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Polevova S, Moiseenko A. Silicon in sporoderms of micro- and megaspores of Isoetes echinospora Durieu registered by EDS and EELS. Protoplasma 2023; 260:663-667. [PMID: 35819547 DOI: 10.1007/s00709-022-01791-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
The present study reveals silica in sporoderms of micro- and megaspores of the modern quillwort Isoetes echinospora Durieu and homologizes layers of the sporoderm in spores of this plant. Here, the presence of silica in sporoderms of microspores has been documented for the first time, and observations of megaspore sporoderms were used to test various methods, such as energy dispersive (EDS) and electron energy loss (EELS) spectroscopies. The results elucidate the occurrence of silicon in the quillworts and will influence on the interpretation of their modern and fossil sporoderms.
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Affiliation(s)
- Svetlana Polevova
- Biological Faculty, Lomonosov Moscow State University, Moscow, Russia.
| | - Andrey Moiseenko
- Biological Faculty, Lomonosov Moscow State University, Moscow, Russia
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Breygina M, Voronkov A, Galin I, Akhiyarova G, Polevova S, Klimenko E, Ivanov I, Kudoyarova G. Dynamics of endogenous levels and subcellular localization of ABA and cytokinins during pollen germination in spruce and tobacco. Protoplasma 2023; 260:237-248. [PMID: 35579760 DOI: 10.1007/s00709-022-01766-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 04/24/2022] [Indexed: 06/15/2023]
Abstract
We used the enzyme-linked immunosorbent assay (ELISA) to assess the level of endogenous hormones in spruce pollen, and immunolocalization and confocal microscopy to study hormone localization in spruce and tobacco pollen. During pollen activation, the levels of ABA, zeatin, and its riboside significantly decreased. After the initiation of polar growth, the levels of all cytokinins increased sharply; ABA level also increased. In dormant spruce pollen grains, zeatin and ABA were localized uniformly throughout the cytoplasm. Zeatin was not detected in the nuclei, and the antheridial cell showed higher levels than the vegetative cell; ABA signal was detected in the cytoplasm and the nuclei. In germinating pollen, both hormones were detected mainly in plastids. The similar pattern was found in growing pollen tubes; signal from ABA also had a noticeable level in the cytosol of the tube cell, and was weaker in the antheridial cell. Zeatin fluorescence, on the other hand, was more pronounced in the antheridial cell. In non-germinated grains of tobacco, zeatin was localized mainly in organelles. ABA in dormant pollen grains demonstrated uniform localization, including the nuclei and cytoplasm of both cells. After germination, zeatin was accumulated in the plasmalemma or cell wall. ABA signal in the cytoplasm decreased; in the nuclei, it remained high. In growing tubes, the strongest zeatin and ABA signals were observed at the plasma membrane. The differences in ABA and cytokinin localization between species and dynamic changes in their level in spruce pollen highlight the key spatial and temporal parameters of hormonal regulation of gymnosperm pollen germination.
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Affiliation(s)
- Maria Breygina
- Biological Faculty, Lomonosov Moscow State University, Leninskiye gory 1-12, Moscow, 119991, Russia.
| | - Alexander Voronkov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya St. 35, Moscow, 127276, Russia
| | - Ilshat Galin
- Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia
| | - Guzel Akhiyarova
- Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia
| | - Svetlana Polevova
- Biological Faculty, Lomonosov Moscow State University, Leninskiye gory 1-12, Moscow, 119991, Russia
| | - Ekaterina Klimenko
- Biological Faculty, Lomonosov Moscow State University, Leninskiye gory 1-12, Moscow, 119991, Russia
| | - Igor Ivanov
- Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia
| | - Guzel Kudoyarova
- Institute of Biology, Ufa Research Centre, Russian Academy of Sciences, pr. Oktyabrya 69, 450054, Ufa, Russia
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Breygina M, Maksimov N, Polevova S, Evmenyeva A. Bipolar pollen germination in blue spruce (Picea pungens). Protoplasma 2019; 256:941-949. [PMID: 30788602 DOI: 10.1007/s00709-018-01333-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
Direct growth of a pollen tube is an effective mechanism of sperm delivery characteristic for the majority of seed plants. In most cases, only one tube grows from one grain to perform the delivery function; meanwhile in Picea the appearance of two tubes from a single pollen grain is quite common during in vitro germination. Here, we describe the phenomenon of bipolar germination and test two hypotheses on its nature and possible role in gametophyte functioning. The hypothesis on "trophic" function of multiple tubes provoked by poor nutrition discussed in literature was not confirmed by in vitro growth tests; bipolar germination strongly decreased with lowering sucrose availability. The highest proportion of bipolar germination occurred in optimal conditions. We then assumed that bipolar germination occurs because turgor pressure is a non-directional force and effective systems of cell wall mechanical regulation are lacking. In hypertonic medium, bipolar germination was sufficiently lower than in isotonic medium, which was consistent with prediction of the «mechanical» hypothesis. Scanning electron microscopy and fluorescence microscopy analysis of pollen morphology and cell wall dynamics during both types of germination showed that the appearance of a single tube or bipolar germination depends on the extension of exine rupture. Cell wall softening by short-term ·OH treatment sufficiently decreased the percent of bipolar germination without affecting total germination efficiency. We concluded that mechanical properties of the cell wall and turgor pressure could shift the balance towards one of the germination patterns.
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Affiliation(s)
- M Breygina
- Lomonosov Moscow State University, Russian Federation, Moscow, 119991, Russia.
| | - N Maksimov
- Lomonosov Moscow State University, Russian Federation, Moscow, 119991, Russia
| | - S Polevova
- Lomonosov Moscow State University, Russian Federation, Moscow, 119991, Russia
| | - A Evmenyeva
- Lomonosov Moscow State University, Russian Federation, Moscow, 119991, Russia
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Gabarayeva N, Polevova S, Grigorjeva V, Severova E, Volkova O, Blackmore S. Suggested mechanisms underlying pollen wall development in Ambrosia trifida (Asteraceae: Heliantheae). Protoplasma 2019; 256:555-574. [PMID: 30341717 DOI: 10.1007/s00709-018-1320-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Accepted: 10/11/2018] [Indexed: 05/05/2023]
Abstract
By a detailed ontogenetic study of Ambrosia trifida pollen, tracing each stage of development with TEM, we aim to understand the establishment of the pollen wall and to unravel the mechanisms underlying sporoderm development. The main steps of exine ontogeny in Ambrosia trifida, observed in the microspore periplasmic space, are as follows: spherical units, gradually transforming into columns, then to rod-like units; the appearance of the initial reticulate tectum; growth of columellae under the tectum and initial sporopollenin accumulation on them; the appearance of the endexine lamellae, first in fragments, then in long laminae; the cessation of the glycocalyx growth and its detachment from the plasma membrane, resulting in the appearance of gaps; massive accumulation of sporopollenin on the tectum, columellae, and endexine, and the appearance of the foot layer at the young post-tetrad stage, accompanied by establishment of caveae in sites of the former gaps; and final massive sporopollenin accumulation. This sequence of developmental events in all probability corresponds to the sequence of self-assembling micellar mesophases. This gives (together with earlier findings and experimental modeling of exine) strong evidence that the genome and self-assembly share control of exine formation. In this sense, self-assembly itself can be seen as an inherent mechanism of evolution.
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Affiliation(s)
- Nina Gabarayeva
- Komarov Botanical Institute, Russian Academy of Sciences, Popov St. 2, St. Petersburg, Russia, 197376.
| | | | - Valentina Grigorjeva
- Komarov Botanical Institute, Russian Academy of Sciences, Popov St. 2, St. Petersburg, Russia, 197376
| | - Elena Severova
- Moscow State University, Leninski Gory, 1, Moscow, Russia, 119991
| | - Olga Volkova
- Moscow State University, Leninski Gory, 1, Moscow, Russia, 119991
| | - Stephen Blackmore
- Royal Botanic Garden Edinburgh, 20a Inverleith Row, Edinburgh, EH3 5LR, UK
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Polevova S, Breygina M, Matveyeva N, Yermakov I. Periplasmic multilamellar membranous structures in Nicotiana tabacum L. pollen grains treated with Ni²⁺ or Cu²⁺. Protoplasma 2014; 251:1521-5. [PMID: 24802108 DOI: 10.1007/s00709-014-0651-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/18/2014] [Indexed: 06/03/2023]
Abstract
Essential trace elements Ni(2+) and Cu(2+) can block pollen germination without causing cell death. Mechanisms of this effect remain unclear. Using TEM, we studied the effects of Ni(2+) or Cu(2+) treatment on the ultrastructure of the aperture regions in tobacco pollen preparing to germinate in vitro, since in these zones, the main fluxes of water, ions, and metabolites cross the plasmalemma. Neither Ni(2+) nor Cu(2+) altered the cytoplasm ultrastructure, but both affected the reorganization of apertural periplasm during pollen activation. Numerous multilamellar membranous structures continuous with the plasma membrane could be seen in hydrated but not yet activated pollen. When the normal activation was completed, the structures disappeared and the plasmalemma became smooth. In the presence of 1 mM Ni(2+) or 100 μM Cu(2+), these structures preserved its original appearance. It is assumed to be the storage form for the membrane material, which is to provide an initial phase of the pollen tube growth. Ni(2+) and Cu(2+) affect the utilization of these membranes, thereby, blocking the pollen germination.
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Affiliation(s)
- Svetlana Polevova
- Higher Plants Department, Faculty of Biology, Lomonosov Moscow State University, Lenin Hills, Moscow, Russia, 119234,
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Breygina M, Matveyeva N, Polevova S, Meychik N, Nikolaeva Y, Mamaeva A, Yermakov I. Ni(2+) effects on Nicotiana tabacum L. pollen germination and pollen tube growth. Biometals 2012; 25:1221-33. [PMID: 22983762 DOI: 10.1007/s10534-012-9584-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 09/03/2012] [Indexed: 11/27/2022]
Abstract
To investigate the mechanisms of Ni(2+) effects on initiation and maintenance of polar cell growth, we used a well-studied model system-germination of angiosperm pollen grains. In liquid medium tobacco pollen grain forms a long tube, where the growth is restricted to the very tip. Ni(2+) did not prevent the formation of pollen tube initials, but inhibited their subsequent growth with IC(50) = 550 μM. 1 mM Ni(2+) completely blocked the polar growth, but all pollen grains remained viable, their respiration was slightly affected and ROS production did not increase. Addition of Ni(2+) after the onset of germination had a bidirectional effect on the tubes development: there was a considerable amount of extra-long tubes, which appeared to be rapidly growing, but the growth of many tubes was impaired. Studying the localization of possible targets of Ni(2+) influence, we found that they may occur both in the wall and in the cytoplasm, as confirmed by specific staining. Ni(2+) disturbed the segregation of transport vesicles in the tips of these tubes and significantly reduced the relative content of calcium in the aperture area of pollen grains, as measured by X-ray microanalysis. These factors are considered being critical for normal polar cell growth. Ni(2+) also causes the deposition of callose in the tips of the tube initials and the pollen tubes that had stopped their growth. We can assume that Ni(2+)-induced disruption of calcium homeostasis can lead to vesicle traffic impairment and abnormal callose deposition and, consequently, block the polar growth.
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Affiliation(s)
- Maria Breygina
- Department of Plant Physiology, School of Biology, Lomonosov Moscow State University, 119991, Moscow, Russia.
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