Characterization of Pigmentation and Cellulose Synthesis in Colored Cotton Fibers

Abstract

Naturally colored cotton (Gossypium hirsutum L.) fibers (CCFs) are of interest in the textile industry because they require little dyeing and result in less environmental pollution. Pigmentation is one of the most important factors that differentiate CCFs from white cotton fiber (WCF) during fiber maturation. Many factors are involved in pigmentation, some of which we compared between CCFs and WCF with isogenetic backgrounds. These included the type of pigment, the activity of phenylalanine ammonia lyase (PAL), the concentration of total carbohydrates, and the type of soluble saccharide. We aimed to determine the causes of different fiber colors and found that flavonoids were the dominant type of pigment in the CCFs. At maturity (50 d post anthesis [DPA]), the WCF had only about 1/3 the amount of flavonoids as the brown cotton fiber (BCF) and 1/10 that of the green cotton fiber (GCF). During the course of fiber maturation (in particular, the stage before 8 DPA), CCFs had much higher PAL activity than the WCF. Of the fibers, the GCF had the highest concentration of carbohydrates over the course of maturation. However, higher concentrations of total carbohydrates did not always lead to higher concentrations of cellulose. This was very likely due to the synthesis of flavonoids and their derivatives consuming a large amount of carbohydrates that otherwise might be used for the synthesis of cellulose.