scholarly journals Changes in photosynthetic apparatus of tobacco leaves in conditions of virus infection and shortage of nitrogen

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 449-451
Author(s):  
V.Z. Ulinets ◽  
V.P. Polischuk
Keyword(s):  
Virus Infection ◽  
Nitrogen Starvation ◽  
Photosynthetic Apparatus ◽  
Negative Influence ◽  
Comparative Investigation ◽  
Photochemical Activity ◽  
Fluorescence Induction ◽  
Ps Ii ◽  
Tobacco Leaves ◽  
Ps I

Data of the comparative investigation of the viral infection (TMV) and nitrogen starvation in the ratio of chlorophyll a/b, photochemical activity of PS I and PS II, pigment-protein structure of chloroplasts thylakoids and parameters of the fluorescence induction of tobacco leaves are presented. The changes of the structural and functional characteristics of the photosynthetic apparatus testify to negative influence of this factors on the function of both photosystems with primary inhibition of PS II.

scholarly journals The effect of drought on the photosynthetic apparatus condition in some Ficus Carica cultivars

2019 ◽  
pp. 109-119
Author(s):  
T. B. Gubanova ◽  
R. A. Pilkevich ◽  
A. A. Kharchenko ◽  
I. V. Bernatsky
Keyword(s):  
Drought Tolerance ◽  
Photosynthetic Apparatus ◽  
High Sensitivity ◽  
Photochemical Activity ◽  
Fluorescence Induction ◽  
Water Holding Capacity ◽  
Ficus Carica ◽  
Resistant Cultivar ◽  
Chlorophyll Fluorescence Induction ◽  
Water Holding

The results of field and laboratory studies of drought tolerance in some Ficus carica cultivars of various origins are presented. It has been found out that under the conditions of the Southern Coast of the Crimea, the cultivar Sabrutsiya Rozovaya is characterized by high drought tolerance. Low resistance to dehydration was noted in the cultivars Vladimirska Krupna, Pomoriyskiy 6, Franziana Biella. It was revealed that in August, a decrease in water holding capacity occurs in all the studied cultivars. Using Chlorophyll Fluorescence Induction (CFI) method, an integrated assessment of the photosynthetic apparatus in the leaves of Ficus carica cultivars under conditions of simulated wilting is given. It has been demonstrated that drought is the cause of decrease in the photosynthesis light phase efficiency, the part of chlorophyll involved in the transfer of energy from light harvesting antenna complexes to reaction centers and the enhancement of non-photochemical photo quenching. A resumption of photosynthetic activity was observed with the normalization of leaf water supply in the resistant cultivar Sabrutsiya Rozovaya and the medium-resistant cultivar Iyulskiy. In the cultivars characterized with low drought tolerance, Vladimirska Krupna, Pomoriyskiy 6 and Ranniy iz Sozopol, the resumption of the water content in leaves was followed by a decrease in the variable fluorescence and photochemical activity of PS 2, which indicates further stress development in these cultivars and high sensitivity of their photosynthetic apparatus to dehydration. During the fruit ripening, on the background of water holding capacity decrease, water deficit in leaf tissues within 20-25% results in irreversible disturbances in the photosynthetic apparatus activity in Ficus carica cultivars that is proved by a decrease in the viability index below the vitality norm and may adversely affect the preparation of plants for transition to a state of rest.

Changes in Photosynthetic Apparatus in the Juvenile Rice Canopy and a Possible Function of Photosystem I in the Bottom Leaves

1999 ◽  
Vol 54 (11) ◽  
pp. 915-922 ◽  
Author(s):  
Jun-ya Yamazaki ◽  
Yasumaro Kamimura ◽  
Yasutomo Sugimura
Keyword(s):  
Electron Transport ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Performance ◽  
Cytochrome F ◽  
Transport Capacity ◽  
Ps Ii ◽  
Electrochromic Shift ◽  
The Third ◽  
Ps I ◽  
Light Utilization

Abstract Changes in the photosynthetic apparatus and relative antenna sizes of photosystem (PS) I and PS II were measured in the rice canopy. We used juvenile rice seedlings to examine light utilization and its absorption in the bottom leaves and obtained the following results: (1) When referred to chlorophyll (Chl), levels of the electrochromic shift at 550 nm and cytochrome ƒ decreased from the sixth to the third leaves, but there was no loss of pigment (P)-700. As a consequence, the PS II/PS I ratio significantly decreased from 1.5 in the sixth leaves to 0.9 in the third leaves. (2) The electron transport capacity in the sixth leaves was 1.5-times larger than that in the third leaves. (3) The levels of cytochrome b6 referred to Chl were almost constant from top to bottom. (4) The photosynthetic performance of the leaf de­creased concomitant with the depth, whereas the respiration was slightly increased. From these results, we hypothesize that there are maintenance mechanisms when the imbalances of light absorption and electron transport capacity occur in the bottom leaves.

Über die prompte und verzögerte Fluoreszenz des Chlorophylls während der Photomorphogenese des photosynthetischen Apparates grüner Pflanzen / The Prompt and Delayed Light Emission of Chlorophyll During Photomorphogenesis of the Photosynthetic Apparatus of Green Plants

1972 ◽  
Vol 27 (10) ◽  
pp. 1202-1204 ◽  
Author(s):  
Robert Bauer ◽  
Ulrich F. Franck
Keyword(s):  
Light Emission ◽  
Electron Flow ◽  
Photosynthetic Apparatus ◽  
Anaerobic Conditions ◽  
Ps Ii ◽  
Delayed Light Emission ◽  
Ps I ◽  
Active Electron ◽  
Induced Changes ◽  
Kautsky Effect

The greening process of etiolated bean and maize leafs was followed by measuring the prompt and delayed light emission of chlorophyll. Above all it was concluded that the development of photosynthetic Systems I and II could be observed by studying the formation of the Kautsky -effect. First light-induced changes in the chlorophyll fluorescence intensity do not occur until 2,5 h of irradiation. It could be shown that they reflect the function of PS II reaction centers and under anaerobic conditions the electron flow between PS II and PS I. Full active electron flow from water to NADP is first to presume with the appearence of all characteristics of the Kautsky -effect (O—I—D—P curve at 3 h of irradiation).

The electrochromic signal, redox reactions in the cytochrome bf complex and photosystem functionality in photoinhibited tobacco leaf segments

1998 ◽  
Vol 25 (7) ◽  
pp. 775 ◽  
Author(s):  
W. S. Chow ◽  
A. B. Hope
Keyword(s):  
Electron Flow ◽  
Cytochrome F ◽  
Rate Coefficients ◽  
Band Shift ◽  
Strong Light ◽  
Ps Ii ◽  
Tobacco Leaves ◽  
Cytochrome Bf Complex ◽  
Ps I ◽  
Leaf Segments

Photosynthetic electron transport in vivo was investigated in tobacco leaves pre-illuminated with strong light under conditions where Photosystem (PS) II repair was inhibited by lincomycin. Flash-induced redox changes of cytochrome b563, cytochrome f and plastocyanin, and the electrochromic (EC) signal (caused by a carotenoid band-shift due to charge separation across thylakoid membranes) from leaf segments were measured by deconvoluting absorbance changes at 520, 554, 564 and 575 nm. The EC signal was composed of easily separable fast and slow components. The fast EC signal decreased linearly with the loss of functional PS II centres, but there was a residual fast EC phase which was attributable to PS I centres alone. Inactivation of PS II centres by photoinhibitory light was also well-correlated with the quenching of variable fluorescence measured as the ratio of variable to maximum fluorescence, Fv/Fm. On complete photoinactivation of PS II centres, the slow rise of the flash-induced EC signal became more prominent, suggesting enhanced electrogenic charge transfer across the cytochrome bf complex as part of a path of electron flow involving PS I. Thus, both PS I and the cytochrome bf complex appeared to be fully functional after treatment of tobacco leaves with photoinhibitory light at room temperature. In totally photoinhibited leaf segments, the rate coefficients of cyt fIII re-reduction increased from 59 s-1 (+ lincomycin, no photoinhibitory light) to 130 s-1, and that of cytochrome b563 reduction also increased, from 270 s-1 to 500 s-1, suggesting that the prevailing plastoquinol concentration was higher after photoinhibitory light treatment. The source of the electrons entering the pool under these conditions was probably a high concentration of NADPH and reduced ferredoxin.

Isolierung von PS II-Partikeln mit in vivo Eigenschaften aus Euglena gracilis, Stamm Z / Isolation of PS II-Particels with in vivo Characteristics from Euglena gracilis, Stamm Z

1982 ◽  
Vol 37 (3-4) ◽  
pp. 256-259 ◽  
Author(s):  
F. Schuler ◽  
P. Brandt ◽  
W. Wießner
Keyword(s):  
Euglena Gracilis ◽  
Fluorescence Emission ◽  
Improved Method ◽  
Ps Ii ◽  
Ps I ◽  
Emission And Absorption Spectra ◽  
Chlorophyll Protein ◽  
Ps Ii Activity ◽  
Photosystem Ii Particles

Abstract An improved method for isolation of (photosystem II)-particles from Euglena gracilis, strain Z was established. PS II-particles isolated by ultrasonic treatment and following differential centrifugation show fluorescence emission and absorption spectra identical with in vivo properties of Euglena gracilis. These PS II-particles have only PS II-activity and contain CP a, the typical chlorophyll-protein-complex of PS II. No contamination of PS I-components are detectable.

scholarly journals Cell wall and organelle modifications during nitrogen starvation in Nannochloropsis oceanica F&M-M24

2021 ◽  
Author(s):  
Roncaglia Bianca ◽  
Papini Alessio ◽  
Chini Zittelli Graziella ◽  
Rodolfi Liliana ◽  
Mario R. Tredici
Keyword(s):  
Cell Wall ◽  
Wall Thickness ◽  
Lipid Droplets ◽  
Nitrogen Starvation ◽  
Photosynthetic Apparatus ◽  
Ultrastructural Changes ◽  
Total Biomass ◽  
Nannochloropsis Oceanica ◽  
Final Phase ◽  
Cell Functions

AbstractNannochloropsis oceanica F&M-M24 is able to increase its lipid content during nitrogen starvation to more than 50% of the total biomass. We investigated the ultrastructural changes and the variation in the content of main cell biomolecules that accompany the final phase of lipid accumulation. Nitrogen starvation induced a first phase of thylakoid disruption followed by chloroplast macroautophagy and formation of lipid droplets. During this phase, the total amount of proteins decreased by one-third, while carbohydrates decreased by 12–13%, suggesting that lipid droplets were formed by remodelling of chloroplast membranes and synthesis of fatty acids from carbohydrates and amino acids. The change in mitochondrial ultrastructure suggests also that these organelles were involved in the process. The cell wall increased its thickness and changed its structure during starvation, indicating that a disruption process could be partially affected by the increase in wall thickness for biomolecules recovery from starved cells. The wall thickness in strain F&M-M24 was much lower than that observed in other strains of N. oceanica, showing a possible advantage of this strain for the purpose of biomolecules extraction. The modifications following starvation were interpreted as a response to reduction of availability of a key nutrient (nitrogen). The result is a prolonged survival in quiescence until an improvement of the environmental conditions (nutrient availability) allows the rebuilding of the photosynthetic apparatus and the full recovery of cell functions.

Fluorescence as a tool in photosynthesis research: application in studies of photoinhibition, cold acclimation and freezing stress

1989 ◽  
Vol 323 (1216) ◽  
pp. 281-293 ◽  
Keyword(s):  
Quantum Yield ◽  
Cold Acclimation ◽  
Spinacia Oleracea ◽  
Photosynthetic Apparatus ◽  
Fluorescence Induction ◽  
High Light ◽  
Thermal Dissipation ◽  
Freezing Stress ◽  
Chlorophyll Fluorescence Induction ◽  
Freezing And Thawing

Chlorophyll fluorescence induction (at 20 °C and 77 K) and quenching were analysed in relation to effects of environmental stresses imposed by chilling in high light and by freezing and thawing of spinach ( Spinacia oleracea L.) leaves. The data indicate that cold acclimation of spinach plants, which leads to increased frost tolerance of the leaves, results in decreased susceptibility to photoinhibition of photosynthesis at chilling temperatures. When plants acclimated to 18 °C and 260-300 µmol quanta m -2 s -1 were exposed to higher light (550 µmol quanta m -2 s -1 ) at 4 °C, they developed strong photoinhibition, as characterized by decreased quantum yield of O 2 evolution and decreased ratio of variable: maximum fluorescence (F V /F M ) of photosystem II. The decrease in F V /F M resulted from a decline in F V and an increase in F 0 . The F V /F M ratio was lowered to a significantly greater extent when induction was recorded at 20 °C, as compared with 77 K. The effects related to photoinhibition were fully reversible at 18 °C in dim light. Plants that had been cold-acclimated for 10 days exhibited slightly decreased quantum yield and lowered F V /F M ratio. However, they did not show further photoinhibition on exposure to 550 µmol quanta m -2 s -1 at 4 °C. The reversible photoinhibition is discussed as a protective pathway serving for thermal dissipation of excessive light energy. It is hypothesized that such a mechanism prevents destruction of the photosynthetic apparatus, until other means of protection become effective during long-term acclimation to high light. Inhibition of photosynthetic carbon assimilation caused by freezing and thawing of leaves in the dark was closely correlated with inhibition of photochemical fluorescence quenching (q Q ). As a sensitive response of the thylakoid membranes to freezing stress, the energy-dependent quenching, q E , was inhibited. Only more severe impact of freezing caused a significant decline in the F V /F M ratio. It is concluded that measurements of fluorescence induction signals ( F V /F M ratios) provide a sensitive tool with which to investigate photoinhibition, whereas freezing damage to the photosynthetic system can be detected more readily by the quenching coefficients q Q and q E than by F V /F M ratios.

scholarly journals Photosystem II: Thermodynamics and Kinetics of Electron Transport from QA- to QB(QB- ) and Deleterious Effects of Copper(II)

1993 ◽  
Vol 48 (3-4) ◽  
pp. 234-240 ◽  
Author(s):  
G. Renger ◽  
H. M. Gleiter ◽  
E. Haag ◽  
F. Reifarth
Keyword(s):  
Oxygen Evolution ◽  
Manganese Content ◽  
Fluorescence Emission ◽  
Laser Flash ◽  
Fluorescence Induction ◽  
Oxygen Evolving Complex ◽  
Ps Ii ◽  
Thermodynamics And Kinetics ◽  
Redox Active ◽  
Kinetics Of

Studies on thermodynamics and kinetics of electron transfer from QA- to QB(QB-) were performed by monitoring laser flash induced changes of the relative fluorescence emission as a function of temperature (220 K < T < 310 K) in isolated thylakoids and PS II membrane fragments.In addition, effects of bivalent metal ions on PS II were investigated by measuring conventional fluorescence induction curves, oxygen evolution, manganese content and atrazine binding mostly in PS II membrane fragments. It was found: a) the normalized level of the fluorescence remaining 10 s after the actinic flash (Ft/F0) steeply increases at temperatures below -10 to - 20 °C, b) the fast phase of the transient fluorescence change becomes markedly retarded with decreasing temperatures, c) among different cations (Cu2+, Zn2+, Cd2+, Ni2+, Co2+) only Cu2+ exhibits marked effects in the concentration range below 100 μᴍ and d) Cu2+ decreases the normalized variable fluorescence, inhibits oxygen evolution and diminishes the affinity to atrazine binding without affecting the number of binding sites. The content of about four manganeses per functionally competent oxygen evolving complex is not changed by [Cu2+] < 70 μᴍ.Based on these findings it is concluded: i) a temperature dependent equilibrium between an inactive (I) and active (A) state of QA- reoxidation by QB(QB- ) is characterized by standard enthalpies ΔH° of 95 kJ mol-1 and 60 kJ mol-1 and standard entropies ΔS° of 370 kJ K-1 mol-1 and 240 kJ K-1 mol-1 in isolated thylakoids and PS II membrane fragments, respectively, ii) the activation energies of QA- reoxidation by plastoquinone bound to the QB site are about 30 kJ mol-1 (thylakoids) and 40 kJ mol-1 (PS II membrane fragments) in 220 K < T < 300 K, and iii) Cu2+ causes at least a two-fold effect on PS II by modifying the atrazine binding affinity at lower concentrations ( ~ 5 μᴍ) and interference with the redox active tyrosine Yz at slightly higher concentration ( ~ 10 μᴍ) leading to blockage of oxygen evolution.

Photoinactivation of Photosynthetic Electron Transport under Anaerobic and Aerobic Conditions in Isolated Thylakoids of Spinach

1992 ◽  
Vol 47 (1-2) ◽  
pp. 63-68 ◽  
Author(s):  
Rekha Chaturvedi ◽  
M. Singh ◽  
P. V. Sane
Keyword(s):  
Electron Transport ◽  
Photosynthetic Electron Transport ◽  
Oxygen Evolving Complex ◽  
Reaction Centre ◽  
Ps Ii ◽  
Ps I ◽  
S2 State ◽  
The Stability ◽  
Oxygen Evolving ◽  
Spinach Thylakoids

Abstract The effect of exposure to strong white light on photosynthetic electron transport reactions of PS I and PS II were investigated in spinach thylakoids in the absence or presence of oxygen. Irrespective of the conditions used for photoinactivation, the damage to PS II was always much more than to PS I. Photoinactivation was severe under anaerobic conditions compared to that in air for the same duration. This shows that the presence of oxygen is required for prevention of photoinactivation of thylakoids. The susceptibility of water-splitting complex in photoinactivation is indicated by our data from experiments with chloride-deficient chloroplast membranes wherein it was observed that the whole chain electron transport from DPC to MV was much less photoinhibited than that from water. The data from the photoinactivation experiments with the Tris-treated thylakoids indicate another photodam age site at or near reaction centre of PS II. DCMU-protected PS II and oxygen-evolving complex from photoinactivation. DCMU protection can also be interpreted in terms of the stability of the PS II complex when it is in S2 state.

scholarly journals The chlorophyll a/b -proteins of PS I and PS II are immunologically related

FEBS Letters ◽  
1986 ◽  
Vol 199 (2) ◽  
pp. 227-233 ◽  
Author(s):  
Paula K. Evans ◽  
Jan M. Anderson
Keyword(s):  
Chlorophyll A ◽  
Ps Ii ◽  
Ps I
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