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

对豆科山蚂蝗族花序、花和荚果的结构多样性进行了研究，并探讨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。总状花序的石斛属植物，花在花序轴的各个方向上呈螺旋状排列，或仅在花序轴的远轴侧排列，或先在花序轴的远轴方向排列，再呈螺旋状排列。另一方面，在具有假总状花序的其他属中，部分花序中的花被花序轴上的苞片包着，代表限制在部分花序轴的远轴侧的排列或中间排列模式。因此，假总状花序的部分花序被假定为对应于总状花序。通过缩小对着的叶子的大小和形状 ...更多信息 由总状花序包围的茎的顶端部分可转化为假总状花序，形成单苞片.花的结构对山蚂蝗族的两种花型，即简单型和爆发型，进行了形态解剖学和形态发生学的研究。爆发型的植物主要分布在Alysopus、Christia、Codariocalyx、Desmodium等属中，尾叶山蚂蝗属、密孢草属和乌拉草属除外;简单型的植物主要分布在无叶山蚂蝗属、Campylotropis、石斛属、Desmodium（仅尾叶山蚂蝗属）、鸡眼草属、胡枝子属、叶山蚂蝗属和Tadehagi等属中。形态解剖学观察表明，爆发型翅与龙骨瓣通过龙骨瓣外侧的组织突起紧密融合，融合点到花瓣基部的长度大于爆发型翅。这些特征与花瓣的爆裂密切相关。与分子系统发育树比较，认为爆裂型花是由单纯型花演化而来的，花的结构是石斛属植物重要的分类性状。利用花的结构，已知种的界限变得清晰，并在新几内亚区分了一个新种（Ohashi，Ye和Nemoto，出版中）。荚果结构研究了山蚂蝗族（Desmodieae）3个亚族25个属68种植物的荚果结构多样性。厚壁组织层在果皮中的位置、厚度和分布方式存在显著差异，果皮结构可分为5种类型，果皮结构可分为5种类型的连接结构。在此基础上提出了果皮和连接结构的演化趋势，并认为Alysopus属的果皮结构最具特征，角果发育程度最高。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