Font Size: a A A

Classification And Systematics Of The Stachyuraceae

Posted on:2007-07-21Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y P ZhuFull Text:PDF
GTID:1100360185994788Subject:Botany
Abstract/Summary:PDF Full Text Request
The family Stachyuraceae consists of a single genus Stachyurus and is endemic to East Asia. The present study examined its habits, morphology, pollen morphology including exine ultrastructure, floral organogenesis, and molecular phylogeny based on multiple regions of DNA sequences. We made a taxonomic revision combining all of the available data on the Stachyuraceae. The results have been summarized as follows:1. Habits and plant morphologyBased on extensive field work, literature survey and herbarium study, we did research on the morphological variations within and between populations, including habits, leaves, inflorescences, flowers, and fruits, and discussed their taxonomic implications. The results showed that some characters, such as shape of leaves and tooth number of leaf-margins, were not taxonomically reliant characters since they varied greatly within the same group; while the characters, such as hairs on leaves, venation of leaves, length and color of flowers or inflorescences, and length of fruits, were good characters for the classification of Stachyurus as they are usually stable.2. Pollen morphology and exine ultrastructurePollen exine ultrastructure of five species in Stachyurus and one species of its sister group, Crossosoma californicum, were investigated under transmission electron microcopy (TEM) for the first time. The pollen morphology of Crossosoma californicum was studied under Scanning Electron Microcopy (SEM). Combining the previous research on the pollen morphology, the present study indicated that: the plants of Stachyurus shared the common characters in pollen morphology and exine ultrastructure. Their pollen grains are subspheroidal to spheroidal, and germination aperture is 3-colpate; pollen exine has punctuate to foveolate sculpture; it is easy to distinguish exine and intine (except S. salicifolius); the columella is clear with few perforation in exine. Pollen characters do not support two sections below Stachyurus, but can be used as important characters in the species taxonomy. They also do not...
Keywords/Search Tags:Stachyuraceae, Stachyurus, Morphology, Palynology, Pollen exine ultrastructure, Floral organogenesis, Molecular systematics, Phylogenetic relationship, Taxonomic revision
PDF Full Text Request
Related items