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

2018 ◽  
Vol 8 (2) ◽  
pp. 198-207
Author(s):  
Marta Campos Alonso
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Osmotic Stress ◽  
Austral Summer ◽  
Rapid Decline ◽  
Filamentous Cyanobacterium ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Fluorescence Measurements ◽  
James Ross Island

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.

scholarly journals Limitation of photosynthetic processes in photosystem II in alpine mosses exposed to low temperatures: Response of chlorophyll fluorescence parameters

2018 ◽  
Vol 8 (2) ◽  
pp. 218-229 ◽  
Author(s):  
Yeray Folgar Cameán ◽  
Miloš Barták
Keyword(s):  
Chlorophyll Fluorescence ◽  
Low Temperature ◽  
Photosystem Ii ◽  
Temperature Stress ◽  
Low Temperature Stress ◽  
Ps Ii ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Fluorescence Measurements ◽  
Sphagnum Girgensohnii

In this study, we evaluated the effects of low and sub-zero temperature on the fast chlorophyll fluorescence transient (OJIP) and OJIP-derived parameters in 4 different mosses: Sphagnum girgensohnii, Polytrichum formosum, Hylocomium splendens and Pleurozium schreberi. The low temperature stress was applied on the mosses for 90 min. at 3 different temperatures (5°C, -1°C and -10°C). To investigate the effects of this stress on the functioning of photosystem II (PS II), the chlorophyll fluorescence measurements were taken at control temperature (22°C) and, after a 90 min. acclimation period, at each experimental temperature. The shape of OJIP curves and chlorophyll fluorescence parameters were found temperature-dependent in all the species. The mosses differed in their sensitivity to the stress but general trends in response to low temperature were similar. The results support the idea that S. girgensohnii is less resistant to low temperature stress than the other species. We were also interested in the K and L steps in OJIPs, representing different disorders caused by low temperature. The K-step was seen in P. formosum and P. schreberi and the L-step in H. splendens and S. girgensohnii.

Genetic variability and identification of quantitative trait loci affecting plant growth and chlorophyll fluorescence parameters in the model legume Medicago truncatula under control and salt stress conditions

2014 ◽  
Vol 41 (9) ◽  
pp. 983 ◽  
Author(s):  
Sarah Exbrayat ◽  
Georges Bertoni ◽  
Mohamad Reza Naghavie ◽  
Ali Peyghambari ◽  
Mounavar Badri ◽  
...  
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Quantitative Trait Loci ◽  
Genetic Variability ◽  
Plant Growth ◽  
Medicago Truncatula ◽  
Quantitative Trait ◽  
Chlorophyll Fluorescence Parameters ◽  
Model Legume ◽  
Fluorescence Parameters

Salinity is one of the major stresses that limits crop production worldwide and affects most physiological activities in plants. In order to study the genetic control of salt stress in the model legume Medicago truncatula Gaertn., an experiment was undertaken to determine the genetic variability and to identify quantitative trait loci (QTLs) controlling several traits related to plant growth and physiology in a population of recombinant inbred lines. Shoot and root DW, relative water content, leaf area, chlorophyll content, chlorophyll fluorescence parameters, and Na+ and K+ in shoots and roots were measured. The experiment was carried out with three replications. ANOVA showed a large genetic variation and transgressive segregation for the traits studied, suggesting putative complex tolerance mechanisms. A total of 21 QTLs were detected under control conditions and 19 QTLs were identified under 100 mm salt stress conditions, with three QTLs being common to both situations. The percentage of total phenotypic variance explained by the QTLs ranged from 4.6% to 23.01%. Overlapping QTLs for different traits were also observed, which enables us to discriminate independent traits from linked ones. The results should be helpful information for further functional analysis of salt tolerance in M. truncatula.

Antarctic strain of green filamentous alga Zygnema sp. shows a high resistance to photoinhibition under simulated polar conditions

2015 ◽  
Vol 5 (2) ◽  
pp. 176-184 ◽  
Author(s):  
Giridharan Thangaraj
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
High Resistance ◽  
Austral Summer ◽  
High Light ◽  
Filamentous Alga ◽  
Fluorescence Signal ◽  
Light Harvesting Complexes ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters

This study deals with treatment-dependent differences in sensitivity of Antarctic filamentous alga Zygnema sp. to photoinhibition. Zygnema sp. (strain EEL201) was collected at the James Ross Island, Antarctica (57° 52´ 57´´ W, 63° 48´ 02´´ S). In a laboratory, the alga was cultivated on agar first and then innoculated to liquid medium. They were exposed to a short-term (30 min.) high light (HL) treatments. Particular treatments comprised 600, 1 400 and 2 100 and 3 500 μmol m-2 s-1 of photosynthetically active radiation (PAR). Photosynthetic efficiency of Zygnema sp. in individual HL treatments was monitored by chlorophyll fluorescence parameters, potential (FV/FM) and actual (FPSII) quantum yield of photochemical processes in photosystem II in particular. Zygnema sp. showed a high resistance to HL since it both chlorophyll fluorescence parameters recovered to about 70% of initial values after 4 h in dark. Chlorophyll fluorescence measured immediately after particular treatment, showed HL-dependent decrease in absolute values of chlorophyll fluorescence signal and consequent uncompleted recovery as well. Quenching of F0, an indicator of changes in light-harvesting complexes of photosystem II, did not show dose-dependent response, however, general trend was a decrease found immediately HL treatment with consequent uncompleated recovery. In general, Zygnema sp. exhibited high resistance to PAR doses that the species can whitness in the field during austral summer. Thus the species could be considered highly adapted for high light and has effective mechanisms to cope with photoinhibition. Involvement of particular photoprotective mechanism, their activation and share in natural environment is a topic for future studies.

scholarly journals Effects of sea salt stress on reflectance spectrum and chlorophyll fluorescence parameters inBambusa oldhamiileaves

2014 ◽  
Vol 34 (17) ◽  
Author(s):  
吴寿国 WU Shouguo ◽  
余学军 YU Xuejun ◽  
李凯 LI Kai ◽  
蒋玉俭 JIANG Yujian ◽  
张汝民 ZHANG Rumin
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Reflectance Spectrum ◽  
Sea Salt ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters

scholarly journals Lead-Induced Changes in Fluorescence and Spectral Characteristics of Pea Leaves

2019 ◽  
Vol 11 (16) ◽  
pp. 1885 ◽  
Author(s):  
Marlena Kycko ◽  
Elżbieta Romanowska ◽  
Bogdan Zagajewski
Keyword(s):  
Remote Sensing ◽  
Chlorophyll Fluorescence ◽  
Spectral Characteristics ◽  
Hyperspectral Remote Sensing ◽  
Lead Ions ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Fluorescence Measurements ◽  
Pb Ions ◽  
Remote Sensing Indices

Chlorophyll fluorescence parameters can provide useful indications of photosynthetic performance in vivo. Coupling appropriate fluorescence measurements with other noninvasive techniques, such as absorption spectroscopy or gas exchange, can provide insights into the limitations to photosynthesis under given conditions. Chlorophyll content is one of the dominant factors influencing the conditions of a vegetation growing season, and can be tested using both fluorescence and remote sensing methods. Hyperspectral remote sensing and recording the narrow range of the spectrum can be used to accurately analyze the parameters and properties of plants. The aim of this study was to analyze the influence of lead ions (Pb, 5 mM Pb(NO3)2) on the growth of pea plants using spectral properties. Hyperspectral remote sensing and chlorophyll fluorescence measurements were used to assess the physiological state of plants seedlings treated by lead ions during the experiment. The plants were growing in hydroponic cultures supplemented with Pb ions under various conditions (control, complete Knop + phosphorus (+P); complete Knop + phosphorus (+P) + Pb; Knop (-P) + Pb, distilled water + Pb) affecting lead uptake via the root system. Spectrometric measurements allowed us to calculate the remote sensing indices of vegetation, which were compared with chlorophyll and carotenoids content and fluorescence parameters. The lead contents in the leaves, roots, and stems were also analyzed. Spectral characteristics and vegetation properties were analyzed using statistical tests. We conclude that: (1) pea seedlings grown in complete Knop (with P) and in the presence of Pb ions were spectrally similar to the control plants because lead was not transported to the shoots of plants; (2) lead most influenced plants that were grown in water, according to the highest lead content in the leaves; and (3) the effects of lead on plant growth were confirmed by remote sensing indices, whereas fluorescence parameters identified physiological changes induced by Pb ions in the plants.

scholarly journals Differential responses of ribulose-1,5-bisphosphate carboxylase/oxygenase activities of two Vigna unguiculata cultivars to salt stress

2005 ◽  
Vol 17 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Maria Erivalda Farias de Aragão ◽  
Marjorie Moreira Guedes ◽  
Maria de Lourdes Oliveira Otoch ◽  
Maria Izabel Florindo Guedes ◽  
Dirce Fernandes de Melo ◽  
...  
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Chlorophyll Content ◽  
Vigna Unguiculata ◽  
Shoot Growth ◽  
Bisphosphate Carboxylase ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Root And Shoot Growth ◽  
Specific Activities

Vita 3 and Vita 5 are two Vigna unguiculata cultivars that differ in their capacities for survival in saline environments; Vita 3 is more tolerant and Vita 5 more sensitive. Both cultivars were submitted to salt stress with 0.1 M NaCl. After 8 days, root and shoot growth from both cultivars was reduced but reduction was more pronounced in Vita 5. Furthermore, leaf area was also reduced in this cultivar. Chlorophyll content and chlorophyll fluorescence parameters were not affected by salt stress, but the specific activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) decreased in Vita 3 and increased in Vita 5. The use of immunological techniques also revealed that the Rubisco content from Vita 3 decreased while that of Vita 5 increased. The discussion of these results is aimed at reaching a better understanding of the differences between these cultivars in relation to salt stress.

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