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The characterization of colleters in Rubiaceae is crucial for understanding their role in plant function. Analyzing colleters in Palicourea tetraphylla and Palicourea rudgeoides aims to deepen the understanding of these structures morphoanatomical and functional characteristics. The study reveals colleters with palisade epidermis and a parenchymatic central axis, classified as standard type, featuring vascularization and crystals. Colleter secretion, abundant in acidic mucopolysaccharides, proteins, and phenolic compounds, protects against desiccation. The ontogenesis, development, and senescence of the colleters are quite rapid and fulfill their role well in biotic and abiotic protection because these structures are present at different stages of development in the same stipule. Pronounced protrusions on the colleters surface, coupled with the accumulation of secretion in the intercellular and subcuticular spaces, suggest that the secretory process occurs through the wall, driven by pressure resulting from the accumulation of secretion. The microorganisms in the colleters' secretion, especially in microbiota-rich environments such as the Atlantic Forest, provide valuable information about plant-microorganism interactions, such as resistance to other pathogens and organisms and ecological balance. This enhanced understanding of colleters contributes to the role of these structures in the plant and enriches knowledge about biological interactions within specific ecosystems and the family taxonomy.
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The order Sapindales is comprised of nine families and in Brazil it is represented by six, including Rutaceae Juss., which constitutes the largest group of this order. A variety of species of Zanthoxylum L. are distributed throughout the country, and among them is the species Zanthoxylum kleinii (R.S. Cowan) P.G. Waterman, which is found in the states of Brazil. This study aimed to characterize the morphoanatomy of the leaf, petiole, rachis, and stem of the species Z. kleinii. Histochemical tests were performed, and the sections were visualized under optical and scanning electron microscopy. The analysis showed that the morphoanatomical characteristics of the species are: hypoestomatic leaflets; stomata classified as anomocytic, tetracytic, and anisocytic; dorsiventral mesophyll; cavities that produce a secretion of lipid nature, present in the leaflet, rachis, and petiole; colleters distributed in the leaf; presence of simple non-glandular trichomes in all structures; and prismatic crystals in the petiole. Histochemical tests indicated the presence of phenolic and lipophilic compounds, mucilage, and lignin. With the result of this research, it was possible to identify the nature of the compounds secreted by the secretory structures of the leaves; in addition, the morphoanatomical characterization of Z. kleinii can provide relevant data for future studies for other organs of the species not yet described. Furthermore, contributing concomitantly with data for the genus, in this way, supporting to differentiate them. RESEARCH HIGHLIGHTS: Ultrastructural features observed by microscopic techniques. Calcium oxalate crystals present in the rachis. Microchemical tests confirmed the presence of colleters in the leaflet.
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Microscopia Eletrônica de Varredura , Folhas de Planta , Zanthoxylum , Folhas de Planta/anatomia & histologia , Folhas de Planta/ultraestrutura , Folhas de Planta/química , Zanthoxylum/química , Zanthoxylum/anatomia & histologia , Zanthoxylum/ultraestrutura , Brasil , Caules de Planta/anatomia & histologia , Caules de Planta/ultraestrutura , Caules de Planta/química , Microscopia , Tricomas/ultraestrutura , Tricomas/anatomia & histologiaRESUMO
Chrysolaena flexuosa (Sims.) H. Rob. is a South American species in the tribe Vernonieae, with potential ornamental value: it has attractive inflorescences, is suitable for pot cultivation, and its cypselae are useful for dried flower arrangements. Apart from studies on the growth dynamics of this species under cultivation, chromosome number, DNA content, ploidy level, size, pollen viability, and the characterization of phenotypic and genetic variability, it is noteworthy that other aspects regarding the floral architecture, reproductive mode, and gametophyte formation of C. flexuosa have not yet been studied. For this reason, our study encompasses a floral morphoanatomical survey and a comprehensive assessment of gametophyte development in the species. As a result of this study, we report new floral morphotypes, confirming that the morphological variability of the species might be greater than speculated. The morphoanatomy of the androecium and gynoecium and the male and female gametophyte developmental characteristics are uniform in all the populations studied despite the different ploidy levels. Chrysolaena flexuosa has five tetrasporangiate stamens of the dicotyledonous type of development; all the populations studied displayed a unilocular inferior ovary with a single anatropous, unitegumented, and tenuinucellar ovule. Given that all the embryo sacs observed were of the Polygonum-type development regardless of the ploidy level, we infer that the populations analyzed are fertile and undergo sexual reproduction. Our results not only contribute further research in the field of breeding systems and propagation of this species, but also promote the successful introduction of C. flexuosa to the plant ornamental market.
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Asteraceae , Flores , Flores/anatomia & histologia , Flores/crescimento & desenvolvimento , Asteraceae/anatomia & histologia , Asteraceae/crescimento & desenvolvimento , Asteraceae/genética , Pólen/anatomia & histologia , Pólen/ultraestruturaRESUMO
We investigated the male and female reproductive tracts of Gyretes sp. with light and transmission electron microscopies. The male has a pair of testes with a single coiled follicle, followed by short efferent ducts, which have a similar shape and diameter to the testes. Long ducts (epididymides) with differential epithelium open in a pair of long vasa deferentia that lead to the accessory glands. Glycoprotein secretions from the vas deferens epithelium constitute the spermatostyle for spermatozoa aggregation. The female has numerous ovarioles per ovary, a coiled fertilization duct, an accessory gland, and an elongated vagina. Spermatozoa are stored as unaggregated cells in the fertilization duct. In Gyrinidae, the testes and accessory glands show diverse shapes, and the female sperm storage organs vary in shape, size, and type and may play a role in the interaction with sperm aggregates. Testes with a single follicle and vasa deferentia opening in the accessory glands of Gyretes sp. are features shared with other Gyrinidae and other Adephaga. We proposed adding this latter trait to characterize this suborder of beetles. The morphology of the reproductive organs in both sexes contributes to comparative analyses and knowledge of the reproductive biology of Gyretes and may provide additional features for systematics.
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Besouros , Animais , Masculino , Feminino , Brasil , Sêmen , Genitália Masculina/anatomia & histologia , Espermatozoides , TestículoRESUMO
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.
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The Laeliinae Subtribe (Epidendroideae-Orchidaceae) is exclusively Neotropical, composed of 43 genera and 1466 species, presenting great floral and vegetative diversity. The genus Laelia has restricted geographic distribution, with species in Brazil and Mexico. However, in molecular studies, the Brazilian species have not been included despite remarkably similar floral structures in both Mexican and Brazilian groups of species. The main objective of the present study is to analyze vegetative structural characters of 12 species of Laelia in Mexico to find similarities to recognize them as a taxonomic group and their relationship with possible ecological adaptations. This work supports the proposal to recognize 12 species of Laelias from Mexico as a taxonomic group (except for the new species recognized as Laelia dawsonii J. Anderson), since a strong similarity was found, translated by 90% of structural characters shared by the Mexican Laelias, given the relationship between the structural characters and the altitudinal distribution in which the groups of Mexican Laelias species are found. We propose that Laelias of Mexico be recognized as a taxonomic group and their structural characteristics allow for better understanding of adaptation of species to their environment.
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The increase in frequency and intensity of drought events have hampered coffee production in the already threatened Amazon region, yet little is known about key aspects underlying the variability in yield potential across genotypes, nor to what extent higher productivity is linked to reduced drought tolerance. Here we explored how variations in morphoanatomical and physiological leaf traits can explain differences in yield and vulnerability to embolism in 11 Coffea canephora genotypes cultivated in the Western Amazon. The remarkable variation in coffee yield across genotypes was tightly related to differences in their carbon assimilation and water transport capacities, revealing a diffusive limitation to photosynthesis linked by hydraulic constraints. Although a clear trade-off between water transport efficiency and safety was not detected, all the studied genotypes operated in a narrow and/or negative hydraulic safety margin, suggesting a high vulnerability to leaf hydraulic failure (HF), especially on the most productive genotypes. Modelling exercises revealed that variations in HF across genotypes were mainly associated with differences in leaf water vapour leakage when stomata are closed, reflecting contrasting growth strategies. Overall, our results provide a new perspective on the challenges of sustaining coffee production in the Amazon region under a drier and warmer climate.
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Coffea , Coffea/genética , Café , Folhas de Planta/fisiologia , Fenótipo , Fotossíntese/fisiologia , SecasRESUMO
Introducción: En condiciones naturales, las raíces del arbusto, Phyllanthus acuminatus, producen bajas concentraciones de metabolitos secundarios de interés medicinal. Esto abre una oportunidad para el cultivo in vitro, para aumentar la concentración de metabolitos. Objetivo: Determinar las condiciones óptimas de cultivo líquido para raíces pilosas de P. acuminatus. Métodos: Se utilizó la evaluación del crecimiento de la biomasa según porcentaje de inóculo inicial (0.50 y 0.10 %), porcentaje de nutrientes de los medios (100, 50 y 25 %) y tasa de agitación (90, 100 y 110 min-1) (N= 15 repeticiones). Resultados: Las mejores condiciones de cultivo líquido fueron: 0.10 % de inóculo inicial, nutrientes al 25 % y 90 min-1 para la tasa de agitación. Hay diferencias entre las raíces pilosas y las raíces no transformadas. Conclusiones: es factible producir raíces pilosas de P. acuminatus a gran escala, aplicando e implementando las condiciones evaluadas de porcentaje de inóculo, nutrientes en el medio y tasas de agitación utilizadas en este estudio.
Introduction: Under natural conditions, the roots of the shrub, Phyllanthus acuminatus, produce low concentrations of secondary metabolites of medicinal interest. This opens an opportunity for in vitro culture, to increase metabolite concentration. Objective: To determine the optimal liquid culture conditions for hairy roots of P. acuminatus. Methods: We used biomass growth evaluation according to initial inoculum percentage (0.50 and 0.10 %), percentage of medium nutrients (100, 50 and 25 %) and agitation rate (90, 100 and 110 min-1) (N=15 replications). Results: The best liquid culture conditions were: 0.10 % of initial inoculum, nutrients at 25 % and 90 min-1 for the agitation rate. There are differences among hairy roots and non-transformed roots. Conclusions: It is feasible to produce P. acuminatus hairy roots at a large scale, applying and implementing the evaluated conditions of inoculum percentage, nutrients in the medium and agitation rates.
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Técnicas In Vitro , Raízes de Plantas , Phyllanthus/crescimento & desenvolvimento , Biotecnologia , Costa RicaRESUMO
Colleters are secretory structures involved in the protection of young and developing plant organs. Although the presence of colleters in Gentianales is described as a synapomorphy, studies on the morphofunctionality of colleters and the mechanisms underlying the synthesis and release of colleter secretion in Gentianaceae are scarce. Here, we described the ontogeny and the morphological and functional aspects of colleters of Prepusa montana, revealed the nature of the key compounds present in the secretion, and explored the cellular aspects of the synthesis and release of secretion and senescence of colleters. Samples of the stem apical meristem with leaf primordium and young leaves; adult and senescent leaves were observed using light and electron microscopy. The colleters, located in the axil of the leaf, have a protodermal origin and develop asynchronously. They are digitiform, possessing a short peduncle and a secretory head containing homogeneous cells with dense cytoplasm and abundant endoplasmic reticulum and Golgi bodies. The secretion, composed of polysaccharides and proteins, is accumulated in schizogenous spaces and released through the separation of peripheral secretory cells and loosening of the external periclinal wall. Presumably, senescence is caused by programmed cell death. The morphoanatomical characterization of P. montana leaf colleters described here is the first record for the genus and the peculiar accumulation of colleter secretion in schizogenous spaces expanding our knowledge on the diversity of these secretory structures. Our results also provide insights into programmed cell death as an eminent topic related to secretory structures.
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Gentianaceae , Meristema , Microscopia Eletrônica , Montana , Folhas de PlantaRESUMO
Tillandsia L. is the largest genus of the family Bromeliaceae, containing 755 species and seven subgenera. Morphoanatomical studies of leaves provide useful characteristics to phylogenetic, taxonomic, and ecological analyses. This study aims to characterize and compare the leaves of 24 species of the four subgenera of Tillandsia that occur in Bahia and also perform adaptative inferences to environmental responses. The results of the species' morphoanatomical studies were compared through dissimilarity analysis. The species have rosulate leaves with varying lengths and widths. The peltate trichomes present variation in the indument density and the length of their wing and central disk. The stomata are longitudinally distributed in one or both sides of the limb. The mesophyll is dorsiventral and presents aquiferous and chlorophyllic parenchymas. The vascular bundles are collateral and partially covered by fibers, except for Tillandsia linearis. Based on the dissimilarity analysis, it was possible to identify the formation of five groups. Group G1 was composed of T. linearis, which diverged from the other species of the subgenus. Group G2 was formed by the remaining species of the subgenus Phytarrhiza. G3 and G4 presented the species of the subgenus Diaphoranthema and Tillandsia, respectively. Group G5 gathered 11 species of the subgenus Anoplophytum and presented higher variability than the other subgenera. Based on the results, the morphoanatomical characteristics can be used to characterize and group Tillandsia species, besides confirming the morphological variability of these species to the epiphyte habit in different environments, especially xeric ones.