College of Life Sciences, Peking University, Beijing, China.
Int Rev Cell Mol Biol. 2013;304:1-55. doi: 10.1016/B978-0-12-407696-9.00001-4.
Sex is a universal phenomenon in the world of eukaryotes. Attempts have been made to understand regulatory mechanisms for plant sex determination by investigating unisexual flowers. The cucumber plant is one of the model systems for studying how sex determination is regulated by phytohormones. A systematic investigation of the development of unisexual cucumber flowers is summarized here, and it is suggested that the mechanism of the unisexual flower can help us to understand how the process leading to one type of gametogenesis is prevented. Based on these findings, we concluded that the unisexual cucumber flowers is not an issue of sex differentiation, but instead a mechanism for avoiding self-pollination. Sex differentiation is essentially the divergent point(s) leading to heterogametogenesis. On the basis of analyses of sex differentiation in unicellular organisms and animals as well as the core process of plant life cycle, a concept of "sexual reproduction cycle" is proposed for understanding the essential role of sex and a "progressive model" for future investigations of sex differentiation in plants.
性是真核生物界的普遍现象。人们试图通过研究单性花来了解植物性别决定的调控机制。黄瓜植物是研究植物激素如何调控性别决定的模式系统之一。本文总结了对单性黄瓜花发育的系统研究，并提出单性花的机制有助于我们理解如何阻止导致一种配子发生的过程。基于这些发现，我们得出结论，单性黄瓜花不是性别分化的问题，而是避免自花授粉的机制。性别分化本质上是导致异型配子发生的分歧点。基于对单细胞生物和动物性别分化的分析以及植物生命周期的核心过程，提出了“有性生殖周期”的概念，以理解性的基本作用，并为未来植物性别分化的研究提出了“递进模型”。
