Correlations between Antioxidative Enzyme Activities and Antioxidative Substrates and Senescence ir Broccoli (Brassica oleracea L.) Flower Buds at Different Storage Temperatures

Abstract

Changes in the antioxidative enzyme activities and substrates of broccoli (Brassica oleracea L.) flower buds stored at 8, 16 and 24°C were investigated; the correlations between senescence and these functions are discussed. The chlorophyll and protein content decreased with time; the rate of decrease was faster at the high temperature than at lower ones. The malondialdehyde content increased with increasing temperature and time. The correlations between these senescence indices and antioxidative enzyme activities differed with storage temperature. At 8°C, senescence did not progress; no relation was observed. However, at 16TC, catalase (CAT) and ascorbate peroxidase (APX) were related to the senescence indices, whereas superoxide dismutase (SOD), CAT, APX and peroxidase (POX) were highly correlated to them at 24°C. However, at all temperatures high correlations between the senescence indices and content of antioxidative substances, such as ascorbic acid and /3 -carotene, existed. These results indicate that increasing antioxidative enzyme activities and the concurrent reduction in substrates are closely related to senescence of broccoli flower buds.