| Sorbus taishanensis belongs to the genus Rosaceae Sorbus,is a unique species in taishan,the current investigation of only one,has been included in the rare and endangered species directory of Shandong.It is of great significance to study the endangered mechanism of Sorbus taishanensis and to explore the effective protection measures for the protection of rare wild plant germplasm resources.In this study,the taxonomic status of Sorbus taishanensis was determined by morphological and molecular characterization.The natural habitat,climatic conditions,associated community characteristics,seed biology and physiology and ecology were studied in this paper.The endangered mechanism of Sorbus taishanensis was established,and reasonable and feasible protective measures were put forward according to its cause.The results are as follows:1.Morphological markers and DNA Barcodes molecular markers were used to study the taxonomic status of Sorbus taishanensis.Morphological markers were used to separate the leaves of the genus Sorghum and the leaf group.The results showed that ITS2,mat K and rbc L barcode can be separated from the outer group.The sequence of MP The trees are clustered together with the Subg.Sorbus species.The classification of Sorbus taishanensis was much higher than that of variants or subspecies,and it was supported as an independent species.2.Sorbus taishanensis habitat is located in Taishan Yuquan Temple area near the stone(E117 ° 05'0633,N36 ° 16'4627),the elevation of 1086 m above sea level,the growth space for the east high west low slope,the growth of space is small.The plots of east is the mountain,and the west is facing a cliff.The soil is thin and the roots are stony.The community type is coniferous and broad-leaved mixed forest,and there are 35 species belonging to 18 families and 35 genera in 100m2 samples.The dominant species are Pinus tabuliformis Carrière,Fraxinus rhynchophylla,Forsythia suspensa and Vitis amurensis Among them,Forsythia suspensa and Vitis amurensis have the greatest influence on its growth.Sorbus taishanensis is a small high bud plant,the community in the high buds up to about 50%.The surrounding communities of Sorbus taishanensis salsa were divided into tree layers,shrub layer,herb layer and Sorbus taishanensis is located in the lower layer of the tree layer.The rank of Patrick's richness index was herb layer> shrub layer> tree layer,Simpson dominance index was arbor layer> shrub layer> herb layer,Shannon-Wiener diversity index was shrub layer> tree layer> herbs Layer,Pielou evenness index is shrub layer> tree layer> herb layer.Sorbus taishanensis is at a disadvantage in the community,is not conducive to its survival and development.From the natural habitat analysis of Sorbus taishanensis,the topography and community have some influence on its growth and reproduction.3.The effect of ecological climatic conditions on the growth of Sorbus taishanensis was mainly due to the influence of extreme weather conditions on pollination,seed formation and fruit development.Too high air humidity affect the quality and yield of seeds in the period of fruit development;Higher humidity easily lead to rotten fruit,wind speed easily lead to early fall off the fruit in the period of fruiting.4.Studies on the seed biology of Sorbus taishanensis found that the fruit of Sorbus taishanensis was spherical pear,and the seed coat had no appendage.Compared with other sage plant seeds,Sorbus taishanensis seed thickness and width of the smallest seed seed weight of about 3.295 g,seed water content of 12.74%.Sorbus taishanensis seed development is not complete,full seed ratio is very low,only 3.2%;from the embryo anatomy,most of the embryo is not fully developed,and some even no embryo,embryo development of only 4.3%.TTC method measured the seed vigor was 0.26,and the staining is not obvious,very low vitality.Seed coat has little effect on the mechanical disorder of seed germination.Similar to other Sorbus plants,the natural germination rate of Sorbus taishanensis is very low,and its seed has deep dormancy,which is very difficult for its germination and reproduction.Poor seed development,poor quality of seed germ and low germination potential of seeds are important factors of endangered terrestrial.5.In this study,the petiole,shoot buds and seeds were used as explants for tissue culture and rapid propagation.The results showed that:(1)The callus induction of petiole was better on MS + NAA 0.1 mg/L +6-BA 1.0 mg/L or MS + NAA 0.1 mg/L +6-BA 2.0 mg/L medium(2)The stem segments with top buds as explant culture,which are better sterilization method is 75% alcohol for 40 s,mercury 4 min.The suitable for induction medium was WPM + IBA 0.05 mg/L +6-BA 1.0 mg/L,the late buds were susceptible to browning and rooting difficult,and the proliferation medium needed to be further explored.(3)The embryo culture was carried out with seeds as explants.The best disinfecting method was 75% alcohol for 15 s and mercury for 15 min.The appropriate induction medium was MS + 6-BA 0.5 mg/L + NAA 0.05 mg/L + Hydrolyzed casein 200 mg/L,and can promote its growth and development in the direction of cluster buds.Another temperature treatment is conducive to seed germination,while slowing the rate of endophytic bacteria growth.Sorbus taishanensis tissue culture technology system still need to further explore.6.According to the biological and ecological characteristics of Sorbus taishanensis and its living conditions,the technical scheme of protection of Sorbus taishanensis was put forward.One is to take on-site protection,naturalization,restoration of residual species and the establishment of in vitro preservation of gene pool and other measures to implement protection;the second is develop the environmental protection plan of Sorbus taishanensis;The third is to strengthen the physiological and environmental biology The fourth is to accelerate the legal construction of endangered plant protection and to strengthen public education.The fifth is to speed up the research process of specific rejuvenation measures to study the establishment of Sorbus taishanensis tissue culture technology system. |
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