The effect of copper on chlorophyll organization during greening of barley leaves |
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| Authors: | Caspi Varda Droppa Magdolna Horváth Gábor Malkin Shmuel Marder Jonathan B Raskin Victor I |
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| Institution: | (1) Department of Agricultural Botany, The Hebrew University of Jerusalem, Faculty of Agriculture, P.O. Box 12, Rehovot, 76100, Israel;(2) Department of Plant Physiology, University of Horticulture and Food Industry, P.O.Box 53, Budapest, H-1502, Hungary;(3) Department of Biological Chemistry, The Weizmann Institute of Science, P.O. Box 26, Rehovot, 76100, Israel |
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| Abstract: | The effect of copper on chlorophyll organization and function during greening of barley was examined, using chlorophyll fluorescence and photoacoustic techniques. Copper was found to inhibit pigment accumulation and to retard chlorophyll integration into the photosystems, as evident from low temperature (77 K) fluorescence spectra. Resolution of the minimal fluorescence (F0) into active and inactive parts, indicated a higher inactive fraction with copper treatment. This was attributed to chlorophyll molecules which failed to integrate normally, a conclusion supported by the longer fluorescence lifetime observed in copper treated plants. A lower ratio of chlorophyll a to b and fluorescence induction transients, showing accelerated Photosystem II closure, both indicate that copper treatment resulted in a larger light-harvesting antenna. Another effect of copper treatment was the suppression of oxygen evolution, indicating a decrease in photosynthetic capacity. We suggest that the non-integrated chlorophyll fraction sensitizes photodamage in the membrane, contributing to disruption of electron flow and pigment accumulation. |
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| Keywords: | chlorophyll fluorescence oxygen evolution photoacoustic photodamage Photosystem II |
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