Alkalization of the chloroplast stroma caused by light-dependent proton flux into the thylakoid space

Heldt, Hans W.; Werdan, Karl; Milovancev, Mirjana; Geller, Gerlinde

doi:10.1016/0005-2728(73)90137-0

Cited by 466 publications

(259 citation statements)

References 43 publications

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“…However, since these Cu(OH) 2 particles has been shown to have increased dissolution at acidic pH and lower dissolution at basic pH, 31 the majority of dissolution probably occurs in the soil (pH 5.7) rather than in the neutral or slightly basic conditions of cell or chloroplast interiors. 46,47 Linear growth rates (cm wk À1 ), maximum height, leaf production rate, leaf loss rate (as leaves desiccate and senesce), maximum number of leaves, and week of maximum leaf production were calculated from physical measurements and are shown in Figures S1ÀS6. Few effects due to ENM exposure were seen under any growth condition, although LE plants exposed to Cu-(OH) 2 had reduced growth rates, leaf production rates, and maximum number of leaves with increasing exposure concentrations (linear regressions, p < 0.05).…”

Section: Resultsmentioning

confidence: 99%

Environmental Stresses Increase Photosynthetic Disruption by Metal Oxide Nanomaterials in a Soil-Grown Plant

Conway

Beaulieu

et al. 2015

ACS Nano

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Despite an increasing number of studies over the past decade examining the interactions between plants and engineered nanomaterials (ENMs), very few have investigated the influence of environmental conditions on ENM uptake and toxicity, particularly throughout the entire plant life cycle. In this study, soil-grown herbaceous annual plants (Clarkia unguiculata) were exposed to TiO 2 , CeO 2 , or Cu(OH) 2 ENMs at different concentrations under distinct light and nutrient levels for 8 weeks. Biweekly fluorescence and gas exchange measurements were recorded, and tissue samples from mature plants were analyzed for metal content. During peak growth, exposure to TiO 2 and CeO 2 decreased photosynthetic rate and CO 2 assimilation efficiency of plants grown under high light and nutrient conditions, possibly by disrupting energy transfer from photosystem II (PSII) to the Calvin cycle. Exposure Cu(OH) 2 particles also disrupted photosynthesis but only in plants grown under the most stressful conditions (high light, limited nutrient) likely by preventing the oxidation of a primary PSII reaction center. TiO 2 and CeO 2 followed similar uptake and distribution patterns with concentrations being highest in roots followed by leaves then stems, while Cu(OH) 2 was present at highest concentrations in leaves, likely as ionic Cu. ENM accumulation was highly dependent on both light and nutrient levels and a predictive regression model was developed from these data. These results show that abiotic conditions play an important role in mediating the uptake and physiological impacts of ENMs in terrestrial plants.

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Section: Resultsmentioning

confidence: 99%

Environmental Stresses Increase Photosynthetic Disruption by Metal Oxide Nanomaterials in a Soil-Grown Plant

Conway

Beaulieu

et al. 2015

ACS Nano

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“…Moreover, the pH in the stroma increases in the light [29] due to proton pumping into the thylakoids [30]. This higher pH amplifies the inhibitory 0 0…”

Section: Discussionmentioning

confidence: 99%

Regulation of glucose-6-phosphate dehydrogenase in spinach chloroplasts by ribulose 1,5-diphosphate and NADPH/NADP+ ratios

Lendzian

Bassham

1975

Biochimica et Biophysica Acta (BBA) - Bioenergetics

104

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“…Cu 21 transport was the most rapid, with an initial rate of 1.4 mM/s. The internal volume of thylakoid membranes was determined to be about 3.3 mL/mg chlorophyll (Heldt et al, 1973 The determination of the initial rate of uptake as a function of Cu 21 concentration shows that Cu 21 uptake saturates at a concentration of approximately 0.6 mM added Cu 21 (Fig. 4).…”

Section: Divalent Cation Transport Across Chloroplast Thylakoid Membrmentioning

confidence: 95%

“…Copper is required for proteins located within the thylakoid lumen, such as polyphenol oxidase and plastocyanin (Heldt et al, 1973;Merchant and Dreyfuss, 1998). This requirement and the fact that copper is added to apoplastocyanin in the lumen (Merchant and Dreyfuss, 1998) indicate that there must be a mechanism by which copper crosses the thylakoid membrane.…”

mentioning

confidence: 99%

Copper Transport Across Pea Thylakoid Membranes

2004

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The initial rate of Cu2+ movement across the thylakoid membrane of pea (Pisum sativum) chloroplasts was directly measured by stopped-flow spectrofluorometry using membranes loaded with the Cu2+-sensitive fluorophore Phen Green SK. Cu2+ transport was rapid, reaching completion within 0.5 s. The initial rate of uptake was dependent upon Cu2+ concentration and saturated at about 0.6 μm total Cu2+. Cu2+ uptake was maximal at a thylakoid lumen pH of 7.0. Cu2+ transport was inhibited by Zn2+ but was largely unaffected by Mn2+ and Cu+. Zn2+ inhibited Cu2+ transport to a maximum of 60%, indicating that there may be more than one transporter for copper in pea thylakoid membranes

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Alkalization of the chloroplast stroma caused by light-dependent proton flux into the thylakoid space

Cited by 466 publications

References 43 publications

Environmental Stresses Increase Photosynthetic Disruption by Metal Oxide Nanomaterials in a Soil-Grown Plant

Environmental Stresses Increase Photosynthetic Disruption by Metal Oxide Nanomaterials in a Soil-Grown Plant

Regulation of glucose-6-phosphate dehydrogenase in spinach chloroplasts by ribulose 1,5-diphosphate and NADPH/NADP+ ratios

Copper Transport Across Pea Thylakoid Membranes

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