Reproductive Allocation of Dendrobium sinense,an Endemic Orchid Species to Hainan Island

Key words: 
• Dendrobium sinense /
• age class /
• clonal growth /
• reproduction allocation

Abstract: Dendrobium sinense is a perennial epiphytic orchid,which belongs to the genus of Dendrobium and the family of Orchidaceae.Under nature conditions,D.sinense has a low seed setting rate and the environmental requirements for seed germination is very stringent.Besides sexual propagation,asexual ways like clonal propagation is also found in D.sinense.In this study,five transects were set up in Bawang Ridge of Hainan Province to monitor the dynamic change of D.sinense population and study the reproductive allocation rules of D.sinense plants at different age,in order to supply scientific evidence for the conservation of epiphytic orchids.The results showed that during the whole life history of D.sinense,individuals with at least four pseudobulbs could have sexual reproduction,and the investment paid into sexual reproduction increased year by year.Whereas,the clonal propagation of D.sinense was not limited by individual size.According to the ratio of reproductive organ biomass to total biomass,the proportion of resources devoted to reproductive activities was maintained at about 27% through the whole life history.Clonal reproduction was found always being the dominant ones between the two reproduction methods.