Study On Geographical Distribution And Seed Characteristics Of Sabina Squamata

Sabina squamata,also known as purple cypress（tree or shrub）,is an important timber,aromatic and greening plant with broad prospects for development and utilization.In the past,Zibai Mountain was one of its concentrated distribution areas.However,in modern times,due to excessive man-made development and utilization,the Sabina squamata on Zibai Mountain has been rare,resulting in population degradation.Therefore,in this study,the Sabina squamata community on Zibai Mountain Nature Reserve and Foping Nature Reserve was investigated,and the community characteristics of Sabina squamata were analyzed.At the same time,the potential distribution of Sabina squamata was predicted by Max Ent model,and the seed characteristics of Sabina squamata were studied in order to provide reference for the formulation of long-term regional ecological layout and tree species management,provide a theoretical basis for expanding the population of Sabina squamata and lay a foundation for the protection and sustainable management of Sabina squamata resources.The main research results are as follows:1.The Sabina squamata in Zibai Mountain Reserve and Foping Nature Reserve in Shaanxi Province is distributed at an altitude of 2400-2700 m,with poor site conditions and difficulties in natural regeneration.A total of 39 families and 72 genera and 75 species of plants were recorded in the sample plots of the distribution area.the main plants are Abies fargesii,Pinus armandii,Corylus heterophylla var.sutchuanensis,Betula albosinensis,Fargesia qinlingensis,Rhododendron concinnum,Spiraea mongolica,Salix pseudotangii,Potentilla glabra var.mandshurica,Eriophorum scheuchzeri,Oxalis griffithii,Aconitum pendulum,etc.Temperate genera are dominant in this community,accounting for 73.60%.The species diversity of the community is as follows:herb layer>shrub layer>tree layer.2.A total of 280 distribution data of Sabina squamata were collected.After screening and sorting,it is found that Sabina squamata is mainly distributed in Tibet,Yunnan,Sichuan,Gansu,Shaanxi,Hubei and other provinces and regions.The vertical distribution range is between 1800 and 4650 m.Environmental variables have different effects on the distribution of suitable growth area of Sabina squamata,and the decisive environmental variables are altitude and precipitation in the warmest season.The total potential suitable area of Sabina squamata currently accounts for 20.4%of China’s land area.The total potential suitable area of Sabina squamata will shrink in the future,and has a tendency to transfer to higher altitude.3.The seed of Sabina squamata is comprehensive dormancy,and the physiological post-ripening of seed,the obstacle of water permeability of seed shell and the endogenous inhibitor all affect the seed germination.Low temperature stratification after GA₃solution treatment can relieve the dormancy of Sabina squamata to some extent.In the process of seed stratification,the content of storage matter decreased in varying degrees,among which the treatment of soaking in 400 mg/L GA₃solution for 3 days combined with low temperature stratification decreased the most,indicating that the internal metabolism of seeds was the strongest.