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Androdioecy is the rarest sexual system among plants. The majority of androdioecious species are herbaceous plants that have evolved from dioecious ancestors. Nevertheless, some woody and androdioecious plants have hermaphrodite ancestors, as in the Annonaceae, where androdioecious genera have arisen several times in different lineages. The majority of androdioecious species of Annonaceae belong to the Neotropical tribe Malmeeae. In addition to these species, Pseudoxandra spiritus-sancti was recently confirmed to be androdioecious. Here, we describe the morphology of male and bisexual flowers of Pseudoxandra spiritus-sancti, and investigate the evolution of androdioecy in Malmeeae. The phylogeny of tribe Malmeeae was reconstructed using Bayesian inference, maximum parsimony and maximum likelihood of 32 taxa, using DNA sequences of 66 molecular markers of the chloroplast genome, sequenced by next generation sequencing. The reconstruction of ancestral states was performed for characters associated with sexual systems and floral morphology. The phylogenetic analyses reconstructed three main groups in Malmeeae, (Malmea (Cremastosperma, Pseudoxandra)) sister to the rest of the tribe, and (Unonopsis (Bocageopsis, Onychopetalum)) sister to (Mosannona, Ephedranthus, Klarobelia, Oxandra, Pseudephedranthus fragrans, Pseudomalmea, Ruizodendron ovale). Hermaphroditism is plesiomorphic in the tribe, with four independent evolutions of androdieocy, which represents a synapomorphy of two groups, one that includes three genera and 14 species, the other with a single genus of seven species. Male flowers are unisexual from inception and bisexual flowers possess staminodes and functional stamens. Pseudoxandra spiritus-sancti is structurally androdioecious., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Premise of the Study: The grass subfamily Anomochlooideae is phylogenetically significant as the sister group to all other grasses. Thus, comparison of their structure with that of other grasses could provide clues to the evolutionary origin of these characters., Methods: We describe the structure, embryology, and development of the flower and partial inflorescence of the monotypic Brazilian grass Anomochloa marantoidea. We compare these features with those of other early-divergent grasses such as Pharus and Streptochaeta and closely related Poales such as Ecdeiocolea., Key Results: Anomochloa possesses several features that are characteristic of Poaceae, notably a scutellum, a solid style, reduced stamen number, and an ovary with a single ovule that develops into a single indehiscent fruit. Interpretation of floral patterning in Anomochloa is problematic because the ramification pattern of the florets places the bracts and axes in unusual positions relative to the primary inflorescence axis. Our study indicates that there is a single abaxial carpel in Anomochloa, probably due to a cryptic type of pseudomonomery in Anomochloa that resembles the pseudomonomery of other grasses. On the other hand, the Anomochloa flower differs from the "typical" grass flower in lacking lodicules and possessing four stamens, in contrast with the tristaminate condition that characterizes many other grasses., Conclusions: Using the median part of the innermost bract as a locator, we tentatively homologize the inner bract of the Anomochloa partial inflorescence with the palea of other grasses. In this interpretation, the pattern of monosymmetry due to stamen suppression differs from that of Ecdeiocolea.

Extrafloral nectaries are nectar-secreting structures that are especially common among the woody flora of the Brazilian cerrado, a savanna-like vegetation. In this study, we provide morphological and anatomical descriptions of extrafloral nectaries (EFNs) occurring on vegetative and reproductive organs of several plant species from the cerrado, and discuss their function and ecological relevance. We describe the morphology and anatomy of EFNs of 40 species belonging to 15 woody families using scanning electron microscopy and light microscopy. We categorise EFNs following a structural-topographical classification, and characterise the vascularised and complex nectaries, amorphous nectaries and secretory trichomes. Fabaceae, Bignoniaceae, Malpighiaceae and Vochysiaceae were the plant families with the majority of species having EFNs. Ten species possess more than one morphotype of gland structure. Observations and experimental field studies in the cerrado support the anti-herbivore role of EFN-gathering ants in this habitat. Additional morphological studies of EFNs-bearing plants, including other growth forms (e.g. herbs and lianas), are being undertaken and will hopefully cast further light on the ecological relevance of these glands in the cerrado, especially with respect to their attractiveness to multiple visitors.

Background: Nectar is offered by numerous flowering plants to attract pollinators. To date, the production and secretion of nectar have been analyzed mainly in eudicots, particularly rosids such as Arabidopsis. However, due to the enormous diversity of flowering plants, further research on other plant species, especially monocots, is needed. Ananas comosus (monocot) is an economically important species that is ideal for such analyses because it produces easily accessible nectar in sufficient quantities. In addition, the analyses were also carried out with Nicotiana tabacum (dicot, asterids) for comparison. Results: We performed transcriptome sequencing (RNA-Seq) analyses of the nectaries of Ananas comosus and Nicotiana tabacum, to test whether the mechanisms described for nectar production and secretion in Arabidopsis are also present in these plant species. The focus of these analyses is on carbohydrate metabolism and transport (e.g., sucrose-phosphate synthases, invertases, sucrose synthases, SWEETs and further sugar transporters). In addition, the metabolites were analyzed in the nectar, nectaries and leaves of both plant species to address the question of whether concentration gradients for different metabolites exist between the nectaries and nectar The nectar of N. tabacum contains large amounts of glucose, fructose and sucrose, and the sucrose concentration in the nectar appears to be similar to the sucrose concentration in the nectaries. Nectar production and secretion in this species closely resemble corresponding processes in some other dicots, including sucrose synthesis in nectaries and sucrose secretion by SWEET9. The nectar of A. comosus also contains large amounts of glucose, fructose and sucrose and in this species the sucrose concentration in the nectar appears to be higher than the sucrose concentration in the nectaries. Furthermore, orthologs of SWEET9 generally appear to be absent in A. comosus and other monocots. Therefore, sucrose export by SWEETs from nectaries into nectar can be excluded; rather, other mechanisms, such as active sugar export or exocytosis, are more likely. Conclusion: The mechanisms of nectar production and secretion in N. tabacum appear to be largely similar to those in other dicots, whereas in the monocotyledonous species A. comosus, different synthesis and transport processes are involved. [ABSTRACT FROM AUTHOR]

Replicated trait evolution can provide insights into the mechanisms underlying the evolution of biodiversity. One example of replicated evolution is the awn, an organ elaboration in grass inflorescences. Awns are likely homologous to leaf blades. We hypothesized that awns have evolved repeatedly because a conserved leaf blade developmental program is continuously activated and suppressed over the course of evolution, leading to the repeated emergence and loss of awns. To evaluate predictions arising from our hypothesis, we used ancestral state estimations, comparative genetics, anatomy, and morphology to trace awn evolution. We discovered that awned lemmas that evolved independently share similarities in developmental trajectory. In addition, in two species with independently derived awns and differing awn morphologies (Brachypodium distachyon and Alopecurus myosuroides), we found that orthologs of the YABBY transcription factor gene DROOPING LEAF are required for awn initiation. Our analyses of awn development in Brachypodium distachyon, Alopecurus myosuroides, and Holcus lanatus also revealed that differences in the relative expansion of awned lemma compartments can explain diversity in awn morphology at maturity. Our results show that developmental conservation can underlie replicated evolution and can potentiate the evolution of morphological diversity., (© 2024 The Author(s). New Phytologist © 2024 New Phytologist Foundation.)

Mutualisms may be more or less sensitive to environmental conditions depending on the diversity and responses of the species involved. Ants frequently form mutualistic associations with plants bearing extrafloral nectaries (EFNs): the ants protect the plants from herbivores and receive food resources (i.e., nectar) in return. As ectotherms, ants are strongly influenced by temperature, and temperature shifts can affect ant-plant interactions in ways that often depend on species functional traits. In this study, we explored the influence of EFN size and leaf surface temperature on ant-plant interactions in a Caatinga dry forest in Brazil. We observed the ants visiting 14 EFN-bearing plant species at different times of day over 12 sampling months; we also measured leaf surface temperatures during these periods. We next quantified EFN size for 68 individuals from the 14 plant species. The observational data were used to characterize the heat tolerance of the attendant ant species (i.e., based on levels of foraging activity). We then evaluated the mutualism's degree of functional resilience using two indices: functional redundancy (i.e., the number of ant species interacting with a given plant species) and thermal response diversity (i.e., variability in the heat tolerance of the ant species interacting with a given plant species). We found that leaf surface temperature, but not EFN size, had an influence on mutualism functional resilience. As temperatures increased, both functional redundancy and thermal response diversity decreased. This result implies that warmer global temperatures could heighten the vulnerability of facultative ant-plant mutualisms, regardless of plant traits., Competing Interests: Declarations. Conflict of interest: The authors declare that there is no conflict of interest/competing interests. This study does not contain any experiments using animal species that require ethical approval., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Understanding the mechanisms that enable species coexistence is a central question in ecology, as it helps to comprehend species diversity. One of the most common stabilizing mechanisms of coexistence is niche segregation, which can prevent the competitive exclusion of the fittest competitor. Niche segregation can manifest itself at various temporal and spatial scales, allowing provide essential insights into understanding the stabilizing mechanisms facilitating the coexistence of species. We assessed coexistence patterns among flower-dwelling spiders in two ways, in the first set of analyses, we investigated the factors influencing the quantity of spider individuals and species. The second approach we investigate the spatio-temporal segregation between species, effectively examining the coexistence patterns. We observed that the presence of inflorescences per plant, the number of flowers per inflorescence, and the presence of EFNs play a significant role in increasing spider abundance and richness. We find only a marginal seasonal effect, suggesting that spiders have constant access to resources throughout the year. Our niche overlap analysis demonstrated synchrony in the spatial occupation of niches by different spider species. The coexistence patterns appeared to be unaffected by the number of inflorescences. The greater number of inflorescences will enable a greater availability of niches, and consequently more abundance and richness of species of spiders the plant can sustain. Our results suggest that, to mitigate the adverse consequences of competitive interactions, spiders tend to adopt spatial partitioning as a strategy to facilitate the coexistence of spiders living in reproductive structures on plants in the Brazilian savanna., Competing Interests: Declarations. Conflict of interest: The authors declare no conflict of interests. Ethics approval: Not applicable. Consent to participate: Not applicable. Consent for publication: Not applicable., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

About one third of vascular plants develop glandular trichomes, which produce defensive compounds that repel herbivores and act as a natural biofactory for important pharmaceuticals such as artemisinin and cannabinoids. However, only a few regulators of glandular structures have been characterized so far. Here we have identified two closely-related MYB-like genes that redundantly inhibit the formation of glandular cells in tomatoes, and they are named as GLAND CELL REPRESSOR (GCR) 1 and 2. The GCR genes highly express in the apical cells of tomato trichomes, with expression gradually diminishing as the cells transition into glands. The spatiotemporal expression of GCR genes is coordinated by a two-step inhibition process mediated by SlTOE1B and GCRs. Furthermore, we demonstrate that the GCR genes act by suppressing Leafless (LFS), a gene that promotes gland formation. Intriguingly, homologous GCR genes from tobacco and petunia also inhibit gland formation, suggesting that the GCR-mediated repression mechanism likely represents a conserved regulatory pathway for glands across different plant species.The spatiotemporal formation of glands in tomato trichomes is regulated by two MYB-like transcription factors, named as GCR1 and 2, whose expression is tightly restricted by SlTOE1B. GCR1 and 2 inhibit gland formation by repressing LFS expression. [ABSTRACT FROM AUTHOR]

Lophopterys floribunda is a Neotropical species of Malpighiaceae endemic to Brazil, occurring in both the Amazon and Atlantic Forest. Instead of the typical bi-glandular sepals reported for Neotropical Malpighiaceae, this species presents a single, large gland on the lateral sepals. In addition, ant patrolling was observed at the apex of bracts and bracteoles during fieldwork. Thus, this work aimed to describe the sepalar gland of L. floribunda and other secretory structures in its flowers and inflorescence. Samples of bracts, bracteoles, sepals, petals, and anther were collected and submitted to usual anatomical techniques. Unexpected nectaries at the apex of bracts and bracteoles, not visible to the naked eye, were described and represent a new type of structure for the family due to both their position and size. Mutualistic ants consume the exudate produced by these tiny nectaries, and such structures enable a specific visitation pattern for Lophopterys. Typical epithelial elaiophores occur on the lateral sepals, formed by an invaginated epidermis, which predominantly produce lipid secretion. The petal marginal glands are anatomically similar to the standard type of colleter, which exude mucilaginous substances. The exudate produced by the petal marginal glands was considered to have an additional role of contributing to the maintenance of the closed bud during the beginning of development. The globose epidermal cells containing lipids, proteins, and polysaccharides observed in the connective may be responsible for the typical aroma emitted by these flowers. The diversity of secretory structures reported here has application in both systematic and ecological studies of Malpighiaceae. [ABSTRACT FROM AUTHOR]

Bromeliaceae display many water-use strategies, from leaf impounding tanks to Crassulacean acid metabolism (CAM) photosynthesis and absorbing trichomes. Recent studies show that trichomes in inflorescences of bromeliads can exude viscous secretions, protecting against various stresses, including excessive water loss. In light of this, and considering the knowledge gap regarding inflorescence trichomes in bromeliads, we aimed to investigate the presence, source and chemical nature of inflorescence secretions in species of the Tillandsioideae (Bromeliaceae) and to describe the anatomy of their floral bracts focusing on trichome structure and position. We conducted a prospection of secretory activity and anatomy in floral bracts in 52 species of Tillandsioideae and 1 early divergent Bromeliaceae species. We used histochemical tests to investigate the presence and nature of secretion combined with standard light microscopy methods. Secretion appears in all studied species of tribe Vrieseeae, in Guzmania species, Wallisia cyanea , Tillandsia streptopylla (Tillandsieae) and Catopsis morreniana (Catopsideae). It is absent in Vriesea guttata (Vrieseeae), Racinaea crispa and various Tillandsia species (Tillandsieae). Secretion is produced by peltate trichomes on the adaxial surface of young bracts and comprises hydrophilic and lipophilic substances. Bract anatomy revealed an internal mucilage-secreting tissue with wide distribution within the subtribe Vrieseinae. Our results point to a broad occurrence of secretion associated with bracteal scales in inflorescences of Tillandsioideae. Secretory function is strongly related to trichomes of the adaxial surface, whereas the indumentum of the abaxial side is lacking or likely associated with water absorption; the latter case is especially related to small, xeric plants. Exudates might engage in colleter-like roles, protecting against desiccation, high-radiation and herbivores. Directions for future research are presented. [ABSTRACT FROM AUTHOR]

Since being established, the phylogenetic position of Elatinaceae has been controversial, but recent phylogenetic studies place it in Malpighiales as the sister group of Malpighiaceae. Molecular data support this relationship, but some morphological aspects of it are still poorly understood, especially floral evolution in Elatinaceae and its relationship with closely related lineages. Based on representatives of the two accepted genera in Elatinaceae, Bergia and Elatine, we describe the floral anatomy of the family, compare it to that of the phylogenetically closest families, and discuss the relevance of anatomical floral characters. Based on the available data, the presence of a glandular connective and hypostase are possible synapomorphies of the Elatinaceae + Malpighiaceae clade. The calyx glands present in Elatinaceae comprise cells with phenolic content without secretory activity. Some characters are autapomorphies for Elatinaceae, such as a reduction in the number of microsporangia and a thin-walled endothecium. However, other characteristics, such as a gamosepalous calyx, non-functional calyx glands, axile placentation, pendulous ovules, and intercarpellary vascular complexes, also occur in other families in the Malpighiales. The autapomorphies of Elatinaceae are evidence of structural adaptations of the flower in favor of autogamy, which could explain numerous morphological reversions. This aspect constitutes a marked difference in the Elatinaceae + Malpighiaceae clade since the latter is allogamous and Elatinaceae is autogamous and represents a relevant change in the evolutionary history of the two lineages. [ABSTRACT FROM AUTHOR]

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Summary: The genus Kielmeyera (Calophyllaceae) includes around 50 species distributed mainly in Brazil. The complex evolutionary history of Kielmeyera is reflected in its great morphological variation and in the difficulty in distinguishing closely related species. Thus, at least three species complexes, namely the K. coriacea, K. petiolaris and K. rubriflora complexes, have been recognised within the genus. Here we assess the variation of leaf anatomical characters across all the taxa included in the Kielmeyera coriacea complex. Our results revealed that seven anatomical characters can be used to identify three distinct groups within this complex. The Kielmeyera coriacea subsp. tomentosa leaf is particularly distinct regarding mesophyll structure, stomata distribution, and size of stomatal chambers. Therefore, we propose to once again accept K. tomentosa at species rank and recognise three species within the complex: K. coriacea, K. grandiflora and K. tomentosa. We demonstrate the enormous potential of evaluating leaf anatomy variation to delimit species in Kielmeyera and in Calophyllaceae. [ABSTRACT FROM AUTHOR]

Insect herbivores assess plants by integrating responses elicited by a variety of external and internal cues and signals mediated by physical and chemical traits. We investigated host assessment behaviours of adult females of the Eucalyptus‐feeding psyllid, Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae), on 10 species and subspecies (comprising preferred and non‐preferred hosts) using video recordings, electrical penetration graph (EPG) technology, and histological examination of tissues surrounding secondary veins. Our video recordings indicated that the shortest first searching time (mean 7.5 s) occurred on preferred hosts. Females placed on novel (non‐preferred) hosts jumped off leaves in <10 s. We found that host acceptance occurred surprisingly rapidly after stylet penetration, e.g., between 7 and 11 s on preferred eucalypts, suggesting a strong role for gustatory cues. Our histological studies provided no evidence of physical barriers to phloem access. Females produced eight EPG waveforms, as observed for other psyllids and aphids, but the durations of PG (xylem activity) and PE2 (phloem ingestion), in particular, were unlike those recorded for any other hemipteran. On preferred hosts, phloem ingestion represented 21.5% (mean duration 4 h 18 min) of individual feeding bouts, whereas on non‐preferred hosts, there was almost no ingestion from phloem. Xylem ingestion on non‐preferred hosts represented 20.1% (mean duration 4 h 1 min) of feeding bouts, presumably to imbibe water. Thus, contrary to widespread belief, female G. brimblecombei did not feed exclusively from phloem even on preferred hosts, but also regularly ingested from the xylem. This is surprising considering that nymphs construct lerps consisting of approximately 16% sugars, and suggests that adults feed from phloem for shorter periods than offspring. Rapid assessment of hosts could also mean that positive stimuli induced by sugars are opposed by negative gustatory stimuli experienced in non‐vascular tissues. The most likely source of such stimuli are water‐soluble polyphenolic compounds that are widespread in cell vacuoles. [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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Copyright of Rodriguésia is the property of Revista Rodriguesia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Marrubium L., is a problematic genus of Lamiaceae family with approximately 40 taxa that some of its species grow in Iran. In the current study, we studied infrageneric taxonomic relationships among six Iranian Marrubium species using morphological and anatomical traits, and molecular genetic techniques, including inter simple sequence repeats (ISSR), chloroplast DNA (cpDNA) and nuclear ribosomal internal transcribed spacer (ITS). We investigated five individuals per each species. Most of the studied qualitative and quantitative morphological characteristics differed significantly (P ≤ 0.001) among these species, and we found five morphotype groups in the PCA plot of morphological traits. Leaf blade anatomical structure was dorsi-ventral in all species. Meanwhile, we observed a significant variation in most of the studied anatomical variables. Based on anatomical features, these species were clustered into three groups. Results of ISSR study revealed that the total genetic diversity at the species level (Ht) was higher than within each species (Hs). These findings were supported by the results of AMOVA test, Gst and Nm values. According to STRUCTURE analysis and Nei's genetic distance, these species were divided into 5 genotype groups. The studied species were clustered separately in cpDNA and ITS trees of phylogenetic studies. We observed a high level of infraspecific divergence in the evaluated species. In addition, the employed taxonomical markers have enough potential to separate the investigated species. However, the clustering patterns of the species based on the examined techniques were not the same, except those for M. parviflorum Fisch. & C.A. Mey., and M. crassidens Bioss., that were clustered closely in most cases. It can be concluded that the evaluated species revealed a taxonomically complex group resulting from high infraspecific variation, polyploidy and hybridization. [ABSTRACT FROM AUTHOR]

The aerial environment appears to structurally modify roots, which frequently show specializations for absorbing water and nutrients. Among those specializations are the velamen, a multiseriate epidermis generally composed of dead mature cells, and greater degrees of lignification in the endodermis, exodermis, and pith. Vanilla phaeantha is a hemiepiphyte used here as a model of study to determine which root characteristics demonstrate the most plasticity in response to aerial and terrestrial environments. It produces roots growing under three conditions: (1) aerial and free, growing from the highest branches towards the ground; (2) aerial roots attached to the phorophyte; and (3) terrestrial. Samples taken 3 cm from the apices were used to prepare histological slides. The tissues and other anatomical structures were measured and histochemically characterized. The most plastic characteristics were the external periclinal thicknesses of the exodermis and the total area occupied by the aerenchyma lacunae. The free roots were the longest, did not evidence root hairs, and had the largest number of the aerenchyma lacunae; they also evidenced greater thicknesses of the exodermis in contact with the epidermis walls that helped maintain their shapes. Terrestrial roots had root hairs around the entire circumference and intense infestations of mycorrhiza, indicating their involvement in nutrient acquisition. The adhering roots evidenced free regions similar to those of aerial roots, as well as adhering regions showed characteristics similar to terrestrial roots (with root hairs and mycorrhiza infestations). [ABSTRACT FROM AUTHOR]

In ant–plant mutualisms mediated by plant-based liquid resources (e.g., extrafloral and pericarpial nectar), third-party exploiters are often present. Usually, the costs of having exploiters species seem to have little to no effect on ant–plant mutualistic interaction. However, little is known about how and to what extent exploiters affect mutualistic interactions. In this study, we evaluated the cascading effects of Rhinoleucophenga myrmecophaga (Diptera) predatory larvae on the outcomes of the interaction between mutualistic ants and a pericarpial nectary (PN)-bearing plant, Cordiera elliptica (Rubiaceae). In a manipulative experiment controlling for the presence of ants and/or predatory larvae, we evaluated arthropods and larvae, plant fitness, and pericarpial nectar production. We found that: (a) the presence of larvae decreased ant abundance by 50% resulting in an increase of arthropod number by 38%; (b) the absence of ants negatively influenced larva development and survival; (c) fruits with larvae and without ants had lower volume and weight, fewer viable seeds, and a higher parasitism rate; and (d) the pericarpial nectar sugar concentration is higher in plants with larvae and without ants. We showed that the outcomes of the multitrophic relationship between ants, R. myrmecophaga larvae, and an PN-bearing plant led to costly cascading effects on this mutualistic relationship. This interaction can range from negative to positive, in which the predatory fly larvae directly and indirectly influence ants number and behavior, and consequently the plant fitness. [ABSTRACT FROM AUTHOR]

The diversity of secondary metabolites of individual plants results from multiple enzymatic processes in planta and various environmental factors, such as temperature, moisture, and soil conditions. Chemical composition analysis of plants can lead to a new method to understand relationship among comparable plants along with biological classification such as genetic and anatomical method. In this study, the chemical diversity of nine different Lauraceae species was investigated, and the plant samples were chemically analyzed and classified. Multivariate analysis methods, such as PLS-DA, were used to select important metabolites distinguishing the nine Lauraceae species. The selected metabolites were identified through preparative LC-MS or MS/MS fragment pattern analysis. In addition, the chemical dendrogram for the nine Lauraceae species was interpreted through molecular network analysis and compared with the genetic dendrogram. This approach enabled us to compare the complete chemical compositions of multiple plant samples to identify relationships among plants. [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]

Plant recognition has great potential in forestry research and management. A new method combined back propagation neural network and radial basis function neural network to identify tree species using a few features and samples. The process was carried out in three steps: image pretreatment, feature extraction, and leaf recognition. In the image pretreatment processing, an image segmentation method based on hue, saturation and value color space and connected component labeling was presented, which can obtain the complete leaf image without veins and background. The BP-RBF hybrid neural network was used to test the influence of shape and texture on species recognition. The recognition accuracy of different classifiers was used to compare classification performance. The accuracy of the BP-RBF hybrid neural network using nine dimensional features was 96.2%, highest among all the classifiers. [ABSTRACT FROM AUTHOR]

Background and Aims Eriocaulaceae exhibit a great variety of floral traits associated with insect (e.g. nectariferous structures) and wind pollination (unisexual flowers, exposed sexual organs and small pollen grains), as well as the 'selfing syndrome' (small flowers, short distance between stigma and anthers, and temporal overlap of male and female phases). Paepalanthus bifidus , P. subtilis and P. tortilis are related species that differ in form, size and colour of floral structures. We aimed to investigate the pollination and reproductive biology of these three species. Methods We analysed the floral biology, floral visitors, pollinator behaviour, and the contribution of insects, wind and spontaneous geitonogamy to fruit set. We also evaluated the floral colour and scent of the species. Colour reflectance of capitula of each species was measured and plotted in models of insect vision. Floral scent samples were extracted and the compounds were compared to vegetative scent samples. Key Results In all species, the staminate and pistillate flowers are arranged in alternating cycles with a temporal overlap between these phases. Ants were the most frequent floral visitors and were effective pollinators in P. bifidus and P. tortilis , while flies were occasional pollinators in P. tortilis. Floral visitors were not observed in P. subtilis. In all species, fruits were produced by spontaneous geitonogamy, with no evidence of wind pollination. According to the models of insect vision, the colours of the capitula of P. bifidus and P. subtilis are the most inconspicuous for ants and flies. We found no difference between the emission of volatiles of inflorescences and vegetative structures. Conclusions This study suggests that ant pollination might be more widespread in Eriocaulaceae than currently assumed. Furthermore, for small monocarpic plants, mixed mating strategies are most favourable, by ensuring reproduction either by outcrossing when pollinators are abundant or by spontaneous geitonogamy when pollinations are scarce/absent. [ABSTRACT FROM AUTHOR]

Background and Aims Psidium is the fourthth largest genus of Myrtaceae in the Neotropics. Psidium guajava is widely cultivated in the tropics for its edible fruit. It is commercially under threat due to the disease guava decline. Psidium cattleyanum is one of the 100 most invasive organisms in the world. Knowledge of the phylogenetic relationships within Psidium is poor. We aim to provide a review of the biology, morphology and ecology of Psidium , a phylogenetic tree, an infrageneric classification and a list of species. Methods Morphological and geographic data were obtained by studying Psidium in herbaria and in the field between 1988 and 2020. Forty-six herbaria were visited personally. A database of approx. 6000 specimens was constructed, and the literature was reviewed. Thirty species (about a third of the species in the genus) were sampled for molecular phylogenetic inference. Two chloroplast (psb A– trn H and ndh F) and two nuclear (external transcribed spacer and internal transcribed spacer) regions were targeted. Phylogenetic trees were constructed using maximum likelihood (ML; RaxML) and Bayesian inference (BI; MrBayes). Key Results Psidium is a monophyletic genus with four major clades recognized as sections. Section Psidium (ten species), to which P. guajava belongs, is sister to the rest of the genus; it is widespread across the Neotropics. Section Obversifolia (six species; restricted to the Brazilian Atlantic Forest), which includes P. cattleyanum , is sister to the innermost clade composed of sister sections Apertiflora (31 species; widespread but most diverse in the Brazilian Atlantic Forest) +  Mitranthes (26 species; widespread in dry forests and probably diverse in the Caribbean). Characters associated with diversification within Psidium are discussed. Conclusions Research on pre-foliation, colleters, leaf anatomy, leaf physiology, staminal development, placentation and germination associated with the anatomy of the opercular plug is desirable. Studies are biased towards sections Psidium and Obversifolia , with other sections poorly known. [ABSTRACT FROM AUTHOR]

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Main conclusion: The extrafloral nectaries ofS. occidentaliswere studied structurally and anatomically (at secretory and post-secretory developmental stages). Role of extrafloral nectaries as a common plant-adoptive characteristic in context to diversity and phylogenetic pattern was also speculated while exploring other collaborative evolutionary implications of this plant. Extrafloral nectaries (EFNs) are widespread and evolutionarily labile traits that have repeatedly and remarkably evolved in vascular plants. Morphological descriptions of the EFNs of certain plant species are common in the literature, but they rarely relate morphology with histology, gland distribution and secretory characteristics. Studies relating EFNs features, i.e., morphology and distribution with their differential visitation by insects, viz. ants and the cost of maintenance to the plants are important to understand the evolution of these glands. Therefore, in this study a morphological, anatomical (structure and ultrastructure) and secretory characterization of EFNs occurring on Senna occidentalis L. is made with the implications of gland attributes discussed from a functional perspective. S. occidentalis L. (Caesalpiniaceae) is an economically important species from industrial, medicinal and agricultural perspective. Observations from the result showed that shape of the EFNs (size 1–2 mm) ranged to globular, ovoid–conical, dome-shaped, fusiform or cylindrical with conical tip. The EFNs were sessile, positioned interpetiolar or seated at the base of petiole. Light and transmission electron microscopic studies showed the specific internal structures of the extrafloral nectary. Two developmental stages of the EFNs (secretory and post-secretory) were recognized. Our current understanding of the phylogenetic patterns of EFNs makes them powerful candidates for future work exploring the drivers of their evolutionary origins, shifts, and losses. [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]

Background and Aims Floral developmental studies are crucial for understanding the evolution of floral structures and sexual systems in angiosperms. Within the monocot order Poales, both subfamilies of Eriocaulaceae have unisexual flowers bearing unusual nectaries. Few previous studies have investigated floral development in subfamily Eriocauloideae, which includes the large, diverse and widespread genus Eriocaulon. To understand floral variation and the evolution of the androecium, gynoecium and floral nectaries of Eriocaulaceae, we analysed floral development and vasculature in Eriocaulon and compared it with that of subfamily Paepalanthoideae and the related family Xyridaceae in a phylogenetic context. Methods Thirteen species of Eriocaulon were studied. Developmental analysis was carried out using scanning electron microscopy, and vasculature analysis was carried out using light microscopy. Fresh material was also analysed using scanning electron microscopy with a cryo function. Character evolution was reconstructed over well-resolved phylogenies. Key Results Perianth reductions can occur due to delayed development that can also result in loss of the vascular bundles of the median sepals. Nectariferous petal glands cease development and remain vestigial in some species. In staminate flowers, the inner stamens can emerge before the outer ones, and carpels are transformed into nectariferous carpellodes. In pistillate flowers, stamens are reduced to staminodes and the gynoecium has dorsal stigmas. Conclusions Floral morphology is highly diverse in Eriocaulon , as a result of fusion, reduction or loss of perianth parts. The nectariferous carpellodes of staminate flowers originated first in the ancestor of Eriocaulaceae; petal glands and nectariferous branches of pistillate flowers originated independently in Eriocaulaceae through transfer of function. We present a hypothesis of floral evolution for the family, illustrating a shift from bisexuality to unisexuality and the evolution of nectaries in a complex monocot family, which can contribute to future studies on reproductive biology and floral evolution in other groups. [ABSTRACT FROM AUTHOR]

The present study describes the floral morphology and evaluates pollen viability for the bromeliad Nidularium minutum Mez. during the flowering period 2018‒2019 through histochemistry and pollen germination tests. The inflorescences are nidular, capituliform with short branches bearing two to three odourless, bisexual and greenish-white flowers and with an androecium shorter than the gynoecium, consisting of six stamens with anthers featuring rimose dehiscence. The ovules are anatropous, displaying a small appendage in the chalazal region. The first flower opened in late November 2018 and flowering peak was in January 2019. Anthesis started at 6:55 a.m. and lasted until 8:49 a.m. Pollen/ovule ratio indicates facultative autogamy. The pollen grains are monads, medium to large, 2-(3)-porate, reticulate heterobrochate with abundant pollenkitt. A high frequency of unviable pollen grains with discrepant sizes was observed. The mature pollen grain is considered recalcitrant and therefore sensitive to desiccation. In vitro pollen germination after 48 hours was higher in BKM medium (64.77%) compared to SM (38.51%). Pollen viability was overestimated in all histochemistry tests, with Alexander (72.46%) being the closest to the in vitro germination rate. The results obtained for N. minutum bring new information about its floral biology as a subsidy to the cultivation of ornamental bromeliads that are at risk of extinction. [ABSTRACT FROM AUTHOR]

Summary: Here we describe Microlicia woodgyeriana R.Romero & Paranhos, a new species from Serra do Bota, northern Minas Gerais, Brazil. We compare it with its morphologically similar species, M. crassa R.Romero, M. martiana O.Berg ex Triana, M. rugosa R.Romero & Versiane, and M. setosa DC. Additionally, we provide a distribution map, illustrations, field images, and a description of the leaf anatomy of M. woodgyeriana. The new species is known only from a population within an unprotected area, and it should be considered as "Critically Endangered" according to IUCN categories and criteria. [ABSTRACT FROM AUTHOR]

Martin placed the lateral embryo, which occurs only in grasses, adjacent to the broad embryo at the base of his family tree of seed phylogeny. Since Poales and Poaceae are derived monocots, we questioned the evolutionary relationship between the lateral embryo and other kinds of monocot embryos. Information was compiled on embryo and seed characteristics for the various families of monocots, kind of embryogenesis for families in Poales and germination morphology of families with lateral (only Poaceae) and broad embryos. The kinds of monocot embryos are broad, capitate, lateral, linear fully developed, linear underdeveloped and undifferentiated, but only broad and lateral embryos are restricted to Poales. Asterad embryogenesis occurs in Poaceae with a lateral embryo and in Eriocaulaceae, Rapataceae and Xyridaceae with a broad embryo. In developing grass seeds, the growing scutellum (cotyledon) pushes the coleoptile, mesocotyl and coleorhiza to the side. In the organless broad embryo, the cotyledonary sector is larger than the epicotyledonary sector. During germination of grass seeds, the coleorhiza and then the coleoptile emerge, while in a seed with a broad embryo the elongating cotyledon pushes the epicotyledonary sector outside the seed, after which a root–shoot axis is differentiated at a right angle to the cotyledon inside the seed. Broad and lateral embryos are closely related; however, the lateral embryo is more advanced in seed/embryo traits and germination morphology than the other kinds of monocot embryos, suggesting that its position on the family tree of seed phylogeny should be higher than of the other monocot embryos. [ABSTRACT FROM AUTHOR]

Main conclusion: The cytological changes underlying the formation of an apoplasmic barrier in the multi-layered extrafloral nectaries of Citharexylum myrianthum are compatible with the synthesis, transport and deposition of suberin. In terms of ontogenesis and function, the intermediate layers of these nectaries are homologous with the stalks of nectar-secreting trichomes. Anticlinal cell wall impregnations are common in trichomatic nectaries and their functions as endodermis-like barriers have been discussed because of possible direct effects on the nectary physiology, mainly in the nectar secretion and resorption. However, the cytological events linked to nectary wall impregnations remain little explored. This study documents the ontogenesis and the fine structure of the EFN cells, and cytological events linked to the wall impregnations of multi-layered extrafloral nectaries (EFNs) in Citharexylum myrianthum Cham. (Verbenaceae). EFNs are patelliform, and differentiated into (a) a multicellular foot, which is compound in structure and vascularised with phloem strands, (b) a bi-layered intermediate region with thickened cell walls and (c) a single-layered secretory region with palisade-like cells. EFNs are protodermal in origin, starting with a single protodermal cell and ending with the complex, multi-layered structure. The cell wall impregnations first appear in the very young EFN and increase towards maturity. Lipid patches (assumed to be suberin) are deposited on the inner faces of the primary walls, first along the anticlinal walls and then extend to the periclinal walls. On both walls, plasmodesmata remain apparently intact during the maturation of the EFNs. In the peripheral cytoplasm there are abundant polymorphic plastids, well-developed Golgi bodies often close to rough endoplasmic reticulum profiles, mitochondria and polyribosomes. Cytological events linked to the wall impregnations are consistent with suberin synthesis, transport and deposition. Our findings offer new insights into the structure-properties of specialised nectary cell walls and so should contribute to our knowledge of the physiological and protective roles of this structure in nectar glands. [ABSTRACT FROM AUTHOR]

Xyridaceae are represented in New Caledonia only by the genus Xyris , the description of which was last revised in the 1960s, and three endemic species were recognized there at that time, X. pancheri , X. neocaledonica and X. guillauminii. However, no specimens of X. guillauminii were reported from P or L, although some type material was present. In addition, most material was unidentified at the species level in international herbaria (up to 45% for the NOU herbarium), showing that the family had not been studied in the framework of the Flore de la Nouvelle-Calédonie. In total, 129 herbarium specimens were examined for an ascendant hierarchical classification and a principal coordinates analysis based on 18 morphological characters regarded as diagnostic at the species level (including six used in the original revision). The analyses revealed three well-delimited groups that potentially correspond to species-level units. A sub-sampling of 21 specimens, representative of these three groups, was studied anatomically (leaf cross-sections) and by scanning electron microscopy (leaf surface and seeds) and provided ten additional characters. This additional dataset validated the taxonomy in three species-level units. The resulting entities were then compared with nomenclatural types, which showed that the first corresponded to X. neocaledonica , the second represents a well-delimited, undescribed species, and the third includes types of both X. pancheri and X. guillauminii , this last being in need of synonymization. The findings of the present study provide a basis for undertaking a taxonomic revision of Xyris in New Caledonia, including the description of the new species. All New Caledonian species have an axile placentation and a trilocular ovary, so they belong to Xyris section Pomatoxyris , which is no longer endemic to Australia. [ABSTRACT FROM AUTHOR]

The Bromeliaceae are a largely Neotropical family originating in open, dry environments. Vriesea Lindl., the third largest genus of the family, is traditionally divided between two sections. About 90% of the species of the genus occur in Brazil, where the centre of diversity is the Atlantic Rainforest. Leaf morphoanatomical studies conducted on bromeliad species have confirmed the importance of structural characters for ecological, and also for systematic purposes. Because of the wide morphological, ecological and taxonomic diversity of Vriesea, and its importance in ecosystems associated with the Atlantic Rainforest, we selected 24 Vriesea species and used anatomical and histochemical analyses to describe the leaf anatomy aiming to identify potential systematic characters, and point out possible traits that responded to environmental conditions during the evolution of the genus. The leaves are hypostomatic with peltate trichomes. They present epidermis with thickened cell walls, with lignin and pectin, covered by cuticle and epicuticular wax. The mechanical hypodermis is usually one-layered. Water-storage parenchyma occurs in both surfaces of the leaf blade. The chlorenchyma is located in the median portion of the blade. Air lacunae are associated with brachiform parenchyma. The vascular bundles are collateral, arranged alternately with the air lacunae and surrounded by a sheath of sclerified and/or parenchyma cells. Extravascular fibres occur in most of the species and are positioned below the mechanical hypodermis on the adaxial surface of the leaf blade. Leaf anatomical analysis can be useful in differential characterisation of small groups of related species but does not seem to reflect species assemblages according to the taxonomic sections or substrate type, but is consistent among the Brazilian analysed species of Vriesea. [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]

Copyright of Rodriguésia is the property of Revista Rodriguesia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rodriguésia is the property of Revista Rodriguesia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rodriguésia is the property of Revista Rodriguesia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We studied the rates of leaf decomposition and loss of leaf constituents (lignin and cellulose) of a native plant species using the litterbag experiment during different seasonal periods (flood and drought) in periodically flooded ecosystems, locally known as "Ipucas". The effects of flood, edge and fungal colonization on leaf degradation were evaluated. The results show that leaf decomposition is very slow, and influenced by seasonality, flooding and leaf chemical quality. Low moisture and leaf structural components contribute to the slow rate of decomposition. In addition, the fungal biomass was sensitive to the edge effect, with higher values in the center, probably due to the edge losing moisture earlier than the center after the end of rainy season. In addition, the positive correlation of fungal biomass with flooding demonstrates the importance of seasonality in these temporally flooded ecosystems, indicating that global changes in rainfall patterns may disrupt carbon cycling and probably nutrient cycling in periodically flooded environments. [ABSTRACT FROM AUTHOR]

Physical disturbances, such as fire, may affect the relationship between ants and plants. We evaluated the extent to which severe fires alter the protective effect of ants against the herbivores of an extrafloral-nectary bearing tree. We performed an ant removal experiment and sampled the ant fauna from the same trees over 4 years: the pre-fire year, the fire-year, and again 1 and 2 years later. Ants reduced insect herbivory in the pre-fire year and in the fire-year but failed to provide any plant protection in the two years after fire. The magnitude of the ant effect on herbivory did not differ between the pre-fire year and the fire-year. Fire reduced the abundance of ants with strictly arboreal-nesting habits. However, in the fire year (but not in the subsequent ones), this decline was compensated by an increase in the abundance of arboreal generalists and ground-nesting ants foraging in trees. Our results indicate that severe fires can affect the strength and direction of the ant effects on herbivory by altering the structure of the arboreal ant community and the abundance of insect herbivores. Fire disturbance is thus an important factor of conditionality of ant-plant mutualisms in fire-prone habitats, like the Cerrado savannas. [ABSTRACT FROM AUTHOR]