Ecological Strategy Of Endangered Plant Changium Smyrnioides Wolff

In this thesis, biological and ecological traits, reproduction, seeds dispersion, seeds germination and seedlings survivorship and growth of endangered plant Changium smyrnioides and its comparison plant Anthriscus sylvestri were carried out by theories and methods of population statistics and reproductive biology, we drew these conclusions:1. C. smyrnioides can capture light efficiently, and has a short soon growth season every year, for its biological and ecological traits such as structure character and especially growth season. C. smyrnioides are typically found in small population under the deciduous trees in subtropical evergreen broad-leaved forest, before other herbaceous species grow rapidly and impede sunlight they have finished their growth season. C. smyrnioides is not a shade-tolerant species, takes the escaping overshadow strategy. A. sylvestri has the distinct ability to expand densely and occupy extra horizontal and vertical space, so it can increase light absorption and out-compete other herbaceous. A. sylvestri takes the strong competition strategy and become the dominant species for long time in the community.2. C. smyrnioides and A. sylvestri take the different reproductive strategies: C. smyrnioides has sexual reproduction only, but A. sylvestri has both sexual reproduction and vegetative reproduction. C. smyrnioides and A. sylvestri populations both take the excessive flowers - few fruits strategy, but the total numbers of flowers, fruits, and seeds per plant of C. smyrnioides are less than A. sylvestri. C. smyrnioides emphasizes particularly on survivorship during the choice between procreation and survivorship, and allocate more production to individual growth; A. sylvestri pays attention to procreation, though individual has once sexual reproduction during the lifetime, it can take vegetative reproduction every year.3. The seed dispersal patterns of both species are contagious. Following time, the contagious distribution of C. smyrnioides changed to stochastic distribution; the pattern of A. sylvestri is still contagious, but the Lloyd index descends. The seed production of C. smyrnioides was much less than that of A. sylvestris, so the seed density of the seed bank from after dispersal to before the germination. Both the seed banks of the two species were uncontinue in time, C. smyrnioides maintained the seed bank by multi-procreation, while A. sylvestris by clone.4. Both of the two species seeds were dormancy during autumn and winter, and began to germinate in early spring. The results showed that temperature was a main factor affecting the seed germination of winter species such as C. smyrnioides and A. sylvestris. The germination temperature ranges of the both species were between5 and 15. At 15, the germination of two species seeds were inhibited; at 18 seeds almost could not germinate. The optimal temperature for germination of C. smyrnioides was 10; the optimal temperature of A. sylvestris was 5. The seed percent germination was correlated negatively to temperature. The change of daily temperature affected seeds germination, and the germination was increased with daily variety of temperature. Light was not a main factor for their germination, both of the two species seeds were not light sensitive, and there was little difference for germination in light and in dark. C. smyrnioides seeds lost their availability more easily than A. sylvestris in natural habitat. The optimal seed moisture content of C. smyrnioides (5.9%-6.4%) was higher than A. sylvestris <3.7 %) . The seed quality of C. smyrnioides was better than A. sylvestris, but the numbers of seeds were less than A. sylvestris. The difference of germination patterns of the two species is not obvious, and the germination process of C. smyrnioides is not the reason for it's endanger. Few seeds production was a weekly tache for population generation of endanger species.5. The survivorship and growth of C. smyrnioides seedlings are best under 65% RI, and this light condition is similar...