Diversity and evolution of reproductive organs in the tribe Desmodieae of Leguminosae

研究了豆科铁杉科花序、花和荚果的结构多样性，并推测了结构间的关系及其系统发育意义。花序结构研究了总状花序和假总状花序的结构关系。在总状花序的石斛属中，花沿花序轴各方向呈螺旋状排列，或只在花序轴的背面排列，或先在花序轴的背面排列，然后呈螺旋状排列。另一方面，在假花序状花序的其他属中，由花序轴上的苞片所支撑的部分花序内的花代表了限制在部分花序轴背面的排列或中间排列模式。因此，假定假总状花序的部分花序对应于总状花序。随着对生叶的大小和形态的减小，在单苞片中，被总状花序包围的茎的远端部分可以转变为假苞片。花的结构用形态学、解剖学和形态遗传学的方法研究了石杉科的两种花，即单型花和爆型花。除尾草属、碧萝丝属和乌拉尔属外，桔梗属、桔梗属、桔梗属均为爆炸型，而葡萄属、弯曲属、石斛属、桔梗属（仅尾草属）、金盏花属、胡枝子属、叶根属和塔德哈属均为简单型。形态学和解剖学观察表明，爆炸型翼与龙骨瓣通过龙骨瓣外侧的组织突起紧密融合，龙骨瓣翼与龙骨瓣的融合点到花瓣基部的长度比爆炸型翼长。这些特征与花瓣的爆炸密切相关。与分子系统发育树相比较，认为爆炸型花是由失去花蜜的简单型花进化而来的。花的结构是石斛属植物的重要分类特征。利用花的结构，已知物种的界限变得清晰，并在新几内亚从它们中区分出一个新种（Ohashi， Ye和Nemoto， in press）。豆荚结构研究了石杉科3个亚族25属68种石杉的豆荚结构多样性。果皮中厚壁组织层的位置、厚度和分布模式存在显著差异，果皮结构分为5种类型，节理结构分为5种类型。在此基础上，假设了果皮和节理结构的进化趋势，认为果皮结构最具特征，豆荚最先进。少

The structural diversity of inflorescences, flowers and pods were investigated in the tribe Desmodieae of Leguminosae, and then the relationships among structures and their phylogenetic implications were assumed.1. Inflorescence structureThe structural relationships between racemose and pseudoracemose inflorescences were examined. In genus Dendrolobium with racemose inflorescences, flowers are arranged in all direction of the inflorescence axis in spiral, only in the abaxial side of the axis, or first in the abaxial direction and then in spiral. On the other hand, in other genera with pseudoracemose inflorescences flowers in the partial inflorescence subtended by the bract borne on the inflorescence axis represent the arrangement restricted in the abaxial side of the partial inflorescence axis or the intermediate pattern of arrangement. Thus, the partial inflorescences of the pseudoracemes are assumed to correspond to the racemes. By reduction in size and form of the subtending leaves … More into the simple bract the distal part of shoot surrounded by racemes may be transformed into the pseudoraceme.2. Flower structureTwo types of flowers in tribe Desmodieae, that is, simple and explosive types, were examined morphologically, anatomically and morphogenetically. The explosive type was observed in genera of Alysicarpus, Christia, Codariocalyx, Desmodium except D.caudatum, Pycnospora and Uraria, while the simple type was observed in Aphyllodium, Campylotropis, Dendrolobium, Desmodium (only D.caudatum), Kummerowia, Lespedeza, Phyllodium and Tadehagi. Morphological and anatomical observations revealed that wings are tightly fused with keel-petals via a protuberance of tissues on the outside of the keel-petal in the explosive type, and that the length from the fused point to the base of petal is longer in keel-petals than wings in explosive type. These features are closely related with the explosion of petals. In comparison with a molecular phylogenetic tree the explosive type of flower was considered to be evolved from the simple type of flower involving the loss of floral nectaryThe flower structure was shown to be important as a taxonomic character in Dendrolobium. Using the flower structure the delimitation of known species becomes clear and a new species was distinguished from them in New Guinea (Ohashi, Ye and Nemoto, in press).3. Pods structureThe structural diversity of pods were examined on 68 species representative of three subtribe and 25 genera in tribe Desmodieae. There were noteworthy variations in the position, thickness and distribution pattern of sclerenchyma layer in the pericarp, and five types of pericarp structures and five types of joint structures were distinguished. On the basis of these types evolutionary trends of pericarp and joint structures were assumed, and the genus Alysicarpus has the most characteristic pericarp structure and was regarded as having the most advanced pod. Less