Study On Community Characteristics And Seed Propagation Technique Of Endngered Species Bupleurum Dracaenoides

Bupleurum dracaenoides Huan C.Wang,Z.R.He&H.Sun(Umbelliferae),is a new species discovered in 2013,the larest woody plants in Asia,its height up to 1.5m.The distribution range of B.dracaenoides is so narrow that we can only found few discontinuous Vegetationlived of it in the middle and lower reaches of Jinsha River Valley in southwest china.It lives in a special habitat,and few in number.So far,the researches on biology and related studies of B.dracaenoides has not been carried on.Based on these,This paper comprehensively conducted a study on from community ecology and population biology,and emphatically conducted the artificial breeding and cultivation test.Aiming to reveal the community ecology,population biology,the growth period of growth characteristics,and to find a way possible expansion of artificial reproduction,to explore the optimum condition for artificial cultivation.eventually,to provide basic data for the population propagation,protection measures and conservation biology research of the endangered species.At same time,it laying the groundwork for the reasonable exploitation and utilization in the future.The results indicate that:1.The native vegetation of the distribution area of B.dracaenoides is mid-montane humit evergreen broadleaved forest.At present,it is limestone scrub or sparse irrigation grass.The survey about the 7 populations indicated that the community of the associated vascular plants has 51 families,90 genera,116 species in total.The vertical structure of community is simple,and it can be only divided into shrub layer and herb layer.The shrub species are few,but herb layer species are relatively abundant,given priority to with drought resistance and annual herb.The species composition and life types of the community are consistent with the environment of plateau monsoon climate.2.The 7 populations of B.dracaenoides showed it is a scattered distribution.The population structure was analyzed from two levels of plant basal diameter and growth period,the population size of the population of the nine Bay No.1(JDW1)was relatively large,and the population structure was relatively stable,Others are basically declining type.3.B.dracaenoides bears large inflorescences,has a long flowering period,at June-September,and it bear fruit at September-October.Only 1-6 strains in each population will flowering and bear fruits,but it has a high seed yield with about 20000 grains per plant on average.Its seed transmission is simple,and the diffusion range is small,mainly scattered in the plant near 5 meters,It is not conducive to the update and seedling seed germination as the harsh environment.4.Seeds have a dormant and morphological after-ripening period.The seed embryo is small and in an undifferentiated state in the current year,and the shape is heart-like.It needs to be developed for a period of time to become a mature embryo.By using different processing methods(different temperature,different concentration of gibberellin,different chemical reagents,ultraviolet radiation and microwave radiation)to handle its seeds,can effectively break the seed dormancy,contribute to the rapid development of mature embryo,and then improve the germination rate of seeds.The optimum temperature for seed germination was 20℃,and the germination rate of seeds in each group up to 70-83%,which was much higher than that in the control group.5.Under the indoor conditions,the seed germination rate is higher,the germination time is shorter,the seedling emergences are neat and strong.Within a year,the plant can grow to about 24cm,the leaf number can reach 27,the vigorous growth period mainly concentrated at June to September,before October,the plant height and leaf number slightly positive correlation;after that,the plants grew slowly,woody stems began to harden,lower leaves of the stem began to wither and fall off,the stem section closely.Then,the leaves were fascicled in the top.Compared to the wild habitats,plants in the interior grew very fast,which means it can be rapid propagated through artificial seed germination indoor.