Distribution of the cytoplasmic DNA in male cells of the Convolvulaceae and its systematic significance
旋花科植物雄性细胞的细胞质DNA存在状况及其系统学意义

The distribution of cytoplasmic DNA in generative and sperm cells of four species in four genera in the Convolvulaceae, i. e. , Calonyction aculeatum , Ipomoea aquatica , Quamoclit pennata and Cuscuta japonica, has been detected using DAPI fluorescent staining method. Cytoplasmic DNA is found to occur in generative and sperm cells of all the species except for Cuscuta japonica. This result, together with the previous reports that cytoplasmic DNA is also distributed in male cells of five species in Ipomoea, Pharbitis and Calystegia, may indicate that the presence of cytoplasmic DNA in generative and sperm cells is a general feature of the Convolvulaceae. The absence of such DNA in male cells in the genus Cuscuta supports the establishment of this genus as an independentfamily, the Cuscutaceae.