打碗花生殖细胞、精细胞及卵细胞中的细胞质类核

CYTOPLASMIC NUCLEOIDS IN THE GENERATIVE CELL, SPERM CELL AND EGG CELL OF CALYSTEGIA HEDERACEA

已有不少超微结构的资料阐明被子植物双亲和单亲母系质体遗传的细胞学基础。近年应用DAPI荧光染色的方法,可快速地从检测质体DNA存在的状况确定被子植物中具双亲遗传潜能的种。从质体的类核存在与否判断质体遗传方式为母系遗传或双亲遗传与已有的遗传分析结论基本一致,只有少数种类是矛盾的。DAPI荧光技术可以认为是研究细胞质遗传机理的一个重要手段。我们曾证明旋花科牵牛属植物生殖细胞、精细胞中存在细胞质类核,确定其具双亲或单亲父系质体遗传的潜能,并用RFLP技术进一步确定其为质体父系遗传型。本研究证明旋花科的打碗花属生殖细胞、精细胞和卵细胞中细胞质类核存在的状况与牵牛属的相似,提供了打碗花可能在质体遗传上与牵牛属 具相同的遗传方式的资料。

Cytoplasmic nucleoids in the generative cell of mature pollens, sperm cells of pollens cultured in vitro and egg cell of mature embryo sac in Calystegia hederacea Wall, were studied by means of the DNA fluorochrome DAPI in conjunction with epifluorescence microscopy for in situ detection of cytoplasmic DNA in cells. Results showed that many cytoplasmic DNA nucleoids were present in the generative cell and sperm cells.Two types of nucleoids were observed,one with big and strong fluorescent dots, and the other with small and weak fluorescence. Many dot-shaped and a few circle-shaped nucleoids were randomly distributed in the thin layered cytoplasm of the egg cell. It was suggested that different types of nucleoids might represent plastid DNA and mitochondrion DNA respectively. Results provided cytological data that Calystegia hederacea had the potential of plastid DNA biparental inheritance, and the mode of which merits further study via molecular biological methods.