Desiccation-induced changes in photochemical processes of photosynthesis and spectral reflectance in Nostoc commune (Cyanobacteria, Nostocales) colonies from polar regions
| Název česky | Suchem způsobené změny ve fotochemických procesech fotosyntézy a spektrální odrazivosti u polárních kolonií Nostoc commune |
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| Autoři | |
| Rok publikování | 2017 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | Phycological research |
| Fakulta / Pracoviště MU | |
| Citace | |
| www | http://onlinelibrary.wiley.com/doi/10.1111/pre.12157/epdf |
| Doi | http://dx.doi.org/10.1111/pre.12157 |
| Klíčová slova | chlorophyll fluorescence; cyanobacteria; dehydration; Normalized Difference Vegetation Index (NDVI); Photochemical Reflectance Index (PRI) |
| Popis | Cyanobacterium Nostoc commune is a species highly resistant against desiccation. In this study, we investigated changes in photochemical processes of photosynthesis and spectral reflectance indices during controlled desiccation of the colonies from Antarctica. In a dehydration process, water potential (WP) reached -3 MPa and values of potential (F-v/F-m) and effective quantum yields (Phi PSII) of photosystem II were kept to high value until 90% of water was lost from the colony, and these values decreased rapidly by further loss of water. This indicates that the colony loses water mostly from the exopoly-saccharidic envelope, not from cells during the initial part of dehydration (relative water content, RWC = 100-10%). Other suggestions of inhibition of photosynthetic processes after 90% loss of water were the increase of the chlorophyll fluorescence parameter F-p/F-s. The F-m' was higher than Fm in hydrated colonies because of state transition which change energy distribution between PS I and PS II, but decreased to same level as Fm in dehydrated colonies. The Normalized Difference Vegetation Index (NDVI) and Photochemical Reflectance Index (PRI) showed concave- and convex-curvilinear relationship with RWC, respectively. The changes of NDVI values were, however, statistically insignificant. PRI values were predominantly below 0 because of phycobiliprotein involvement. These results were compared with the same species in the Arctic region. This is, according to our best knowledge, the first measurement of changes in spectral reflectance indices during desiccation of cyanobacteria. |
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