Chilling-Enhanced Photooxidation

Abstract

Chilling temperatures (5°C) and high irradiance (1000 microeinsteins per square meter per second) were used to induce photooxidation in detached leaves of cucumber (Cucumis sativus L.), a chilling-sensitive plant. Chlorophyll a, chlorophyll b, ,B carotene, and three xanthophylls were degraded in a light-dependent fashion at essentially the same rate.Lipid peroxidation (measured as ethane evolution) showed an 02 dependency. The levels of three endogenous antioxidants, ascorbate, reduced glutathione, and a tocopherol, all showed an irradiance-dependent decline. a-Tocopherol was the first antioxidant affected and appeared to be the only antioxidant that could be implicated in long-term protection of the photosynthetic pigments. Results from the application of antioxidants having relative selectivity for '02, 02-, or OH indicated that both '02 and 2-were involved in the chilling-and light-induced lipid peroxidation which accompanied photooxidation. Application of D20 (which enhances the lifetime of '02) corroborated these results. Chilling under high light produced no evidence of photooxidative damage in detached leaves of chilling-resistant pea (Pisum sativum L.). Our results suggest a fundamental difference in the ability of pea to reduce the destructive effects of free-radical and '02 production in chloroplasts during chilling in high light.

The protective function of the xanthophyll cycle in photosynthesis

“…In striking contrast, ethane production was observed to drastically increase during light stress at 3°C, thus indicating the occurrence of lipid peroxidation. Chilling-induced photooxidative lipid peroxidation was previously observed by Wise and Naylor [15] in chilled cucumber leaves.…”

Seasonal changes in antioxidants in red spruce as affected by ozone

“…The filtrate was dried under a stream of nitrogen and redissolved in 500-1000/«1 acetone prior to analysis. Separation was performed according to Wise & Naylor (1987), except that detection was at 290 nm.…”

Isolation, Chromosomal Localization, and Differential Expression of Mitochondrial Manganese Superoxide Dismutase and Chloroplastic Copper/Zinc Superoxide Dismutase Genes in Wheat1

“…Both chloroplasts and mitochondria can produce active oxygen species either under normal growth conditions or during exposure to various stresses. The PSI electron-transport chain contains a number of autooxidizable enzymes that reduce O 2 to superoxide (Badger, 1985; Asada and Takahashi, 1987; Asada, 1994), and evidence indicates that superoxide and H 2 O 2 can also be produced by PSII under high-light intensities (Landgraf et al, 1995).During mitochondrial respiration, reactive oxygen species are also generated via the reactions of the electrontransport chain (Rich and Bonner, 1978;Bowler et al, 1991).Active oxygen species are also generated during chemical and environmental stresses, including chilling and freezing (Wise and Naylor, 1987;Senaratna et al, 1988; Kendall and McKersie, 1989;Tsang et al, 1991;McKersie et al, 1993), drought (Perl-Treves and Galun, 1991; Price and Hendry, 1991), desiccation (Senaratna et al, 1985;Leprince et al, 1990), flooding (Hunter et al, 1983;Van Toai and Bolles, 1991), herbicide treatment (Malan et al, 1990; Kurepa et al, 1997), pathogen attack (Montalbini and Buonaurio, 1986; Buonaurio et al, 1987; Koch and Slusarenko, 1990), and ionizing radiation (Niwa et al, 1977).SODs are a group of metalloenzymes that protect cells from superoxide radicals by catalyzing the dismutation of the superoxide radical to molecular O 2 and H 2 O 2 . SODs are categorized into two families with unrelated DNA sequences.…”

“…Active oxygen species are also generated during chemical and environmental stresses, including chilling and freezing (Wise and Naylor, 1987;Senaratna et al, 1988; Kendall and McKersie, 1989;Tsang et al, 1991;McKersie et al, 1993), drought (Perl-Treves and Galun, 1991; Price and Hendry, 1991), desiccation (Senaratna et al, 1985;Leprince et al, 1990), flooding (Hunter et al, 1983;Van Toai and Bolles, 1991), herbicide treatment (Malan et al, 1990; Kurepa et al, 1997), pathogen attack (Montalbini and Buonaurio, 1986; Buonaurio et al, 1987; Koch and Slusarenko, 1990), and ionizing radiation (Niwa et al, 1977).…”