Relationship between CO2 assimilation, photosynthetic electron transport, and active O2 metabolism in leaves of maize in the field during periods of low temperature

• Published in: Plant physiology (Bethesda) Vol. 116; no. 2; pp. 571 - 580
• Main Authors: Fryer, M.J. (University of Essex, Essex, UK.), Andrews, J.R, Oxborough, K, Blowers, D.A, Baker, N.R
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01-02-1998
• Subjects: ACIDE ASCORBIQUE; ACIDO ASCORBICO; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Agronomy. Soil science and plant productions; ANALISIS CUANTITATIVO; ANALYSE QUANTITATIVE; ANTIOXIDANTES; ANTIOXIDANTS; ANTIOXYDANT; ASCORBIC ACID; Biological and medical sciences; CELL MEMBRANES; CHILLING INJURY; Chlorophylls; COLD; Cooling; Corn; DEHYDROASCORBIC ACID; Economic plant physiology; ELECTRON TRANSFER; Enzymes; ENZYMIC ACTIVITY; ESTRES; FEUILLE; FOTOSISTEMAS; FRIO; FROID; Fundamental and applied biological sciences. Psychology; GLUTATHIONE REDUCTASE (NAD(P)H); HOJAS; LEAVES; LIPID PEROXIDATION; LIPOXIGENASA; LIPOXYGENASE; Low temperature; MEMBRANAS CELULARES; MEMBRANE CELLULAIRE; METABOLISM; METABOLISME; METABOLISMO; Net assimilation, photosynthesis, carbon metabolism. Photorespiration, respiration, fermentation (anoxia, hypoxia); Nutrition. Photosynthesis. Respiration. Metabolism; OXIDOREDUCTASES; OXIDOREDUCTIONS; OXIDORREDUCTASAS; OXIGENO; OXIRREDUCION; OXYDOREDUCTASE; OXYDOREDUCTION; OXYGEN; OXYGENE; PEROXIDACION LIPIDICA; PEROXIDASAS; PEROXIDASES; PEROXYDASE; PEROXYDATION DES LIPIDES; Photosynthesis; Photosynthesis, respiration. Anabolism, catabolism; PHOTOSYSTEM II; PHOTOSYSTEME; PHOTOSYSTEMS; Plant physiology and development; Plants; QUANTITATIVE ANALYSIS; REINO UNIDO; ROYAUME UNI; SINTOMAS; STRESS; STRESS RESPONSE; SUPEROXIDE DISMUTASE; Superoxides; SUPEROXIDO DISMUTASA; SUPEROXYDE DISMUTASE; SYMPTOME; SYMPTOMS; TOCOFEROLES; TOCOPHEROL; TOCOPHEROLS; UNITED KINGDOM; Whole Plant, Environmental, and Stress Physiology; ZEA MAYS; United Kingdom; Europe; Assimilation; Oxidative stress; Monocotyledones; Zea mays; Carbon dioxide; Electron transfer; Lipids; Plant leaf; Antioxidant; Cereal crop; Field experiment; Photosystem 2; Gramineae; Angiospermae; Spermatophyta; Photosynthesis; Sandy loam soil; Low temperature; Peroxidation
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.116.2.571

Measurements of the quantum efficiencies of photosynthetic electron transport through photosystem II (phi(PSII)) and CO2 assimilation (phi(CO2)) were made simultaneously on leaves of maize (Zea mays) crops in the United Kingdom during the early growing season, when chilling conditions were experienced. The activities of a range of enzymes involved with scavenging active O2 species and the levels of key antioxidants were also measured. When leaves were exposed to low temperatures during development, the ratio of phi(PSII)/phi(CO2) was elevated, indicating the operation of an alternative sink to CO2 for photosynthetic reducing equivalents. The activities of ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase, and superoxide dismutase and the levels of ascorbate and alpha-tocopherol were also elevated during chilling periods. This supports the hypothesis that the relative flux of photosynthetic reducing equivalents to O2 via the Mehler reaction is higher when leaves develop under chilling conditions. Lipoxygenase activity and lipid peroxidation were also increased during low temperatures, suggesting that lipoxygenase-mediated peroxidation of membrane lipids contributes to the oxidative damage occurring in chill-stressed leaves