Chloroplast protection in greening leaves

Gillham, David J.; Dodge, A. D.

doi:10.1111/j.1399-3054.1985.tb08662.x

Cited by 19 publications

(5 citation statements)

References 15 publications

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“…Oxygen toxicity has been implicated in processes associated with environmental stress. Steady increases in the ascorbate and glutathione content, and ascorbate peroxidase activity occurred during chlorophyll synthesis (Gillham & Dodge 1985). Pea leaves grown under high irradiances contained significantly higher levels of glutathione-and dehydroascorbate reductase than those at lower light levels (Gillham & Dodge 1987).…”

Section: Introductionmentioning

confidence: 98%

The use of 3‐amino‐1,2,4‐triazole to investigate the short‐term effects of oxygen toxicity on carbon assimilation by Pisum sativum seedlings

Amory

Ford

Pammenter

et al. 1992

Plant Cell & Environment

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To study the in vivo short-term effect of hydrogen peroxide on plant metabolism, 2 mol m~^ 3-amino-1,2,4-triazole, a catalase inhibitor, was applied through the transpiration stream to Pisum sativum seedlings, and gas exchange characteristics, ascorbate peroxidase, glutathione reductase and catalase activities, and levels of hydrogen peroxide and formate were determined. Carbon dioxide assimilation rates were inhibited after the addition of aminotriazole: photorespiratory conditions exacerbated this inhibition. Carbon dioxide response curves showed that aminotriazole reduced both the RuBP regeneration rate and the efficiency of the carboxylation reaction of Rubisco. Catalase activity was completely inhibited 200 min after the application of this inhibitor, but no concomitant increase in H2O2 concentration was found. Under enhanced photorespiratory conditions, H2O2 concentrations increased. This suggests that under normal environmental conditions hydrogen peroxide is metabolized via alternative mechanisms. The aminotriazole treatment had no effect on the ascorbate peroxidase and glutathione reductase activities, but caused a substantial increase in the formate pool size. These results suggest that hydrogen peroxide is metabolized by reacting with glyoxylate to produce formate and CO2. The increased production of formate may reduce the flow of carbon through the normal photorespiratory pathway and may also be used anaplerotically as a precursor of products of 1 -C metabolism other than serine. This would prevent the return of photorespiratory carbon to the RPP pathway, leading to a smaller RuBP pool size which would in turn result in a decrease in carboxylation conductance (carboxylation efficiency) and regeneration rate of RuBP.

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Section: Introductionmentioning

confidence: 98%

The use of 3‐amino‐1,2,4‐triazole to investigate the short‐term effects of oxygen toxicity on carbon assimilation by Pisum sativum seedlings

Amory

Ford

Pammenter

et al. 1992

Plant Cell & Environment

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“…This hypothesis essentially arose from studies carried out on carotenoid‐free mutants ( Mayfield and Taylor 1984; Oelmüller 1989; Hess et al 1994) and on plants treated with norflurazon (NF) ( Mayfield and Taylor 1984; Oelmüller and Mohr 1986; Ernst and Schefbeck 1988; Oelmüller 1989), a herbicide that totally inhibits carotenoid synthesis ( Barry and Pallett 1990). Carotenoids are known to play a major protective role against the oxygen‐dependent photodamage of photosynthetic apparatus ( Gillham and Dodge 1985; Sandmann et al 1993; Barber 1994; Niyogi 1999). They act by quenching chlorophyll triplet states and singlet oxygen formed in photosystem reaction centres and the chlorophyll fluorescence in light‐harvesting complexes ( Siefermann‐Harms 1987; Young et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Plastid photodamage and Cab gene expression in barley leaves

Rocca

Vecchia

Barbato

et al. 2000

Physiologia Plantarum

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treated plants had some strikingly altered membranes and The effects of norflurazon (NF) and amitrole (AM), two contained only very small quantities of chlorophylls. Despite bleaching herbicides which inhibit carotenogenesis, were compared in leaves of 7-day-old barley (Hordeum 7ulgare L. cv the presence of severely photodamaged plastids, cells of AM-Express) plants grown in damaging light. The herbicide effects treated leaves contained high levels of Lhcb1 transcript. This were analysed with respect to chloroplast organization, photo-transcript, on the contrary, was completely absent in the cells of NF-treated plants. These findings suggest that in order to synthetic functionality and nuclear photodependent expression of the Lhcb1 gene, which codes for the Lhcb1 light-harvesting block expression of nuclear genes coding for plastid-resident chlorophyll a/b binding protein of photosystem II. Both herbi-proteins, photodamage leading to the complete dismantling of thylakoids and to the total absence of any form of photosyn-cides caused dramatic photooxidation of organelles, which thetic pigment is required. were photosynthetically unfunctional. Plastids of NF-treated plants lacked thylakoids and pigments. Plastids of AM-

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“…Exposing higher plant materials to excess light energy is known to induce the photobleaching of photosynthetic pigments. That this reaction involves oxygen radicals is demonstrated by the photoprotection role of anti-radical species, mainly atocopherol (Merzlyak et al, 1986), superoxide dismutase (Gillham and Dodge, 1985), ascorbate (Szigeti and Vagujfalvi, 1984;Gillham and Dodge, 1985;), flavonols (Takahama, 1982;Wagner et al, 1988) and carotenoids (Merzlyak, 1986;Gillham and Dodge, 1985;Siefermann-Harms, 1987;Krinsky, 1978). The proposed mechanism of chlorophyll (Chi)?…”

Section: Introductionmentioning

confidence: 99%

Energy Dissipation and Photoprotection Mechanisms During Chlorophyll Photobleaching in Thylakoid Membranes

Miller

Carpentier

1991

Photochem & Photobiology

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The kinetics of chlorophyll photobleaching were followed in whole thylakoid membranes as well as in photosystem I and photosystem I1 submembrane fractions. The onset of photobleaching was characterized by a slow rate which indicated the presence of energy traps implicated in the photoprotection of the bulk pigments. The pigments in photosystem I submembrane fractions bleached at a faster rate than those in photosystem I1 counterparts, the latter being more sensitive towardsphotoinhibition. An analysis of the pigment-protein complexes isolated from whole thylakoid membranes during the course of a photobleaching experiment has shown that the core-antenna complexes, including CP29, are more sensitive to illumination than the peripheral complexes. The absorption spectra of the CPI and CP2Y complexes presented a blue shift of the red absorption maximum after partial photobleaching, indicative of a non-homogeneous bleaching of the holochromes in these complexes. An analysis of these data points towards the involvement of CP2Y in a photoprotection mechanism at the level of photosystem 11. The weaker resistance of photosystem I to photobleaching relative to photosystem I1 and its stronger resistance to photoinhibition is discussed in terms of an energy dissipation pathway in thylakoid membranes.

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Chloroplast protection in greening leaves

Cited by 19 publications

References 15 publications

The use of 3‐amino‐1,2,4‐triazole to investigate the short‐term effects of oxygen toxicity on carbon assimilation by Pisum sativum seedlings

The use of 3‐amino‐1,2,4‐triazole to investigate the short‐term effects of oxygen toxicity on carbon assimilation by Pisum sativum seedlings

Plastid photodamage and Cab gene expression in barley leaves

Energy Dissipation and Photoprotection Mechanisms During Chlorophyll Photobleaching in Thylakoid Membranes

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