Assayedcontinuous light intensities were 12, 25 and 50 μmolm−2 s−1,using 40W white light fluorescent tubes, while experiments withdiscontinuous illumination were performed with a photoperiodof 16 h light/8 h dark using 25 μmolm−2 s−1 light. Superficialcolour was measured daily in all broccoli heads. Samples wereplaced in a well-ventilated chamber isolated from external lightsources at 22 ◦C.