Cotton flower color changes dramatically after blooming
Three different flower color species were studied (Figure 2). YZ1 represents the most common cream-colored flower of G. hirsutum. T586 represents the red flower species, and 3-79 represents the yellow-colored flowers of G. barbadense. Flowers of these cotton species were collected from 11 am on the day of anthesis (0 DPA) to 6 am on the second day of anthesis (1 DPA) for analysis. All of the flowers changed the color during this period. Red pigment accumulated throughout the flower development (Figure 2A). The flower of YZ1 was cream at 11 am, and appeared a little bit red at 12 am, gradually accumulating to 6pm and then dramatically increasing color to 6 am on 1 DPA (Figure 2A). The flower of T586 was light red at 11 am, afterwards the red color deepened and the petal was dark red at 6 am on 1 DPA. Although the flower color of 3-79 was primarily yellow, red color was still emerged from the edge of the petal at 6 pm on 0 DPA and then increased further (Figure 2A). All of the flower color changes corresponded to an accumulation of anthocyanins (Figure 2B). T586 had about two times higher anthocyanin content than YZ1 and 3-79 during flower development in correspondence with its much intense color than the other species (Figure 2B). These results showed that anthocyanin biosynthesis was enhanced during flower development, conferring the petals with an intense red color. Dramatic anthocyanin accumulation occurred during the night of 0 DPA for YZ1 (Figure 2B).