Effect of quercetin on electron transfer in photosystems I and II of pea chloroplasts

The effect of such flavonoid as quercetin and its oxidized from on electron transfer was studied in subchloroplast preparations of the Photosystem II (PS(2) and Photosystem I (PS(1)). Quercetin and its oxidized form are shown to inhibit the electron transfer in the PS(2) acceptor and donor sites, respectively. They also function as an electron donor or and electron acceptor in PS(1)), respectively