Study On Protection And Breeding Of Germplasm Resources And Application In Plant Landscaping Of The Glyptostrobus Pensilis

Glyptostrobus pensilis is an ancient relic plant with precious genetic resources,known as"living fossil".However,limited by its biological characteristics and genetic diversity,as well as under the human activity interference and dual stress of ecological factors,the number of wild populations of Glyptostrobus pensilis is decreasing sharply.So,it has been listed as one of the endangered tree species by Chinese Plant Red Book.Therefore,it is imperative to carry out research work on the protection and breeding of germplasm resources of Glyptostrobus pensilis.Aiming at the shortcomings in the research field of germplasm conservation of Glyptostrobus pensilis,this study used plant tissue culture methods,molecular markers and plant landscaping methods to systematically carry out research on the protection and breeding methods of Glyptostrobus pensilis germplasm resources and explored the specific application methods of Glyptostrobus pensilis in plant landscaping.The results were as follows.Established immature embryo culture and tissue culture rapid propagation system of Glyptostrobus pensilis,and carried out field regression research.The study found that immature embryos of Glyptostrobus pensilis whose samples were collected from August to November were cultured in 1/2 DCR medium for 7-10 days to induce the development of intact plants and then obtained sterile seedlings of Glyptostrobus pensilis.Using hypocotyls of aseptic seedlings of Glyptostrobus pensilis as in vitro materials to be cultured on 1/2 MS supplemented with different concentrations of6-BA and NAA 0.5 mg/L medium can induce callus and indeterminacy bud,and then to establish a rapid reproduction system.The results showed that adventitious buds were induced on 1/2 MS+6-BA 2.0 mg/L+NAA 0.5 mg/L+VC 5.0 mg/L+sucrose 24.0g/L+agar 8.0 g/L medium,and the induction rate could reach 100%.The average number of adventitious buds induced by each hypocotyl could reach 2.4.The adventitious buds growing to 3-4 cm inoculated in 1/2 MS+IBA 0.1 mg/L+VC 5.0mg/L+sucrose 24.0 g/L+agar 8.0 g/L medium could effectively induce adventitious buds to produce root,and the rooting rate reached to 20%.They could be transplanted and refined after 40 days of rooting.After being cultivated in the nursery for 1-2months and returning to the wild environment,the plants could grow well,and the survival rate of returned seedlings reached 90%.Established and optimized the SRAP-PCR reaction system of Glyptostrobus pensilis,and based on which we could analyze the genetic diversity of source plants and offspring population.The results showed that the optimal SRAP-PCR reaction system of Glyptostrobus pensilis is that 100 ng DNA,0.4 mmol/L dNTPs,2.5 mmol/L Mg²⁺,1.5 U Ex Taq and 0.5?mol/L primers;or 140 ng DNA,0.3 mmol/L dNTPs,2.0mmol/L Mg²⁺,1.5 U Ex Taq,0.7?mol/L primers.Using the selected SRAP-PCR reaction system,18 pairs of primers with clear and large numbers of bands could be selected.And then the analysis of genetic diversity of the offspring population could reveal the genetic structure and degree of variation of the sexual offspring population.The results showed that the genetic variation coefficients of the two source plants P1and P2 was 0.9298,and the average genetic similarity coefficient between the source plant P1 and the offspring population was 0.7407,and the average genetic similarity coefficient between the source plant P2 and the offspring population was 0.7614,as well as the average similarity coefficient of offspring S1-S8 was 0.7676.It could be inferred that the degree of variation between the source plant P1,P2 and the offspring population were higher than the degree of variation between the source plant P1 and P2,and the genetic similarity between the offspring was also quite different.It was proved that the in vitro culture of immature zygotic embryos of Glyptostrobus pensilis could effectively improve the genetic diversity of the population of Glyptostrobus pensilis.The landscape planning design of Glyptostrobus pensilis community was carried out by using garden planning methods and related theories of plant landscaping.Based on the comprehensive consideration of plant ecological habits,spatial levels,and seasonal changes,and combined with the spatial atmosphere and landscape effects created by plants,there were 4 principles of planting designing and 5 levels of artificial structure of Glyptostrobus pensilis communities had been provided.A detailed planting design for the Glyptostrobus pensilis forest wetland area was provided in Jiatai Water and Wet Agricultural Park Project in Pingyao Town,Hangzhou City,and the designing results were visually presented in the form of drawings to provide ideas and references for the application practice of Glyptostrobus pensilis in garden landscaping and plant landscape construction.