1
|
de Oliveira EM, Schmidt ÉC, Pereira DT, Bouzon ZL, Ouriques LC. Effects of UV-B radiation on germlings of the red macroalga Nemalion helminthoides (Rhodophyta). J Microsc Ultrastruct 2016; 4:85-94. [PMID: 30023214 PMCID: PMC6014211 DOI: 10.1016/j.jmau.2015.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/26/2015] [Accepted: 11/10/2015] [Indexed: 11/11/2022] Open
Abstract
Studies have clearly demonstrated the damaging effects of UV-B exposure on macroalgae, but few have reported the impact of UV-B on spore germination and development at juvenile stages. Therefore, this work aimed to analyze the effects of UV-B radiation on germlings of Nemalion helminthoides at the tetrasporophytic phase. To accomplish this, germlings of N. helminthoides were cultivated in the laboratory and separated into two groups. The control group was exposed onlyto photosynthetic radiation, while the treatment group was exposed to photosynthetic radiation + UV-B for 2 hours during a period of 12 days. Control germlings showed increasing cellular proliferation and accumulation of reserve substances, as well as intense ramification in the last observed stages between 9 days and 12 days of development. Moreover, the chloroplasts presented a typical globular pyrenoid, profusely traversed by thylakoid membranes. Treated germlings, by contrast, showed intracellular damage, such as cell wall thickness, loss of chloroplast organization, changes in mitochondrial cristae, and increasing atrophy of the Golgi bodies. Additionally, changes in developmental patterns were observed, including loss of polarity in the first divisions of carpospores and abnormal stem ramification. The quantification of autofluorescence data coincided with the ultrastructural changes observed in the chloroplasts of cells exposed to UV-B. It can be concluded that exposure to radiation changed the developmental pattern and morphology of the germlings of N. helminthoides.
Collapse
Affiliation(s)
- Eliana M de Oliveira
- Post-Graduate Program in Cell Biology and Development, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina 88049-900, CP 476, Florianópolis, Santa Catarina, Brazil.,Central Laboratory of Electron Microscopy, Federal University of Santa Catarina 88049-900, CP 476, Florianópolis, Santa Catarina, Brazil
| | - Éder C Schmidt
- Post-Graduate Program in Cell Biology and Development, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina 88049-900, CP 476, Florianópolis, Santa Catarina, Brazil
| | - Debora T Pereira
- Post-Graduate Program in Cell Biology and Development, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina 88049-900, CP 476, Florianópolis, Santa Catarina, Brazil
| | - Zenilda L Bouzon
- Post-Graduate Program in Cell Biology and Development, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina 88049-900, CP 476, Florianópolis, Santa Catarina, Brazil
| | - Luciane C Ouriques
- Post-Graduate Program in Cell Biology and Development, Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina 88049-900, CP 476, Florianópolis, Santa Catarina, Brazil
| |
Collapse
|
5
|
Gruber A, Roleda MY, Bartsch I, Hanelt D, Wiencke C. SPOROGENESIS UNDER ULTRAVIOLET RADIATION IN LAMINARIA DIGITATA (PHAEOPHYCEAE) REVEALS PROTECTION OF PHOTOSENSITIVE MEIOSPORES WITHIN SORAL TISSUE: PHYSIOLOGICAL AND ANATOMICAL EVIDENCE 1. JOURNAL OF PHYCOLOGY 2011; 47:603-614. [PMID: 27021990 DOI: 10.1111/j.1529-8817.2011.00998.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
To study the effect of different radiation conditions on sporogenesis of Laminaria digitata (Huds.) J. V. Lamour., excised disks were induced to form sporangia under PAR (P), PAR + ultraviolet-A (UVA) (PA), and PAR + UVA + ultraviolet-B (UVB) (PAB) conditions in the laboratory. Vitality of meiospores, released from sori induced under different radiation conditions in the laboratory and from sori of wild sporophytes acclimated to in situ solar radiation in the presence and absence of ultraviolet radiation (UVR), was measured in terms of their germination capacity. Sorus induction in disks of laboratory-grown sporophytes was not hampered under light supplemented with UVR, and sorus area was not significantly different among P, PA, and PAB. Vitality and germination rate of meiospores released from sori induced under different radiation treatments was comparable. Likewise, screening of UVR of the natural solar radiation did not promote higher germination rates of meiospores released from wild sporophytes. Germination rates were, however, higher in meiospores released from laboratory-induced sori compared to sori of wild sporophytes. Higher DNA damage (formation of cyclobutane pyrimidine dimers, CPDs) was observed in laboratory-grown nonsorus compared to sorus tissue, while CPDs were nondetectable in both sorus and nonsorus tissue of wild sporophytes. To explain the apparent protection of developing meiospores and the unexpected UV resistance of soral tissue, concurrent anatomical investigations of sporogenic tissue were performed. We observed the previously unreported existence of two types of sterile paraphysis cells. One type of paraphysis cells, the most frequent type, contained several red-fluorescing plastids. The other type, less frequently occurring, was completely filled with substances emitting blue fluorescence under violet excitation, presumably brown algal phenolic compounds (phlorotannins). Cells of this type were irregularly scattered within the sorus and did not contain red-fluorescing plastids. Meiospore-containing sporangia were positioned embedded between both types of paraphysis cells. In vegetative tissue, blue autofluorescence was observed only in injured parts of the blade. Results of our study suggest that the sorus structure with phlorotannins localized in the specialized paraphysis cells may be able to screen harmful UVR and protect UV-sensitive meiospores inside the sporangia.
Collapse
Affiliation(s)
- Ansgar Gruber
- Biologische Anstalt Helgoland, Alfred Wegener Institute for Polar and Marine Research, 27498 Helgoland, GermanySection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, 22609 Hamburg, GermanySection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Michael Y Roleda
- Biologische Anstalt Helgoland, Alfred Wegener Institute for Polar and Marine Research, 27498 Helgoland, GermanySection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, 22609 Hamburg, GermanySection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Inka Bartsch
- Biologische Anstalt Helgoland, Alfred Wegener Institute for Polar and Marine Research, 27498 Helgoland, GermanySection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, 22609 Hamburg, GermanySection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Dieter Hanelt
- Biologische Anstalt Helgoland, Alfred Wegener Institute for Polar and Marine Research, 27498 Helgoland, GermanySection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, 22609 Hamburg, GermanySection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Christian Wiencke
- Biologische Anstalt Helgoland, Alfred Wegener Institute for Polar and Marine Research, 27498 Helgoland, GermanySection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, GermanyBiozentrum Klein Flottbek, University of Hamburg, Ohnhorst-Str. 18, 22609 Hamburg, GermanySection Functional Ecology, Department Seaweed Biology, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| |
Collapse
|