Evolutionary study of one-leaf plants (Gesneriaceae)

单叶性表现在单叶类和链果属（苦苣苔科）中。它们的植物体由一个大的子叶组成。它们在整个生活史中从不形成茎或叶，它们在子叶片的基部产生花序。本研究旨在通过分子系统发育分析和比较形态发生研究来阐明单叶类的进化。研究材料不仅包括异生苦苣苔亚科，也包括等生苦苣苔亚科。它们是在婆罗洲、马来半岛包括泰国、马达加斯加、南非和巴西的三次植物学考察中收集的。苦苣苔亚科的胚保持在鱼雷期，种子萌发时或萌发后，根端和芽端分别从下胚轴尖和两子叶之间形成。茎尖生长太慢，不能形成营养芽，在单叶植物中，有一个不发育的分生组织，称为沟分生组织B ...更多信息 直接从生殖枝顶端脱落。沟分生组织被认为是同源的茎尖，而不是从头分生组织。子叶基部的基生分生组织的活动延长，从而产生子叶。基本分生组织的演化过程及其机制仍有待解决。然而，茎生种的Strepotocarpus和唇柱苣苔的形态分析表明，有一个相似的发育模式之间的大子叶和叶的，这两个叶生长主要是由于在基部的分生细胞。它们的叶没有明显的板状分生组织典型的其他双子叶植物叶。这似乎是可能的抑制板分生组织发生更强烈的子叶比叶，导致在建立的基础分生组织在anisocotylous苦苣苔亚科。总之，单叶植物可能是通过胚胎发生的延迟和随后的营养枝生长的抑制而进化的。少

Monophylly is exhibited in Monophyyllaea and in Streptocarpus (Gesneriaceae). Their plant body consists of a single large cotyledon. They never form stems or foliage leaves throughout their life history, and they produce inflorescences at the base of the cotyledon lamina. This research aims to clarify the evolution of the monophylly based on the molecular phylogenetic analysis and comparative morphogenesis. Research materials include not only anisocotylous Gesnerioideae but also isocotylous Cyrtandroideae. They were collected in Borneo, Malay Peninsula including Thai, Madagascar, South Africa, and Brazil on three botanical expeditions. The embryo of anisocotylous Gesnerioideae remains at the torpedo stage, and during or after seed germination the root apex and then shoot apex are formed from the hypocotyl tip and between the two cotyledons respectively. The shoot apex grows too slow to form the vegetative shoot, and in monophyllous plants a rudimentary meristem called groove meristem b … More ecomes directly the reproductive shoot apex. The groove meristem is considered to be homologous to the shoot apex, not a de novo meristem. The accrescent cotyledon is produced by the prolonged activity of the basal meristem located on the cotyledon base. The evolutionary course of the basal meristem and the underlying mechanism still remains to be solved. However, morphological analysis of caulescent species of Streptocarpus and Chirita shows that there is a similarity in the developmental mode between their large cotyledon and the foliage leaves ; the both leaves grow mainly due to the meristematic cells in the basal portion. Their foliage leaves do not have an apparent plate meristem typical of other dicotyledon-leaves. It seems likely that the suppression of the plate meristem occurred more strongly in their cotyledon than the foliage leaves, resulting in the establishment of the basal meristem in anisocotylous Gesnerioideae. In conclusion, one-leaf plants may have evolved through retardation of the embryogenesis and consequent suppression of the vegetative shoot growth. Less