caa a22 4500 397521022 CHVBK 20180308164632.0 cr unu---uuuuu 161202e199509 xx s 000 0 eng 10.1093/jxb/46.9.1195 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.9.1195 Characterization of chilling effects on photosynthetic performance of maize crops during early season growth using chlorophyll fluorescence [Elektronische Daten] [James R. Andrews, Michael J. Fryer, Neil R. Baker] Changes in a range of chlorophyll fluorescence parameters were monitored for leaves of crops of three Zea mays cultivars (MO17, CB3 and LG11) during early canopy development when large fluctuations in air temperatures occur. Crops were sown on 1 May 1993 and measurements made between 17 May and 7 June. Measurements of the ratio of variable to maximal fluorescence of dark-adapted leaves (Fv/Fm) and the quantum efficiency of photosystem II photochemistry (φPSII), the efficiency of excitation energy transfer to open photosystem II reaction centres (Fv'/Fm') and the photochemical quenching coefficient (qP) for leaves operating at a photon flux density of 250 μmol m−2 s−1 were made during the day at 3 h intervals. Fluctuations were observed in Fv/Fm, φPSII and Fv'/Fm' throughout the period and significant decreases occurred during periods of low temperatures and high photon flux densities, indicating chill-induced photoinhibition of photosynthesis. Changes in Fv/Fm were highly correlated with changes in φPSII for all three cultivars. Measurements of φPSII, Fv'/Fm', qP and the quantum efficiency of CO2 assimilation (φCO2) at a photon flux density of 1000 μmol m−2 s−1 were made for leaves at 08.00 h each morning and demonstrated that changes in φPSII were highly correlated with changes in CO2 assimilation. Chill-induced changes in φPSII were shown to be correlated with changes in the quenching of excitation energy in the antennae of photosystem II and not with changes in the redox state of the electron acceptors of photosystem II. It is concluded that measurements of Fv/Fm and φPSII provide useful, rapid and non-invasive probes of the photosynthetic performance of maize leaves in the field during periods of chill-induced photoinhibition. © Oxford University Press RESEARCH PAPERS nationallicence Maize nationallicence Zea mays nationallicence chilling nationallicence chlorophyll fluorescence nationallicence photosynthesis nationallicence photon flux density nationallicence Andrews James R. Department of Biology, University of Essex, Colchester CO4 3SQ, Essex, UK aut Fryer Michael J. Department of Biology, University of Essex, Colchester CO4 3SQ, Essex, UK aut Baker Neil R. Department of Biology, University of Essex, Colchester CO4 3SQ, Essex, UK aut Journal of Experimental Botany Oxford University Press 46/9(1995-09), 1195-1203 0022-0957 46:9<1195 1995 46 exbotj https://doi.org/10.1093/jxb/46.9.1195 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.9.1195 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Andrews James R. Department of Biology, University of Essex, Colchester CO4 3SQ, Essex, UK aut NATIONALLICENCE 700 1- Fryer Michael J. Department of Biology, University of Essex, Colchester CO4 3SQ, Essex, UK aut NATIONALLICENCE 700 1- Baker Neil R. Department of Biology, University of Essex, Colchester CO4 3SQ, Essex, UK aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/9(1995-09), 1195-1203 0022-0957 46:9<1195 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford