Oxidants and antioxidants during aging of Chrysanthemum petals.

BARTOLI CARLOS G; SIMONTACCHI MARCELA; MONTALDI EDGARDO; PUNTARULO SUSANA

PLANT SCIENCE

Elsevier

Año: 1997 vol. 129 p. 157 - 165

0168-9452

proteins. a-Tocopherol content increased at the onset of aging, and decreased as aging progressed. Total thiol content followed the a-tocopherol pattern during aging. Petals’ ascorbic acid content started to decline when the flowers were excised. Control petals were exposed to 1 mM paraquat during 24 h and neither the production of oxygen radicals nor the content of hydroperoxides were significantly affected by the treatment. Paraquat exposure did not significantly modified the activities of glutathione reductase and catalase, but superoxide dismutase activity was increased. n-Tocopherol content was not affected by paraquat. but total thiols content decreased by 50%. Flowers showing browning that involved 50-100% of the petal, were exposed to 1 mM paraquat over 24 h. The activities of superoxide dismutase, glutathione reductase, and catalase were not affected. Paraquat exposure led to a 3-fold increase in oxygen radical generation, and to a 59% increase in hydroperoxide content in aged petals. The data presented here suggest that oxidative stress and a concerted antioxidant response are associated with the initial stages of aging in Dendranthema mor$olium petals. 0 1997 Elsevier Science Ireland Ltd.