2007 Fiscal Year Final Research Report Summary
Phylogeographic analysis on the disjunct distribution of rare vascular plants of the Ryukyus
| Project/Area Number |
17570083
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Biodiversity/Systematics
|
|---|
| Research Institution | University of the Ryukyus |
|---|
Principal Investigator |
YOKOTA Masatsugu University of the Ryukyus, Faculty of Science, Professor (90166885)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
DENDA Tetsuo University of the Ryukyus, Faculty of Science, Associate Professor (50284948)
|
|---|
| Project Period (FY) |
2005 – 2007
|
| Keywords | the Ryukyu Archipelago / disjunct distribution / Cycas revoluta / Ophiopogon reversus / Ophiorrhiza japonica var. amamiana / Oxygyne shinzatoi / Lonicera japonica var. miyagusukiana / Ligustrum tamakii |
|---|
| Research Abstract |
We confirmed the variation of seed morphology in Cycas revoluta (Cycadaceae) of the Ryukyus, however, variation in seed morphology had no geographical tendency and we could not recognize any interspecific taxa in C. revoluta based on seed morphology.
Karyotypes of Ophiopogon reversus (Convallariaceae) collected from four localities in Taiwan and one locality on Yonaguni-jima Island in the southern Ryukyus were reported for the first time. The karyotype of O. reversus was different from O. jaburan in having one pair of short submedian chromosomes with secondary constrictions at the proximal region of the long arms.
We examined the floral morph of tetraploid Ophiorrhiza japonica var. amamiana and diploid O. japonica var. japonica (Rubiaceae) to elucidate the association of distyly and ploidy levels. Chloroplast DNA phylogeny was reconstructed to determine the number of tetraploidization events and floral morph shifts in O. japonica. In cpDNA sequencing analysis, no haplotype was shared bet
… More
ween the two varieties. The cpDNA hap lotype network displayed the monophyly of O. japonica var. amamiana, suggesting a single origin of this variety. Because O. japonica var. amamiana having the morphological and cytological entity is recognized as a single lineage and clearly separated from O. japonica var. japonica, this variety can be considered to be a distinct species.
Hayataella (Rubiaceae) is a monotypic genus endemic to Taiwan that comprises H. michelloides. To elucidate the systematic treatment of Hayataella, molecular phylogenetic analyses based on nrDNA and cpDNA were conducted with four Ophiorrhiza species. In the Bayesian and the most parsimonious trees, H. michelloides was included in the Ophiorrhiza clade. The monotypic status of Hayataella is, therefore, not considered appropriate, and the combination Ophiorrhiza michelloides is supported.
The chromosome characteristics and molecular phylogenetic position of Oxygyne shinzatoi (Burmanniaceae) endemic to Okinawa Island were studied. The basic chromosome number of the genus was thought to be x=9. Based on the 18S rDNA sequence, O. shinzatoi was consistently found to belong to the monophyletic group of tribe Thismieae. Distance analysis from the most recent common ancestor indicated that O. shinzatoi had the lowest substitution rate among the species of tribe Thismieae. Combined with the basic chromosome numbers and the substitution rate characteristics, O. shinzatoi can be considered to be one of the basal taxon of tribe Thismieae. Less
|
