The project was supported by NSFC.
1. Investigating the ecology environment and present situation of the endemic Cycas plants to Yunnan, especially the population structure and dynamics of C. Hongheensins and C. tanqingii. The results show that C. hongheensis is a critically endangered species because the number its individuals had decreased by 47% from 1992 to 2002 and no flowering and fruiting tree has found. While the population of C. tanqingii in Xiaoheijiang River is in a status of restoration because there are more young individuals and its age structure takes on the relatively stable shape of pyramid.
2. 5 species were karyomorphological studied for the first time, and the relationships among were discussed based on the karyomorphological data.
3. Study of the genetic diversity of C. guizhouensis and C. balansae complex using ISSR molecular marks. The genetic diversity of C.guizhouensis was low (P=35.90%, HT=0.1082), especially at population level (P=14.21%, He=0.0587) while the differentiation among populations was significant (Gst=0.4321). The members of C. balansae complex (C. balansae, C. tanqingii, C parvulus. C.simplicipinna and C. shiwandashanica) should be separated species based on the data of ISSR molecular markers.
4. 13 Cycas species were conserved ex situ in Kunming Botanical garden, 8 of which were conserved ex situ in Kunming Botanical garden for the first time. All but C. hongheensis grow well up to date.
Key waords: Cycas;Population structure and dynamics; ISSR; conservation genetics