Seed priming with proline improved photosystem II efficiency and growth of wheat (Triticum aestivum L.)

Abstract Background Proline can promote growth of plants by increasing photosynthetic activity under both non-stress and abiotic stress conditions. However, its role in non-stressed conditions is least studied. An experiment was conducted to assess as to whether increase in growth of wheat due to seed priming with proline under non-stress condition was associated with proline-induced changes in photosystem II (PSII) activity. Seeds of four wheat varieties (S-24, Sehar-06, Galaxy-13, and Pasban-90) were primed with different concentrations of proline (0, 5, 15 and 25 mM) for 12 h and allowed to grow under normal conditions. Biomass accumulation and photosynthetic performance, being two most sensitive features/indicators of plant growth, were selected to monitor proline modulated changes. Results Seed priming with proline increased the fresh and dry weights of shoots and roots, and plant height of all four wheat varieties. Maximum increase in growth attributes was observed in all four wheat varieties at 15 mM proline. Maximum growth improvement due to proline was found in var. Galaxy-13, whereas the reverse was true for S-24. Moreover, proline treatment changed the Fo, Fm, Fv/Fo, PIABS, PITot in wheat varieties indicating changes in PSII activity. Proline induced changes in energy fluxes for absorption, trapping, electron transport and heat dissipation per reaction center indicated that var. Galaxy-13 had better ability to process absorbed light energy through photosynthetic machinery. Moreover, lesser PSII efficiency in var. S-24 was due to lower energy flux for electron transport and greater energy flux for heat dissipation. This was further supported by the fact that var. S-24 had disturbance at acceptor side of PSI as reflected by reduction in ΔVIP, probability and energy flux for electron transport at the PSI end electron acceptors. Conclusion Seed priming with proline improved the growth of wheat varieties, which depends on type of variety and concentration of proline applied. Seed priming with proline significantly changed the PSII activity in wheat varieties, however, its translation in growth improvement depends on potential of processing of absorbed light energy by electron acceptors of electron transport chain, particularly those present at PSI end.

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Different strategies of acclimation of photosynthesis, electron transport and antioxidative activity in leaves of two cotton species to water deficit

Functional Plant Biology ◽

10.1071/fp15247 ◽

2016 ◽

Vol 43 (5) ◽

pp. 448 ◽

Cited By ~ 9

Author(s):

Xiao-Ping Yi ◽

Ya-Li Zhang ◽

He-Sheng Yao ◽

Hong-Hai Luo ◽

Ling Gou ◽

...

Keyword(s):

Electron Transport ◽

Water Deficit ◽

Heat Dissipation ◽

Photosynthetic Apparatus ◽

Light Energy ◽

Photochemical Quenching ◽

Antioxidant Systems ◽

Mehler Reaction ◽

Cotton Species ◽

Excess Light

To better understand the adaptation mechanisms of the photosynthetic apparatus of cotton plants to water deficit conditions, the influence of water deficit on photosynthesis, chlorophyll a fluorescence and the activities of antioxidant systems were determined simultaneously in Gossypium hirsutum L. cv. Xinluzao 45 (upland cotton) and Gossypium barbadense L. cv. Xinhai 21 (pima cotton). Water deficit decreased photosynthesis in both cotton species, but did not decrease chlorophyll content or induce any sustained photoinhibition in either cotton species. Water deficit increased ETR/4 − AG, where ETR/4 estimates the linear photosynthetic electron flux and AG is the gross rate of carbon assimilation. The increase in ETR/4 − AG, which represents an increase in photorespiration and alternative electron fluxes, was particularly pronounced in Xinluzao 45. In Xinluzao 45, water deficit increased the activities of antioxidative enzymes, as well as the contents of reactive oxygen species (ROS), which are related to the Mehler reaction. In contrast, moderate water deficit particularly increased non-photochemical quenching (NPQ) in Xinhai 21. Our results suggest that Xinluzao 45 relied on enhanced electron transport such as photorespiration and the Mehler reaction to dissipate excess light energy under mild and moderate water deficit. Xinhai 21 used enhanced photorespiration for light energy utilisation under mild water deficit but, when subjected to moderate water deficit, possessed a high capacity for dissipating excess light energy via heat dissipation.

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Contribution of Photosynthetic Electron Transport, Heat Dissipation, and Recovery of Photoinactivated Photosystem II to Photoprotection at Different Temperatures in Chenopodium album Leaves

Plant and Cell Physiology ◽

10.1093/pcp/pcg107 ◽

2003 ◽

Vol 44 (8) ◽

pp. 828-835 ◽

Cited By ~ 25

Author(s):

Tsonko D. Tsonev ◽

Kouki Hikosaka

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Heat Dissipation ◽

Chenopodium Album ◽

Photosynthetic Electron Transport ◽

Different Temperatures

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High salicylic acid concentration alters the electron flow associated with photosystem II in barley

Acta agriculturae Slovenica ◽

10.14720/aas.2017.109.2.22 ◽

2017 ◽

Vol 109 (2) ◽

pp. 393 ◽

Cited By ~ 6

Author(s):

Ghader Habibi ◽

Atousa Vaziri

Keyword(s):

Salicylic Acid ◽

Electron Transport ◽

Photosystem Ii ◽

Electron Flow ◽

Peak Level ◽

Oxygen Evolving Complex ◽

High Concentration ◽

Complex Activity ◽

Fluorescence Transient ◽

Psii Activity

In this study, the effects of exogenously applied salicylic acid (0.5 and 5 mM SA) on the rates of photosystem II (PSII) activity was analysed in 4-week-old barley (Hordeum vulgare‘Bahman’ ) seedlings using chlorophyll (Chl) a fluorescence transient (OJIP) measurements. No evident changes in Chl and carotenoid contents as well as chlorophyll fluorescence transient curves were observed in either of the studied concentrations after 24 h of SA application. After 5 d, low SA concentration (0.5 mM) increased PSII activity, Chl b and carotenoid contents in barley seedlings. In contrary, 5 days after 5 mM SA treatment, the maximal quantum efficiency of PSII (Fv/Fm) and the Performance Index (PIABS), as an indicator of PSII structure and functioning, were significantly decreased. This lower Fv/Fm and PIABS coupled with lower levels of Chl b and carotenoids, and lower values of photosynthetic electron transport chain components including the electron transport flux (φEo) and the inferred oxygen evolving complex activity (Fv/Fo). By monitoring the chlorophyll a fluorescence rise kinetics, from the initial “O” level to the “P” (the peak) level, a dramatic increase in “OJ” phase was detected, which coincides with an increased photo-reduction of QA as a result of blockage of electron flow. This study provided the evidence that the high concentration of SA induced damage to different sites of the PSII.

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Site of Action of 2,5-Dimethoxy-3,6-Dichloro-p-Benzoquinone in the Photosynthetic Electron Transport Chain

Zeitschrift für Naturforschung C ◽

10.1515/znc-1981-7-825 ◽

1981 ◽

Vol 36 (7-8) ◽

pp. 656-661 ◽

Cited By ~ 10

Author(s):

G. Sarojini ◽

H. Daniell

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Electron Transport Chain ◽

Electron Transport Rate ◽

Electron Flow ◽

Electron Acceptors ◽

Hill Reaction ◽

Transport Chain ◽

Site Of Action ◽

The Hill

Abstract Electron Acceptors, Photosystem II, Quinones and Quinonediamines Dichlorodimethoxy-/?-benzoquinone (DCDMQ) was tested for its site of action in the photo synthetic electron transport chain. Hill reaction mediated by DCDMQ was insensitive to DBMIB (1 nm) but sensitive to DCMU, suggesting its site of action before plastoquinone but after Q -the primary electron acceptor of photosystem II. Extraction of freeze-dried chloroplasts with heptane and analyzing their capacity to photo-oxidize water using various Hill oxidants revealed that silicomolybdate (SiMO) and DCDMQ could effectively restore the activity. Diaminodurene (DAD) in the presence of ferricyanide could restore 40% of the activity. But ferricyanide alone failed to restore the ability to photo-oxidize water in heptane extracted chloroplasts. Similarly, N a2S 0 3 which is known to cause a bottleneck in the electron flow at plastoquinone affected the ferricyanide Hill reaction. Hill reactions mediated by SiMO and DCDMQ were insensitive to the addition of Na2SO3, suggesting that both these oxidants intercept electrons before plastoquinone. But 50% of the activity was lost when sulfite was added to the Hill reaction mediated by DADox. DNP-INT, melittin and picrylhydrazyl were recently introduced as photosystem II inhibitors inhibiting the electron flow between Q and the PQ pool. While DCBQ and DCDMQ Hill reactions were insensitive to DNP-INT, ferricyanide was highly sensitive. The quinonediamines TMPD and DADox showed 50% decrease in the electron transport rate, similar to heptane extracted or sulfite inhibited chloroplasts. Melittin increased the electron transport rate when ferricyanide or TMPD was the Hill oxidant, while DCBQ and DCDMQ reduction remained unaffected. However, DADox Hill reaction showed 50% inhibition in the presence of melittin. Picrylhydrazyl - which inhibits the electron flow between Q and the PQ pool - inhibited the Hill reaction of all the PS II electron acceptors except that of DCDMQ. It is possible that there is another site of intercepting electrons between Q and plastoquinone before the site where most of the quinonediamines accept electrons.

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735 PB 029 SORGOLEONE: A PHOTOSYSTEM II INHIBITOR PRODUCED BY SORGHUM BICOLOR

HortScience ◽

10.21273/hortsci.29.5.538c ◽

1994 ◽

Vol 29 (5) ◽

pp. 538c-538

Author(s):

Leslie A. Weston ◽

Verónica M. Gonzalez

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Secondary Electron ◽

Potent Inhibitor ◽

Photosynthetic Electron Transport ◽

Significant Inhibition ◽

Electron Acceptors ◽

Variable Fluorescence ◽

Trypsin Treatment ◽

Weed Species

Sorgoleone, the oxidized quinone form of a hydrophobic p-benzoquinone was first isolated from Sorghum root exudates. Sorgoleone is a potent inhibitor of growth in several annual weed species and causes tissue bleaching at concentrations of <25 μ M. These investigations were designed to determine if soreoleone's allelopathic activity was related to an inhibition of photosynthetic electron transport. The effect of sorgoleone versus DCMU (diuron) on inhibition of O2 evolution by broken wheat thylakoids, and in oxygenevolving PSII membranes containing QA and QB primary and secondary electron acceptors in PSII was determined. Sorgoleone was a potent inhibitor of O2 evolution in this system with ∼ 0.04 and 0.78 μ M concentrations required for 50 and 100% inhibition as compared to -0.11 and 2.0 μ M DCMU, respectively. Sorgoleone caused no significant inhibition of PSI mediated photooxidation of ascorbate/dichlorophenolindophenol, establishing that the locus of inhibition by sorgoleone was within the PSII complex. The effect of trypsin treatment of chloroplasts and PSII membranes on sensitivity to inhibition by DCMU and sorgoleone was examined. The comparison of DCMU and sorgoleone upon the formation and decay of flash-induced chlorophyll a variable fluorescence indicates that sorgoleone specifically inhibited the oxidation of QA by QB.

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Molecular mechanisms behind light-induced inhibition of photosystem II electron transport and degradation of reaction centre polypeptides

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/s0005-2728(05)80004-0 ◽

1992 ◽

Vol 1101 (2) ◽

pp. 139-142 ◽

Cited By ~ 5

Author(s):

I VIRGIN ◽

A SALTER ◽

A HAGMAN ◽

I VASS ◽

S STYRING ◽

...

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Molecular Mechanisms ◽

Reaction Centre

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Photosystem II Inhibition by Pyran-enamine Derivatives

Zeitschrift für Naturforschung C ◽

10.1515/znc-1993-3-409 ◽

1993 ◽

Vol 48 (3-4) ◽

pp. 163-167

Author(s):

Koichi Yoneyama ◽

Yoshihiro Nakajima ◽

Masaru Ogasawara ◽

Hitoshi Kuramochi ◽

Makoto Konnai ◽

...

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Thylakoid Membranes ◽

Major Determinant ◽

Ps Ii ◽

Structure Activity Relationships ◽

Structure Activity

Abstract Through the studies on structure-activity relationships of 5-acyl-3-(1-aminoalkylidene)-4-hydroxy-2 H-pyran-2,6(3 H)-dione derivatives in photosystem II (PS II) inhibition, overall lipophilicity of the molecule was found to be a major determinant for the activity. In the substituted N -benzyl derivatives, not only the lipophilicity but also the electronic and steric characters of the substituents greatly affected the activity. Their mode of PS II inhibition seemed to be similar to that of DCMU , whereas pyran-enamine derivatives needed to be highly lipophilic to block the electron transport in thylakoid membranes, which in turn diminished the permeability through biomembranes.

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Interaction of Photosystem II Herbicides with Bicarbonate and Formate in Their Effects on Photosynthetic Electron Flow

Zeitschrift für Naturforschung C ◽

10.1515/znc-1984-0512 ◽

1984 ◽

Vol 39 (5) ◽

pp. 374-377 ◽

Cited By ~ 2

Author(s):

J. J. S. van Rensen

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Electron Flow ◽

Photosynthetic Electron Transport ◽

Hill Reaction ◽

Amaranthus Hybridus ◽

Apparent Affinity ◽

Photosynthetic Electron Flow ◽

Different Characteristics ◽

The Hill

The reactivation of the Hill reaction in CO2-depleted broken chloroplasts by various concentrations of bicarbonate was measured in the absence and in the presence of photosystem II herbicides. It appears that these herbicides decrease the apparent affinity of the thylakoid membrane for bicarbonate. Different characteristics of bicarbonate binding were observed in chloroplasts of triazine-resistant Amaranthus hybridus compared to the triazine-sensitive biotype. It is concluded that photosystem II herbicides, bicarbonate and formate interact with each other in their binding to the Qв-protein and their interference with photosynthetic electron transport.

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Photoinhibition of Electron Transport Activity of Photosystem II in Isolated Thylakoids Studied by Thermoluminescence and Delayed Luminescence

Zeitschrift für Naturforschung C ◽

10.1515/znc-1988-11-1213 ◽

1988 ◽

Vol 43 (11-12) ◽

pp. 871-876 ◽

Cited By ~ 35

Author(s):

Imre Vass ◽

Narendranath Mohanty ◽

Sándor Demeter

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Photosystem I ◽

Half Life ◽

Delayed Luminescence ◽

Transport Activity ◽

Primary Target ◽

Electron Transport Activity ◽

The Stability ◽

Spinach Thylakoids

Abstract The effect of photoinhibition on the primary (QA) and secondary (QB) quinone acceptors of photosystem I I was investigated in isolated spinach thylakoids by the methods of thermoluminescence and delayed luminescence. The amplitudes of the Q (at about 2 °C) and B (at about 30 °C) thermoluminescence bands which are associated with the recombination of the S2QA- and S2QB charge pairs, respectively, exhibited parallel decay courses during photoinhibitory treatment. Similarly, the amplitudes of the flash-induced delayed luminescence components ascribed to the recombination of S20A and S2OB charge pairs and having half life-times of about 3 s and 30 s, respectively, declined in parallel with the amplitudes of the corresponding Q and B thermoluminescence bands. The course of inhibition of thermoluminescence and delayed luminescence intensity was parallel with that of the rate of oxygen evolution. The peak positions of the B and Q thermoluminescence bands as well as the half life-times of the corresponding delayed luminescence components were not affected by photoinhibition. These results indicate that in isolated thylakoids neither the amount nor the stability of the reduced OB acceptor is preferentially decreased by photoinhibition. We conclude that either the primary target of photodamage is located before the O b binding site in the reaction center of photosystem II or QA and OB undergo simultaneous damage.

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