走出歌德的阴影: 迈向更加科学的植物系统学

传统的植物学理论中, 被子植物雌蕊的基本单位心皮被认为是变态的叶(即大孢子叶)通过纵向对折和内卷演化而来。该理论造成了被子植物和裸子植物之间不可逾越的鸿沟。近年来提出的一统理论认为被子植物的心皮由长胚珠的枝和包裹这个枝的叶共同组成, 从而弥合了被子植物与裸子植物之间的鸿沟。最近, 当代植物学界两大权威人物Peter R. Crane和Peter K. Endress分别撰文, 发表了不同于传统理论的观点。Endress认为, 心皮由胚珠和叶性器官组成; 而Crane认为, 所有的胚珠都长在枝上。结合二者的结论, 不难得出“心皮实际上等同于一个长胚珠的枝加上一个叶”的论断。这在某种意义上等于认同了一统理论的观点。两位权威人物观点的转变预示着植物学理论将很快发生根本性的转变。该文向国内植物学同行通报这一最新动态, 以期让我国学者能够了解最新理论。

Stepping out of the Shadow of Goethe: for a More Scientific Plant Systematics

According to the Traditional Theory, a carpel (basic unit of angiosperm gynoecium) is derived from a modified leaf or megasporophyll through longitudinal folding and inward enrolling. Unfortunately, this theory introduces an unnegotiable gap between angiosperms and gymnosperms. Different from the Traditional Theory, the Unifying Theory provides a link bridging the gap mentioned above—an angiosperm carpel is derived from the synorganization between an ovule-bearing branch and an enclosing leaf. Recently two papers authored by leading botanists, Peter R. Crane and Peter K. Endress, respectively, expressed their opinions different from the Traditional Theory of angiosperm evolution. Endress stated that a carpel is result of synorganization between foliar part(s) plus ovule(s); and Crane stated that ovules/seeds are borne on the termini of branches. Combining the two, it is easy to infer that a carpel is equivalent to a foliar part plus an ovuliferous branch, a conclusion in line with the core conception of the Unifying Theory. The subtle changes in perspectives of these two leading botanists imply that there will be a major paradigm shift in botany soon. In order to make our botanists aware of the coming-soon changes in plant evolution theory, we summarize the latest progresses in relevant areas.