One half of the chamber with 35 broccoli heads was kept in complete darkness and the other half with the same number of samples was exposed to different continuous as well as periodic light intensities. The superficial colour of all heads was measured in order to select the best treatment. In a second set of experiments, 35 heads were either treated with the selected dose (12 μmol m−2 s−1) or maintained in the dark. After reading superficial colour, seven headsfrom light or dark treatment were segmented and the inflorescences were frozen using liquid nitrogen and stored at −20 ◦C until use