Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture
Hassallia antarctica is a terrestrial cyanobacterium colonizing various habitats in Antarctica such as soil surface, microbiological mats and seepages. H. antarctica represents one of the cyanobacterial species forming biodiversity of terrestrial autotrophs of James Ross Island, Antarctica. It is a...
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ftmasarykunivojs:oai:ojs.journals.muni.cz:article/12927 2023-05-15T13:46:41+02:00 Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture Alonso, Marta Campos 2018-07-01 application/pdf http://journals.muni.cz/CPR/article/view/12927 eng eng Masaryk Univerzity http://journals.muni.cz/CPR/article/view/12927/11279 http://journals.muni.cz/CPR/article/view/12927 Copyright (c) 2020 Czech Polar Reports https://creativecommons.org/licenses/by-nc-nd/4.0 CC-BY-NC-ND Czech Polar Reports; Vol 8 No 2 (2018); 198-207 Czech Polar Reports; Vol. 8 No. 2 (2018); 198-207 1805-0697 1805-0689 cyanobacterium Antarctics James Ross Island dehydration Kautsky kinetics info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2018 ftmasarykunivojs 2022-06-26T10:16:39Z Hassallia antarctica is a terrestrial cyanobacterium colonizing various habitats in Antarctica such as soil surface, microbiological mats and seepages. H. antarctica represents one of the cyanobacterial species forming biodiversity of terrestrial autotrophs of James Ross Island, Antarctica. It is a filamentous cyanobacterium composing blackish fasciculated clusters thanks to false branching. In our study, sensitivity of the species to dehydration and salt stress was studied. We used H. antarctica culture (CCALA 956) grown on Z liquid medium. Clusters of H. antarctica were placed on wet filter paper and dried naturally at 5°C. During gradual dehydration, relative water content (RWC) was evaluated gravimetrically simultaneously with chlorophyll fluorescence measurements. Slow Kautsky kinetics and the chlorophyll fluorescence parameters (FV/FM, ФPSII) were used to assess dehydration-related decrease in primary photosynthetic processes. It was found that H. antarctica, contrastingly to other terrestrial cyanobacteria from polar habitats, was not able to maintain photosynthetic processes at RWCs as low as 20%. Even during initial phase of dehydration (RWC of 95%) rapid decline in FV/FM occured. Resistance of H. antarctica to osmotic stress was studied by time courses of the chlorophyll fluorescence parameter in response to 3.0, 0.3, and 0.03 M NaCl solution. Both shape of slow Kautsky kinetics and numeric values of chlorophyll fluorescence parameters were affected by osmotic stress. While full inhibitory effect was apparent in 3.0 M NaCl treatment immediately, the salt stress-induced decline in chlorophyll fluorescence parameters was observed at 0.03 M NaCl even after 8 hours of exposition. It was, therefore, concluded that H. antarctica exhibited high resistance to osmotic stress which may help the species to cope with repetitive dehydration events that happen in the field during austral summer season in Antarctica, James Ross Island in particular. Article in Journal/Newspaper Antarc* Antarctica James Ross Island Ross Island Masaryk University Journals Austral Ross Island |
institution |
Open Polar |
collection |
Masaryk University Journals |
op_collection_id |
ftmasarykunivojs |
language |
English |
topic |
cyanobacterium Antarctics James Ross Island dehydration Kautsky kinetics |
spellingShingle |
cyanobacterium Antarctics James Ross Island dehydration Kautsky kinetics Alonso, Marta Campos Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture |
topic_facet |
cyanobacterium Antarctics James Ross Island dehydration Kautsky kinetics |
description |
Hassallia antarctica is a terrestrial cyanobacterium colonizing various habitats in Antarctica such as soil surface, microbiological mats and seepages. H. antarctica represents one of the cyanobacterial species forming biodiversity of terrestrial autotrophs of James Ross Island, Antarctica. It is a filamentous cyanobacterium composing blackish fasciculated clusters thanks to false branching. In our study, sensitivity of the species to dehydration and salt stress was studied. We used H. antarctica culture (CCALA 956) grown on Z liquid medium. Clusters of H. antarctica were placed on wet filter paper and dried naturally at 5°C. During gradual dehydration, relative water content (RWC) was evaluated gravimetrically simultaneously with chlorophyll fluorescence measurements. Slow Kautsky kinetics and the chlorophyll fluorescence parameters (FV/FM, ФPSII) were used to assess dehydration-related decrease in primary photosynthetic processes. It was found that H. antarctica, contrastingly to other terrestrial cyanobacteria from polar habitats, was not able to maintain photosynthetic processes at RWCs as low as 20%. Even during initial phase of dehydration (RWC of 95%) rapid decline in FV/FM occured. Resistance of H. antarctica to osmotic stress was studied by time courses of the chlorophyll fluorescence parameter in response to 3.0, 0.3, and 0.03 M NaCl solution. Both shape of slow Kautsky kinetics and numeric values of chlorophyll fluorescence parameters were affected by osmotic stress. While full inhibitory effect was apparent in 3.0 M NaCl treatment immediately, the salt stress-induced decline in chlorophyll fluorescence parameters was observed at 0.03 M NaCl even after 8 hours of exposition. It was, therefore, concluded that H. antarctica exhibited high resistance to osmotic stress which may help the species to cope with repetitive dehydration events that happen in the field during austral summer season in Antarctica, James Ross Island in particular. |
format |
Article in Journal/Newspaper |
author |
Alonso, Marta Campos |
author_facet |
Alonso, Marta Campos |
author_sort |
Alonso, Marta Campos |
title |
Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture |
title_short |
Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture |
title_full |
Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture |
title_fullStr |
Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture |
title_full_unstemmed |
Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture |
title_sort |
changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of hassallia antarctica culture |
publisher |
Masaryk Univerzity |
publishDate |
2018 |
url |
http://journals.muni.cz/CPR/article/view/12927 |
geographic |
Austral Ross Island |
geographic_facet |
Austral Ross Island |
genre |
Antarc* Antarctica James Ross Island Ross Island |
genre_facet |
Antarc* Antarctica James Ross Island Ross Island |
op_source |
Czech Polar Reports; Vol 8 No 2 (2018); 198-207 Czech Polar Reports; Vol. 8 No. 2 (2018); 198-207 1805-0697 1805-0689 |
op_relation |
http://journals.muni.cz/CPR/article/view/12927/11279 http://journals.muni.cz/CPR/article/view/12927 |
op_rights |
Copyright (c) 2020 Czech Polar Reports https://creativecommons.org/licenses/by-nc-nd/4.0 |
op_rightsnorm |
CC-BY-NC-ND |
_version_ |
1766245080022122496 |