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).

Distribution and Effects of Bentazon in Crop Plants and Weeds

1982 ◽  
Vol 37 (10) ◽  
pp. 889-897 ◽  
Author(s):  
H. K. Lichtenthaler ◽  
D. Meier ◽  
G. Retzlaff ◽  
R. Hamm
Keyword(s):  
Electron Flow ◽  
Photosynthetic Apparatus ◽  
Crop Plants ◽  
Light Conditions ◽  
Low Light ◽  
Tolerant Plants ◽  
Variable Chlorophyll Fluorescence ◽  
Pigment Ratios ◽  
Kautsky Effect ◽  
Uptake And Transport

Abstract The inhibition of photosynthetic CO2-assimilation and of the variable chlorophyll fluorescence as well as uptake and transport of 14C-labelled bentazon and the possibilities for a herbicideinduced shade-type modification of the photosynthetic apparatus were investigated in bentazonsensitive weeds (Galium, Sinapis, Raphanus) and in the tolerant crop plants wheat and maize.1. In weeds the depression of photosynthetic CO2-assimilation is irreversible, whereas tolerant plants recover due to the metabolization of the active herbicide.2. A lower rate of uptake and transport of bentazon associated with its fast metabolization is the reason for the tolerance of crop plants towards bentazon.3. The transport of [14C]bentazon proceeds in the tracheary elements of the xylem. Uptake and transport of bentazon in the weeds are light dependent.4. The loss of variable fluorescence (Kautsky effect) in the leaves after root application o f bentazon proceeds much faster at high-light than at low light conditions and confirms the light-dependency of the bentazon transport.5. In the sensitive dicot weeds bentazon not only inhibits photosynthetic electron flow and depresses CO2-fixation but also induces the formation of shade-type chloroplasts which are less efficient in photosynthetic quantum conversion. This bentazon-induced modification of the photosynthetic apparatus (e.g. changes in ultrastructure, pigment ratios, and levels of chloro-phyll-proteins) contributes to the effectiveness of bentazon as a herbicide.

Involvement of the Xanthophyll Cycle in Regulation of Cyclic Electron Flow around Photosystem II

1996 ◽  
Vol 51 (1-2) ◽  
pp. 47-52 ◽  
Author(s):  
W. I. Gruszecki ◽  
K. Strzałk ◽  
K.P. Bader ◽  
A. Radunz ◽  
G.H. Schmid
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Oxygen Evolution ◽  
Xanthophyll Cycle ◽  
Electron Flow ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Oxygen Evolution ◽  
Cyclic Electron Transport ◽  
Ps Ii ◽  
Low Levels

Abstract In our previous study (Gruszecki et al., 1995) we have postulated that the mechanism of cyclic electron transport around photosystem II, active under overexcitation of the photosynthetic apparatus by light is under control of the xanthophyll cycle. The combination of dif­ferent light quality and thylakoids having various levels of xanthophyll cycle pigments were applied to support this hypothesis. In the present work photosynthetic oxygen evolution from isolated tobacco chloroplasts was measured by means of mass spectrometry under conditions of high or low levels of violaxanthin, being transformed to zeaxanthin during dark incubation in an ascorbate containing buffer at pH 5.7. Analysis of oxygen evolution and of light-induced oxygen uptake indicate that the de-epoxidation of violaxanthin to zeaxanthin results in an increased cyclic electron transport around PS II, thus dimishing the vectorial electron flow from water. An effect similar to de-epoxidation was observed after incubation of thylakoid membranes with specific antibodies against violaxanthin.

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.

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.

Interactions of Herbicides with Photosynthetic Electron Transport

Weed Science ◽  
1991 ◽  
Vol 39 (3) ◽  
pp. 458-464 ◽  
Author(s):  
E. Patrick Fuerst ◽  
Michael A. Norman
Keyword(s):  
Electron Transport ◽  
Membrane Lipids ◽  
Electron Flow ◽  
Membrane Integrity ◽  
D1 Protein ◽  
Photosynthetic Electron Transport ◽  
Peroxidation Of Lipids ◽  
Ps Ii ◽  
Ps I ◽  
Sulfur Protein

The two primary sites of herbicide action in photosynthetic electron transport are the inhibition of photosystem II (PS II) electron transport and diversion of electron flow through photosystem I (PS I). PS II electron transport inhibitors bind to the D1 protein of the PS II reaction center, thus blocking electron transfer to plastoquinone. Inhibition of PS II electron transport prevents the conversion of absorbed light energy into electrochemical energy and results in the production of triplet chlorophyll and singlet oxygen which induce the peroxidation of membrane lipids. PS I electron acceptors probably accept electrons from the iron-sulfur protein, Fa/Fb. The free radical form of the herbicide leads to the production of hydroxyl radicals which cause the peroxidation of lipids. Herbicide-induced lipid peroxidation destroys membrane integrity, leading to cellular disorganization and phototoxicity.

Die Wirkung 2.3-substituierter Naphthochinone auf einzellige Algen und isolierte Spinatchloroplasten/ The Effect of 2,3-Substituted Naphthoquinones on Unicellular Algae and Isolated Spinach Chloroplasts

1979 ◽  
Vol 34 (11) ◽  
pp. 961-963 ◽  
Author(s):  
Klaus Bauer ◽  
Helmu Kodier
Keyword(s):  
Electron Transport ◽  
Dark Respiration ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Flow Mode ◽  
Ps Ii ◽  
Spinach Chloroplasts ◽  
Ps I ◽  
Low Concentrations ◽  
Strong Stimulation

Abstract Short term effects of 2-(C-dichloro-acetylamino)-3-chloro-1,4-naphthoquinone (Hoe 13465, quinonamid*) and 2-amino-3-chloro-1,4-naphthoquinone (Hoe 17399, 06K-quinone) on cell suspensions of Chlorella vulgaris, Anabaena flos aquae, Porphyridium cruentum, and on isolated spinach chloroplasts were studied. The results clearly show that both substances inhibit the photosynthetic O2 production of algal suspensions as well as the electron transport of PS II in spinach chloroplasts. PS I is not inhibited by the action of the two algicides. At low concentrations quinonamid acts as a photosynthetic electron transport blocker, whereas Hoe 17399 is a weak inhibitor of photosynthetic electron flow. Mode of action of the two naphthoquinones is discussed. Both naphthoquinone derivatives can operate as an electron acceptor for PS I at low concentra­tions (10-5-10-6м). In addition there is observed a strong stimulation of dark respiration in algal cells induced by both of the compounds, Hoe 17399 causes a much higher stimulation rate than quinonamid does.

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