Fu Qiang, Sun Jie, Zheng Shaolin, Wang Xin
State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and CAS Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, China.
University of Chinese Academy of Sciences (UCAS), Nanjing 211135, China.
Plants (Basel). 2024 Aug 12;13(16):2239. doi: 10.3390/plants13162239.
Enclosed ovules are a reproductive feature restricted to angiosperms. Although this feature can be used as a criterion for identifying fossil angiosperms, how ovules are enclosed and the nature of the placenta are still foci of debates. A reason underlying these controversies is the lack of reproductive organ fossils shedding light on these issues. These controversies hinder a clear understanding of angiosperm evolution and systematics. Here, we report a new fossil ovary, gen. et sp. nov, from the Middle Jurassic of Liaoning, China. Our fossil clearly demonstrates the existence of ovules in that has a free central placentation. This new feature implies that a placenta in angiosperm gynoecia is homologous to an ovule/seed-bearing axis, and free central placentation is one of the early developed placentations. This discovery is apparently at odds with the current understanding of placentation and its evolution. Apparently, the understanding of angiosperms and their gynoecia should be updated with newly available palaeobotanical data.
封闭胚珠是被子植物特有的繁殖特征。尽管这一特征可作为鉴定化石被子植物的标准，但胚珠是如何被封闭的以及胎座的性质仍是争论的焦点。这些争议背后的一个原因是缺乏能阐明这些问题的生殖器官化石。这些争议阻碍了对被子植物进化和系统发育的清晰理解。在此，我们报道了一种来自中国辽宁中侏罗世的新化石子房，新属新种。我们的化石清楚地证明了具有游离中央胎座的子房内胚珠的存在。这一新特征表明，被子植物雌蕊群中的胎座与着生胚珠/种子的轴是同源的，游离中央胎座是早期发育的胎座类型之一。这一发现显然与目前对胎座及其进化的理解不一致。显然，应根据新获得的古植物学数据更新对被子植物及其雌蕊群的认识。
