Carde J P
Eur J Cell Biol. 1984 May;34(1):18-26.
Non-pigmented plastids were observed in fully differentiated cells from leaves and stem tissues of various species. Although showing important differences in size and shape, these plastids exhibit permanent structural features which allow to get them together as a distinct kind of organelles: the leucoplasts. Leucoplasts are distinct from the proplastids and every intermediate stage of plastid differentiation, from white chromoplasts and tuber amyloplasts. Mature leucoplasts do not contain an autonomous central system of thylakoids structurally independent from the envelope and, therefore, are never green. However, the envelope inner membrane invaginates within the plastid a cisternal or tubular stroma reticulum connected with the intermembrane space of the envelope. In addition, the leucoplast stroma is often less dense than chloroplasts stroma and contain several nucleoids with DNA fibrils. However, 70S ribosomes either scattered in the stroma or attached to the stroma reticulum or the envelope are not visible in ultrathin sections of leucoplasts stained with uranyl and lead. The existence of more discrete particles as dense as ribosomes is suggested. The relationship between the absence of ribosomes and thylakoids is discussed. Except for their specific role in C10 monoterpene synthesis in glandular cells, the functions of leucoplasts in plant cells remains largely up to now a matter of conjecture.
在来自各种物种叶片和茎组织的完全分化细胞中观察到了无色素质体。尽管这些质体在大小和形状上存在重要差异，但它们表现出一些永久性的结构特征，这使得它们能够被归为一种独特的细胞器：白色体。白色体不同于前质体以及质体分化的每个中间阶段，也不同于白色质体和块茎造粉体。成熟的白色体不包含一个在结构上独立于包膜的自主类囊体中央系统，因此，它们从不呈绿色。然而，包膜内膜在质体内内陷形成一个与包膜膜间隙相连的扁平囊状或管状基质网状结构。此外，白色体质体基质通常比叶绿体基质密度小，并且含有几个带有DNA纤维的类核。然而，在用铀酰和铅染色的白色体超薄切片中，无论是分散在基质中、附着在基质网状结构上还是附着在包膜上 的70S核糖体都不可见。有人提出存在更致密的离散颗粒，其密度与核糖体相当。文中讨论了核糖体和类囊体缺失之间的关系。除了它们在腺细胞中C10单萜合成中的特定作用外，白色体在植物细胞中的功能至今在很大程度上仍是一个猜测的问题。
