Desiccation‐induced changes in photochemical processes of photosynthesis and spectral reflectance in <i>Nostoc commune</i> (<scp>C</scp>yanobacteria, <scp>N</scp>ostocales) colonies from polar regions

Trnková, Kateřina; Barták, Miloš

doi:10.1111/pre.12157

Cited by 11 publications

(7 citation statements)

References 37 publications

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“…The differences found in PRI were consistent with the data previously presented by Barták et al (2016). For, N. commune, Trnková et Barták (2016) reported dehydration-induced changes in PRI in Antarctic Nostoc sp. colonies as well.…”

Section: Resultssupporting

confidence: 92%

Changes in spectral reflectance of selected Antarctic and South American lichens caused by dehydration and artificially-induced absence of secondary compounds

Barták¹,

Hájek²,

Amarillo³

et al. 2016

Czech Polar Rep.

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Recently, spectral characteristics of lichens are in focus because of increasing number of spectral data applications in remote sensing of treeless polar and alpine regions. Therefore, species-specific spectral reflectance indices are measured in lichen species dominating polar ecosystems. Hydration status of the lichen thalli, as well as the presence of intrathalline secondary metabolites-which are UV-B absorbing compounds-both affects the spectral reflectance curves as well as numeric values of spectral reflectance indices. In the present paper, the reflectance spectra in 380-800 nm was measured in selected lichens to assess the effects of full hydration, and to evaluate the influence of secondary metabolites, they were wash out from lichen thalli with acetone (i.e. acetone rinsing) and then the spectra were also measured. For these experiments, Antarctic (Xanthoria elegans, Leptogium puberulum, Physconia muscigena and Rhizoplaca melanophthalma) and Argentinean lichens from mountain regions (Parmotrema conferendum and Ramalina celastri) were used. Changes in several spectral reflectance indices were evaluated and discussed in relation with hydration status and the absence of secondary metabolites. For the great majority of studied lichens, MCARI (Modified Chlorophyll Absorption in Reflectance Index) was the most effective index to reflect the changes between dry and wet state of thallus.

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Section: Resultssupporting

confidence: 92%

Changes in spectral reflectance of selected Antarctic and South American lichens caused by dehydration and artificially-induced absence of secondary compounds

Barták¹,

Hájek²,

Amarillo³

et al. 2016

Czech Polar Rep.

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“…This phenomenon is caused by exopolysaccharidic envelopes of cyanobacteria cells, which in the wet state represent a physical barrier for CO 2 transfer. Therefore, photosynthetic processes are limited in fully hydrated thalli and increase with partial dehydration, as shown by Nostoc commune colonies [ 34 ].…”

Section: Discussionmentioning

confidence: 99%

“…However, the decline is species-specific and bi- or triphasic if the supersaturation effect takes place. The latter is true for some cyanolichens and Nostoc commune colonies [ 34 ]. Therefore, in our study, we expected species-specific responses to the ChlF parameters when evaluating the photosystem II activity of lichen photobiont, such as F V /F M , Φ PSII , and steady-state chlorophyll fluorescence (F s ) in gradually desiccating lichen samples.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of Primary Photosynthesis in Desiccating Antarctic Lichens Differing in Their Photobionts, Thallus Morphology, and Spectral Properties

et al. 2021

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Five macrolichens of different thallus morphology from Antarctica (King George Island) were used for this ecophysiological study. The effect of thallus desiccation on primary photosynthetic processes was examined. We investigated the lichens’ responses to the relative water content (RWC) in their thalli during the transition from a wet (RWC of 100%) to a dry state (RWC of 0%). The slow Kautsky kinetics of chlorophyll fluorescence (ChlF) that was recorded during controlled dehydration (RWC decreased from 100 to 0%) and supplemented with a quenching analysis revealed a polyphasic species-specific response of variable fluorescence. The changes in ChlF at a steady state (Fs), potential and effective quantum yields of photosystem II (FV/FM, ΦPSII), and nonphotochemical quenching (NPQ) reflected a desiccation-induced inhibition of the photosynthetic processes. The dehydration-dependent fall in FV/FM and ΦPSII was species-specific, starting at an RWC range of 22–32%. The critical RWC for ΦPSII was below 5%. The changes indicated the involvement of protective mechanisms in the chloroplastic apparatus of lichen photobionts at RWCs of below 20%. In both the wet and dry states, the spectral reflectance curves (SRC) (wavelength 400–800 nm) and indices (NDVI, PRI) of the studied lichen species were measured. Black Himantormia lugubris showed no difference in the SRCs between wet and dry state. Other lichens showed a higher reflectance in the dry state compared to the wet state. The lichen morphology and anatomy data, together with the ChlF and spectral reflectance data, are discussed in relation to its potential for ecophysiological studies in Antarctic lichens.

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“…We used the meth-od and experimental set up optimized for lichens and described elsewhere, see e.g. Trnková et Barták (2017). From the curves, particular chlorophyll fluorescence signals (see Fig.…”

Section: Chlorophyll Fluorescence Measurementsmentioning

confidence: 99%

Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture

Alonso¹

2018

Czech Polar Rep.

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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.

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Desiccation‐induced changes in photochemical processes of photosynthesis and spectral reflectance in Nostoc commune (Cyanobacteria, Nostocales) colonies from polar regions

Cited by 11 publications

References 37 publications

Changes in spectral reflectance of selected Antarctic and South American lichens caused by dehydration and artificially-induced absence of secondary compounds

Changes in spectral reflectance of selected Antarctic and South American lichens caused by dehydration and artificially-induced absence of secondary compounds

Inhibition of Primary Photosynthesis in Desiccating Antarctic Lichens Differing in Their Photobionts, Thallus Morphology, and Spectral Properties

Changes in chlorophyll fluorescence parameters during desiccation and osmotic stress of Hassallia antarctica culture

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