Breakdown of photosynthetic pigments and lipids in spinach leaves with ozone fumigation: Role of active oxygens

摘要: In spinach (Spinacia oleracea L. cv. New Asia) plants fumigated with ozone in light, destruction of chlorophylls and carotenoids formation malondialdehyde (MDA), an indicator lipid peroxidation, were observed. Chlorophyll a leaves started to be broken down 6–8 h after the commencement 0.5 ppm fumigation, whereas MDA increased linearly for initial 8 fumigation followed by more rapid increase. leaf discs excised from 6-h plants, chlorophyll proceeded light but almost completely suppressed under anaerobic condition. Effects exogenously applied scavengers active oxygen species suggest that oxygens, especially superoxide radical (O2-), participated both MDA. Ozone reduced levels endogenous O2-, dismutase (SOD) L-ascorbate, one-half each 3.5 respectively. The results indicate photosynthetic pigments lipids oxygens accumulated as result ozone-induced physiological defense against toxicity. Activity polyphenol oxidase chloroplast membranes 4-h 240% level, suggesting thylakoid had been affected severely before pigment destruction. relations between disintegration thylakoids are discussed.