Poster: Oxidative stress
Abs #
87: Photooxidative injury and antioxidant metabolism in fruits of tomato mutants exposed to natural or reduced UV solar radiation
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Presenter: |
Torres, Carolina A, ctorres@wsu.edu |
Authors | Torres, Carolina A (A) Andrews, Preston K (A) | | Affiliations: |
(A): Washington State University
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Solar radiation can cause photooxidative damage when chlorophyll-containing tissue is incapable of coping with the absorption of excess solar energy. When this damage occurs on the surface of fleshy fruits it is referred to as sunscald, which can result in great economic losses. This type of photodynamic injury occurs especially on immature green fruit during high light and temperature conditions. In the present study we examined the physical (surface reflectance and chlorophyll fluorescence spectroscopy) and biochemical (reactive oxygen species, antioxidant metabolites and enzymes, and pigments) changes occurring in tomato (Lycopersicon esculentum Mill.) fruits during development of photooxidative injury in natural and reduced ultraviolet radiation (UV) environments. Several tomato genotypes with mutations in different antioxidant components were tested, including β-carotene (β) and high pigment-1 (hp). The development of photooxidative injury of immature green fruit, measured by surface reflectance and chlorophyll content, was directly correlated with radiation intensity and time of exposure. Less surface discoloration occurred when fruits were exposed to reduced UV radiation than when they were exposed to natural, high solar radiation. Fruit of β and hp showed significantly less discoloration than wild-type ‘Ailsa Craig’ fruit. The ratio Fv/Fm was found to be significantly higher in hp fruit than ‘Ailsa Craig’, and directly correlated with solar radiation intensity and time of exposure. Ascorbate levels were significantly higher in exocarp of hp fruit than all other genotypes. Changes in other metabolites, such as glutathione, antioxidant enzymes, and carotenoids, were also found among genotypes, UV, and other environmental conditions.
