高等植物花色苷在液泡中的存在状态及其着色效应

摘要

综述了花色苷被摄入液泡的原因、花色苷在液泡中的存在状态及其对植物细胞的着色效应.花色苷在植物细胞质中合成后转运到液泡里是为了解除其对蛋白质和DNA等细胞功能分子的毒性.花色苷的液泡区隔化是花色苷在植物细胞中发挥正常功能的前提.在大多数植物中,花色苷在绝大多数情况下完全溶解在液泡里.但是,花色苷也能在液泡里形成颗粒,这些颗粒可以划分为花色苷体和花色苷液泡包涵体两类.花色苷体由膜包裹,其形成是液泡中小的有色囊泡逐渐合并的结果,发育完全的花色苷体为典型的球状、具比液泡更深的红色;液泡里的花色苷体具高密度,呈现为含高浓度花色苷的不溶性小球;花色苷体的存在可导致液泡的强烈色彩.花色苷液泡包涵体可能具备蛋白质基质,既无膜包裹又无内部结构,其形成是转运进液泡的花色苷与蛋白质基质结合的结果;液泡里的花色苷液泡包涵体形状不规则,象果冻;在花色苷液泡包涵体中,花色苷可能通过氢键连接于蛋白质基质的一个有限空间位点;花色苷液泡包涵体被认为是液泡中花色苷的"陷阱",优先摄取花色素3,5-二糖苷或酰化的花色苷;花色苷液泡包涵体的存在可增加液泡色彩的强度并导致"蓝化".%This review sums up the reasons of anthocyanins being sequestered into vacuole,the existent states of an-tbocyanins in vacuole and the corresponding coloration effects of anthocyanins on plant cells. Transporting of antho-cyanins from the biosynthesis site, namely the cytoplasm of plant cell, into vacuole is to detoxify the toxicity of antho-cyanins on the functional molecules of the cell, such as proteins and DNAs. The vacuolar compartmentalization of an-thocyanins is the prerequisite for anthocyanin function normally in plant cells. In a wide range of plant species and inmost cases,anthocyanins dissolve completely in vacuole. However, in vacuoles, anthocyanins can also form granuleswhich can be classified into two categories, namely anthocyanoplast (ACP) and anthocyaninic vacuolar inclusion(AVI). ACP is membrane-bounded, its formation is the result of the progressive coalescence of the smaller pigmentedvesicles in vacuole and fully developed ACP is typically spherical and more deeply red-colored than the vacuole. Invacuole, ACP is high density and insoluble globule highly concentrated with anthocyanins. The emergence of ACP canprovide intense coloration in the vacuole. AVI may be protein matrix and it possesses neither a membrane boundarynor an internal structure,its formation is the result of the antbocyanins transported into the vacuole bind with a pro-tein matrix. In vacuole, AVI is irregular and jelly-like in shape. In AVIs, the attachment of anthocyanins to the ma-trix protein is likely to be via H-bonds to a sterically restricted site. AVI is suggested to act as vacuolar anthocyanin"trap", preferentially for anthocyanidin 3,5-diglycosides or acylated anthocyanins. The emergence of AVI can en-hance color intensity and results in the "blueness" of color in the vacuole.