Morphoanatomical study of Neotropical Dorstenia (Moraceae) inflorescences reveal new insights and variation in late-diverging species Letícia Maria Parteka, Fernanda Mayara Nogueira, Jorge Ernesto de Araujo Mariath, André Luís Laforga Vanzela, Danilo Massuia Rocha Botanical Journal of the Linnean Society, 2026 Dorstenia species are characterized by their distinctive inflorescence, the coenanthium, a fleshy discoid receptacle that contains staminate or pistillate flowers. Despite being of great importance due to the endangered status of some Dorstenia, few species have been extensively studied, leaving many aspects of their reproductive biology and evolutionary relationships unclear. This study aimed to expand our understanding of Neotropical Dorstenia species, focusing on less-explored aspects. Using light and scanning electron microscopy, we analysed the inflorescences of seven species across all Neotropical sections and conducted ancestral character reconstruction to verify the phylogenetical significance of specific traits. Results showed that aerenchyma development in pistillate flowers may play a role in fruit dispersal through ballistic ejection. Additionally, the secretory structures within the coenanthium, both external and internal, probably serve the dual purpose of attracting pollinators while also providing protection against potential damage from them, although the exact pollination syndrome remains uncertain due to conflicting data. The reproductive characteristics of the Neotropical Dorstenia differ among the three sections, with the late-diverging Emygdioa members exhibiting dioecious coenanthia, implying a transition from mixed-monoecious to dioecious inflorescences in Dorstenia.
Cryoimmobilized anther analysis reveals new ultrastructural insights into Rhynchospora (Cyperaceae) asymmetrical microsporogenesis Danilo M. Rocha, Ulla Neumann, Fernanda M. Nogueira, Georgios Tsipas, André L. L. Vanzela, André Marques Frontiers in Plant Science, 2024 IntroductionThe Cyperaceae family is distinguished by holocentric chromosomes and a distinctive microsporogenesis process, which includes inverted meiosis, asymmetric tetrad formation, selective cell death, and the formation of pseudomonad pollen. Despite significant advances, the ultrastructural details of these processes remain poorly understood.MethodsThis study provides a detailed analysis of microsporogenesis in Rhynchospora pubera using high-pressure freezing, freeze substitution, and transmission electron microscopy, significantly enhancing ultrastructural resolution.Results and discussionOur findings reveal that intracellular organization differs from model species Arabidopsis thaliana and drives nuclear selection, with endoplasmic reticulum vesicles organizing meiotic spindles. Microtubules attach to centromeres located deep within holocentric chromosomes, while extensive cytoplasmic connections facilitate material exchange until callose deposition encloses meiocytes. Lipid distribution contributes to cell asymmetry, resulting in the characteristic asymmetric tetrads. Following meiosis, cytoskeletal elements coordinate nuclear migration and cell plate formation. Pseudomonads exhibit reconfigurations in the endomembrane system, particularly involving the endoplasmic reticulum, which supports functional cell differentiation. Complementary histochemical analyses corroborate these findings, providing insights into the cellular processes governing Rhynchospora microsporogenesis. These findings contribute to a deeper understanding of the developmental processes of Cyperaceae pollen, thereby facilitating future investigations of the underlying molecular mechanisms.
Initial damage produced by a single 15-Gy x-ray irradiation to the rat calvaria skin Matheus da Silva Santin, José Koehler, Danilo Massuia Rocha, Camila Audrey dos Reis, Nadia Fayez Omar, Yasmin Fidler, Maria Albertina de Miranda Soares, José Rosa Gomes European Radiology Experimental, 2020 Background Calvaria skin has a reduced thickness, and its initial damage produced by irradiation was scarcely reported. We aimed to identify the initial effects of x-ray irradiation in the rat calvaria skin. Methods After approval by the Animal Ethical Committee, calvaria skin sections of five Wistar rats per time point were evaluated on days 4, 9, 14, and 25 following a single 15-Gy x-ray irradiation of the head. The control group was composed of five rats and evaluated on day 4. Sections were assessed using hematoxylin-eosin and Masson’s trichrome staining for morphology, inflammation, and fibrosis. Fibrosis was also evaluated by the collagen maturation index from Picrosirius red staining and by cell proliferation using the immunohistochemistry, after 5-bromo-2-deoxyuridine intraperitoneal injection. Results In irradiated rats, we observed a reduction in epithelial cell proliferation (p = 0.004) and in matrix metalloproteinase-9 expression (p < 0.001), an increase in the maturation index, and with a predominance in the type I collagen fibers, on days 9 and 14 (1.19 and 1.17, respectively). A progressive disorganization in the morphology of the collagen fibers at all time points and changes in morphology of the sebaceous gland cells and hair follicle were present until day 14. Conclusions The initial damage produced by a single 15-Gy x-ray irradiation to the rat calvaria skin was a change in the normal morphology of collagen fibers to an amorphous aspect, a temporary absence of the sebaceous gland and hair follicles, and without a visible inflammatory process, cell proliferation, or fibrosis process in the dermis.
Are unusual ultrastructural features occurring in the pollen endomembrane system of Cyperaceae and other angiosperms? Danilo M. Rocha, André L. L. Vanzela, Jorge E. A. Mariath Cell Biology International, 2020 Cyperaceae representatives present peculiar microsporogenesis and microgametogenesis, which raises the question of how regular the sedge pollen is. In order to answer this question, preanthesis pollen grains of Cyperaceae individuals were analyzed under different tools such as light and transmission electron microscopy, which included cytochemistry and immunogold procedures. The results showed that maturing pollen in Cyperaceae presents some unusual endomembrane behaviors. Endoplasmic reticulum and dictyosomes are concerned in classic secretion pathways in vegetative cells, and possibly the late breakdown of degenerative microspores. However, cortical and concentric endoplasmic reticulum are also present and are possibly related to other functions aside the biosynthetic pathway. Unconventional secretion of large membrane‐bound bodies containing cell wall precursors was also observed and confirmed by immunogold. However, since these bodies most likely receive material from dictyosomes, as observed in silver nitrate reaction, the “unconventional” status of this secretion is debatable. Reports of the literature show that these unusual endomembrane formations are not exclusive of the sedge pollen, but little attention have been given to them so far. This could represent an opportunity to re‐examine our understanding on the endomembrane system in pollen cells in general.
Comparative study of microgametogenesis in members of Cyperaceae and Juncaceae: A shift from permanent pollen tetrads to pseudomonads Danilo M Rocha, André L L Vanzela, Jorge E A Mariath Botanical Journal of the Linnean Society, 2018 During microsporogenesis in Cyperaceae, an asymmetric tetrad of microspores is formed, establishing a pseudomonad. Three microspores undergo programmed cell death, whereas the functional microspore goes though microgametogenesis. A full understanding of this process remains elusive, but knowledge of its stages, cell death meaning and coexistence of multiple cell lineages occurring in such restricted spaces is of great cytological interest. Therefore, a comparative study was made in Cyperaceae and Juncaceae to characterize pollen features and development using light and electron microscopy and cytochemical tests. Evidence from sporopollenin suggests that pseudomonads are derived from pollen tetrads like those in Juncaceae, and data collected allowed the establishment of five pseudomonad development stages. In summary, the late meiosis cytokinesis and precocious pollen mitosis I seem to be associated with pseudomonad formation. Vacuolation occurs later, with continuous autophagy of degenerative microspores, suggesting cell death to the benefit of pollen fitness. Reserves are accumulated as starch, depending on environmental conditions. During microgametogenesis, different cellular lineages appear to be isolated by callose, giving each cell metabolic autonomy. This process of pseudomonad establishment allows the formation of a longevous, rapidly germinating, tricellular pollen, which could be key to the great adaptative success of Cyperaceae.
Developmental programmed cell death during asymmetric microsporogenesis in holocentric species of Rhynchospora (Cyperaceae) Danilo M. Rocha, André Marques, Celia G.T.J. Andrade, Romain Guyot, Srinivasa R. Chaluvadi, Andrea Pedrosa-Harand, Andreas Houben, Jeffrey L. Bennetzen, André L.L. Vanzela Journal of Experimental Botany, 2016 Members of the Cyperaceae family exhibit an asymmetric microsporogenesis that results in the degeneration of three out of four meiotic products. Efforts have been made previously to describe the resulting structure, named the pseudomonad, but mechanisms concerning the establishment of cell domains, nuclear development, and programmed cell death are largely unknown. Using the Rhynchospora genus as a model, evidence for cell asymmetry, cytoplasmic isolation, and programmed cell death was obtained by a combination of electron microscopic, cytochemical, immunocytochemical, in situ hybridization, and flow cytometric methods. Degenerative cells were identified at the abaxial region, with the cytoskeleton marking their delimitation from the functional domain after meiosis. After attempting to initiate cell division with an unreplicated genome and abnormal spindle assembly, these cells exhibited a gradual process of cytoplasmic contraction associated with hypermethylation of cytosines and differential loss of DNA. These results indicate that the asymmetric tetrad establishes a functional cell, where one nucleus is preferentially selected to survive. Degenerative haploid cells are then eliminated in a multistep process associated with mitotic disorder, non-random elimination of repetitive DNA, vacuolar cell death, and DNA fragmentation.
Morphoanatomical study of Neotropical Dorstenia (Moraceae) inflorescences reveal new insights and variation in late-diverging species LM Parteka, FM Nogueira, JEA Mariath, ALL Vanzela, DM Rocha Botanical Journal of the Linnean Society 210 (2), 152-166 , 2026 2026.0
Cryoimmobilized anther analysis reveals new ultrastructural insights into Rhynchospora (Cyperaceae) asymmetrical microsporogenesis DM Rocha, U Neumann, FM Nogueira, G Tsipas, ALL Vanzela, ... Frontiers in Plant Science 15, 1518369 , 2025 2025.0 Citations: 3
Evolutionary features of microspore and pollen grain development in Cyperaceae DM Rocha, FM Nogueira, T André, JE de Araujo Mariath, ALL Vanzela Plant Reproduction 36 (4), 333-342 , 2023 2023.0 Citations: 4
Ultrastructural analysis of Rhynchospora ovules: The first record of Cyperaceae megagametophyte on transmission electron microscope FM Nogueira, PVF Nogueira, ALL Vanzela, DM Rocha Micron 140, 102962 , 2021 2021.0 Citations: 1
Are unusual ultrastructural features occurring in the pollen endomembrane system of Cyperaceae and other angiosperms? DM Rocha, ALL Vanzela, JEA Mariath Cell Biology International 44 (10), 2065-2074 , 2020 2020.0 Citations: 2
Initial damage produced by a single 15-Gy x-ray irradiation to the rat calvaria skin M da Silva Santin, J Koehler, DM Rocha, CA Dos Reis, NF Omar, Y Fidler, ... European Radiology Experimental 4 (1), 32 , 2020 2020.0 Citations: 13
Allopolyploidy and genomic differentiation in holocentric species of the Eleocharis montana complex (Cyperaceae) L Johnen, TB de Souza, DM Rocha, LM Parteka, MS Gonzalez-Elizondo, ... Plant Systematics and Evolution 306 (2), 1-17 , 2020 2020.0 Citations: 11
Desenvolvimento do grão de pólen em Cyperaceae: aspectos morfológicos, citológicos e moleculares DM Rocha 2019.0
Comparative study of microgametogenesis in members of Cyperaceae and Juncaceae: a shift from permanent pollen tetrads to pseudomonads DM Rocha, ALL Vanzela, JEA Mariath Botanical Journal of the Linnean Society 188 (1), 59-73 , 2018 2018.0 Citations: 18
Microsporogênese e microgametogênese em Schoenoplectus californicus (CA Mey.) Soják. L Johnen, AG Reutemann, DM Rocha Semina: Ciências Biológicas e da Saúde 38 (1supl), 206-206 , 2017 2017.0
Developmental programmed cell death during asymmetric microsporogenesis in holocentric species of Rhynchospora (Cyperaceae) DM Rocha, A Marques, CGTJ Andrade, R Guyot, SR Chaluvadi, ... Journal of Experimental Botany 67 (18), 5391-5401 , 2016 2016.0 Citations: 16
Female gametophyte development in Eleocharis sellowiana (CYPERACEAE): a species with atypical nuclear staining and polarity of the megaspore mother cell DM Rocha, CGTJ Andrade, ALL Vanzela Plant Systematics and Evolution 301 (4), 1287-1292 , 2015 2015.0 Citations: 7
Three-dimensional architecture of Dorstenia (Moraceae) inflorescences: vascular patterning, integration, and reproductive implications LSA Idalgo, IF Bonfain, FM Nogueira, DM Rocha Available at SSRN 6485699 , 0
MOST CITED SCHOLAR PUBLICATIONS
Comparative study of microgametogenesis in members of Cyperaceae and Juncaceae: a shift from permanent pollen tetrads to pseudomonads DM Rocha, ALL Vanzela, JEA Mariath Botanical Journal of the Linnean Society 188 (1), 59-73 , 2018 2018.0 Citations: 18
Developmental programmed cell death during asymmetric microsporogenesis in holocentric species of Rhynchospora (Cyperaceae) DM Rocha, A Marques, CGTJ Andrade, R Guyot, SR Chaluvadi, ... Journal of Experimental Botany 67 (18), 5391-5401 , 2016 2016.0 Citations: 16
Initial damage produced by a single 15-Gy x-ray irradiation to the rat calvaria skin M da Silva Santin, J Koehler, DM Rocha, CA Dos Reis, NF Omar, Y Fidler, ... European Radiology Experimental 4 (1), 32 , 2020 2020.0 Citations: 13
Allopolyploidy and genomic differentiation in holocentric species of the Eleocharis montana complex (Cyperaceae) L Johnen, TB de Souza, DM Rocha, LM Parteka, MS Gonzalez-Elizondo, ... Plant Systematics and Evolution 306 (2), 1-17 , 2020 2020.0 Citations: 11
Female gametophyte development in Eleocharis sellowiana (CYPERACEAE): a species with atypical nuclear staining and polarity of the megaspore mother cell DM Rocha, CGTJ Andrade, ALL Vanzela Plant Systematics and Evolution 301 (4), 1287-1292 , 2015 2015.0 Citations: 7
Evolutionary features of microspore and pollen grain development in Cyperaceae DM Rocha, FM Nogueira, T André, JE de Araujo Mariath, ALL Vanzela Plant Reproduction 36 (4), 333-342 , 2023 2023.0 Citations: 4
Cryoimmobilized anther analysis reveals new ultrastructural insights into Rhynchospora (Cyperaceae) asymmetrical microsporogenesis DM Rocha, U Neumann, FM Nogueira, G Tsipas, ALL Vanzela, ... Frontiers in Plant Science 15, 1518369 , 2025 2025.0 Citations: 3
Are unusual ultrastructural features occurring in the pollen endomembrane system of Cyperaceae and other angiosperms? DM Rocha, ALL Vanzela, JEA Mariath Cell Biology International 44 (10), 2065-2074 , 2020 2020.0 Citations: 2
Ultrastructural analysis of Rhynchospora ovules: The first record of Cyperaceae megagametophyte on transmission electron microscope FM Nogueira, PVF Nogueira, ALL Vanzela, DM Rocha Micron 140, 102962 , 2021 2021.0 Citations: 1
Morphoanatomical study of Neotropical Dorstenia (Moraceae) inflorescences reveal new insights and variation in late-diverging species LM Parteka, FM Nogueira, JEA Mariath, ALL Vanzela, DM Rocha Botanical Journal of the Linnean Society 210 (2), 152-166 , 2026 2026.0
Desenvolvimento do grão de pólen em Cyperaceae: aspectos morfológicos, citológicos e moleculares DM Rocha 2019.0
Microsporogênese e microgametogênese em Schoenoplectus californicus (CA Mey.) Soják. L Johnen, AG Reutemann, DM Rocha Semina: Ciências Biológicas e da Saúde 38 (1supl), 206-206 , 2017 2017.0
Three-dimensional architecture of Dorstenia (Moraceae) inflorescences: vascular patterning, integration, and reproductive implications LSA Idalgo, IF Bonfain, FM Nogueira, DM Rocha Available at SSRN 6485699 , 0
