In broccoli heads grown in spring and in autumn, and harvested at four various developmental stages antioxidant ability as well as certain indices of plant senescence were investigated. Development of broccoli heads was accompanied by losses of chlorophyll and ascorbic acid. At pre-florescence stage accumulation of soluble phenolics was observed. Activity of peroxidase in the initial stage of growth increased significantly and its high level was mantained during the whole growing period. The profound evolution of ethylene was manifested by plants of the pre-florescence stage.
In broccoli grown in spring the higher contents of chlorophyll and phenolics in comparison with the autumn experiment were observed, as well as slightly higher activities of peroxidase and catalase. Total antioxidant activity was considerably higher in spring than in autumn.