Quenching of chlorophyll a fluorescence by oxygen in normal air in maize leaves grown under nitrogen deficiency conditions

Abstract

We have studied the influence of oxygen removal on the chlorophyll fluorescence induction in maize leaves, grown in control (C) and nitrogen deficient (-N) plots. The removal of oxygen from the air surrounding maize leaves led to the increase of all the fluorescence induction transients, in which the M1-maximum was most sensitive to the oxygen removal. The increase in the P-peak and M1-maximum was related to the relaxation of PSII and NADPH oxidation by oxygen through the PQ pool in normal air during adaptation of maize leaves to the exciting blue light. The oxidation of PSII and NADPH by oxygen involves the oxygen end (oxidation of PQ pool by oxygen) of chlororespiration, which was higher in the maize leaves in the -N plot. We concluded that the PQ pool oxidation by oxygen at the beginning of illumination prevents overreduction of the electron transport chain in maize leaves, when the activity of the Calvin cycle decreases. © Taylor & Francis Group, LLC.