Study On Living Environment And Seed Charateristics Of Cerasus Xueluoensis In Dawei Mountain In Hunan Province

Cerasus xueluoensis C.H.Nan&X.R.Wang,a unique Cerasus germplasm resource in China,is only found scattered and rare in Dawei Mountain in Hunan Province,Dayang Mountain in Zhejiang Province,Lushan Mountain in Jiangxi Province and Lichuan Mountain in Western Hubei Province at an altitude of 1100m¹500m.Axillary buds of C.xueluoensis are usually 3with white or pink,dense drooping flowers.Due to its low tree shape,early flowering,large amount of flowers,gorgeous colors and long flowering period,C.xueluoensis has extremely high ornamental value and potential scientific research value,and there is a serious phenomenon of stealing in folk areas,the germplasm resources need to be protected.Due to the high altitude and special climatic factors in the distribution area,the early introduction experiments were unsuccessful,especially the obstacles to seed germination,which brought difficulties to the further development and utilization of resources of C.xueluoensis.This study takes the natural population of Dawei Mountain in Hunan Province,which is representative of the distribution of C.xueluoensis,as the research object,reveal the ecological relationship between species and environment,community and environment through classification and sorting,and find out the environmental characteristics and species distribution rules of C.xueluoensis population suitable for survival.Meantime,targeted research on introduction and domestication,which explores the dormancy characteristics of C.xueluoensis seeds,analyzes the causes of seed dormancy and finds effective ways to break seed dormancy,so as to find suitable growth conditions for introduction and domestication of C.xueluoensis and provide the most basic technical support for further artificial breeding in the later period.?1?Community characteristics analysis:There are175 species belonging to 128 genera in73 families of vascular plants in the C.xueluoensis community in Dawei Mountain,Hunan Province,with few species and rich species composition.The flora consists of eastern subtropical and subtropical plant distribution areas,and subtropical evergreen broad-leaved forest has prominent attributes.SOM divides 24 quadrats into 4 community types.The associated species of C.xueluoensis population are mainly Rhododendron latoucheae and R.mariesii.The results of community characteristics analysis show that during the introduction and domestication of C.xueluoensis,community A with C.xueluoensis as the dominant species should be taken as a reference to ensure the light demand of C.xueluoensis.?2?Environmental interpretation of community:The distribution of plant species in the survival community of C.xueluoensis is mainly affected by total potassium.Community diversity is negatively correlated with soil organic matter and total potassium.Based on the results of CCA and SOM sorting,altitude is not the main reason affecting the population distribution of C.xueluoensis.The population distribution is mainly affected by soil organic matter,total phosphorus and available nitrogen.The population mainly grows in the forest edge area from shady slope to semi-sunny slope with high content of organic matter and total phosphorus.The results of community environmental interpretation show that the nutrient contents of organic matter,phosphorus and nitrogen should be paid attention to for the planting matrix of C.xueluoensis.?3?Seed dormancy:C.xueluoensis is a comprehensive dormant seed.The palisade layer and wax layer of seed coat lead to the barrier of seed coat permeability,but it is not the main cause of seed dormancy.Both the stock solution and diluent of methanol phase extract of seed coat and seed embryo can significantly hinder the growth of root length and seedling height of cabbage seeds.The key reason for the dormancy of C.xueluoensis seeds is that germination inhibitors in seed coat and embryo hinder seed germination,and the inhibition effect of germination inhibitors in seed embryo is greater than that in seed coat.?4?Dormancy breaking:The starch,dissoluble sugar,dissoluble protein,and ABA content decreased during seed dormancy to germination,ZR and GA content did not change significantly,and the ratio of IAA/ABA was the key factor affecting to the seed germination.The C.xueluoensis seed under stratification condition,treat with GA₃(150mg·L^-1)10h were suitable for germination.The conclusion of this paper shows that in the process of introduction and domestication,the cool environment should be selected in the stage of seed and seedling cultivation,the sufficient light should be guaranteed after the plant is grown,and the adequate supply of organic matter,phosphorus and nitrogen should be paid attention to in the soil matrix.At the same time,the best technical combination scheme of soaking seeds for 10 h at 5?and low temperature stratification and soaking seeds with 150 mg·L^-1GA₃ was adopted in seed treatment.