The Role of D 1* in Light-Induced D 1 Protein Turnover in Leaves

1993 ◽  
Vol 48 (3-4) ◽  
pp. 246-250
Author(s):  
Anna J. Syme ◽  
Harald R . Bolhàr-N ordenkampf ◽  
Christa Critchley
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Light Intensity ◽  
Protein Turnover ◽  
Photochemical Efficiency ◽  
Light Conditions ◽  
Ps Ii ◽  
Light Intensities ◽  
Intact Leaves

Abstract Light-induced degradation of the D 1 protein of photosystem II (PS II) was determined by radioactive pulse-chase labelling experiments in intact leaves of Schefflera polybotrya. PS II photochemical efficiency was monitored by measuring chlorophyll fluorescence. A significant and consistent decline in the Fv/ Fm ratio was taken to indicate photoinhibition. The formation and degradation of a modified form of the D 1 protein, D 1*, was different under photoinhibi-tory or non-photoinhibitory light conditions. At photoinhibitory irradiance greater amounts of D 1 * were formed relative to D 1, and the degradation of D 1* was slower when compared with non-photoinhibitory irradiance. The formation and degradation of D 1* were therefore shown to be at least partly light intensity dependent. Higher light intensities appeared to slow D 1* degradation, which suggests a modification in PS II turnover properties.

scholarly journals The Role of Selected Wavelengths of Light in the Activity of Photosystem II in Gloeobacter violaceus

2021 ◽  
Vol 22 (8) ◽  
pp. 4021
Author(s):  
Monika Kula-Maximenko ◽  
Kamil Jan Zieliński ◽  
Ireneusz Ślesak
Keyword(s):  
Photosystem Ii ◽  
Spectral Composition ◽  
Photosynthetic Electron Transport ◽  
Metabolic Energy ◽  
Light Conditions ◽  
Gloeobacter Violaceus ◽  
Transport Chain ◽  
Cyanobacterial Culture ◽  
Photosynthetic Antennas

Gloeobacter violaceus is a cyanobacteria species with a lack of thylakoids, while photosynthetic antennas, i.e., phycobilisomes (PBSs), photosystem II (PSII), and I (PSI), are located in the cytoplasmic membrane. We verified the hypothesis that blue–red (BR) light supplemented with a far-red (FR), ultraviolet A (UVA), and green (G) light can affect the photosynthetic electron transport chain in PSII and explain the differences in the growth of the G. violaceus culture. The cyanobacteria were cultured under different light conditions. The largest increase in G. violaceus biomass was observed only under BR + FR and BR + G light. Moreover, the shape of the G. violaceus cells was modified by the spectrum with the addition of G light. Furthermore, it was found that both the spectral composition of light and age of the cyanobacterial culture affect the different content of phycobiliproteins in the photosynthetic antennas (PBS). Most likely, in cells grown under light conditions with the addition of FR and G light, the average antenna size increased due to the inactivation of some reaction centers in PSII. Moreover, the role of PSI and gloeorhodopsin as supplementary sources of metabolic energy in the G. violaceus growth is discussed.

Metabolie Reduction of Phenylpropanoid Compounds in Primary Leaves of Rye (Secale cereale L.) Leads to Increased UV-B Sensitivity of Photosynthesis

1993 ◽  
Vol 48 (9-10) ◽  
pp. 749-756 ◽  
Author(s):  
S. Reuber ◽  
J. Leitsch ◽  
G. H. Krause ◽  
G. Weissenböck
Keyword(s):  
Photosystem Ii ◽  
Essential Role ◽  
Phenylalanine Ammonia Lyase ◽  
Ps Ii ◽  
Efficient Inhibitor ◽  
Flavone Glycosides ◽  
Fluorescence Parameter ◽  
Secale Cereale L

Abstract In the epidermal layers of rye primary leaves two flavone glycosides and several hydroxycinnamoyl esters are localized, whereas the mesophyll contains two flavone glucuronides and two anthocyanins. The concentrations of all these potential UV-B protective phenylpropanoid compounds could be reduced by application of 2-aminoindan-2-phosphonic acid (AIP), an efficient inhibitor of phenylalanine ammonia-lyase (EC 4.1.3.5). Photosystem II in the primary leaves of seven-days-old plants, grown in the presence of 20 μm AIP up to an age of 80 h, was more severely affected by UV-B than in control plants with the normal concentration of phenylpropanoid compounds. Damage of photosystem II in vivo was estimated by measuring the chlorophyll a fluorescence (parameter FJFm) of PS II. The results indicate an essential role of phenylpropanoid com pounds as UV-B protectants in rye primary leaves

POST-EFFECTS OF LIGHT CONDITIONS ON DORMANCY OF POTATO MICROTUBERS

2000 ◽  
Vol 48 (2) ◽  
pp. 127-132 ◽  
Author(s):  
K. Tábori ◽  
J. Dobránszki ◽  
A. Ferenczy
Keyword(s):  
Environmental Factors ◽  
Light Intensity ◽  
Tuber Initiation ◽  
Light Conditions ◽  
Combined Treatments ◽  
Slight Effect ◽  
Dormant Period ◽  
Tuber Induction ◽  
Light Intensities

The dormancy of potato microtubers produced under different photoperiodic treatments and light intensities was investigated in the varieties Desiree and Gülbaba. The dormant period was defined as the period between harvest or tuber initiation and the end of dormancy. The effects of environmental factors could be detected due to the use of a hormone-free tuber-producing system. Combined treatments had a slight effect on dormancy, while different light intensities influenced it considerably. The lower the light intensity the longer the dormant period for both cultivars. The effects of light intensities depended on the photoperiodic treatments applied for tuber induction.

scholarly journals Two Quenchers Formed During Photodamage of Phostosystem II and The Role of One Quencher in Preemptive Photoprotection

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alonso Zavafer ◽  
Ievgeniia Iermak ◽  
Mun Hon Cheah ◽  
Wah Soon Chow
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Time Course ◽  
Physiological Role ◽  
Reaction Centre ◽  
Time Resolved ◽  
Fluorescence Quencher

AbstractThe quenching of chlorophyll fluorescence caused by photodamage of Photosystem II (qI) is a well recognized phenomenon, where the nature and physiological role of which are still debatable. Paradoxically, photodamage to the reaction centre of Photosystem II is supposed to be alleviated by excitation quenching mechanisms which manifest as fluorescence quenchers. Here we investigated the time course of PSII photodamage in vivo and in vitro and that of picosecond time-resolved chlorophyll fluorescence (quencher formation). Two long-lived fluorescence quenching processes during photodamage were observed and were formed at different speeds. The slow-developing quenching process exhibited a time course similar to that of the accumulation of photodamaged PSII, while the fast-developing process took place faster than the light-induced PSII damage. We attribute the slow process to the accumulation of photodamaged PSII and the fast process to an independent quenching mechanism that precedes PSII photodamage and that alleviates the inactivation of the PSII reaction centre.

Chlorophyll fluorescence of submerged and floating leaves of the aquatic resurrection plant Chamaegigas intrepidus

2004 ◽  
Vol 31 (1) ◽  
pp. 53 ◽  
Author(s):  
Markus Woitke ◽  
Wolfram Hartung ◽  
Hartmut Gimmler ◽  
Hermann Heilmeier
Keyword(s):  
Chlorophyll Fluorescence ◽  
Shade Tolerance ◽  
Photosynthetic Performance ◽  
Resurrection Plant ◽  
Photon Flux ◽  
Carbon Gain ◽  
Light Conditions ◽  
Total Plant ◽  
Floating Leaves

The role of submerged and floating leaves in plant photosynthetic performance of the aquatic resurrection plant Chamaegigas intrepidus Dinter was investigated by monitoring chlorophyll fluorescence under the fluctuating natural field conditions that characterise the extreme habitat of this species. The performance of the two different leaf types during desiccation–rehydration cycles in the field was examined. PSII quantum efficiency indicates a similar regeneration capacity in both leaf types after water stress. Electron transport rates under controlled light conditions were 3–4 times higher in floating leaves than in submerged leaves. The two leaf types showed specific adaptations to their ambient photosynthetic photon flux densities (PPFD), shade tolerance in the submerged leaves and adaptation to high PPFD in floating leaves. These results imply a significant role of the floating leaves for total plant carbon gain. It is concluded that the combination of high N content of floating leaves and a high availability of CO2 and light at the water surface contributes to the importance of this leaf type for photosynthesis in C. intrepidus.

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.

scholarly journals Nitrogen Biofertilizer Alleviates the Inhibitory Effect of Cadmium on Physiology and Nitrogen Assimilation in Maize Plants

2021 ◽  
Vol 25 (01) ◽  
pp. 98-108
Author(s):  
Hanan Mahmoud Abou-Zeid
Keyword(s):  
Cadmium Toxicity ◽  
Photochemical Efficiency ◽  
Inhibitory Effect ◽  
Cd Stress ◽  
Ps Ii ◽  
Total Carbohydrates ◽  
Maize Plants ◽  
Endogenous Phytohormone ◽  
And Behavior

The present study investigated the role of inoculation with Nitrobien biofertilizer (N-Bio, Azospirillum and azotobacter spp.) on the response of maize plants to cadmium-toxicity (applied as 2 and 10 mM CdSO4). Cd-stress caused a significant reduction in the fresh and dry biomass of leaves and roots as well as a marked disturbance in the anatomical features of roots and stomatal structure and behavior. Cd-stress significantly depressed the total photosynthetic pigments, photochemical efficiency of PS II, total carbohydrates, and proteins content. Furthermore, increasing Cd level prompted oxidative stress measured in terms of malondialdehyde and H2O2 contents in maize plants. Application of N-Bio improved these attributes in Cd-stressed maize plants. Moreover, NO3- uptake and its assimilating enzymes (nitrate reductase, NR; glutamine synthase, GS; and, glutamate dehydrogenase GDH) were significantly increased in N-Bio-pretreated Cd-stressed plants than Cd- stressed ones and that was associated with a decrease of NH4+ content. N-Bio pretreatment also stimulated the accumulation of amino acids and markedly increased endogenous phytohormone content (IAA, GA3) of Cd-stressed maize plants. These results revealed the potentiating effect of N-Bio pretreatment in regulating Cd-induced damages in maize plants. © 2021 Friends Science Publishers

scholarly journals Salt stress change chlorophyll fluorescence in mango

2012 ◽  
Vol 34 (4) ◽  
pp. 1245-1255 ◽  
Author(s):  
Cicero Cartaxo de Lucena ◽  
Dalmo Lopes de Siqueira ◽  
Hermínia Emilia Prieto Martinez ◽  
Paulo Roberto Cecon
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Early Detection ◽  
Leaf Area ◽  
Photochemical Efficiency ◽  
Leaf Abscission ◽  
Hoagland Solution ◽  
Mango Tree

This study evaluated the tolerance of mango cultivars 'Haden', 'Palmer', 'Tommy Atkins' and 'Uba' grafted on rootstock 'Imbú' to salt stress using chlorophyll fluorescence. Plants were grown in modified Hoagland solution containing 0, 15, 30, and 45 mmol L-1 NaCl. At 97 days the parameters of the chlorophyll fluorescence (F0, Fm, Fv, F0/Fm, Fv/Fm, Fv'/Fm', ΦPSII = [(Fm'-Fs)/(Fm')], D = (1- Fv'/Fm') and ETR = (ΦPSII×PPF×0,84×0,5) were determined. At 100 days, the leaf emission and leaf area, toxicity and leaf abscission indexes were determined. In all cultivars evaluated, in different degree, there were decreases in photochemical efficiency of photosystem II, enhanced concentrations from 15 mmol L-1 NaCl. The decreases in the potential quantum yield of photosystem II (Fv/Fm) were 27.9, 18.7, 20.5, and 27.4%, for cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba', respectively, when grown in 45 mmol L-1 NaCl. It was found decreases in leaf emission and mean leaf area in all cultivars from 15 mmol L-1 NaCl. There were increases in leaf toxicity of 33.0, 67.5, 41.6 and 80.8% and in leaf abscission of 71.8, 29.2, 32.5, and 67.9% for the cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba' respectively, when grown in 45 mmol L-1 NaCl. Leaf toxicity and leaf abscission were not observed in 15 mmol L-1 NaCl. The decrease in Fv/Fm ratio were accompanied by decreasing in leaf emission and increased leaf toxicity index, showing, therefore, the potential of chlorophyll fluorescence in the early detection of salt stress in mango tree.

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