彩色棉纤维中类黄酮的氧化与显色的机理研究

Naturally clored cotton is a special cotton with different fiber colour, such as brown, green, grey or yellow, which fibers do not need the dyeing process and can save the cost of production and alleviate the pollution to environment in textile industry, so it is called "eco-friendly cotton". Colour of cotton fibers is caused by biosynthesis, accumulation and coloration of pigments in fiber cells, and the pigments have been recognized to be flavonoids that are polyphenolic compounds. In the previously studies, we more focused to identify the molecular structure of flavonoids and relative genes, but less to study the coloration mechanism of flavoniods in cotton fiber. Previous reports and our researchs showed that the fiber coloration was resulted by flavoniod oxidation, because the colour of fibers on the ovules during in vitro cultivation can be inhibited by some inhibitors of flavonoid oxidases that are added in the culture media. Therefore, in this research project, we will use brown cotton, green cotton and white cotton(CK) as materials to study: (1) the redox features of flavoniods in colored cotton ribers, (2) the regulation of oxidases and genes of flavoniods on fiber coloration, (3) the regulating effects of anti- or pro-oxidants on fiber flavoniod oxidation and coloration, (4)the localization and transportation of flavoniod and its oxidases in different subcellular compartments. This research arms to provide theory and technology for the colored cotton breeding and for the colour modulation and fixation of textile.

彩色棉是纤维具有棕、绿、灰、黄等颜色的棉花，其纤维无需染色，既节省印染成本，又减轻染料对环境的污染，是一种"环保棉"。棉纤维的颜色是色素在纤维中合成、积累和显色的结果，而该色素被认为是一类多酚化合物- - 类黄酮。以往，多数研究偏向于类黄酮的鉴定和相关基因的克隆，缺乏对纤维显色机制的研究。文献报道和我们的研究均表明，彩色棉纤维中的类黄酮需要通过氧化才能显色，因为：在彩色棉胚珠（纤维）离体培养时，通过在培养基中添加氧化抑制剂，可抑制氧化酶的活性和类黄酮的氧化，使彩色棉纤维不显色。为此，本项目拟以棕色棉、绿色棉和白色棉（CK）为材料，研究（1）彩色棉纤维中类黄酮的氧化还原性能，（2）类黄酮氧化酶及其基因对纤维显色的作用，（3）氧化抑制剂（或促进剂）对类黄酮氧化和显色的调节，（4）类黄酮在纤维细胞内的氧化区域及其转运方式。其研究结果，可为彩色棉育种、纺织品调色和固色，提供理论和技术。

彩色棉是纤维具有天然颜色的棉花，无需染色，既节省生产成本，又减轻环境污染，是一种“环保棉”。棉纤维的颜色是色素在纤维中合成、积累和显色的结果，而色素被认为是一种非光合色素——类黄酮。以往，多数研究偏向于类黄酮的鉴定和相关基因的克隆，缺乏对纤维显色机制的研究。为此，本项目以棕色棉、绿色棉和白色棉（CK）为材料，研究了（1）彩色棉纤维中类黄酮的氧化还原性能，（2）类黄酮氧化酶及其基因对纤维显色的作用，（3）氧化抑制剂对类黄酮氧化和显色的调节等。研究结果表明，彩色棉纤维中的类黄酮需要通过氧化才能显色，而氧化主要是由3种氧化酶——儿茶酚氧化酶（Catechol oxidase）、漆酶（Laccase）和过氧化物酶（Peroxidase）摧化的，因为在彩色棉胚珠（纤维）离体培养时，通过在培养基中添加氧化抑制剂，可抑制氧化酶的活性和类黄酮的氧化，使彩色棉纤维不显色或颜色变淡。而且一些金属离子（Fe2+和Cu2+）通过促进氧化酶的活性及其类黄酮的氧化可使纤维提前显色。从而，本项目研究取得了两个方面的成果：一是首次提出了“彩色棉纤维细胞的显色是纤维色素——类黄酮在纤维细胞成熟过程中被氧化的结果”的理论，即：彩色棉显色机理可被描述为“棉纤维显色是类黄酮被氧化的结果” 的假说；二是发表了10篇学术论文。