High light intensity protects photosynthetic apparatus of pea plants against exposure to lead

• Published in: Plant physiology and biochemistry Vol. 44; no. 5; pp. 387 - 394
• Main Authors: Romanowska, E., Wróblewska, B., Droƶak, A., Siedlecka, M.
• Format: Journal Article
• Language: English
• Published: Paris Elsevier Masson SAS 01.05.2006; Elsevier
• Subjects: Adenosine Triphosphate - metabolism; ATP-synthase; Biological and medical sciences; Cell Respiration - drug effects; Chloroplast and mitochondria activity; Chloroplasts - metabolism; Electron Transport - drug effects; Fluorescence; Fundamental and applied biological sciences. Psychology; Glycine - metabolism; Lead; Lead - pharmacology; Light; Metabolism; Mitochondria - metabolism; Mitochondrial Proton-Translocating ATPases - metabolism; Pea; Phosphorylation; Photosynthesis; Photosynthesis - drug effects; Photosynthesis - radiation effects; Photosynthesis, respiration. Anabolism, catabolism; Photosystem I Protein Complex - physiology; Pisum sativum - drug effects; Pisum sativum - metabolism; Pisum sativum - radiation effects; Plant Leaves - drug effects; Plant Leaves - metabolism; Plant Leaves - radiation effects; Plant physiology and development; Respiration; ATP-synthase; Fluorescence; MV; Φ PSII; OEC; Pea; NPQ; PFD; DBMIB; Lead; DCMU; Chloroplast and mitochondria activity; Photosynthesis; Respiration; F v/ F m; PBQ; qP; Enzyme; Growth; Toxicity; Plant leaf; Synthase; Stress; Heavy metal; Mitochondria; Photosystem; Leguminosae; Dicotyledones; Pisum sativum; Angiospermae; Spermatophyta; ATP; Chloroplast
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2006.06.003

The electron transport rates and coupling factor activity in the chloroplasts; adenylate contents, rates of photosynthesis and respiration in the leaves as well as activity of isolated mitochondria were investigated in Pisum sativum L. leaves of plants grown under low or high light intensity and exposed after detachment to 5 mM Pb(NO 3) 2. The presence of Pb 2+ reduced rate of photosynthesis in the leaves from plants grown under the high light (HL) and low light (LL) conditions, whereas the respiration was enhanced in the leaves from HL plants. Mitochondria from Pb 2+ treated HL-leaves oxidized glycine at a higher rate than those isolated from LL leaves. ATP content in the Pb-treated leaves increased to a greater extend in the HL than LL grown plants. Similarly ATP synthase activity increased markedly when chloroplasts isolated from control and Pb-treated leaves of HL and LL grown plants were subjected to high intensity light. The presence of Pb ions was found inhibit ATP synthase activity only in chloroplasts from LL grown plants or those illuminated with low intensity light. Low light intensity during growth also lowered PSI electron transport rates and the Pb 2+ induced changes in photochemical activity of this photosystem were visible only in the chloroplasts isolated from LL grown plants. The activity of PSII was influenced by Pb ions on similar manner in both light conditions. This study demonstrates that leaves from plants grown under HL conditions were more resistant to lead toxicity than those obtained from the LL grown plants. The data indicate that light conditions during growth might play a role in regulation of photosynthetic and respiratory energy conservation in heavy metal stressed plants by increasing the flexibility of the stoichiometry of ATP to ADP production.