Seed Germination And Population Dynamic Charactersof An Rare And Endangered Plant Picea Neoveitchii

Picea neoveitchii Mast.?Pinaceae?,the unique species in China,is the grade two national protected wild precious plants,and also is the grade two national protected rare and endangered plants which has been listed in the Red Book in China.The P.neoveitchii population is very scarce in China,and its population is only distributed in the western Hubei,the south of Huxian,the northern slope of Qinling Mountains,the south of Huxian,the Tianshui and the white Longjiang basin in Gansuat 1300-2000 m above sea level.However,due to the excessive deforestation and human interference,the pure forest of P.neoveitchii is basically disappearing,the survival and growth of the remaining population is seriously threatened and is on the verge of extinction,which is urgent to be protected.In recent years,the endangered situation of P.neoveitchii has aroused great concern for scholars both at home and abroad,the related research mainly focused on the residual geographical distribution,community characteristics and other aspects of the seed morphology,but there are few studies on germination characteristics,population dynamics and so on.Therefore,this paper tries to break the dormancy of the seeds,explicit the necessary conditions for the seed germination and clarify the dynamic characteristics of the population through studying the seed germination characteristics,the breeding technology and the population dynamics of the seedlings.The aim is to provide theoretical basis and technical support for the large area multiplication of the population.The main results are as follows:1.There were significant differences in 1000 grain weight,empty shell rate,water content,viability,length,width and diameter at different altitudes and ages.The age of tree species has significant influence on seed weight,water content,length width ratio,and living power.It showed that there were diversity among seed morphology and some germination indexes at different ages,and the larger the age of tree species was,the decrease of empty shell rate and the greater decrease of living capacity was.Different concentrations of sulfuric acid treatment on seed germination rate and germination potential of P.neoveitchii had no significant effect.At normal temperature?20°C?,the seed germination rate of P.neoveitchii was 0%after being soaked in distilled water and concentrated sulfuric acid;while using 200mg.L^-1gibberellin?GA₃?to treat 42 ages of P.neoveitchii seed 24h,the seed germination rate reached to 70%in 14d and neatly germinated.The greater the age of tree species was,the lower the germination rate was.In spite of this,30%of the seeds were still dormant,which showed that the dormancy of the seeds was integrated,and the seed permeability was not the main cause of the dormancy of the seeds.2.The survival rate of cutting and grafting of P.neoveitchiiwas 0%by cutting and grafting techniques.The study on seed breeding technology of P.neoveitchii showed that the seeds germination rate of 42 ages tree treated with 200 mg.L^-1 GA₃reached to 70%,and the highest and lowest seedling rate were 53.5%and 25.4%,respectively,in different age trees of different altitude.Moreover,it has formed the breeding technology and improved seedling survival rate in the seed germination,shading,seedling diseases and insect pest's prevention and control,watering,fertilization,weeding and other aspects.3.The risk rate,mortality and survival rate of the population were calculated,the corresponding curve was drawn and also a specific time life table was compiled.through the investigation and survival analysis of the endangered plants population in Gansu chagangliang nature reserve.The survival curve of the P.neoveitchii population belongs to Deevey-II.In the age structure,the seedlings and young trees of the population were lacking,the proportion of the adult trees was large and showed spindle shape distribution in P.neoveitchii population.The population dynamics of the population was small,the distribution range was narrow,the population of the young forest was few and population development was declined sharply in the early stage,middle aged trees increased and opulation was relatively stable,and old aged trees were little and the population dried up and exhausted.