Department of Botany and Microbiology, University of Oklahoma, 73019, Norman, OK, USA.
Planta. 1984 Nov;162(5):385-91. doi: 10.1007/BF00393450.
Pollen grains of Plumbago zeylanica L. were serially sectioned and examined using transmission electron microscopy to determine the three-dimensional organization of sperm cells within the microgametophyte and the quantity of membrane-bound organelles occurring within each cell. Sperm cells occur in pairs within each pollen grain, but are dimorphic, differing in size, morphology and organelle content. The larger of the two sperm cells (Svn) is distinguished by the presence of a long (approx. 30 μm) projection, which wraps around and lies within embayments of the vegetative nucleus. This cell contains numerous mitochondria, up to two plastids and, infrequently, microbodies. It is characterized by a larger volume and surface area and contains a larger nucleus than the other sperm cell. The second sperm cell (Sua) is linked by plasmodesmata with the Svn, but is unassociated with the vegetative nucleus. It is smaller and lacks a cellular projection. The Sua contains relatively few mitochondria, but numerous (up to 46) plastids and more microbodies than the other sperm. The degree of dimorphism in their content of heritable cytoplasmic organelles must at fertilization result in nearly unidirectional transmission of sperm plastids into just one of the two female reproductive cells, and preferential transmission of sperm mitochondria into the other.
使君子花粉粒经连续切片后，用透射电子显微镜观察，以确定小配子体中精子细胞的三维结构和每个细胞中出现的膜结合细胞器的数量。每个花粉粒中的精子细胞成对存在，但存在二态性，在大小、形态和细胞器含量上存在差异。两个精子细胞中较大的一个（Svn）的特征是存在一个长（约 30 μm）的突起，该突起缠绕并位于营养核的凹陷处。该细胞含有许多线粒体，多达两个质体，偶尔还有微体。它的体积和表面积比另一个精子细胞大，并且含有更大的核。第二个精子细胞（Sua）通过胞间连丝与 Svn 相连，但与营养核无关。它较小，没有细胞突起。Sua 含有相对较少的线粒体，但含有许多（多达 46 个）质体和比另一个精子更多的微体。在受精时，它们在可遗传的细胞质细胞器含量上的二态性必然导致精子质体几乎单向传递到两个雌性生殖细胞中的一个，而精子线粒体优先传递到另一个。
