Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky.
Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, Kentucky.
J Exp Zool B Mol Dev Evol. 2021 Dec;336(8):642-651. doi: 10.1002/jez.b.22981. Epub 2020 Jul 8.
Flowering plants (angiosperms) perform a unique double fertilization in which two sperm cells fuse with two female gamete cells in the embryo sac to develop a seed. Furthermore, during land plant evolution, the mode of sexual reproduction has been modified dramatically from motile sperm in the early-diverging land plants, such as mosses and ferns as well as some gymnosperms (Ginkgo and cycads) to nonmotile sperm that are delivered to female gametes by the pollen tube in flowering plants. Recent studies have revealed the cellular dynamics and molecular mechanisms for the complex series of double fertilization processes and elucidated differences and similarities between animals and plants. Here, together with a brief comparison with animals, we review the current understanding of flowering plant zygote dynamics, covering from gamete nuclear migration, karyogamy, and polyspermy block, to zygotic genome activation as well as asymmetrical division of the zygote. Further analyses of the detailed molecular and cellular mechanisms of flowering plant fertilization should shed light on the evolution of the unique sexual reproduction of flowering plants.
开花植物（被子植物）进行独特的双受精作用，其中两个精子细胞与胚囊中两个雌性配子细胞融合，以发育成种子。此外，在陆地植物进化过程中，有性繁殖的方式发生了巨大的变化，从早期分化的陆地植物（如苔藓和蕨类植物以及一些裸子植物（银杏和苏铁）中的游动精子，转变为非游动精子，通过花粉管输送到雌性配子中。最近的研究揭示了复杂的双受精过程的细胞动态和分子机制，并阐明了动植物之间的差异和相似之处。在这里，我们结合与动物的简要比较，综述了对开花植物合子动力学的当前理解，涵盖了从配子核迁移、核融合和多精入卵阻止、到合子基因组激活以及合子的不对称分裂。对开花植物受精的详细分子和细胞机制的进一步分析，应该能够揭示开花植物独特有性繁殖的进化。
