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Antioxidant metabolite levels in ozone‐sensitive and tolerant genotypes of snap bean
Author(s) -
Burkey Kent O.,
Wei Caimiao,
Eason Gwendolyn,
Ghosh Parthasarathi,
Fenner Gregory P.
Publication year - 2000
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.2000.110208.x
Subject(s) - ascorbic acid , ozone , antioxidant , phaseolus , glutathione , chemistry , vitamin c , peroxidase , horticulture , botany , vitamin e , food science , biology , biochemistry , enzyme , organic chemistry
Ozone‐sensitive and tolerant genotypes of snap bean ( Phaseolus vulgaris L.) were compared for differences in leaf ascorbic acid (vitamin C), glutathione and α ‐tocopherol (vitamin E) content to determine whether antioxidant levels were related to ozone tolerance. Seven genotypes were grown in pots under field conditions during the months of June and July. Open top chambers were used to establish either a charcoal filtered (CF) air control (36 nmol mol −1 ozone) or a treatment where CF air was supplemented with ozone from 8:00 to 20:00 h with a daily 12 h mean of 77 nmol mol −1 . Fully expanded leaves were analyzed for ascorbic acid, chlorophyll, glutathione, guaiacol peroxidase (EC 1.11.1.7) and α ‐tocopherol. Leaf ascorbic acid was the only variable identified as a potential factor in ozone tolerance. Tolerant genotypes contained more ascorbic acid than sensitive lines, but the differences were not always statistically significant. Genetic differences in glutathione and α ‐tocopherol were also observed, but no relationship with ozone tolerance was found. Guaiacol peroxidase activity and leaf α ‐tocopherol content increased in all genotypes following a one week ozone exposure, indicative of a general ozone stress response. Ozone had little effect on the other variables tested. Overall, ozone sensitive and tolerant plants were not clearly distinguished by differences in leaf antioxidant content. The evidence suggests that screening for ozone tolerance based on antioxidant content is not a reliable approach.