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Płachno BJ, Kapusta M, Świątek P. Syncytia in Utricularia: Origin and Structure. Results Probl Cell Differ 2024; 71:143-155. [PMID: 37996677 DOI: 10.1007/978-3-031-37936-9_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
In animals and plants, multinucleate cells (syncytia and coenocytes) are essential in ontogeny and reproduction. Fuso-morphogenesis is the formation of multinucleated syncytia by cell-cell fusion, but coenocytes are formed as a result of mitosis without cytokinesis. However, in plants, coenocytes are more widespread than true syncytia. Except for articulated laticifers, most plant syncytia have a trophic function. Here, we summarize the results of histological, histochemical, and ultrastructural analyses of syncytia in the Utricularia species from the Lentibulariaceae family. Utricularia syncytia, known only from a few species, are heterokaryotic because the syncytium possesses nuclei from two different sources: cells of maternal sporophytic nutritive tissue (placenta) and endosperm haustorium. Thus, syncytium contains both maternal and paternal genetic material. In species from section Utricularia, syncytia are highly active structures (with hypertrophied nuclei, cell wall ingrowths, and extensive cytoskeleton) that exist only during embryo development. They serve as an example of evolutionary unique trophic structures in the plant kingdom.
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Affiliation(s)
- Bartosz J Płachno
- Department of Plant Cytology and Embryology, Institute of Botany, Faculty of Biology, Jagiellonian University in Kraków, Kraków, Poland.
| | - Małgorzata Kapusta
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Piotr Świątek
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
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Płachno BJ, Kapusta M, Stolarczyk P, Bogucka-Kocka A. Spatiotemporal Distribution of Homogalacturonans and Hemicelluloses in the Placentas, Ovules and Female Gametophytes of Utricularia nelumbifolia during Pollination. Cells 2022; 11:cells11030475. [PMID: 35159284 PMCID: PMC8834615 DOI: 10.3390/cells11030475] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 01/27/2023] Open
Abstract
Utricularia nelumbifolia is a large carnivorous plant that is endemic to Brazil. It forms an extra-ovular female gametophyte, which surpasses the entire micropylar canal and extends beyond the limit of the integument and invades the placenta tissues. Due to the atypical behavior of the female gametophyte, it is interesting to determine the interaction between the gametophyte and sporophytic tissue. Therefore, the aim of this study was to evaluate the role of the placenta, the ovular tissues, the hypertrophied central cell and the integument in guiding the pollen tube in Utricularia nelumbifolia Gardner by studying the distribution of homogalacturonans and hemicelluloses. It was also determined whether the distribution of the homogalacturonans (HG) and hemicelluloses in Utricularia are dependent on pollination. The antibodies directed against the wall components (anti-pectin: JIM5, JIM7, LM19, LM20 and the anti-hemicelluloses: LM25, LM11, LM15, LM20, LM21) were used. Because both low- and high-esterified HG and xyloglucan were observed in the placenta, ovule (integument, chalaza) and female gametophyte of both pollinated and unpollinated flowers, the occurrence of these cell-wall components was not dependent on pollination. After fertilization, low methyl-esterified HGs were still observed in the cell walls of somatic cells and female gametophyte. However, in the case of high-esterified HG, the signal was weak and occurred only in the cell walls of the somatic cells. Because xyloglucans were observed in the cell walls of the synergids and egg cells, this suggests that they play a role in sexual reproduction. Utricularia nelumbifolia with an extra ovule-female gametophyte is presented as an attractive model for studying the male-female dialogue in plants.
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Affiliation(s)
- Bartosz J. Płachno
- Department of Plant Cytology and Embryology, Institute of Botany, Faculty of Biology, Jagiellonian University in Kraków, 9 Gronostajowa St., 30-387 Kraków, Poland
- Correspondence: ; Tel.: +48-12-664-6039
| | - Małgorzata Kapusta
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdańsk, 59 Wita Stwosza St., 80-308 Gdańsk, Poland;
| | - Piotr Stolarczyk
- Department of Botany, Physiology and Plant Protection, Faculty of Biotechnology and Horticulture, University of Agriculture in Kraków, 29 Listopada 54 Ave., 31-425 Kraków, Poland;
| | - Anna Bogucka-Kocka
- Chair and Department of Biology and Genetics, Medical University of Lublin, 20-093 Lublin, Poland;
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Cervantes-Pérez SA, Yong-Villalobos L, Florez-Zapata NMV, Oropeza-Aburto A, Rico-Reséndiz F, Amasende-Morales I, Lan T, Martínez O, Vielle-Calzada JP, Albert VA, Herrera-Estrella L. Atypical DNA methylation, sRNA-size distribution, and female gametogenesis in Utricularia gibba. Sci Rep 2021; 11:15725. [PMID: 34344949 PMCID: PMC8333044 DOI: 10.1038/s41598-021-95054-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 07/20/2021] [Indexed: 12/27/2022] Open
Abstract
The most studied DNA methylation pathway in plants is the RNA Directed DNA Methylation (RdDM), a conserved mechanism that involves the role of noncoding RNAs to control the expansion of the noncoding genome. Genome-wide DNA methylation levels have been reported to correlate with genome size. However, little is known about the catalog of noncoding RNAs and the impact on DNA methylation in small plant genomes with reduced noncoding regions. Because of the small length of intergenic regions in the compact genome of the carnivorous plant Utricularia gibba, we investigated its repertoire of noncoding RNA and DNA methylation landscape. Here, we report that, compared to other angiosperms, U. gibba has an unusual distribution of small RNAs and reduced global DNA methylation levels. DNA methylation was determined using a novel strategy based on long-read DNA sequencing with the Pacific Bioscience platform and confirmed by whole-genome bisulfite sequencing. Moreover, some key genes involved in the RdDM pathway may not represented by compensatory paralogs or comprise truncated proteins, for example, U. gibba DICER-LIKE 3 (DCL3), encoding a DICER endonuclease that produces 24-nt small-interfering RNAs, has lost key domains required for complete function. Our results unveil that a truncated DCL3 correlates with a decreased proportion of 24-nt small-interfering RNAs, low DNA methylation levels, and developmental abnormalities during female gametogenesis in U. gibba. Alterations in female gametogenesis are reminiscent of RdDM mutant phenotypes in Arabidopsis thaliana. It would be interesting to further study the biological implications of the DCL3 truncation in U. gibba, as it could represent an initial step in the evolution of RdDM pathway in compact genomes.
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Affiliation(s)
- Sergio Alan Cervantes-Pérez
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 36824, Irapuato, Guanajuato, Mexico
| | - Lenin Yong-Villalobos
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 36824, Irapuato, Guanajuato, Mexico.,Institute of Genomics for Crop Abiotic Stress Tolerance, Plant and Soil Department, Texas Tech University, Lubbock, TX, 79409, USA
| | - Nathalia M V Florez-Zapata
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 36824, Irapuato, Guanajuato, Mexico.,Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Avenida Paseo Bolívar (Circunvalar) #16-20, Bogotá, DC, 111311, Colombia
| | - Araceli Oropeza-Aburto
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 36824, Irapuato, Guanajuato, Mexico
| | - Félix Rico-Reséndiz
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 36824, Irapuato, Guanajuato, Mexico
| | - Itzel Amasende-Morales
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 36824, Irapuato, Guanajuato, Mexico
| | - Tianying Lan
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260, USA
| | - Octavio Martínez
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 36824, Irapuato, Guanajuato, Mexico
| | - Jean Philippe Vielle-Calzada
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 36824, Irapuato, Guanajuato, Mexico
| | - Victor A Albert
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260, USA.,School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Luis Herrera-Estrella
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 36824, Irapuato, Guanajuato, Mexico. .,Institute of Genomics for Crop Abiotic Stress Tolerance, Plant and Soil Department, Texas Tech University, Lubbock, TX, 79409, USA.
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Płachno BJ, Kapusta M, Świątek P, Banaś K, Miranda VFO, Bogucka-Kocka A. Spatio-Temporal Distribution of Cell Wall Components in the Placentas, Ovules and Female Gametophytes of Utricularia during Pollination. Int J Mol Sci 2021; 22:ijms22115622. [PMID: 34070693 PMCID: PMC8199428 DOI: 10.3390/ijms22115622] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 05/22/2021] [Accepted: 05/23/2021] [Indexed: 01/04/2023] Open
Abstract
In most angiosperms, the female gametophyte is hidden in the mother tissues and the pollen tube enters the ovule via a micropylar canal. The mother tissues play an essential role in the pollen tube guidance. However, in Utricularia, the female gametophyte surpasses the entire micropylar canal and extends beyond the limit of the integument. The female gametophyte then invades the placenta and a part of the central cell has direct contact with the ovary chamber. To date, information about the role of the placenta and integument in pollen tube guidance in Utricularia, which have extra-ovular female gametophytes, has been lacking. The aim of this study was to evaluate the role of the placenta, central cell and integument in pollen tube pollen tube guidance in Utricularia nelumbifolia Gardner and Utricularia humboldtii R.H. Schomb. by studying the production of arabinogalactan proteins. It was also determined whether the production of the arabinogalactan proteins is dependent on pollination in Utricularia. In both of the examined species, arabinogalactan proteins (AGPs) were observed in the placenta (epidermis and nutritive tissue), ovule (integument, chalaza), and female gametophyte of both pollinated and unpollinated flowers, which means that the production of AGPs is independent of pollination; however, the production of some AGPs was lower after fertilization. There were some differences in the production of AGPs between the examined species. The occurrence of AGPs in the placental epidermis and nutritive tissue suggests that they function as an obturator. The production of some AGPs in the ovular tissues (nucellus, integument) was independent of the presence of a mature embryo sac.
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Affiliation(s)
- Bartosz Jan Płachno
- Department of Plant Cytology and Embryology, Faculty of Biology, Institute of Botany, Jagiellonian University in Kraków, 9 Gronostajowa St., 30-387 Kraków, Poland
- Correspondence:
| | - Małgorzata Kapusta
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdańsk, 59 Wita Stwosza St., 80-308 Gdańsk, Poland;
| | - Piotr Świątek
- Faculty of Natural Sciences, Biotechnology and Environmental Protection, Institute of Biology, University of Silesia in Katowice, 9 Bankowa St., 40-007 Katowice, Poland;
| | - Krzysztof Banaś
- Department of Plant Ecology, Faculty of Biology, University of Gdańsk, 59 Wita Stwosza St., 80-308 Gdańsk, Poland;
| | - Vitor F. O. Miranda
- Laboratory of Plant Systematics, School of Agricultural and Veterinarian Sciences, São Paulo State University (Unesp), Jaboticabal CEP 14884-900, SP, Brazil;
| | - Anna Bogucka-Kocka
- Chair and Department of Biology and Genetics, Medical University of Lublin, 20-093 Lublin, Poland;
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Reut MS, Płachno BJ. Unusual developmental morphology and anatomy of vegetative organs in Utricularia dichotoma-leaf, shoot and root dynamics. PROTOPLASMA 2020; 257:371-390. [PMID: 31659470 PMCID: PMC7039851 DOI: 10.1007/s00709-019-01443-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 09/19/2019] [Indexed: 05/05/2023]
Abstract
The terrestrial carnivorous species Utricularia dichotoma is known for a great phenotypic plasticity and unusual vegetative organs. Our investigation on 22 sources/populations revealed that after initiation of a leaf and two bladders on a stolon, a bud was formed in the proximal axil of the leaf, developing into a rosette with up to seven organs. The first two primordia of the bud grew into almost every possible combination of organs, but often into two anchor stolons. The patterns were generally not population specific. The interchangeability of organs increased with increasing rank in the succession of organs on stolon nodes. A high potential of switching developmental programs may be successful in a fluctuating environment. In this respect, we were able to show that bladders developed from anchor stolons experimentally when raising the water table. Anatomical structures were simple, lacunate and largely homogenous throughout all organs. They showed similarities with many hydrophytes, reflecting the plant's adaptation to (temporarily) submerged conditions. The principal component analysis was used in the context of dynamic morphology to illustrate correlations between organ types in the morphospace of U. dichotoma, revealing an organ specific patchwork of developmental processes for typical leaves and shoots, and less pronounced for a typical root. The concept and methods we applied may prove beneficial for future studies on the evolution of Lentibulariaceae, and on developmental morphology and genetics of unusual structures in plants.
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Affiliation(s)
- Markus S Reut
- Department of Plant Cytology and Embryology, Institute of Botany, Faculty of Biology, Jagiellonian University, Kraków, 9 Gronostajowa St, 30-387, Cracow, Poland.
| | - Bartosz J Płachno
- Department of Plant Cytology and Embryology, Institute of Botany, Faculty of Biology, Jagiellonian University, Kraków, 9 Gronostajowa St, 30-387, Cracow, Poland
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Płachno BJ, Świątek P, Jobson RW, Małota K, Brutkowski W. Serial block face SEM visualization of unusual plant nuclear tubular extensions in a carnivorous plant (Utricularia, Lentibulariaceae). ANNALS OF BOTANY 2017; 120:673-680. [PMID: 28541416 PMCID: PMC5691799 DOI: 10.1093/aob/mcx042] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 02/09/2017] [Accepted: 03/23/2017] [Indexed: 05/22/2023]
Abstract
Background and Aims In Utricularia nelumbifolia , the nuclei of placental nutritive tissue possess unusually shaped projections not known to occur in any other flowering plant. The main aim of the study was to document the morphology and ultrastructure of these unusual nuclei. In addition, the literature was searched to find examples of nuclear tubular projections in other plant groups, and the nuclei of closely related species of Utricularia (i.e. sects Iperua , Orchidioides , Foliosa and Utricularia ) were examined. Methods To visualize the complexity of the nuclear structures, transmission electron microscopy (TEM) was used, and 3-D ultrastructural reconstructions were made using the serial block face scanning electron microscopy (SBEM) technique. The nuclei of 11 Utricularia species, i.e. U. nelumbifolia , U. reniformis , U. cornigera , U. nephrophylla (sect. Iperua ), U. asplundii , U. alpina , U. quelchii (sect. Orchidioides ), U. longifolia (sect. Foliosa ), U. intermedia , U. minor and U. gibba (sect. Utricularia ) were examined. Key Results Of the 11 Utricularia species examined, the spindle-like tubular projections (approx. 5 μm long) emanating from resident nuclei located in placental nutritive tissues were observed only in U. nelumbifolia . These tubular nuclear extensions contained chromatin distributed along hexagonally shaped tubules. The apices of the projections extended into the cell plasma membrane, and in many cases also made contact at the two opposing cellular poles, and with plasmodesmata via a short cisterna of the cortical endoplasmic reticulum. Images from the SBEM provide some evidence that the nuclear projections are making contact with those of neighbouring cells. Conclusions The term chromatubules (chromatin-filled tubules) for the nuclear projections of U. nelumbifolia placental tissue was proposed here. Due to the apparent association with the plasma membrane and plasmodesmata, it was also speculated that chromatubules are involved in nucleus-cell-cell communication. However, further experimental evidence is required before any functional hypothesis can be entertained.
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Affiliation(s)
- Bartosz J Płachno
- Department of Plant Cytology and Embryology, Jagiellonian University in Kraków, 9 Gronostajowa St., Cracow, Poland
| | - Piotr Świątek
- Department of Animal Histology and Embryology, University of Silesia in Katowice, 9 Bankowa St., 40-007 Katowice, Poland
| | - Richard W Jobson
- National Herbarium of New South Wales, Mrs Macquaries Road, Sydney, NSW 2000 Australia
| | - Karol Małota
- Department of Animal Histology and Embryology, University of Silesia in Katowice, 9 Bankowa St., 40-007 Katowice, Poland
| | - Wojciech Brutkowski
- Laboratory for Imaging Tissue Structure and Function, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., 02-093 Warszawa, Poland
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Płachno BJ, Kurczyńska E, Świątek P. Integument cell differentiation in dandelions (Taraxacum, Asteraceae, Lactuceae) with special attention paid to plasmodesmata. PROTOPLASMA 2016; 253:1365-72. [PMID: 26454638 PMCID: PMC5009155 DOI: 10.1007/s00709-015-0894-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 10/02/2015] [Indexed: 05/07/2023]
Abstract
The aim of the paper is to determine what happens with plasmodesmata when mucilage is secreted into the periplasmic space in plant cells. Ultrastructural analysis of the periendothelial zone mucilage cells was performed on examples of the ovule tissues of several sexual and apomictic Taraxacum species. The cytoplasm of the periendothelial zone cells was dense, filled by numerous organelles and profiles of rough endoplasmic reticulum and active Golgi dictyosomes with vesicles that contained fibrillar material. At the beginning of the differentiation process of the periendothelial zone, the cells were connected by primary plasmodesmata. However, during the differentiation and the thickening of the cell walls (mucilage deposition), the plasmodesmata become elongated and associated with cytoplasmic bridges. The cytoplasmic bridges may connect the protoplast to the plasmodesmata through the mucilage layers in order to maintain cell-to-cell communication during the differentiation of the periendothelial zone cells.
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Affiliation(s)
- Bartosz J Płachno
- Department of Plant Cytology and Embryology, Jagiellonian University in Kraków, 9 Gronostajowa St., 30-387, Kraków, Poland.
| | - Ewa Kurczyńska
- Department of Cell Biology, University of Silesia, 28 Jagiellońska St., 40-032, Katowice, Poland
| | - Piotr Świątek
- Department of Animal Histology and Embryology, University of Silesia, 9 Bankowa St., 40-007, Katowice, Poland
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Płachno BJ, Świątek P, Kozieradzka-Kiszkurno M, Majeský Ľ, Marciniuk J, Stolarczyk P. Are obligatory apomicts invested in the pollen tube transmitting tissue? Comparison of the micropyle ultrastructure between sexual and apomictic dandelions (Asteraceae, Lactuceae). PROTOPLASMA 2015; 252:1325-33. [PMID: 25652809 PMCID: PMC4561075 DOI: 10.1007/s00709-015-0765-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/20/2015] [Indexed: 05/07/2023]
Abstract
With the exception of the sunflower, little information concerning the micropyle ultrastructure of the family Asteraceae is available. The aim of our study was to compare the micropyle structure in amphimictic and apomictic dandelions. Ultrastructural studies using buds and flowers during anthesis have been done on the micropyle of the sexual and apomictic Taraxacum. In all of the species that were examined, the micropylar canal was completely filled with ovule transmitting tissue and the matrix that was produced by these cells. The ovule transmitting tissue was connected to the ovarian transmitting tissue. The micropyle was asymmetrical because the integument epidermis that forms the transmitting tissue was only on the funicular side. There was a cuticle between the obturator cells and epidermal cells on the other side of integument. The micropylar transmitting tissue cells and theirs matrix reached the synergid apex. The cytoplasm of the transmitting tissue cells was especially rich in rough endoplasmic reticulum (ER), dictyosomes, and mitochondria. No major differences were detected between the micropyle structure of the amphimictic and apomictic species; thus, a structural reduction of obturator does not exist. The ovule transmitting tissue is still active in apomictic dandelions despite the presence of the embryo and endosperm. Differences and similarities between the micropyle structure in the Asteraceae that have been studied to date are discussed.
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Affiliation(s)
- Bartosz J Płachno
- Department of Plant Cytology and Embryology, Jagiellonian University in Kraków, Kraków, 9 Gronostajowa St., 30-387, Kraków, Poland,
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Clivati D, Cordeiro GD, Płachno BJ, de Miranda VFO. Reproductive biology and pollination of Utricularia reniformis A.St.-Hil. (Lentibulariaceae). PLANT BIOLOGY (STUTTGART, GERMANY) 2014; 16:677-82. [PMID: 24834508 DOI: 10.1111/plb.12091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Utricularia reniformis is an endemic Brazilian carnivorous plant, most common in high-altitude grasslands. Knowledge of the reproductive biology of U. reniformis is essential for planning conservation strategies, but it is currently poorly understood. Thus, we studied the floral morphology, floral biology, breeding system and pollination of this species. U. reniformis produces and stores nectar in the flower spur, a classic feature of bee-pollinated flowers, and we recorded Xylocopa sp. and Bombus sp. as pollinators. Moreover, although it is self-compatible it is an obligate animal-pollinated species, as the sensitive stigma avoids self-pollination. However, in natural conditions reproductive success is low due to the rarity of visits from pollinators. We suggest that the low reproductive success caused by a deficit of pollinators may affect gene flow, causing loss of genetic diversity in U. reniformis.
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Płachno BJ, Musiał K, Swiątek P, Tuleja M, Marciniuk J, Grabowska-Joachimiak A. Synergids and filiform apparatus in the sexual and apomictic dandelions from section Palustria (Taraxacum, Asteraceae). PROTOPLASMA 2014; 251:211-7. [PMID: 23974526 PMCID: PMC3893458 DOI: 10.1007/s00709-013-0539-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 08/08/2013] [Indexed: 05/07/2023]
Abstract
An evolutionary trend to reduce "unnecessary costs" associated with the sexual reproduction of their amphimictic ancestors, which may result in greater reproductive success, has been observed among the obligatory apomicts. However, in the case of the female gametophyte, knowledge about this trend in apomicts is not sufficient because most of the ultrastructural studies of the female gametophyte have dealt with amphimictic angiosperms. In this paper, we tested the hypothesis that, in contrast to amphimictic plants, synergids in apomictic embryo sacs do not form a filiform apparatus. We compared the synergid structure in two dandelions from sect. Palustria: the amphimictic diploid Taraxacum tenuifolium and the apomictic tetraploid, male-sterile Taraxacum brandenburgicum. Synergids in both species possessed a filiform apparatus. In T. brandenburgicum, both synergids persisted for a long time without any degeneration, in spite of the presence of an embryo and endosperm. We propose that the persistent synergids in apomicts may play a role in the transport of nutrients to the embryo.
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Affiliation(s)
- Bartosz J Płachno
- Department of Plant Cytology and Embryology, Jagiellonian University, 9 Gronostajowa St., 30-387, Cracow, Poland,
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Płachno BJ, Swiątek P. Actin cytoskeleton in the extra-ovular embryo sac of Utricularia nelumbifolia (Lentibulariaceae). PROTOPLASMA 2012; 249:663-70. [PMID: 21786167 PMCID: PMC3382281 DOI: 10.1007/s00709-011-0306-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 07/10/2011] [Indexed: 05/25/2023]
Abstract
The actin cytoskeleton in the mature female gametophyte of angiosperms has been examined in only a few dicot and monocot species. The main purposes of this study were to identify how the actin cytoskeleton is arranged in the mature extra-ovular embryo sac in Utricularia nelumbifolia (Lentibulariaceae). We found that the extra-ovular part of the central cell has a well-developed actin cytoskeleton: actin microfilaments formed of long strands which run longitudinally or transversally to the long axis of the embryo sac. The exerted part of the central cell, which is exposed to the environment of the ovary chamber, is highly vacuolated and in the thin peripheral cytoplasm possesses a complicated network of actin microfilaments. The epidermal cells of the placenta that are in contact with the extra-ovular part of the embryo sac are crushed. The ultrastructure data of these cells are presented. We detected the accumulation of the actin cytoskeleton between the micropylar parts of the synergids and the extra-ovular part of central cell. This actin accumulation is unusual because in typical angiosperms the micropylar parts of the synergids form the apex of the female gametophyte.
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Affiliation(s)
- Bartosz Jan Płachno
- Department of Plant Cytology and Embryology, Jagiellonian University, Grodzka 52, 31-044, Cracow, Poland.
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