Morphology, growth, photosynthesis and pigments in Laminaria ochroleuca (Laminariales, Phaeophyta) under ultraviolet radiation

Young sporophytes of Laminaria ochroleuca were exposed in the laboratory either to a full light spectrum or to light depleted of only ultraviolet-B radiation (UVB) or of the whole ultraviolet radiation (UVR) using cutoff glass filters. The plants were grown under 16:8 h light-dark cycles with 6 h ad...

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Main Authors: Roleda, Michael Y., Hanelt, Dieter, Kräbs, Gudrun, Wiencke, Christian
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Published: Animo Repository 2004
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Online Access:https://animorepository.dlsu.edu.ph/faculty_research/4462
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Institution: De La Salle University
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spelling oai:animorepository.dlsu.edu.ph:faculty_research-52702022-01-02T03:01:17Z Morphology, growth, photosynthesis and pigments in Laminaria ochroleuca (Laminariales, Phaeophyta) under ultraviolet radiation Roleda, Michael Y. Hanelt, Dieter Kräbs, Gudrun Wiencke, Christian Young sporophytes of Laminaria ochroleuca were exposed in the laboratory either to a full light spectrum or to light depleted of only ultraviolet-B radiation (UVB) or of the whole ultraviolet radiation (UVR) using cutoff glass filters. The plants were grown under 16:8 h light-dark cycles with 6 h additional UV exposure in the middle of the light phase. Effective quantum yield of photosystem II (ΔF/Fm′) was measured daily, 1 h before UV exposure, at 2 and 5 h cumulative UV exposure and at 1 and 4 h after UV exposure. Growth was measured using two methods in separate experiments. In the first, a scanner with image analysis software was used to measure surface area every 3 days for 4 weeks. In the second, a growth chamber with online video measuring technique was used to measure growth every 10 min for 2 weeks. Pigments were measured at the end of the experiments. During the first day of UV exposure, the photosynthetic yield of plants exposed to photosynthetically active radiation (PAR) + ultraviolet-A radiation (UVA) and PAR + UVA + UVB was significantly reduced but was able to recover 1 h after the end of UV exposure. An increasing mean ΔF/Fm′ during UV exposure showed partial acclimation of photosynthesis in young sporophytes in the course of several days. However, a higher growth rate was observed in plants exposed to PAR alone, whereas reduced growth and damaged tissue were observed in plants exposed to UVR. Similarly, a lower content of all pigments was measured in thalli exposed to PAR + UVR. The result shows that acclimation of photosynthesis could underestimate the negative effect of this stress factor. Growth, as an integrative process, is a better parameter to explain ecophysiological performance at organism level. It was shown that growth and morphology of young sporophytes of L. ochroleuca are susceptible to UV damage, which could effectively limit the upper distributional range of this species. 2004-01-01T08:00:00Z text https://animorepository.dlsu.edu.ph/faculty_research/4462 info:doi/10.2216/i0031-8884-43-5-603.1 Faculty Research Work Animo Repository Laminariales—Effect of ultraviolet radiation on Biology
institution De La Salle University
building De La Salle University Library
continent Asia
country Philippines
Philippines
content_provider De La Salle University Library
collection DLSU Institutional Repository
topic Laminariales—Effect of ultraviolet radiation on
Biology
spellingShingle Laminariales—Effect of ultraviolet radiation on
Biology
Roleda, Michael Y.
Hanelt, Dieter
Kräbs, Gudrun
Wiencke, Christian
Morphology, growth, photosynthesis and pigments in Laminaria ochroleuca (Laminariales, Phaeophyta) under ultraviolet radiation
description Young sporophytes of Laminaria ochroleuca were exposed in the laboratory either to a full light spectrum or to light depleted of only ultraviolet-B radiation (UVB) or of the whole ultraviolet radiation (UVR) using cutoff glass filters. The plants were grown under 16:8 h light-dark cycles with 6 h additional UV exposure in the middle of the light phase. Effective quantum yield of photosystem II (ΔF/Fm′) was measured daily, 1 h before UV exposure, at 2 and 5 h cumulative UV exposure and at 1 and 4 h after UV exposure. Growth was measured using two methods in separate experiments. In the first, a scanner with image analysis software was used to measure surface area every 3 days for 4 weeks. In the second, a growth chamber with online video measuring technique was used to measure growth every 10 min for 2 weeks. Pigments were measured at the end of the experiments. During the first day of UV exposure, the photosynthetic yield of plants exposed to photosynthetically active radiation (PAR) + ultraviolet-A radiation (UVA) and PAR + UVA + UVB was significantly reduced but was able to recover 1 h after the end of UV exposure. An increasing mean ΔF/Fm′ during UV exposure showed partial acclimation of photosynthesis in young sporophytes in the course of several days. However, a higher growth rate was observed in plants exposed to PAR alone, whereas reduced growth and damaged tissue were observed in plants exposed to UVR. Similarly, a lower content of all pigments was measured in thalli exposed to PAR + UVR. The result shows that acclimation of photosynthesis could underestimate the negative effect of this stress factor. Growth, as an integrative process, is a better parameter to explain ecophysiological performance at organism level. It was shown that growth and morphology of young sporophytes of L. ochroleuca are susceptible to UV damage, which could effectively limit the upper distributional range of this species.
format text
author Roleda, Michael Y.
Hanelt, Dieter
Kräbs, Gudrun
Wiencke, Christian
author_facet Roleda, Michael Y.
Hanelt, Dieter
Kräbs, Gudrun
Wiencke, Christian
author_sort Roleda, Michael Y.
title Morphology, growth, photosynthesis and pigments in Laminaria ochroleuca (Laminariales, Phaeophyta) under ultraviolet radiation
title_short Morphology, growth, photosynthesis and pigments in Laminaria ochroleuca (Laminariales, Phaeophyta) under ultraviolet radiation
title_full Morphology, growth, photosynthesis and pigments in Laminaria ochroleuca (Laminariales, Phaeophyta) under ultraviolet radiation
title_fullStr Morphology, growth, photosynthesis and pigments in Laminaria ochroleuca (Laminariales, Phaeophyta) under ultraviolet radiation
title_full_unstemmed Morphology, growth, photosynthesis and pigments in Laminaria ochroleuca (Laminariales, Phaeophyta) under ultraviolet radiation
title_sort morphology, growth, photosynthesis and pigments in laminaria ochroleuca (laminariales, phaeophyta) under ultraviolet radiation
publisher Animo Repository
publishDate 2004
url https://animorepository.dlsu.edu.ph/faculty_research/4462
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