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Chlorophyll fluorescence and photoacoustic characteristics in relationship to changes in chlorophyll and Ca2+ content of a Cu‐tolerant Silene compacta ecotype under Cu treatment

par Ouzounidou, Georgia;Moustakas, Michael;Lannoye, Robert
Référence Physiologia Plantarum, 93, 3, page (551-557)
Publication Publié, 1995

Article révisé par les pairs

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Résumé :

The effect of Cu toxicity on photosynthetic function, chlorophyll and Ca2+ content of Cu‐tolerant Silene compacta plants grown in nutrient solution was studied. Since, in plants grown under 8 μM Cu, the chlorophyll and Ca2+ concentration as well as the photosystem II (PSII) photochemistry were increased, compared to the control, the development of an adaptive mechanism of the Cu‐tolerant ecotype of S. compacta to 8 μM Cu is suggested. Increased Cu tolerance of the S. compacta ecotype reflects modulation of the photosynthetic apparatus to optimize photosynthesis. However, exposure of plants to 160 μM Cu resulted in a marked increase of the fraction of closed PSII centres and decreased quantum yield of PSII electron transport (ΦPSU) which was accompanied by a significant decline of relative quantum yield for O2 evolution (Aox/Apt). The concentration of chlorophyll and Ca2+ in leaves also decreased significantly under 160 μM Cu treatment. Photochemical quenching (qp) displayed a reduction as a result of perturbation of the photosynthetic electron transfer chain, while non‐photochemical quenching (qN) increased. High Cu treatment reduced photosynthetic productivity of S. compacta plants which can be attributed, in part, to pertubation of photosynthetic process and photosynthetic pigments as well as to Ca2+ loss. Copyright © 1995, Wiley Blackwell. All rights reserved