Study On The Genetic Diversity And Fruit Fatty Acid Of Symplocos Paniculata In HuNan Areas

Symplocos paniculata is a new woody oil plant, with highly fruit oil yield, oil content of fruit can reach as high as 36.6%.Utilization rate of the whole fruit can reach 100%. Symplocos paniculataadaptability is strong and can be vertical distributed between 80-2500 m in the mountains and valleys.Symplocos paniculata can also grow well in the barren mountains and land, which is the ideal tree for bioremediation. The seed oil contains two kinds of unsaturated fatty acid which are the human body essential.The two kinds of unsaturated fatty are oleic acid and linoleic acid and their content up to more than 70%. At the same time,the stearic acid content is low, so the oil of Symplocos paniculatais healthy and can be as edible vegetable oil.Meanwhile,it also can be the ideal raw material for biodiesel production.Therefore, the development and utilization of resources has good ecological, economic and social benefits. However, for a long time, Symplocos paniculata germplasm resources has been in the wild state. System evaluation of genetic diversity, improved variety breeding, germplasm conservation, fruit growth and the rule of accumulation of fatty acids is basically blank. For the full development and utilization of this wild resources, this paper lays the foundation for building Symplocos paniculata germplasm genetic diversity evaluation system, mining quality germplasm resources and establishing high quality germplasm preservation system and comprehensive utilization development system by surveying the resources which are mainly distributed in Hunan province, analysising the genetic diversity of Symplocos paniculata by using morphological markers and ISSR molecular markers,carrying out the Symplocos paniculata somatic embryo breeding technology research and studying the rule of Symplocos paniculata fruit growth and fatty acid accumulation.The main research conclusions are as follows:1.The main phenotypic traits observation and record method and character evaluation standard of Symplocos paniculata germplasm resources were improved and standardized.6 representative populations of Symplocos paniculata were selected from the regions where the Symplocos paniculata resources was concentrated.2.Symplocos paniculata in the natural population manifested rich morphological diversity. There are significant differences among populations and among individuals within populations. Phenotypical characteristic of tree body properties, fresh fruit grain, seed grain, longitudinal diameter of fruit had extremely significant difference and strong genetic differentiation.Tree form, petiole length, fruit shape index and fruit dense degree had low genetic differentiation. There were different degrees of difference within the population in addition to Symplocos paniculata from Daoxian.3.The experiment of single factor and orthogonal design was used to establish ISSR-PCR amplification system on Symplocos paniculate. An optimal reaction system contained total volume 20μL including template DNA at 80ng, Mg2+ at 3mmol/L, dNTP at 0.2mmol/L, radom primers at 0.5μmol/L, TaqDNA polymerase at 1.25U, 10×PCR Buffer at 2uL and ddH2O at 10.9μL.Then followed by 30 cycles each with pre-degeneration at 94 ℃ for 4 min, denaturation at 94 ℃ for 30 s, anneal at 54 ℃ for 45 s, extended at 72 ℃ for 90 s, extended at 72 ℃ for 7 min and preserved at 4℃. It could provide reference for genetic diversity analysis of Symplocos paniculata or similar species.4.5 primers with rich polymorphism were screened out and DNA diversity analysis was conducted within 68 Symplocos paniculata of 6 populations.74 ISSR markers were amplified from these clones with 73 polymorphic loci and polymorphism ratio was 98.65%.The expected heterozygosity (He) of 6 populations was ranged from 0.10949 to 0.24805, the maximumwas region B of Daweishan, data showed was 0.24805, the minimum was Hengshan, data showed was 0.10949. Hence, region B of Daweishan was abundant in genetic diversity and the population of Hengshan was high genetic identity.5.The results of UPGMA cluster analysis show that 6 populations were divided into three categories, the first major categories was region A and B of Daweishan and Hengshan population, the second major categories was Yueyang and Daoxian population, Longshan was separated into the third categories. The similar geographical provenance were easily clustered into one group, which was basically identical with morphological characters. Individual clustering analysis,68 samples were divided into 11 groups, basicallyaccording to geographical origin to clustering. But Longshan population was divided into 6 groups and different from others.6.The modified MS was the best basic medium for the immature embryo of Symplocos paniculata.Callus could be induced efficiently on the medium of GMS+0.2mg/L6-BA+0.1mg/LNAA,which was suitable for somatic embryogenesis. Somatic embryogenesis differentiation rate and proliferation rate on the medium of modified MS+0.25 mg/L6-BA+0.15 mg/LNAA can reach 71.99% and 76.56% respectively.The seedling percentage can reach 85% on the half of modified MS plusing 1.5% sugar.7.The rule of fruit growth in each group was consistent.The morphological development progress of fruit can generally be divided into three periods:fast growing of fruit size, slow growing of fruit size and the period of color change of pericarp.The oil accumulation began from the slow growing period and in the fruit color change period, the color of pericarp changed from green to purple. Oil content of fruit increased with the fruit growing up. At the fruit maturation period,the average oil content was 34.32%, the highest oil content was up to 36.6%(regionA of Daweishan),the lowest oil content was only 31.32%(regionB of Daweishan).8. Oil cells and parenchyma cells who have oil bodies were presented in the whole fruits and the main tissues where conducting oil accumulation were mesocarp, endosperm and embryo respectively.Fatty acid of Symplocos paniculata fruit oil was mainly composed of oleic, linoleic, linolenic,palmitic and stearic acid.There was a high correlation among oleic acid,linoleic acid and highest temperature, sunshine duration.