Anthocyanins contents
Besides the color difference of buds at low temperature (Figure 1C, D), the mutant GS and the wild DH line PS have a different color of seeds and seedlings hypocotyl (Figure 1A, B). Although more than 600 anthocyanins have been reported, the core structures of anthocyanins, which could be absorbed in both visible lights and ultraviolet, have only six types that’s cyanidin, delphinidin, malvidin, pelargonidin, peonidin and petunidin (Saigo et al. , 2020). Total anthocyanin and six types of anthocyanidins were tested to check the content of anthocyanins and anthocyanidins in buds between GS and PS in cold winter (between 0 and 50 C). In this test experiment, a purple broccoli accession (PB) was used as a check to compare. As expected, the total anthocyanin content of the buds in PB was the highest among these three materials, while the total anthocyanin content in the buds of GS is about 66% of PS (Table 2). Cyanidin and delphinidin contents in GS were 45% and 26% lesser than in PS, respectively. Malvidin content was very low even in the purple broccoli sample and similar in PS and GS. In all broccoli samples, there were no pelargonidin, peoidin and petunidin (Table 2).
Table 2 Total anthocyanins and six types of anthocyanidins contents