A phylogenetic study of primitive angiosperms

本研究从古植物学的观点和新植物学的观点对原始被子植物的生殖系统进行了研究。M.Nishida，H.Nishida，Suzuki和Takahashi从古植物学的观点和Tobe，上田，Kosuge和Oginuma从新植物学的观点进行了研究。H.Nishida在北海道的Kodaira-cho上白垩统采集到了一个可能是二叶植物的被子植物果实，并讨论了木兰花到二叶植物的进化途径; Suzuki分析了北海道和俄罗斯Saghalien上白垩统可能是最早的双子叶植物木化石，并描述了它们的木材结构细节; Takahashi鉴定了3种不同类型的花粉，包括来自俄罗斯Saghalien上白垩统的Clavatipollenites之一，此外，还鉴定了来自北海道下白垩统的8种不同类型的ephedroid花粉。Tobe和Oginuma在日本各地采集金鱼藻活体材料，分析其繁殖特征，首次发现2n=78和2n=120;上田和Kosuge都基于甘油醛-3-磷酸脱氢酶（gap A）的DNA序列分析了毛茛科作为原始被子植物的代表之一的系统发育，在这些研究中，我们积累了许多关于原始被子植物进化和形态学方面的信息。

In this research project, the phylogeny of primitive angiosperms was studied from a viewpoint of paleobotany by M.Nishida, H.Nishida, Suzuki, and Takahashi as well as from a viewpoint of neobotany by Tobe, Ueda, Kosuge, and Oginuma.M.Nishida collected a permineralized angiosperm fructification from the Upper Cretaceous of Monbetsu-cho, Hokkaido and described its reproductive structure similar to the one of Magnoliales and paleoherbs ; H.Nishida collected a possibly dileniid angiosperm fructification from the Upper Cretaceous of Kodaira-cho, Hokkaido and discussed an evolutionary pathway from a magnoliid flower to a dileniid one ; Suzuki analyzed the possibly earliest dicotyledonous wood fossils from the Upper Cretaceous of Hokkaido, and of Saghalien of Russia, and described details of their wood structure ; Takahashi identified 3 distinct types of pollen including the one of Clavatipollenites from the Upper Cretaceous of Saghalien of Russia and, in addition, 8 distinct types of ephedroid pollen from the Lower Cretaceous of Hokkaido.On the other hand, Tobe and Oginuma both collected living materials of Ceratophyllum from various places in Japan to analyze its reproductive features and found 2n=78 and 2n=120 for the first time ; Ueda and Kosuge both analyzed a phylogeny of Ranunculaceae as one of representatives of primitive angiosperms on the basis of DNA sequences of glyceraldehyde-3-phosphate dehydrogenase(gap A), and discussed a possibility that is is comprised of multiple gene component.In these researches, we have accumulated many various information on evolutionary and morphological aspects of primitive angiosperms.