Effects of copper and cadmium on photosynthesis in cucumber cotyledons

Title:

Effects of copper and cadmium on photosynthesis in cucumber cotyledons

Creator:

Burzyński, M. and Żurek, A.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:17479ff4-0755-46fe-9a9b-981b8f839581
uuid:17479ff4-0755-46fe-9a9b-981b8f839581
issn:0300-3604
doi:10.1007/s11099-007-0038-9

Subject:

chlorophyll content and fluorescence, dithiothreitol, gas exchange, glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglyceric acid kinase, and stomatal conductance

Type:

model:article and TEXT

Format:

bez média and svazek

Description:

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; Fv/Fm), and photochemical and nonphotochemical quenching of Chl fluorescence (qP and qNP) was negligible. In contrast, a decrease of PS2 quantum efficiency (ΦPS2) 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 CO2 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. and M. Burzyński, A. Żurek.

Language:

Multiple languages

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Coverage:

239-244

Source:

Photosynthetica | 2007 Volume:45 | Number:2

Harvested from:

CDK

Metadata only:

false