Studies of reproductive morphological characters and early evolution in monocots in the light of molecular information

为了更好地了解基于分子数据的单子叶植物亲缘关系以及单子叶植物的早期进化，利用基生单子叶植物和相关类群对单子叶植物的生殖形态特征进行了研究。主要发现如下。石竹科(石见草目)具珠被闭孔(自形)和珠心闭孔(半形)。与已知的信息相反，天南星科(泽泻目)具有胚乳发育的细胞型。因此，泽泻目的进化很可能是从细胞型进化到日耳型，再从细胞型进化到核型。核桃科(薯科)有一个下位子房和一个隔蜜腺，这是该科的多形性。下位卵巢是真卵母细胞的同形突触，但从下位卵巢到上位卵巢的颠倒发生了多次。隔蜜腺普遍存在于单子叶植物中(石竹科除外)，在单子叶植物的进化过程中丢失了三次。此外，还讨论了花药壁的形成方式和种子结构(种皮和外胚乳)与单子叶植物进化的关系。

For better understanding of monocot relationships based on molecular data as well as of early evolution in monocots, reproductive morphological characters were investigated using basal monocots and related taxa. Major findings are as follows. Acoraceae (Acorales) have an integumentary obturator (as autapomorphy) and a nucellar obturator as a plesiomorphy. Contrary to previously known information, Araceae (Alismatales) have the cellular type of endosperm development. Thus, evolution is likely to have occurred from the cellular to the helobial type, and from the heobial to the nuclear type in Alismatales. Nartheciaceae (Dioscoreales) have an inferior ovary and a septal nectary as plesiomorphies in the family. The inferior ovary is a synapomorphy of eumonocots, but a reversal from the inferior to the superior ovary occurs many times. The septal nectary, which is prevalent in monocots (except in Acorales), is lost three times in evolution of monocots. Besides, anther wall formation mode and seed structure (seed coat and perisperm) were also discussed in relation to monocot evolution.