| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥900,000 (Direct Cost: ¥900,000)
|
|---|
| Research Abstract |
The relationships between reproductive sysytem and genetic diversity were analyzed by field observation of reproductive ecology and electrophoretic study of allozymic variation in several aquatic macrophyte taxa.
1. Plants repoduced exclusively by vegetative reproduction : The study of Egeria and Elodea, both of which are introduced plants and reproduce by plant fragments, revealed no genetic polymorphism, suggesting the spread of the rametes of the same clone.
2. Plants which usuallly reproduce vegetatively but sometimes reproduce sexually : Hydrilla verticillata, in which sexual reproduction is limited to some special situations, usually show no polymorphism within the populations, but the occurrence of a toal of 27 genotypes was confirmed. Rare chances of sexual reproduction were considered to bring about the increase of genetic diversity. In case of Lemna minor, only five genotypes were found throughout Japan. This fact supports the view that this species almost exclusively reproduce clonally.
3. Plants with both sexual and vegetative reproduction : Typha angustifolia, an outbreeding species, showed more diverse genetic variation than T.latifolia, an inbreeding species. It was also shown in T.angustifolia that the populations of seedlings had higher level of genetic diversity than the adult populations.
4. Plants with sexual reproduction only : In Trapa, 20 genotypes were confirmed. However, this diversity seemed small as compared with enormous variaty of fruit morphology. This may be a special case of Trapa.
|
