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Pellucid punctuations and lines in the leaf blade are common in Casearia , but for some of its species these structures are mentioned as inconspicuous, not visible or obscure. Cavities and ducts have been anatomically described and correlated with pellucid punctuations and lines, respectively, in only six species from the genus; however, the distinction between these types of secretory structures remains unclear. Therefore, we aimed to anatomically describe the pellucid punctuations and lines in leaves of 47 species of Casearia . Leaf blade samples were obtained from herbarium and field collected material and processed according to standard methods for light microscopy analysis. Cavities and ducts were absent in only four of the 47 species ( C. commersoniana , C. javitensis and C. spruceana of section Piparea , and C. eicheleriana of section Casearia ). In the remaining species, cavities corresponded to pellucid punctuations, while ducts corresponded with lines. The majority of species have both structures randomly distributed throughout the leaf blade, however, in C. bahiensis , these structures are concentrated along the leaf margin, while in C. aquifolia and C. crassinervis they were predominant along the midrib. Our data show that anatomical analyses are essential for distinguishing between cavities and ducts. We also demonstrate that the distribution of cavities and ducts provides useful information for the taxonomy of Casearia at both the species and section levels. [ABSTRACT FROM AUTHOR]

Premise of research. Casearia sylvestris (Salicaceae) is widely used in traditional medicine and possesses various types of secretory structures, but the mechanisms and compartments involved in the secretory processes have not been elucidated. This study aims to describe the chemical nature of the secretions produced by all secretory structures of C. sylvestris leaves and to identify the compartments and mechanisms of synthesis, storage, and release of secretion. Methodology. Shoot samples were collected and analyzed using standard techniques for light microscopy and for scanning and transmission electron microscopy. Histochemical tests were performed to identify the main classes of exudate compounds. Pivotal results. The subcellular compartments involved in the secretory process of the taniferous idioblasts, cavities, ducts, and colleters were identified, with all organelles being consistent with the chemical nature of secretion. In the colleters, plastids with osmiophilic compounds are related to the production of oil, while dictyosomes are associated with syntheses of polysaccharide secretion. The smooth endoplasmic reticulum, periplastidial reticulum, and plastids present in the secretory epithelium of the cavities and ducts produce the oleoresin, while dictyosomes are involved with hydrophilic secretion. Conclusions. Ultrastructure variation among the organelles of the four types of secretory structures studied, as well as the chemical complexity of exudates produced by them, revealed particularities that enabled the description of models for the secretory mechanism of each. Novelties that reveal the mechanisms involved in the release of secretion through the cell wall are presented. [ABSTRACT FROM AUTHOR]

Salicaceae possess a range of leaf teeth types, many characterized as nectariferous salicoid or violoid teeth. One large genus, Casearia, deviates from this generalization in having theoid teeth. Although taxonomic descriptions of Casearia have included reports of glands at the apex of teeth, there have been no descriptions of their anatomy or functional role. Here, we aim to describe the anatomy of the theoid teeth of 43 Casearia spp. Leaf samples from herbarium specimens were processed for light and scanning electron microscopy. Leaves of C. sylvestris were collected and fixed in the field for histochemical tests, revealing only polysaccharides in secretory epidermal cells and outside of these cells. The glands have precocious development and are composed of a non-vascular central axis covered with a palisade-like secretory epidermis. During senescence, the cells of the palisade-like secretory epidermis and central axis appear to lose their typical form, with some cell walls disintegrating. In the mature leaf, an abscission zone at the base of the gland causes detachment of the gland. The placement, anatomical structure, precocious activity and polysaccharide secretion (in C. sylvestris) allow the recognition of the glands associated with the marginal teeth in Casearia as colleters. Similar studies are needed for other genera in order to clarify how colleters have evolved in Salicaceae and how they are functionally and anatomically related to other teeth types in the family. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: An anatomical and developmental study of distantly related fleshy fruits in the monocots was undertaken to better understand the evolution of baccate fruits in the monocot clade as a whole. We studied 14 species with fleshy fruits spanning the Alismatales, Arecales, Asparagales, Commelinales, Dioscoreales, Liliales, and Poales to determine various mechanisms through which baccate fruits attain fleshiness at maturity. METHODS: Flowers and fruits of various stages were collected, sectioned, stained, and examined using light microscopy and scanning electron microscopy. KEY RESULTS: Three basic pathways for attaining fleshiness were identified within the species examined (true berries, with a uniform pericarp; typical drupes, with an endocarp differentiated by the presence of stony pyrenes; and specialized drupes, involving mesocarp and endocarp differentiated by stone pyrenes). Furthermore, developmental characters differentiating basic fruit types were identified. CONCLUSIONS: Fleshy fruits in the monocots do not develop through a single shared pathway, indicating that fleshiness has evolved multiple times within the clade. [ABSTRACT FROM AUTHOR]

The taxonomy of neotropical Salicaceae, a family that now includes the majority of the former Flacourtiaceae, has been problematic, especially because they display very diverse morphology and have several characteristics in common with many other families. Recent phylogenetic studies have proposed substantial changes at both family and generic levels. Considering the importance of anatomy as an aid for taxonomy, the gathering of anatomical data for the family is fundamental to help clarify the taxonomic problems. Leaves belonging to Abatia americana (four samples), Banara brasiliensis (2), Casearia arborea (4), C. decandra (5), C. gossypiosperma (2), C. obliqua (1), C. sylvestris (3), C. ulmifolia (3), Prockia crucis (3), and Xylosma prockia (4) and the closely related Carpotroche brasiliensis (3) from Achariaceae, were studied by standard microscopy techniques. The leaves were anatomically described, emphasizing their differences and similarities. Similar characters for the neotropical Salicaceae (former Flacourtiaceae) and Salicaceae strictu sensu were recognized, such as the presence of salicoid leaf teeth, brachyparacytic stomata, secondary growth of the petiole, abundance of crystals, collateral and arch-shaped vascular system at the midrib, and sclerenchyma accompanying the bundles. These data demonstrate that leaf anatomy can provide evidence to assist with the taxonomy of Salicaceae, at family, generic, and specific levels. [ABSTRACT FROM AUTHOR]

The occurrence of nonarticulated laticifers has been recorded in the literature for Apocynaceae, but little information is available on their structure and the chemical compounds in their latex. The objective of this study was to describe, anatomically and histochemically, the laticifers and latex found in the roots, stems, and leaves of Mandevilla atroviolacea (Stadelm) Woodson, a genus in the Apocynaceae. Laticifer anatomy was examined by light microscopy, and the chemical nature of the exuded latex was studied using cytochemistry. Articulated laticifers were present in M. atroviolacea. The lactiferous system in stems and leaves originated from both procambium and ground meristem, and it was determined to be functional, as indicated by changes in the cytoplasm immediately subsequent to its formation. However, in tuberous roots, laticifers originated from the vascular cambium, phellogen, and parenchymatous cortical cells. The primary wall of laticifers consists of pectins and cellulose and is thicker than that of adjacent cells. The laticifer secretion contained an emulsion of lipophilic substances rich in neutral lipids, resin oils, and possibly rubber. The presence of articulated laticifers is reported for the first time for Apocynoideae, contributing to the knowledge and understanding of these structures in the family Apocynaceae. [ABSTRACT FROM AUTHOR]

Besides being vital tools in taxonomic evaluation, the anatomy of plant secretory structures and the chemical composition of their secretions may contribute to a more thorough understanding of the roles and functions of these secretory structures. Here we used standard techniques for plant anatomy and histochemistry to examine secretory structures on leaves at different stages of development of Prockia crucis, to evaluate the origin and development of the structures, and to identify the disaccharides and monosaccharides in the exudates. Fructose, glucose, and sucrose constituted up to 49.6% of the entire secretion. The glands were confirmed to be extrafloral nectaries (EFNs); this is the first report of their presence in the genus Prockia. These EFNs are globular, sessile glands, with a central concavity occurring on the basal and marginal regions of the leaf. The epidermis surrounding the concavity is secretory, forming a single-layered palisade that strongly reacts with periodic acid-Schiff's reagent (PAS) and xylidine Ponceau, indicators of total polysaccharides and total proteins, respectively, in the exudate. On the basis of the similarity of these glands to the salicoid teeth in Populus and Salix, we suggest that these three taxa are phylogcnetically close. [ABSTRACT FROM AUTHOR]

• The leaf ontogenesis of Myrtoideae species revealed that the subepidermal layer is a hypodermis that originates from periclinal divisions of the ground meristem. • The occurrence of a hypodermis in representatives of Myrtaceae needs to be better studied and discussed in relation to the phylogeny of the family. • This study demonstrates the importance of ontogeny to understand plant structures so they can be properly used in taxonomic and phylogenetic interpretations. The ninth largest family of angiosperms is Myrtaceae, which comprises 127 genera and over 6000 species. The leaf anatomy of Myrtaceae has been widely studied and can be used in phylogenetic analyses and species delimitations in complexes within the family. A multiple epidermis and hypodermis have been described for the leaves of representatives of the family but have not been confirmed using ontogenetic studies, which could lead to incorrect interpretations about these tissues. Thus, we studied the leaf ontogenesis of the following 9 species in subfamily Myrtoideae: tribe Syzigieae - Syzigium cumini ; tribe Myrteae - Myrceugenia alpigena and M. euosma (subtribe Luminae), Psidium sartorianum, P. guajava, Campomanesia adamantium and Pimenta pseudocaryophyllus (subtribe Pimentinae), Myrcianthes pungens and M. gigantea (subtribe Eugeniinae). Shoot apices and leaves up to the fourth node were transversally and longitudinally sectioned following techniques used for plant anatomy. Leaf development in all species is from apical, intercalary, dorsal, marginal and plate meristematic activity. Protodermal periclinal divisions only occur to give rise to secretory cavities. The results show that in all the species the subepidermal layer is a hypodermis, which originates from periclinal divisions of the ground meristem. The occurrence of this layer could have phylogenetic implications according to reports in the literature, reinforcing the relationships among the subtribes in current topologies of Myrteae. However, the occurrence of a hypodermis in representatives of other subtribes of Myrteae and Syzigieae need to be better studied and discussed in relation to the phylogeny of Myrtaceae. [ABSTRACT FROM AUTHOR]

• The pericarp anatomy of Eugeniinae species revealed Myrcianthes pungens (which is in the genus sister to Eugenia) has a drupe-like fruit. • In species of Eugeniinae, the dorsal and ventral meristems in the ovary wall give rise to a mesocarp with three distinct regions. • This work supports the importance of ontogenic studies to appropriately delimit pericarp layers and may help reveal patterns in the pericarp structure that can contribute to estimating phylogenetic relationships. The genus Eugenia is of great ecological importance and due to being very diverse has been the subject of a comprehensive phylogenetic and taxonomic review to create an accurate classification. This study sought to describe the pericarp ontogeny of species in the subtribe Eugeniinae to reveal anatomical features that can be used to characterize morphologically similar sections. Buds, flowers, and fruits were collected at different development stages from herbarium specimens and plants in the field. Herbarium material underwent a reversal procedure, and fresh material was submitted to conventional anatomical analysis techniques and evaluated under an optical light microscope. By analyzing the species, we verified some promising characteristics, such as the following: a drupe-like fruit in Myrcianthes pungens (which is in the genus sister to Eugenia) that is a novelty for this species; trichomes in the inner epidermis of the ovary in species in Eugenia sect. Hexachlamys and E. sect. Pilothecium ; and the absence of intercellular spaces in the most internal layers of the mesocarp in a species of E. section Speciosae. Representatives from the subtribe showed predominant cell division in the layers subjacent to the exocarp (dorsal meristem) and endocarp (ventral meristem) and the outer, middle and inner mesocarp. [ABSTRACT FROM AUTHOR]

• Pericarp development in Campomanesia Ruiz & Pav. (Myrtaceae) species with a systematic point of view. • Results corroborate the literature for the genus delimitation. • Number of internal secretory cavities layers can distinguish species. • Presence of sclereids in ovary can distinguish species. • Presence of sclereids in fruit can be a characteristic to delimit the subtribe. Campomanesia (Myrtaceae) comprises approximately 45 species restricted to South America, 35 of which are found in Brazil. In this study, we ontogenetically analyzed species in the genus with the objectives of understanding and comparing the ovary and pericarp parts, highlighting characters that distinguish the species and providing information that could help to elucidate phylogenetic relationships in the future. We examined flower buds, flowers and fruits from herbarium specimens of 12 species. Results corroborate features that can be used as synapomorphies for the genus, such as the high number of locules, the development of one ovule per locule or the total sterilization of locules, and glandular locule wall. Campomanesia aurea, C. cavalcantina and C. xanthocarpa fruits have one or two layers of secretory cavities around the locules, whereas the remaining species have one layer. Sclereids were found in the ovarian mesophyll of C. guazumifolia, C. rufa and C. sessiliflora, while in the other species these only became evident when the pericarp was fully formed. The presence of trichomes and crystals was not consistent across species. Some anatomical characteristics, such as the disposition of secretory cavities in the outer and inner regions of the mesophyll and mesocarp, the presence or absence of sclereids, and the presence of trichomes and crystals at determined development phases, are promising to distinguish species in the genus. These features were compared with species in other closely related genera of Myrtaceae. [ABSTRACT FROM AUTHOR]

Past phylogenetic studies of the monocot order Alismatales left several higher-order relationships unresolved. We addressed these uncertainties using a nearly complete genus-level sampling of whole plastid genomes (gene sets representing 83 protein-coding and ribosomal genes) from members of the core alismatid families, Tofieldiaceae and additional taxa (Araceae and other angiosperms). Parsimony and likelihood analyses inferred generally highly congruent phylogenetic relationships within the order, and several alternative likelihood partitioning schemes had little impact on patterns of clade support. All families with multiple genera were resolved as monophyletic, and we inferred strong bootstrap support for most inter- and intrafamilial relationships. The precise placement of Tofieldiaceae in the order was not well supported. Although most analyses inferred Tofieldiaceae to be the sister-group of the rest of the order, one likelihood analysis indicated a contrasting Araceae-sister arrangement. Acorus (Acorales) was not supported as a member of the order. We also investigated the molecular evolution of plastid NADH dehydrogenase, a large enzymatic complex that may play a role in photooxidative stress responses. Ancestral-state reconstructions support four convergent losses of a functional NADH dehydrogenase complex in Alismatales, including a single loss in Tofieldiaceae. [ABSTRACT FROM AUTHOR]

A phylogenetic analysis of the early branching lineages of the monocotyledons is performed using data from two plastid genes ( rbcL and matK), five mitochondrial genes ( atp1, ccmB, cob, mttB and nad5) and morphology. The complete matrix includes 93 terminals representing Acorus, the 14 families currently recognized within Alismatales, and numerous lineages of monocotyledons and other angiosperms. Total evidence analysis results in an almost completely resolved strict consensus tree, but all data partitions, genomic as well as morphological, are incongruent. The effects of RNA editing and potentially processed paralogous sequences are explored and discussed. Despite a decrease in incongruence length differences after exclusion of edited sites, the major data partitions remain significantly incongruent. The 14 families of Alismatales are all found to be monophyletic, but Acorus is found to be included in Alismatales rather than being the sister group to all other monocotyledons. The placement is strongly supported by the mitochondrial data, atp1 in particular, but it cannot be explained as an artifact caused by patterns of editing or by sampling of processed paralogues. [ABSTRACT FROM AUTHOR]