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.

Short-term responses of primary processes in PS II to low temperature are sensitively indicated by fast chlorophyll fluorescence kinetics in Antarctic lichen Dermatocarpon polyphyllizum

2017 ◽  
Vol 7 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Michaela Marečková ◽  
Miloš Barták
Keyword(s):  
Chlorophyll Fluorescence ◽  
Low Temperature ◽  
High Energy ◽  
Temperature Decrease ◽  
Temperature Dependent ◽  
Dark Light ◽  
Ps Ii ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Quinone Acceptor

In this study, we investigated the effects of low temperature on the fast chlorophyll fluo-rescence transient (OJIP) and OJIP-derived parameters in chlorolichen Dermatocarpon polyphyllizum expossed to a gradually decreasing temperature (22°C, 18°C, 14°C, 12°C, 10°C, 7°C and 4°C). The segments of lichen thalli were exposed to a certain temperature either in dark- and light-adapted state for 10 minutes in order to evaluate the effects on chlorophyll fluorescence parameters. The initial photochemical phase of the transient (O-J) due to reduction of the primary quinone acceptor (QA) was found temperature dependent. The K-step was apparent for the samples measured at the temperature above 12°C, but not below 10oC in light-adapted lichen thalli. With the thallus temperature decrease, majority of the chlorophyll fluorescence parameters derived from OJIP (ET0/RC, Psi_0, and DI0/RC) showed no change in light-adapted samples but a decrease in dark-adapted samples. The effects of dark- / light-adaptation of the lichen samples on the OJIP and OJIP-derived parameters was attributed to the differences in production/utilization of high-energy products of primary photochemical processes of photosynthesis in dark- and light-adapted state, respectively. The other parameters (ABS/RC, TR0/RC) showed a decrease with thallus temperature decrease both in light- and dark-adapted samples. The results suggest that fast chlorophyll fluorescence trasient is an useful tool to investigate temperature-dependent changes in photosystem II in chlorolichens, their photobionts, respectively.

scholarly journals Antioxidant Defense, Chlorophyll Fluorescence and VvCBF4-VvNAC1 Genes Expression in Grapevine Cultivars (Vitis Vinifera L.) in Response to Cold Stress

2021 ◽  
Author(s):  
M. A. Aazami ◽  
M. Asghari Aruq ◽  
M. B. Hassanpouraghdam
Keyword(s):  
Chlorophyll Fluorescence ◽  
Low Temperature ◽  
Cold Stress ◽  
Temperature Stress ◽  
Low Temperature Stress ◽  
Vitis Vinifera L ◽  
Agricultural Industry ◽  
Genes Expression ◽  
Significant Damage ◽  
Photochemical Quantum Yield

Abstract Background: Cold stress is one of the limitative factors of different species of crops on the planet, causing significant damage to the Iranian agricultural industry every year. Grapes are the product of temperate warm zones and sensitive to early autumn cold and spring cold. The current study the effects of cold stress (+1 °C for 4, 8, and 16 hours) on three grapevine cultivars (Ghiziluzum, Khalili, and Perllete) were investigated. Results: The results showed that cold stress caused significant changes in the antioxidant and biochemicals content in the studied cultivars. Furthermore, examining the chlorophyll fluorescence indices, cold stress caused a significant increase in minimal fluorescence (F0), a decrease in maximal fluorescence (Fm), and the maximum photochemical quantum yield of photosystem II (Fv/Fm) in all cultivars. According to the obtained results, among the three studied cultivars, ‘Perllete’ with the highest increase in proline content and the activity of antioxidant enzymes and also, having the lowest accumulation of malondialdehyde, hydrogen peroxide, electrolyte leakage, and F0 as well as less decrease in Fm and Fv/Fm had the higher tolerance to the cold stress than ‘Ghiziluzum’ and ‘Khalili’ cultivars. VvCBF4 and VvNAC1 genes expression was increased in all three cultivars at +1 °C at 8 hours and then decreased. The increase in VvCBF4 and VvNAC1 genes expression in ‘Perllete’ cultivar was higher than the other two cultivars. Conclusion: ‘Perllete’ and ‘Ghiziluzum’ showed the highest tolerance to low temperature stress, respectively. ‘Khalili’ was sensitive to low temperature stress.

The effect of shock freezing on physiological properties and consequent growth of Antarctic filamentous (Stigeoclonium sp.) and coccal alga (Diplosphaera chodatii) on agar plates

2019 ◽  
Vol 9 (1) ◽  
pp. 37-48
Author(s):  
Alla Orekhova ◽  
Miloš Barták ◽  
Aleyna Özkar ◽  
Josef Elster
Keyword(s):  
Chlorophyll Fluorescence ◽  
Liquid Medium ◽  
Liquid Nitrogen ◽  
Physiological Status ◽  
Ps Ii ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Interspecific Differences ◽  
Subzero Temperatures ◽  
Physiological Properties

In this study, we investigated the effects of shock freezing on physiological properties and consequent growth of in the Antarctic alga Stigeoclonium sp. and comparative coccal alga Diplosphaera chodatii on agar plates. Culture of algae grown in liquid medium were used to study subzero temperatures on the species resistance to shock freezing. Then, microalgae were frozen in liquid nitrogen and inoculated on BBM agar after thawing. Physiological status of algae was evaluated by chlorophyll fluorescence parameters during 28 days. The results showed that interspecific differences existed in their tolerance to shock freezing, as well as their consequent growth rate on agars. Direct effects of freezing in liquid nitrogen was demonstrated in chlorophyll fluorescence parameters recorded immediately after thawing the samples (in liquid medium). In spite of the fact that majority of cells was destroyed by shock freezing, the potential of photochemical processes in PS II (FV/FM) remained constant in D. chodatii. It may indicate high resistance of the species to freezing/thawing cycles and a capability of the surviving cells, core chlorophylls in PS II respectively, to perform photosynthetic processes related to PS II. Contrastingly, Stigeoclonium sp. showed a shock freezing-dependent decrease in FV/FM. When shock-frozen, thawed and inoculated on agar plates, the culture of D. chodatii, and Stigeoclonium sp. showed cultivation time-dependent increase in chlorophyll fluorescence parameters (FV/FM, FS).

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 The Differential Responses of Chlorophyll Fluorescence Parameters and Lipid Metabolism to Low Temperature between Cycas Bifida and C. panzhihuaensis

2020 ◽  
Author(s):  
Yanling Zheng ◽  
Meng Wang ◽  
Shijun Hu ◽  
Jianrong Wu ◽  
Zhixiang Yu
Keyword(s):  
Chlorophyll Fluorescence ◽  
Lipid Metabolism ◽  
Low Temperature ◽  
Freezing Tolerance ◽  
Low Temperatures ◽  
Photosynthetic Activity ◽  
Membrane Lipids ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Differential Responses

Abstract Background: Our previous work showed that freezing tolerance of Cycas panzhihuaensis was higher than that of C. bifida. However, the mechanisms underlying the differential freezing tolerance of the two species is not clear. Photosynthesis is one of the most temperature-sensitive processes. Lipids play important roles in membrane structure, signal transduction and energy storage which are closely related to stress response of plants. Hence, the chlorophyll fluorescence parameters and lipid profiles of the two species were characterized to explore the dynamic changes of photosynthetic activity and lipid metabolism following low temperature and subsequent recovery. Results: The photosynthetic activity decreased significantly with the decrease of temperatures in C. bifida, reaching to zero after recovery, which however, was little affected in C. panzhihuaensis. Lipid composition of C. bifida was more affected by cold and freezing treatments than C. panzhihuaensis. Compared to the control, the proportions of all the lipid categories recovered to the original level for C. panzhihuaensis but those of most lipid categories changed significantly for C. bifida after 3 d of recovery. Particularly, the glycerophospholipids and prenol lipids of C. bifida degraded severely during recovery period for C. bifida. The changes of acyl chain length and double bond index (DBI) occurred in more lipid classes immediately after low temperatures in C. panzhihuaensis than those in C. bifida. DBI of the total main membrane lipids of C. panzhihuaensis was significantly higher than that of C. bifida following all the treatments. Conclusions: The results of chlorophyll fluorescence parameters confirmed that the freezing tolerance of C. panzhihuaensis was higher than that of C. bifida. The lipid metabolism of the two species had differential responses to low temperatures. The homeostasis and plastic adjustment of lipid metabolism and the higher level of DBI of the main membrane lipids might contribute to the higher tolerance of C. panzhihuaensis to low temperature.

Sign in / Sign up

Export Citation Format

Share Document