ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Runner bean plants (Phaseolus coccineus L., cv Piekny Jas) were treated with excess Cu (20 mg l−1 in the form of CuSO4.5H2O) at different stages of growth to investigate, 10 days after the element treatment, the effect of Cu on acyl lipid and polypeptide composition of the thylakoid membranes and their PSII photochemistry. The plants treated with Cu in the initial stage of leaf growth showed a strong reduction in the area and fresh weight of the primary leaves. The concentration of chlorophyll and acyl lipids slightly increased when calculated on leaf area or fresh weight basis. The decrease in individual acyl lipid classes expressed on chlorophyll basis was accompanied by lower accumulation of some extrinsic polypeptides of the oxygen evolving complex and decrease in PSll activity (80% of control). Chlorophyll a fluorescence measurements suggest an inhibitory effect of Cu on the acceptor side of PSII due to induced inhibition of the Calvin cycle and down-regulation of electron transport. However, plants treated with Cu by the end of the intensive growth stage of the primary leaves showed chlorosis and almost unchanged leaf area. Moreover, significant changes in acyl lipid content as well as a distinct loss of core antenna PSII polypeptides and oxygen evolving complex subunits were observed. Changes in chlorophyll a fluorescence parameters of the thylakoid membranes suggest that low PSII activity (50% of control) may result from an alteration both in the acceptor and donor sides of PSII and its reaction centre. The growth stage of plants in which Cu was applied to plants and the duration of Cu action appears to be of great importance for the interpretation of experimental data.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1994.tb03010.x
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