Pre-Symptomatic Detection of Viral Infection in Tobacco Leaves Using PAM Fluorometry

Chlorophyll fluorescence imaging was used to study potato virus X (PVX) infection of Nicotiana benthamiana. Infection-induced changes in chlorophyll fluorescence parameters (quantum yield of photosystem II photochemistry (ΦPSII) and non-photochemical fluorescence quenching (NPQ)) in the non-inoculated leaf were recorded and compared with the spatial distribution of the virus detected by the fluorescence of GFP associated with the virus. We determined infection-related changes at different points of the light-induced chlorophyll fluorescence kinetics and at different days after inoculation. A slight change in the light-adapted steady-state values of ΦPSII and NPQ was observed in the infected area of the non-inoculated leaf. In contrast to the steady-state parameters, the dynamics of ΦPSII and NPQ caused by the dark–light transition in healthy and infected areas differed significantly starting from the second day after the detection of the virus in a non-inoculated leaf. The coefficients of correlation between chlorophyll fluorescence parameters and virus localization were 0.67 for ΦPSII and 0.76 for NPQ. In general, the results demonstrate the possibility of reliable pre-symptomatic detection of the spread of a viral infection using chlorophyll fluorescence imaging.

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Chlorophyll Fluorescence Imaging-Based Duckweed Phenotyping to Assess Acute Phytotoxic Effects

Plants ◽

10.3390/plants10122763 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2763

Author(s):

Viktor Oláh ◽

Anna Hepp ◽

Muhammad Irfan ◽

Ilona Mészáros

Keyword(s):

Chlorophyll Fluorescence ◽

Fluorescence Imaging ◽

Photochemical Efficiency ◽

Chlorophyll Fluorescence Imaging ◽

Imaging Method ◽

Growth Responses ◽

Chlorophyll Fluorescence Parameters ◽

Vast Number ◽

Fluorescence Parameters ◽

Phytotoxic Effects

Duckweeds (Lemnaceae species) are extensively used models in ecotoxicology, and chlorophyll fluorescence imaging offers a sensitive and high throughput platform for phytotoxicity assays with these tiny plants. However, the vast number of potentially applicable chlorophyll fluorescence-based test endpoints makes comparison and generalization of results hard among different studies. The present study aimed to jointly measure and compare the sensitivity of various chlorophyll fluorescence parameters in Spirodela polyrhiza (giant duckweed) plants exposed to nickel, chromate (hexavalent chromium) and sodium chloride for 72 h, respectively. The photochemistry of Photosystem II in both dark- and light-adapted states of plants was assessed via in vivo chlorophyll fluorescence imaging method. Our results indicated that the studied parameters responded with very divergent sensitivity, highlighting the importance of parallelly assessing several chlorophyll fluorescence parameters. Generally, the light-adapted parameters were more sensitive than the dark-adapted ones. Thus, the former ones might be the preferred endpoints in phytotoxicity assays. Fv/Fm, i.e., the most extensively reported parameter literature-wise, proved to be the least sensitive endpoint; therefore, future studies might also consider reporting Fv/Fo, as its more responsive analogue. The tested toxicants induced different trends in the basic chlorophyll fluorescence parameters and, at least partly, in relative proportions of different quenching processes, suggesting that a basic distinction of water pollutants with different modes of action might be achievable by this method. We found definite hormetic patterns in responses to several endpoints. Hormesis occurred in the concentration ranges where the applied toxicants resulted in strong growth inhibition in longer-term exposures of the same duckweed clone in previous studies. These findings indicate that changes in the photochemical efficiency of plants do not necessarily go hand in hand with growth responses, and care should be taken when one exclusively interprets chlorophyll fluorescence-based endpoints as general proxies for phytotoxic effects.

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Screening of growth phases of Antarctic algae and cyanobacteria cultivated on agar plates by chlorophyll fluorescence imaging

Czech Polar Reports ◽

10.5817/cpr2019-2-15 ◽

2019 ◽

Vol 9 (2) ◽

pp. 170-181

Author(s):

Kristýna Dufková ◽

Miloš Barták ◽

Jana Morkusová ◽

Josef Elster ◽

Josef Hájek

Keyword(s):

Chlorophyll Fluorescence ◽

Fluorescence Imaging ◽

Basal Medium ◽

Photosynthetic Performance ◽

Chlorophyll Fluorescence Imaging ◽

Nostoc Commune ◽

Chlorophyll Fluorescence Parameters ◽

Fluorescence Parameters ◽

Cultivation Time ◽

Antarctic Algae

Recently, chlorophyll fluorescence imaging is frequently used non-invasive method to monitor the metabolic state and photosynthetic activities of vascular plants and other autotrophic organisms. In our study, we used the measurements of chlorophyll fluorescence kinetics to follow the development of culture of Antarctic algae (Macrochloris rubrioleum, Zygnema sp.) and cyanobacteria (Hassalia antarctica, Nostoc commune). On the cultures grown on agar plates, Bold´s Basal Medium (BBM), slow Kautsky kinetics supplemented with saturation pulses were measured repeatedly in a week interval. On the kinetics, typical points (OPSMT) were distinguished and species-specific and time of cultivation-dependent differences in shape of the OPSMT kinetics evaluated. We tested sensitivity of various chlorophyll fluorescence parameters to cultivation time on agar plates. In the algae, the most pronounced changes were the decrease in maximum quantum yield of photosystem II (FV/FM) and quenching of basal chlorophyll fluorescence qF0 (M. rubrioleum, Zygnema sp.). In cyanobacteria, chlorophyll fluorescence parameters did not show clear trends with the time of cultivation. F0 quenching (qF0) reached positive values in H. antarctica, while it was negative in N. commune. In both cases, however, qF0 showed an increase with cultivation time. The differences are discussed as well as the potential of the emerging area of the application of chlorophyll fluorescence imaging for evaluation of photosynthetic performance of algal/cyanobacterial cultures on agar plates.

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Enhanced sensitivity of Arabidopsis anthocyanin mutants to photooxidation: a study with fluorescence imaging

Functional Plant Biology ◽

10.1071/fp08069 ◽

2008 ◽

Vol 35 (8) ◽

pp. 714 ◽

Cited By ~ 30

Author(s):

Ling Shao ◽

Zhan Shu ◽

Chang-Lian Peng ◽

Zhi-Fang Lin ◽

Cheng-Wei Yang ◽

...

Keyword(s):

Oxidative Stress ◽

Chlorophyll Fluorescence ◽

Fluorescence Imaging ◽

Photosynthetic Apparatus ◽

Chlorophyll Fluorescence Imaging ◽

Prolonged Treatment ◽

Partial Recovery ◽

Wild Type ◽

Short Term Treatment ◽

Chlorophyll Fluorescence Parameters

Chlorophyll fluorescence imaging and antioxidative capability in detached leaves of the wild-type Arabidopsis thaliana ecotype Landsberg erecta (Ler) and in three mutants deficient in anthocyanin biosynthesis (tt3, tt4 and tt3tt4) were investigated under photooxidation stress induced by methyl viologen (5 μm) in the light. In comparison with the wild-type (WT) plant, photooxidation resulted in significant decreases in the contents of total phenolics and flavonoid, total antioxidative capability and chlorophyll fluorescence parameters (Fv/Fm, qP, ΦPSII, NPQ and ETR) as determined by chlorophyll fluorescence imaging, and in an increase in cell-membrane leakiness in the three anthocyanin mutants. The sequence of sensitivity to photooxidation in the leaves of the four phenotypes were tt3tt4 (deficient in both chalcone synthase locus (CHS) and dihydroflavonol 4-reductase locus (DFR)) > tt4 (deficient in CHS) > tt3 (deficient in DFR) > WT. The results demonstrate that anthocyanins might, along with other antioxidants, protect the photosynthetic apparatus against photooxidative damage. An interesting phenomenon was observed over the 270 min of the photooxidative treatment, that is, fluorescence imaging revealed that qP, ΦPSII and ETR appeared in three phases (fall → partial recovery → rapid fall). This was considered to be a modulation of reversible deactivation in PSII to cope with the moderate oxidative stress in the first two stages of short-term treatment (<150 min), followed finally by damage to PSII under severe oxidative stress with prolonged treatment.

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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

Czech Polar Reports ◽

10.5817/cpr2017-1-8 ◽

2017 ◽

Vol 7 (1) ◽

pp. 74-82 ◽

Cited By ~ 6

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.

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EFFECTS OF PESTICIDE ON THE CHLOROPHYLL FLUORESCENCE PARAMETERS IN NO-HEADING CHINESE CABBAGE

Acta Horticulturae ◽

10.17660/actahortic.2010.856.28 ◽

2010 ◽

pp. 211-216

Author(s):

Z.K. Gao ◽

T. Zhao ◽

M. Wang ◽

W.L. Zhang ◽

J.P. He ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Chinese Cabbage ◽

Chlorophyll Fluorescence Parameters ◽

Fluorescence Parameters ◽

Heading Chinese Cabbage

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Photoinduced toxicity of fluoranthene on primary processes of photosynthesis in lichens

The Lichenologist ◽

10.1017/s0024282907006111 ◽

2006 ◽

Vol 39 (1) ◽

pp. 91-100 ◽

Cited By ~ 11

Author(s):

Marie KUMMEROVÁ ◽

štěpán ZEZULKA ◽

Jana KRULOVÁ ◽

Jan TŘÍSKA

Keyword(s):

Chlorophyll Fluorescence ◽

Bioconcentration Factor ◽

Lichen Species ◽

Chlorophyll Fluorescence Parameters ◽

Fluorescence Parameters ◽

Photochemical Processes ◽

Symbiotic Algae ◽

Lasallia Pustulata ◽

Photoinduced Toxicity ◽

Umbilicaria Hirsuta

The effect of increasing concentrations (0·01, 0·1, 1 and 5 mg l−1) of intact (FLT) and photo-modified (phFLT) fluoranthene and the duration of exposure (1, 2, 3, 5 and 7 days) on the chlorophyll fluorescence parameters (F0, FV/FM, and ΦII) of symbiotic algae in the thalli of two foliose lichens Lasallia pustulata and Umbilicaria hirsuta was investigated. In addition the FLT concentration in thalli of both lichen species was determined and a bioconcentration factor (BCF) was calculated. The results obtained demonstrated that the concentrations of FLT and especially phFLT (1 and 5 mg l−1) applied affected primary photochemical processes of photosynthesis in the algae of both lichen species. The F0 value increased and the FV/FM and ΦII values decreased. The fluoranthene content in the thallus of both lichen species increased with increasing FLT concentration in the environment.

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Photosynthetic response to nitrogen source and different ratios of nitrogen and phosphorus in toxic cyanobacteria, Microcystis aeruginosa FACHB-905

Journal of Limnology ◽

10.4081/jlimnol.2016.1458 ◽

2016 ◽

Cited By ~ 3

Author(s):

Guotao Peng ◽

Zhengqiu Fan ◽

Xiangrong Wang ◽

Chen Chen

Keyword(s):

Chlorophyll Fluorescence ◽

Algal Blooms ◽

Freshwater Ecosystems ◽

Cyanobacterial Blooms ◽

Photosynthetic Response ◽

Nitrogen And Phosphorus ◽

Ammonium Toxicity ◽

Chlorophyll Fluorescence Parameters ◽

Fluorescence Parameters ◽

N Assimilation

The frequent outbreak of cyanobacterial blooms has become a worldwide phenomenon in freshwater ecosystems. Studies have elucidated the close relationship between harmful algal blooms and nutrient contents, including the loading of nitrogen and the ratios of nitrogen (N) and phosphorus (P). In this study, the effect of inorganic (nitrate and ammonium) and organic (urea) nitrogen at varied N/P ratios on the Microcystis aeruginosa FACHB-905 accumulation and photosynthesis was investigated. The optimal NO3/P in this study were 30~50 indicated by the cell abundance (4.1×106/mL), pigment concentration (chlorophyll a 3.1 mg/L, phycocyanin 8.3mg/L), and chlorophyll fluorescence parameters (rETR, Ek, α, φPSII and Fv/Fm values), while too high NO3-N (N/P=100:1) would cause an intracellular nitrate inhibition, leading to a decrease of photosynthetic activity. In addition, low concentration of NH4-N (N/P=4:1) would favor the M. aeruginosa growth and photosynthesis, and high NH4/P ratio (>16) would rise the ammonium toxicity of algal cells and affect the N assimilation. In urea treatments, M. aeruginosa responded similarly to the NH4-N treatments both in growth curves and pigment contents, and the favorable N/P ratio was between 16~30, suggested by the chlorophyll fluorescence parameters. The results demonstrated that the various chemical forms of N and N/P ratios have a significant impact on Microcystis abundance and photosynthesis. More work is needed to figure out the mechanism of nitrogen utilization by Microcystis and the photosynthetic response to nutrient stress at the molecular level.

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