Effect of excess Cu on the photosynthetic apparatus of runner bean leaves treated at two different growth stages

Maksymiec, Waldemar; Russa, Ryszard; Urbanik‐Sypniewska, Teresa; Baszyński, Tadeusz

doi:10.1034/j.1399-3054.1994.910424.x

Cited by 20 publications

(26 citation statements)

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“…Some authors observed negative Cu and Cd action on different stages of the light phase of photosynthesis (electron transport) (Maksymiec et al 1994, Maksymiec and Baszyński 1996, Myśliwa-Kurdziel et al 2002, and references therein). Other authors claim that in the first place heavy metals attack Calvin-cycle enzymes, localized in chloroplast stroma (Weigel 1985, Sheoran et al 1990).…”

Section: Discussionmentioning

confidence: 92%

Effects of copper and cadmium on photosynthesis in cucumber cotyledons

Burzyński¹,

Żurek²

2007

Photosynt.

101

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The effects of 20 and 50 μM concentrations of Cu and Cd on photosynthesis in cucumber (Cucumis sativus L.) cotyledons were studied by the measurements of gas exchange characteristics, chlorophyll (Chl) fluorescence parameters, photosynthetic pigment contents, and two Calvin cycle enzymes activities: glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and 3-phosphoglyceric acid kinase (PGK). To minimize indirect metal action, seedlings were treated with metals in the stage of green, fully developed cotyledons. The metals reached the cotyledon tissue after 48 h of treatments, though symptoms of metal action were not visible at that time. The effect of metals on the light phase of the photosynthesis parameters such as potential efficiency of photosystem 2 (PS2; F v /F m ), and photochemical and nonphotochemical quenching of Chl fluorescence (q P and q NP ) was negligible. In contrast, a decrease of PS2 quantum efficiency (Φ PS2 ) was much more noticeable. Changes in the pigment contents were slight, as only 50 μM Cd decreased Chl a and b contents in small extent. On the contrary, metals in both concentrations drastically decreased (50 and more % of control) the net photosynthetic rate and the stomatal conductance, but not the internal CO 2 concentration. The activities of both GAPDH and PGK were also decreased by metals, although the effect on PGK was more prominent, particularly on its potential activity (dithiothreitol in extraction and incubation media). Hence Cu and Cd affected the synthesis of enzyme proteins rather than they influenced their modifications. The effects of both metals on most of the measured photosynthesis parameters were similar, but the accumulation of Cd in the cotyledons was significantly higher than Cu accumulation. Thus Cu was more toxic for the photosynthesis of cucumber cotyledons than Cd.Additional key words: chlorophyll content and fluorescence; dithiothreitol; gas exchange; glyceraldehyde-3-phosphate dehydrogenase; 3-phosphoglyceric acid kinase; stomatal conductance.

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Section: Discussionmentioning

confidence: 92%

Effects of copper and cadmium on photosynthesis in cucumber cotyledons

Burzyński¹,

Żurek²

2007

Photosynt.

101

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“…growing on soil contaminated with Pb, Zn, and Cu. On the other hand, numerous studies indicate (Maksymiec et al 1994, Poskuta and Wacławczyk-Lach 1995, Maksymiec and Baszyński 1996, Krupa and Moniak 1998, Larsson et al 1998) that heavy metals alter this photosynthetic parameter more markedly. Thus, the disturbances in potential efficiency of PS2 under heavy metals' stress depend on the plant genera and age, time of exposure to metals, and their contents in leaf tissues.…”

Section: Discussionmentioning

confidence: 94%

Changes of photosynthetic parameters in cucumber leaves under Cu, Cd, and Pb stress

Burzyński¹,

Kłobus²

2004

Photosynt.

152

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The effects of Cu, Cd, and Pb toxicity on photosynthesis in cucumber leaves (Cucumis sativus L.) were studied by the measurements of gas exchange characteristics, chlorophyll (Chl) fluorescence parameters, and Chl content. Concentrations of metals in sequence of 20 µM Cu, 20 and 50 µM Cd, and 1 000 µM Pb decreased the plant dry mass to 50-60 % after 10 d of treatment whereas 50 µM of Cu decreased it to 30 %. The content of Cd in leaves of plants treated with 50 µM Cd was three times higher than the contents of Cu and Pb after plant treatment with 50 µM Cu or 1 000 µM Pb. Hence Cd was transported to leaves much better than Cu and Pb. Nevertheless, the net photosynthetic rate and stomatal conductance in leaves treated with 50 µM Cu or Cd were similarly reduced. Thus, Cu was more toxic than Cd and Pb for photosynthesis in cucumber leaves. None of the investigated metals decreased internal CO 2 concentrations. Also the effect of metals on potential efficiency of photosystem 2, PS2 (F v /F m ) was negligible. The metal dependent reduction of PS2 quantum efficiency (Φ PS2 ) after plant adaptation in actinic irradiation was more noticeable. This could imply that reduced demand for ATP and NADPH in a dark phase of photosynthesis caused a down-regulation of PS2 photochemistry. Furthermore, in leaves of metal-treated plants the decrease in water percentage as well as lower contents of Chl and Fe were observed. Thus photosynthesis is not the main limiting factor for cucumber growth under Cu, Cd, or Pb stress.

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“…Several heavy metals have been suspected of inducing inhibition of photosynthesis through reduced carbon metabolism (Van Assche and Clijsters 1990, Maksymiec et al 1994, Baron et al 1995, Ouzounidou and Constantinidou 1999. In addition, the impact of Cu on sunflower leaf WUE indicates the reduced control over water loss Mitchell 1991, Moustakas et al 1997).…”

Section: Discussionmentioning

confidence: 96%

Hormone-induced protection of sunflower photosynthetic apparatus against copper toxicity

Ouzounidou¹,

Ilias

2005

Biologia plant.

101

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The effects of excess Cu as affected by the application of exogenous hormones (gibberellic acid -GA 3 and indole-3-acetic acid -IAA) with respect to sunflower (Helianthus annuus L.) growth, physiology, and metabolism were studied. Application of 100 µM IAA lessened the toxic effects of 80 µM Cu in roots indicating greater root length and root hair formation, while addition of 100 µM GA 3 ameliorated the toxic effect mainly to the shoot. The content of photosynthetic pigments significantly declined under Cu stress, whereas application of hormones led to a substantial preservation of chlorophylls and carotenoids. Under Cu stress, the rate constant of energy trapping by photosystem 2 (PS2) reaction centres (RCs) was reduced as a result of physical dissociation of the light-harvesting complex (LHC) from PS2 core, while application of IAA and especially GA 3 resulted in stability of the LHC of PS2 RCs. The drop in net photosynthetic (P N ) and transpiration (E) rates with preserved or slightly reduced variable to maximum fluorescence ratio (F v /F m ) in the presence of 80 µM Cu could be explained by a possible inhibition of the enzymatic processes in the Calvin cycle. Application of 100 µM IAA and 100 µM GA 3 lessened Cu effects mainly on P N . Water use efficiency was also improved under hormone exposure.

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Effect of excess Cu on the photosynthetic apparatus of runner bean leaves treated at two different growth stages

Cited by 20 publications

References 0 publications

Effects of copper and cadmium on photosynthesis in cucumber cotyledons

Effects of copper and cadmium on photosynthesis in cucumber cotyledons

Changes of photosynthetic parameters in cucumber leaves under Cu, Cd, and Pb stress

Hormone-induced protection of sunflower photosynthetic apparatus against copper toxicity

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