Conclusions Expression patterns suggest that CRC, HEC, NGA and SPT homologs establish ovary and style identity in Aristolochia fimbriata. Only NGA,HEC3 and SPT genes may play a role in the early differentiation of the stigmatic lobes, but none of the genes studied seems to control late stigma differentiation in the gynostemium. The data gathered so far raises the possibility that such transient expression early on provides sufficient signal for late stigma differentiation or that unidentified late identity genes are controlling stigma development in the gynostemium. Our data does not rule out the possibility that stigmas could correspond to staminal filaments with convergent pollen-receptive surfaces.

Species of the genus Burmannia possess distinctive and highly elaborated flowers with prominent floral tubes that often bear large longitudinal wings. Complicated floral structure of Burmannia hampers understanding its floral evolutionary morphology and biology of the genus. In addition, information on structural features believed to be taxonomically important is lacking for some species. Here we provide an investigation of flowers and inflorescences of Burmannia based on a comprehensive sampling that included eight species with various lifestyles (autotrophic, partially mycoheterotrophic and mycoheterotrophic). We describe the diversity of inflorescence architecture in the genus: a basic (most likely, ancestral) inflorescence type is a thyrsoid comprising two cincinni, which is transformed into a botryoid in some species via reduction of the lateral cymes to single flowers. Burmannia oblonga differs from all the other studied species in having an adaxial (vs. transversal) floral prophyll. For the first time, we describe in detail early floral development in Burmannia. We report presence of the inner tepal lobes in B. oblonga, a species with reportedly absent inner tepals; the growth of the inner tepal lobes is arrested after the middle stage of floral development of this species, and therefore they are undetectable in a mature flower. Floral vasculature in Burmannia varies to reflect the variation of the size of the inner tepal lobes; in B. oblonga with the most reduced inner tepals their vascular supply is completely lost. The gynoecium consists of synascidiate, symplicate, and asymplicate zones. The symplicate zone is secondarily trilocular (except for its distal portion in some of the species) without visible traces of postgenital fusion, which prevented earlier researchers to correctly identify the zones within a definitive ovary. The placentas occupy the entire symplicate zone and a short distal portion of the synascidiate zone. Finally, we revealed an unexpected diversity of stamen-style interactions in Burmannia. In all species studied, the stamens are tightly arranged around the common style to occlude the flower entrance. However, in some species the stamens are free from the common style, whereas in the others the stamen connectives are postgenitally fused with the common style, which results in formation of a gynostegium.

The family Rapateaceae represents an early-divergent lineage of Poales with biotically pollinated showy flowers. We investigate developmental morphology and anatomy in all three subfamilies and five tribes of Rapateaceae to distinguish between contrasting hypotheses on spikelet morphology and to address questions on the presence of nectaries and gynoecium structure. We support an interpretation of the partial inflorescence (commonly termed spikelet), as a uniaxial system composed of a terminal flower and numerous empty phyllomes. A terminal flower in an inflorescence unit is an autapomorphic feature of Rapateaceae. The gynoecium consists of synascidiate, symplicate, and usually asymplicate zones, with gynoecium formation encompassing congenital and often also postgenital fusions between carpels. Species of Rapateaceae differ in the relative lengths of the gynoecial zones, the presence or absence of postgenital fusion between the carpels and placentation in the ascidiate or plicate carpel zones. In contrast with previous reports, septal nectaries are lacking in all species. The bird-pollinated tribe Schoenocephalieae is characterized by congenital syncarpy; it displays an unusual type of gynoecial (non-septal) nectary represented by a secretory epidermis at the gynoecium base.

For obtaining insights into gene networks during plant reproductive development, having transcriptomes of specific cells from developmental stages as starting points is very useful. During development, there is a balance between cell proliferation and differentiation, and many cell and tissue types are formed. While there is a wealth of transcriptome data available, it is mostly at the organ level and not at specific cell or tissue type level. Therefore, methods to isolate specific cell and tissue types are needed. One method is fluorescent activated cell sorting (FACS), but it has limitations such as requiring marker lines and protoplasting. Recently, single-cell/nuclei isolation methods have been developed; however, a minimum amount of genetic information (marker genes) is needed to annotate/predict the resulting cell clusters in these experiments. Another technique that has been known for some time is laser-assisted microdissection (LAM), where specific cells are microdissected and collected using a laser mounted on a microscope platform. This technique has advantages over the others because no fluorescent marker lines must be made, no marker genes must be known, and no protoplasting must be done. The LAM technique consists in tissue fixation, tissue embedding and sectioning using a microtome, microdissection and collection of the cells of interest on the microscope, and finally RNA extraction, library preparation, and RNA sequencing. In this protocol, we implement the use of normal slides instead of the membrane slides commonly used for LAM. We applied this protocol to obtain the transcriptomes of specific tissues during the development of the gynoecium of Arabidopsis . Key features • Laser-assisted microdissection (LAM) allows the isolation of specific cells or tissues. • Normal slides can be used for LAM. • It allows the identification of the transcriptional profiles of specific tissues of the Arabidopsis gynoecium., Competing Interests: Competing interestsThe authors declare no competing interests., (©Copyright : © 2024 The Authors; This is an open access article under the CC BY-NC license.)

Background and Aims: SPATULA (SPT) encodes a basic Helix-Loop-Helix transcription factor in Arabidopsis thaliana that functions in the development of the style, stigma and replum tissues, all of which arise from the carpel margin meristem (CMM) of the gynoecium. Here, we use a comparative approach to investigate the evolutionary history of SPT and identify changes that potentially contributed to its role in gynoecium development., Methods: We investigate SPT's molecular and functional evolution using phylogenetic reconstruction, yeast-2-hybrid analyses of protein-protein interactions, microarray-based analyses of protein-DNA interactions, plant transformation assays, RNA in-situ hybridization, and in-silico analyses of promoter sequences., Key Results: We demonstrate the SPT lineage to have arisen at the base of euphyllophytes from a clade of potentially light-regulated transcription factors through gene duplication followed by the loss of an Active Phytochrome Binding (APB) domain. We also clarify the more recent evolutionary history of SPT and its paralog ALCATRAZ (ALC), which appear to have arisen through a large-scale duplication within Brassicales. We find that SPT orthologs from diverse groups of seed plants share strikingly similar capacities for protein-protein and protein-DNA interactions, and that SPT coding regions from a wide taxonomic range of plants are able to complement loss-of-function spt mutations in transgenic Arabidopsis. However, the expression pattern of SPT appears to have evolved significantly within angiosperms, and we identify structural changes in SPT's promoter region that correlate with the acquisition of high expression levels in tissues arising from the CMM in Brassicaeae., Conclusions: We conclude that changes to SPT's expression pattern made a major contribution to the evolution of its developmental role in the gynoecium of Brassicaeae. By contrast, the main biochemical capacities of SPT, as well as many of its immediate transcriptional targets, appear to have been conserved at least since the base of living angiosperms., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Primulina scutellifolia is described as a new species from Khanh Hoa Province, southern Central Vietnam. It is distinct in the genus in having scutellate leaves that make it a highly potential ornamental plant. The new species looks like P. annamensis in general shapes, sizes and colours of habit, inflorescence, flower, and leaf but is distinguishable by adaxially glabrous and abaxially strigose leaves with serrate margins, scutellate leaf blade and appressed downwards tomentose petiole, sparsely glandular hairs on apical 1/2 of the gynoecium and trapeziform one-lipped stigma with slightly emarginated apex. [ABSTRACT FROM AUTHOR]

A new variety Abrus precatorius L. var. albo-spermum Hassan, Rahman et Afroz, var. nov. is described and illustrated from Bangladesh. The new variety is closest to Abrus preactorius L., but differs by its white coloured oval shaped seeds, short gynoecium which is half the length of longer filaments and with a short style. [ABSTRACT FROM AUTHOR]

Premise of research. Anacardiaceae comprise two subfamilies (Anacardioideae and Spondioideae) with small nectariferous flowers that are typically morphologically bisexual, whereas sometimes only the androecium or gynoecium is functional. In most Spondioideae, flowers are typically polysymmetric and obdiplostemonous, with as many antepetalous carpels as there are sepals (or petals), but frequently not all carpels are fertile, and the gynoecium can also be pseudomonomerous or more rarely monomerous. Pseudomonomery has received little or no attention in Spondioideae, and here we compare flowers of Spondias tuberosa , where all carpels form a locule but only one yields a fully developed ovule, and Tapirira guianensis , where only one carpel is fertile. Methodology. In these two species, we studied the flower structure and development using microtome serial sections, and light and scanning electron microscopy. Pivotal results. Both species share morphologically bisexual flowers with a similar floral bauplan and developmental pathway toward functionally male flowers. Their gynoecia share a syncarpous and entirely synascidiate ovary with the former center of the floral apex exposed between the free (and entirely plicate) styles and stigmas. In addition, the position of their single fertile locule varies in each flower and in S. tuberosa remains unclear until the development of the ovules. Conclusions. Functionally unisexual flowers and pseudomonomery likely evolved independently several times in Spondioideae and Anacardiaceae as a whole, and the structural differences between pseudomonomerous gynoecia in each subfamily are the results of heterochronic development. The evolutionary and functional significance of pseudomonomerous gynoecium in Anacardiaceae remains to be explored. [ABSTRACT FROM AUTHOR]

The floral anatomy and development of species belonging to all sections of Xyris (Xyris , Nematopus and Pomatoxyris) were investigated comparatively to elucidate gynoecium evolution in the genus, because placentation has been one of the key characters in recognizing its taxonomic sections. In species of section Pomatoxyris (axile placentation), the tricarpellate syncarpous ovary consists of a fertile synascidiate zone, whereas the symplicate zone is fertile only in its lower portion. In species of section Xyris (parietal placentation), the ovary has a short almost sterile synascidiate zone, whereas the more extensive symplicate zone is fertile. In species of section Nematopus (free-central or basal placentation), there is an extremely short and sterile trilocular, completely septate zone at the ovary base. Such differences are related to different patterns of gynoecium development. The ancestral character state reconstruction of placentation types shows that axile placentation is the most likely ancestral condition in Xyris , from which parietal and free-central placentation were derived by shortening of the septa during the evolution of the genus. Basal placentation evolved from free-central placentation and appeared independently several times in section Nematopus. Because the phylogenetic position of X. ptariana and X. teinosperma (section Nematopus) is unknown, either the axile placentation in these species is a reversal or highlights the need for a revised infrageneric classification. [ABSTRACT FROM AUTHOR]

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Gynoecium and fruit micromorphology and anatomy were studied using light microscopy in three species of Campanuloideae belonging to the tribes Cyanantheae (Platycodon grandiflorus), Wahlenbergieae (Jasione montana), and Campanuleae (Adenophora liliifolia) of the native and cultivated flora of Ukraine, to elucidate structural adaptations for fruit dehiscence. The studied species differed in flower/fruit orientation, carpel number, ovary insertion, and capsule-opening position, and the information provided a background for the discovery of common anatomical features influencing fruit dehiscence. In the studied species, the synascidiate and symplicate zones in the ovary and prominent placentae were found to be located near the mid-region of the ovary. The distinct innervation of the ovary wall and ovules was described. In P. grandiflorus, the septa and fruit wall contained a lignified parenchyma in a subepidermal position, while in J. montana and A. liliifolia, lignification was observed only in proximal portions of the septa, above the placenta (J. montana), or was noted as a narrow strand from the ovary base to the mid-region, called “axicorn” (A. liliifolia). In all the studied species, unlignified endocarpium was detected. The semi-inferior capsule of P. grandiflorus has been defined as a capsule of the Forsythia-type, with a sclerenchymatous layer in the inner zone of the mesocarpium. In J. montana and A. liliifolia, a new histogenetic type of capsule is described as Campanula-type, without lignified layers in the fruit wall and with lignified tissue in the septa, which enabled dehiscence. Our study proposed for the first time the classification of the capsules found in the studied species based on the development of openings in the superior or inferior regions of the fruits. The upright fruits of P. grandiflorus and J. montana reveal incomplete dorsiventral dehiscence in the superior region of the fruit, while dehiscence of pendent fruits of A. liliifolia is hippocrepiform-septifragal interlocular and occurs in the inferior region of the fruit at its base, as revealed previously in Campanula latifolia fruit.

Premise: Celtis is the most species‐rich genus of Cannabaceae, an economically important family. Celtis species have been described as wind‐pollinated and andromonoecious. However, the andromonoecy of Celtis has been debated because there are reports of monoclinous flowers with non‐opening anthers on short filaments. Our objective was to study the floral morphogenesis of Celtis to establish the breeding system and to better understand the developmental patterns that lead to the formation of reduced flowers in the genus. Methods: Flowers and floral buds of Celtis species were studied using scanning electron microscopy, high‐resolution x‐ray computed tomography, and light microscopy. Results: All flowers initiate stamens and carpels during early floral development, but either stamens or carpels abort during later stages. Thus, at anthesis, flowers are either functionally pistillate or functionally staminate. In pistillate flowers, stamens abort late and become staminodes with normal‐looking anthers. These anthers have no functional endothecium and, in most of the species studied, produce no viable pollen grains. The gynoecium is pseudomonomerous, and its vascularization is similar in the sampled species. In staminate flowers, the gynoecium aborts early resulting in small pistillodes. No vestiges of petals were found. Conclusions: The species studied are monoecious and not andromonoecious as described earlier. The absence of petals, the carpel and stamen abortion, and the pseudomonomerous gynoecium result in the reduced flowers of Celtis species. The use of high‐resolution x‐ray computed tomography was essential for a more accurate interpretation of ovary vascularization, confirming the pseudomonomerous structure of the gynoecium. [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. praecoxwere 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. InA. 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 200µm 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. [ABSTRACT FROM AUTHOR]

Doubled haploidy serves as an effective tool for enhancing genetic gain in plant breeding programs. Androgenesis, an extensively-employed form of doubled haploidy, involves totipotent induction within the immature microgametophyte followed by agamous embryogenesis and chromosome doubling. Protocol development for in vitro androgenesis is reliant upon the application of species- (and oftentimes genotype-) specific induction stimuli as well as phenotypic markers that reflect cellular reprogramming. In cell cultures, however, the latter is impeded readily by pseudo-embryogenic structures of somatic origin. In this study, gynoecium-derived trichomes of soybean were intentionally incorporated into isolated microspore cultures. Trichome morphology was then compared to early-dividing zygotic and apozygotic plant embryos previously reported, as were nuclei orientation and cross wall composition. Lastly, autofluorescence intensity was measured for trichomes and various microspore phenotypes, the results of which implied that autofluorescence post-light exposure may be a useful parameter for culture purification and/or quality control. The findings herein demonstrate that trichomes serve a pseudo-embryogenic role during in vitro androgenesis in soybean and necessitate extra caution when identifying sporophytic tissues in species with floral pubescence. Key message: This manuscript draws morphological parallels between eudicot embryos and gynoecial trichomes, and may be used as a reference/cautionary guide for the identification of pseudo-embryos in vitro. [ABSTRACT FROM AUTHOR]

Orchid gynostemium, the fused organ of the androecium and gynoecium, and ovule development are unique developmental processes. Two DROOPING LEAF / CRABS CLAW (DL / CRC) genes, PeDL1 and PeDL2, were identified from the Phalaenopsis orchid genome and functionally characterized. Phylogenetic analysis indicated that the most recent common ancestor of orchids contained the duplicated DL/CRC -like genes. Temporal and spatial expression analysis indicated that PeDL genes are specifically expressed in the gynostemium and at the early stages of ovule development. Both PeDL s could partially complement an Arabidopsis crc-1 mutant. Virus-induced gene silencing (VIGS) of PeDL1 and PeDL2 affected the number of protuberant ovule initials differentiated from the placenta. Transient overexpression of PeDL1 in Phalaenopsis orchids caused abnormal development of ovule and stigmatic cavity of gynostemium. PeDL1, but not PeDL2, could form a heterodimer with Phalaenopsis equestris CINCINNATA 8 (PeCIN8). Paralogous retention and subsequent divergence of the gene sequences of PeDL1 and PeDL2 in P. equestris might result in the differentiation of function and protein behaviors. These results reveal that the ancestral duplicated DL/CRC -like genes play important roles in orchid reproductive organ innovation. [ABSTRACT FROM AUTHOR]

In recent years, cellular glycans are increasingly recognized as a universal basis for the storage and transmission of biological information. Lectins, carbohydrate-binding proteins, play a key role in this process. A very interesting model for studying the processes of intercellular interaction and recognition is self-incompatibility in plants. This is one of the main mechanisms by which angiosperms prevent inbreeding and promote cross-pollination. Heteromorphic incompatibility is the most interesting type of self-incompatibility, because in heterostyle species S-genes are associated with morphological features of flowers. The genus Linum is very interesting in terms of studying the mechanisms of pollination. Among the representatives of this genus there are both self-pollinating species (homostyled species) and cross-pollinating species (heterostyled species). The aim of the study was to analyze the lectin profile in the pistils and stamens of both flower morphs of three model species, which are characterized by different types of self-incompatibility: L. grandiflorum Desf., L. perenne L. and L. thracicum Degen. It was found that the lectin profile of androceum and gynoecium of heterostyled Linum species consists of 40 fractions regardless of genotype. It was found that lectins of L. perenne have the highest activity, and lectins of L. grandiflorum has the lowest. The activity of lectins of L. thracicum occupies an intermediate position. The relationship between the level of lectin activity and the type of self-incompatibility has been identified, suggesting that lectins may be involved in the regulation of self-incompatibility. A method of complete extraction and purification of lectins of different types of Linum by affinity chromatography using galactose and glucose-containing carriers has been developed. [ABSTRACT FROM AUTHOR]

Introducction: Gaiadendron punctatum is a hemiparasitic species of Loranthaceae (Tribe Gaiadendreae) that is widely distributed in mountainous regions of Central and South America. Embryological and phylogenetic studies in the family indicate a trend towards reduction of the gynoecium and ovules, the morphology of which supports the current circumscription of Tribe Gaiadendreae (Gaiadendron and Atkinsonia). Molecular phylogenetic studies suggest that Nuytsia, Atkinsonia and Gaiadendron diverged successively, forming a grade at the base of the Loranthaceae, but support values are low. Objetive: In the present study, the floral anatomy of Gaiadendron punctatum was investigated in order to provide additional data to permit comparisons among the three basal-most genera in the Loranthaceae and reevaluate their relationships. Methods: Flowers of G. punctatum were collected at different developmental stages and serial sections were prepared and analyzed by light microscopy. Results: Inflorescence development is acropetal; the flowers are bisexual with an inferior ovary surmounted by a calyculus, a ring-shaped structure lacking vascular tissue; the ovary is comprised of seven basal locules, each with an ategmic, tenuinucellate ovule. Above the locules is a mamelon that is fused with the adjacent tissues. The androecium is comprised of seven epipetalous stamens, the anthers with fibrous endothecium dehiscence through a single longitudinal slit, releasing tricolpated pollen. Conclusions: The results of this study show that Gaiadendron and Atkinsonia share versatile, dorsifixed anthers, while Gaiadendron and Nuytsia share the same mode of anther dehiscence. On the other hand, Gaiadendron shares with members of Tribe Elytrantheae an amyliferous mamelon and an unvascularized calyculus. Combined phylogenetic analyses of morphological and molecular data are desirable to determine whether Tribe Gaiadendreae comprises a clade, a grade or if the two genera are more distantly related. [ABSTRACT FROM AUTHOR]

Rubus glaucus is widely distributed throughout the three mountain ranges of Colombia, where the blackberry growers have highlighted the need to standardize the supply of planting material, starting with plant breeding schemes that lead to more productive varieties with morphological characteristics that ease agricultural activities. Plant breeding activities have improved by considering the pollination mechanisms of plants. The implementation of controlled sexual hybridization depends on these pollination mechanisms, and several plant breeding methods have been adapted to crop pollination patterns. Morphological characteristics and studies on the floral biology of R. glaucus Benth were conducted to improve plant breeding processes. In addition, a study on pollen viability and stigma receptivity were performed. The reported morphological characteristics of R. glaucus enabled characterization of its flowers as complete and perfect with a regular, actinomorphic, perianth heterochlamydeous, dialipetalous, and dialisepalous structure. Meanwhile, the evaluation of different collection times for pollen viability revealed significant differences. The highest pollen viability occurred at 10:00 am, followed by 9:00 am. Qualitative evaluation of stigma receptivity led to the conclusion that the highest stigma receptivity is at anthesis at 12:00 m.

The use of morphological features of flowers in the taxonomy of plants is becoming increasingly important. The structure of the Zephyranthes candida (Lindl.) Herb. flowers on permanent cross-sectional and longitudinal sections was studied using a light microscope. The genus Zephyranthes belongs to the subtribe Hippeastrinae Walp. tribe Hippeastreae Sweet., family Amaryllidaceae s.l. Microscopic studies of the flower are considered as a tool to identify hitherto unknown structural adaptations of plants to specialized pollination methods and to elucidate the first stages of fruit morphogenesis, as many features of the fruit appear at the flower stage. The morphometric parameters, morphology, anatomy, and vascular anatomy of the ovary were described by using the flower’s transverse sections. Ten flowers of Z. candida were sectioned using standard methods of Paraplast embedding and serial sectioning at 20 μm thickness. Sections were stained with Safranin and Astra Blau and mounted in Eukitt. It was found that in the studied species the tepals have multi-bundle traces of 10–12 leading bundles. We consider the gynoecium of the studied species to be eusincarpous. The vascular system of the inferior ovary consists of three dorsal and three septal bundles, paired ventral bundles of carpels, which form ovule traces. For the first time, the presence of the following gynoecium zones was detected: a synascidiate structural zone with a height of about 360 μm and a fertile symplicate structural zone with a height of about 1560 μm and a hemisymplicate zone of 480 μm. Septal nectaries appear in the hemisymplicate zone and open with nectary split at the base of the style, the total height of the septal nectary is 760 μm. The ovary roof is 280 μm. Bifurcated dorsal and septal bundles of carpels have been identified, which can be considered as adaptations of the early stages of fruit morphogenesis to opening. Anatomical features of the ovary of Z. candida are numerous vascular bundles in the pericarpium, non-lignified endocarp at the flower stage, we consider as adaptations to the formation of juicy fruit. New data on the anatomical structure of the flower are a significant addition to the information on antecological and post-anthetic features of the studied species. Also, these data can be used in the construction of parsimony branches of the family Amaryllidaceae.

Summary: Kiwifruit (Actinidia chinensis) is a dioecious, long‐living woody perennial vine. Reduced generation time and induction of hermaphroditism can accelerate crop improvement and facilitate alternative farming for better food security in the face of climate change.Previous studies identified that CENTRORADIALIS genes CEN and CEN4 act to repress flowering, whilst the male‐specific Shy Girl (SyGl) gene with homology to type‐C cytokinin response regulators could repress gynoecium development in model plants. Here we use CRISPR/Cas9 to mutagenize CEN, CEN4 and SyGl in the male kiwifruit A. chinensis 'Bruce'.Biallelic mutations of CEN and CEN4 generated rapid‐flowering male plants, and simultaneous targeting of CEN4 and SyGl gave rise to rapid‐flowering hermaphrodites with restored gynoecial function and viable pollen, providing functional evidence for the role of SyGl in suppression of feminization. Analysis of ovary tissues identified genes that contribute to carpel development and revealed that SyGl affected both cytokinin profiles and the expression of genes involved in cytokinin metabolism and signalling. The plant lines generated by CEN4/SyGl knockout could self‐pollinate and produce fast‐flowering offspring.These results establish that SyGI acts as the suppressor of feminization in kiwifruit and demonstrate the potential for accelerated breeding in an outcrossing horticultural woody perennial. [ABSTRACT FROM AUTHOR]

The general morphology, micromorphology, and anatomy of the flowers of Clivia miniata, Clivia nobilis, and Scadoxus multiflorus were studied using light microscopy. The studied species have large syntepalous and trimerous flowers, short floral tubes with adnate stamens, and inferior ovaries that develop baccate fruit. The gynoecium in the studied species consists of synascidiate, symplicate, and hemisymplicate zones. The style is composed of postgenitally fused carpels. The few ovules are located in a locule in the synascidiate and symplicate zones in C. miniata and C. nobilis, whereas in S. multiflorus, solitary ovules occupy the synascidiate zone in each locule. The septal nectaries are located in the hemisymplicate zone and occupy the uppermost 29% to 56% of the ovary height. Septal nectaries are of the nonlabyrinthine lilioid-type, covered with secretory tissue only in its lower portion. Nectary channels are apical or subapical and open near the style base. A common pattern of the venation of the floral parts was observed in all species: Tepal traces and stamen traces were fused in the ovary wall, the style was supplied by dorsal carpellary bundles, and ovules were supplied by ventral carpellary bundles entering the ovary from the bottom. The observed gynoecium inner structure provides adaptations for the development of fleshy fruit, with thickened parenchymous ovary wall, ovary base, and ovary roof, and numerous branched vascular bundles in the ovary wall around locules. [ABSTRACT FROM AUTHOR]

Gynoecium and fruit micromorphology and anatomy were studied using light microscopy in three species of Campanuloideae belonging to the tribes Cyanantheae (Platycodon grandiflorus), Wahlenbergieae (Jasione montana), and Campanuleae (Adenophora liliifolia) of the native and cultivated flora of Ukraine, to elucidate structural adaptations for fruit dehiscence. The studied species differed in flower/fruit orientation, carpel number, ovary insertion, and capsule-opening position, and the information provided a background for the discovery of common anatomical features influencing fruit dehiscence. In the studied species, the synascidiate and symplicate zones in the ovary and prominent placentae were found to be located near the mid-region of the ovary. The distinct innervation of the ovary wall and ovules was described. In P. grandiflorus, the septa and fruit wall contained a lignified parenchyma in a subepidermal position, while in J. montana and A. liliifolia, lignification was observed only in proximal portions of the septa, above the placenta (J. montana), or was noted as a narrow strand from the ovary base to the mid-region, called “axicorn” (A. liliifolia). In all the studied species, unlignified endocarpium was detected. The semi-inferior capsule of P. grandiflorus has been defined as a capsule of the Forsythia-type, with a sclerenchymatous layer in the inner zone of the mesocarpium. In J. montana and A. liliifolia, a new histogenetic type of capsule is described as Campanula-type, without lignified layers in the fruit wall and with lignified tissue in the septa, which enabled dehiscence. Our study proposed for the first time the classification of the capsules found in the studied species based on the development of openings in the superior or inferior regions of the fruits. The upright fruits of P. grandiflorus and J. montana reveal incomplete dorsiventral dehiscence in the superior region of the fruit, while dehiscence of pendent fruits of A. liliifolia is hippocrepiform-septifragal interlocular and occurs in the inferior region of the fruit at its base, as revealed previously in Campanula latifolia fruit. [ABSTRACT FROM AUTHOR]

Flowers of the five species from the four sections of the genus Gagea (that is, G. lutea, G. pusilla, G. reticulata, G. fragifera, and G. serotina (syn. Lloydia serotina) were investigated by light microscopy. All investigated species had similar flower organization, vertical zonality of the gynoecium, and floral vascularization. In all species, the flowers were trimerous, with the superior ovary and short complete or semicomplete syntepalous zone at the base. The presence of the syntepalous zone allows consideration of such flowers as an intermediate between hypogynous and perigynous. All investigated species had nectaries at the base of the tepals. However, in Gagea s. str., they were represented by relatively small nectariferous areas of the tepals located at the beginning of the synascidiate zone of the gynoecium. In contrast, the nectaries in G. serotina were represented by elongated tepalar outgrowths located higher, at the level of the fertile symplicate zone of the gynoecium. Considering reports on the potential peltate origin of the nectaries in G. serotina, it is probably incorrect to interpret them as homologous to the nectaries in Gagea s. str. The gynoecium in the studied species demonstrated identical vertical zonality with synascidiate, symplicate, and asymptomatic zones, and corresponded to type C of the syncarpous gynoecium. At the base of the ovary, three carpels were congenitally isolated (primary synascidiate zone); however, they were isolated only postgenitally (secondary synascidiate zone). This secondary synascidiate zone originated from a symplicate zone due to the fusion of the carpelar margins. Although it looks like a synascidiate zone, for correct interpretation of the gynoecium’s vertical structure, it should be considered symplicate. The vascularization of the flower in all investigated species was similar, with the participation of lateral vascular bundles in the supply of placentas. [ABSTRACT FROM AUTHOR]

In order to uncover the molecular mechanisms of FRUITFULL(FUL)homologous genes involving in regulating flower and fruit development in buckwheat, an 837 bp of FeFUL2 cDNA containing a 690 bp full ORF(Open Reading Frame)encoding 229 amino acids(GenBank Accession Number MG779493.1)was isolated from a Fagopyrum esculentum mutant line with long pistil and long stamen (lpls) through homologous cloning. Moreover, the FeFUL2 cDNA contains a 30 bp 5'UTR(untranslated region, UTR)and a 117 bp 3'UTR including poly-A. The results showed that the buckwheat FeFUL2 was classified into the core eudicot euFUL lineages of AP1/FUL subfamily MADS-box transcription factors through phylogenetic, protein alignment and sequence analyses. In addition, FeFUL2 was classified transcription contained a highly conservation MADS-box domain(1-57)with 57 amino acids(aa), a secondary conserved K domain(91-159)with 69 aa, as well as two conserved motifs: FUL motif and paleo AP1 motif lying variable C terminal region. The highly conserved MADS domain was responsible for DNA binding, dimerization and nuclear localization of MADS-domain transcription factors. The secondary conserved K domain was involved in the formation of amphipathic helices and responsible for protein dimerization and multimeric complex formation protein-protein interactions. Finally, the C domain was important for transcriptional activation and multimeric complex formation. Moreover, the C terminal region of FeFUL2 was variable in sequence and length comparing with other euFUL-like transcriptors, which suggested that FeFUL2 may play different roles regulating flower and fruit development with FUL-like homologs from other species. qPCR revealed that FeFUL2 expression was detectable in all tissues including root, stem, leaf, tepal, stamen, gynoecium and 4-day-old juvenile fruit. However, FeFUL2 expression level in tepal was significantly higher than those in other organs(LSD, P<0.01). In addition, FeFUL2 expression level in stamen, gynoecium and 4-day-old juvenile fruit displayed no significant differences(LSD,P>0.05), but FeFUL2 expression level in stem and leaf was significantly higher than root(LSD,P<0.05). However, FeFUL2 expression level in stem and leaf showed no significant differences(LSD,P>0.05). Above all, our data suggest that the function of FeFUL2 may show a difference with other euFUL-like gene, and FeFUL2 play a major role involving in perianth development. [ABSTRACT FROM AUTHOR]

Protein farnesylation is a post-translational modification regulated by the ERA1 (Enhanced Response to ABA 1) gene encoding the β-subunit of the protein farnesyltransferase in Arabidopsis. The era1 mutants have been described for over two decades and exhibit severe pleiotropic phenotypes, affecting vegetative and flower development. We further investigated the development and quality of era1 seeds. While the era1 ovary contains numerous ovules, the plant produces fewer seeds but larger and heavier, with higher protein contents and a modified fatty acid distribution. Furthermore, era1 pollen grains show lower germination rates and, at flower opening, the pistils are immature and the ovules require one additional day to complete the embryo sac. Hand pollinated flowers confirmed that pollination is a major obstacle to era1 seed phenotypes, and a near wild-type seed morphology was thus restored. Still, era1 seeds conserved peculiar storage protein contents and altered fatty acid distributions. The multiplicity of era1 phenotypes reflects the diversity of proteins targeted by the farnesyltransferase. Our work highlights the involvement of protein farnesylation in seed development and in the control of traits of agronomic interest.

The organogenesis and development of reproductive organs, i.e., stamen and gynoecium, are important floral characteristics that are closely related to pollinators and reproductive fitness. As a genus from Magnoliaceae, Liriodendron has only two relict species: L. chinense and L. tulipifera. Despite the similar flower shapes of these species, their natural seed-setting rates differ significantly, implying interspecies difference in floral organogenesis and development. MADS-box genes, which participate in floral organogenesis and development, remain unexplored in Liriodendron. Here, to explore the interspecies difference in floral organogenesis and development and identify MADS-box genes in Liriodendron, we examined the stamen and gynoecium primordia of the two Liriodendron species by scanning electron microscopy combined with paraffin sectioning, and then collected two types of primordia for RNA-seq. A total of 12 libraries were constructed and 42,268 genes were identified, including 35,269 reference genes and 6,999 new genes. Monoterpenoid biosynthesis was enriched in L. tulipifera. Genome-wide analysis of 32 MADS-box genes was conducted, including phylogenetic trees, exon/intron structures, and conserved motif distributions. Twenty-six genes were anchored on 17 scaffolds, and six new genes had no location information. The expression profiles of MIKC-type genes via RT-qPCR acrossing six stamen and gynoecium developmental stages indicates that the PI-like, AG/STK-like, SEP-like, and SVP-like genes may contribute to the species-specific differentiation of the organogenesis and development of reproductive organs in Liriodendron. Our findings laid the groundwork for the future exploration of the mechanism underlying on the interspecific differences in reproductive organ development and fitness in Liriodendron. [ABSTRACT FROM AUTHOR]

Thismia is characterized by an exceptionally complicated floral morphology that is currently not understood properly. In the taxonomic literature, descriptive rather than morphological terms are often applied to parts of the flower in Thismia , relating to the general appearance of the floral organs instead of their precise homologies. Precise understanding of the floral structure is complicated by the rarity of Thismia spp. and the paucity of appropriate material. Here we provide a comprehensive study of reproductive organs of three Thismia spp. (T. annamensis , T. javanica and T. mucronata) including the first investigation of inflorescence architecture and early floral development in Thismiaceae. We found a hitherto unknown diversity of the reproductive shoots in the genus, manifested in the number of floral prophylls (two or three, in contrast to a single prophyll in the vast majority of monocots) and in the branching plane resulting in two distinct inflorescence types, a drepanium and a bostryx. We report the non-acropetal sequence of initiation of floral whorls (with stamens being the last elements to initiate), never previously described in monocots, and the gynoecium composed of completely plicate carpels, also a rare feature for monocots. Floral vasculature is relatively uniform in Thismia , but significant interspecific differences are found in tepal innervation, including the number of tepal traces; some of these differences are not immediately related to the external tepal morphology. We argue that the annulus, which acts as a roof of the hypanthium, possesses an androecium nature and represents congenitally fused bases of stamen filaments. We describe the stamens as laminar structures, which are also shortly tubular in the distal part of the supraconnective with the adaxial tubular side forming a skirt-like appendage. Finally, the placentas, which are column-like when mature, are initially parietal, becoming secondarily similar to free-central placentas through schizogenous separation from the ovary wall. [ABSTRACT FROM AUTHOR]

Sporogenesis and gametophytes development in Arabidopsis thaliana (Brassicaceae) was studied. Arabidopsis thaliana was selected for this study as a biogenetic model with a small genome and a short life cycle. Flowers and buds in different developmental stages were removed, fixed in an FAA70, stored in 70 % ethanol, embedded in paraffin and sectioned at 7 − 10 µm with a microtome, stained with Hematoxylin – Eosin and analyzed with a photomicroscope. The results showed the anthers are tetrasporangiate, anther tapetum is of secretory type at the beginning and plasmodial at the end of anther development. Also, microspore tetrads are tetrahedral and rarely tetragonal. In addition, mature pollen grains are spherical, tricolporate, scabrate, and tricellular. The gynoecium is bicarpellate and the ovule is amphitropous, bitegmic, and tenuinucellate. Hypostasis was also observed in basis of nucellus. Endothelium is composed of one cell row and cell divisions of megaspore mother cell results in T-shaped tetrad. The chalazal cell is a functional megaspore that survives and functions in megagametophyte development. The embryo sac development belonged to the Polygonum type and it is curved. The mature embryo sac is composed of 7 cells, one central cell containing polar nuclei, two elongated synergids, a triangular oosphere cell, and three antipodal cells that are degenerated immediately by developing the embryogenesis stage in the mature embryo. [ABSTRACT FROM AUTHOR]

Hidden Markov models (HMMs) have emerged as an important tool for understanding the evolution of characters that take on discrete states. Their flexibility and biological sensibility make them appealing for many phylogenetic comparative applications.Previously available packages placed unnecessary limits on the number of observed and hidden states that can be considered when estimating transition rates and inferring ancestral states on a phylogeny.To address these issues, we expanded the capabilities of the R package corHMM to handle n‐state and n‐character problems and provide users with a streamlined set of functions to create custom HMMs for any biological question of arbitrary complexity.We show that increasing the number of observed states increases the accuracy of ancestral state reconstruction. We also explore the conditions for when an HMM is most effective, finding that an HMM is an appropriate model when the degree of rate heterogeneity is moderate to high.Finally, we demonstrate the importance of these generalizations by reconstructing the phyllotaxy of the ancestral angiosperm flower. Partially contradicting previous results, we find the most likely state to be a whorled perianth, whorled androecium, whorled gynoecium. The difference between our analysis and previous studies was that our modelling explicitly allowed for the correlated evolution of several flower characters. [ABSTRACT FROM AUTHOR]

Schistochila gradsteinii Thouvenot sp. nov., is added to the five Schistochila Dumort. species formerly known in New Caledonia. The new species is distinctive by the lack of underleaves, bilobed leaves entire margined, with larger ventral lobes oblong-lanceolate to oblong-ovate, apiculate, dorsal lobes oblong-ovate, inserted on the dorsal surface of ventral lobes, the free margins not reaching the ventral margins, leaf cells with seemingly 3-layered trigones, stems with a conspicuous epidermis. It shares with the endemic S. vitreocincta (Herzog) X.L.He & Glenny some features distinctive from the rest of the genus. In addition, the occurrence of S. vitreocincta is clarified, the gynoecium of S. integerrima Steph. is newly described and a key to the New Caledonian species of Schistochila is provided. [ABSTRACT FROM AUTHOR]

In angiosperms, floral homeotic genes encoding MADS-domain transcription factors regulate the development of floral organs. Specifically, members of the SEPALLATA (SEP) and AGAMOUS (AG) subfamilies form higher-order protein complexes to control floral meristem determinacy and to specify the identity of female reproductive organs. In rice, the AG subfamily gene OsMADS13 is intimately involved in the determination of ovule identity, since knock-out mutant plants develop carpel-like structures in place of ovules, resulting in female sterility. Little is known about the regulatory pathways at the base of rice gynoecium development. To investigate molecular mechanisms acting downstream of OsMADS13, we obtained transcriptomes of immature inflorescences from wild-type and Osmads13 mutant plants. Among a total of 476 differentially expressed genes (DEGs), a substantial overlap with DEGs from the SEP -family Osmads1 mutant was found, suggesting that OsMADS1 and OsMADS13 may act on a common set of target genes. Expression studies and preliminary analyses of two up-regulated genes encoding Zinc-finger transcription factors indicated that our dataset represents a valuable resource for the identification of both OsMADS13 target genes and novel players in rice ovule development. Taken together, our study suggests that OsMADS13 is an important repressor of the carpel pathway during ovule development. [ABSTRACT FROM AUTHOR]

Subtribe Eleusininae (Chloridoideae, Poaceae) comprise 237 species with little morphological diversity in inflorescence structure. This diversity may be explained by an evolution from complex (pyramidal, highly branched) to simpler (digitate, barely branched) morphologies. However, only mature specimens have been studied; the developmental analyses of the inflorescences are rare. We analysed the inflorescence, spikelet and flower development of 17 species of Eleusininae using scanning electron microscopy. In the early stages of the transition to flowering of the studied species, the inflorescence meristem elongates initiating primary branches acropetally. The differentiation of these branches along the main axis is either basipetal or amphipetal. Although the initiation of secondary branches along primary branches may be acropetal or amphipetal, their differentiation follows an amphipetal direction. The florets in spikelets are initiated acropetally. We found abnormal orientation of stamens and gynoecium in florets of Leptochloa chloridiformis. The analysis of the ontogeny has enriched current knowledge of inflorescences in the subtribe. In addition, the developmental patterns revealed the existence of more than one developmental pattern leading to similar mature inflorescence forms. The results will support future efforts on postulating trends of developmental patterns across Poaceae. [ABSTRACT FROM AUTHOR]