圆瓣姜花花部维管束解剖及其系统学意义

Vascular System Anatomy of the Flower of Hedychium forrestii (Zingiberaceae) and Its Systematic Significance

摘要:

用石蜡切片技术研究了圆瓣姜花(Hedychium forrestii Diels)的花部维管束系统解剖结构，探讨了同源异形的各轮花器官维管束来源和属性。结果表明，圆瓣姜花的2枚花瓣状结构为外轮雄蕊成员；唇瓣是三重结构，其中脉源于1枚外轮雄蕊维管束系统，两侧脉源于2枚内轮雄蕊维管束系统；上位腺体为隔膜蜜腺。本研究支持Thompson和Gregory关于姜科唇瓣是三重结构的观点；与其他姜科植物一样，圆瓣姜花子房延长部形成的上位腺体属于隔膜蜜腺而不是雄蕊成员。与已研究过的姜花属植物比较，姜花属花器官维管束系统的来源与走向是一致的，同源异形现象在姜花属植物花的进化中扮演极为重要的角色，可为解释花器官属性提供重要线索。

Abstract:

The flowers of Zingiberaceae have higher degrees of organ fusion and specialization with one functional stamen and two lateral subsidiary structures, which result in controversial explanations on the derivation and nature of the floral organs. However, the origin and course of the floral vasculature may provide credible evidence to understand the nature of floral structures. This paper reported the floral anatomy of Hedychium forrestii Diels with paraffin method. The floral vasculature of H. forrestii is described and the nature of labellum and petaloid subsidiary structures is discussed. The labellum is supposed to represent one member of the outer androecial whorl by the median bundle and two members of the inner whorl by its two lateral traces. While the two petaloid structures, the petaloid staminodes, receive vascular traces of two adaxial sets of carpellary dorsals, representing two inner androecial members. Present evidence is in support of the Thompson and Gregory’s view that the labellum is a triple structure in Zingiberaceae. As in other species of Zingiberaceae, the epigynous glands on the prolongation of the flower in H. forrestii are vascularized emergences of the ovary, which are of modified gynoplural nectary but not androecial member. Comparison with other species studied, the origin and course of floral vasculature are consistent in the tribe Hedychium, which indicated that homeosis played an important role in the evolution of the flower in Zingiberaceae.