| Pteroceltis tatarinowii is a unique fiber tree species in China and an important material for Xuanpaper.In this study,three fine individuals of Pteroceltis tatarinowii were selected after primary and secondary selection in Jingxian County,Anhui Province.The techniques of seed germination and cutting of Pteroceltis tatorinowii were also discussed.The main results are as follows:(1)Plus tree selection for bark of Pteroceltis tatarinowii:On the basis of investigating the germplasm resources of Pteroceltis tatarinowii in Jingxian County,Anhui Province,taking large growth,long fiber length of bark,large fiber length-width ratio and high content of cellulose as the main indexes for selection,the criteria for selection of Pteroceltis tatarinowii were put forward for the first time as follows:strong tree,disease-free and insect pest-free,sprout volume of more than 0.20 m3,fibre length of more than 2900μm,ratio of fiber length to width of more than 275.The primary selection was carried out by using the method of 3 dominant trees,and the repeated selection was carried out according to the fiber morphology,and three plus trees of Pteroceltis tatarinowii were finally selected according to the fiber composition.They were Pteroceltis tatarinowii No.1,Pteroceltis tatarinowii No.5 and Pteroceltis tatarinowii No.20,which grew in Xiangyang Village,Yangong Guba,Jingchuan Town,and Gaoshan Village,Tingxi Town,respectively.(2)The main fine traits of the plus tree:Pteroceltis tatarinowii No.1 has the largest sprout volume,and Pteroceltis tatarinowii No.5 has the highest cellulose content and the largest sprout volume.Pteroceltis tatarinowii No.20 has the longest fiber length,the largest aspect ratio and the lowest lignin content.The sprouts of superior plants have large volume,high content of holocellulose and cellulose,and low lignin.The average basal diameter of sprouts of superior plants was 4.70 cm,the average cross-sectional area of sprouts was 455.03 cm2,the average length of sprouts was 6.82 m,and the average volume of sprouts was 0.99 m3.The fiber length,fiber width and ratio of fiber length to width of bark were 3021.49 μm,10.84 μm and 282.02 respectively.The length of bark fibers mainly concentrates between 2800-3400 μm,accounting for 65.00-78.00%.The morphology of bark fibers conforms to normal distribution,and the bark fibers are all well-organized.The average moisture content of bark fiber was 10.46%,ash 5.63%,phenyl alcohol extract 7.67%,holocellulose 62.84%,cellulose 43.31%,lignin 9.63%and pentosan 20.77%.(3)Seed germination technique.The seeds of Pteroceltis tatarinowii have physiological dormancy,and the germination treatment is particularly important.The germination rate and germination potential of Pteroceltis tatarinowii seeds treated with different concentration of gibberellin were 37.33%and 15.33%respectively.The difference between the treatment with different concentration of gibberellin and other treatments was significant.The germination rate and germination potential of Pteroceltis tatarinowii seeds treated with different low temperature(4℃)stratification time for 90 days were the highest,78.6%and 34.00%respectively.The best way to break dormancy of seeds was low temperature stratification for 90 days.(4)Cutting propagation of plus tree:In order to preserve the fine characteristics of plus tree and provide asexually propagated seedlings for regionalized experiment of variety breeding.Orthogonal experiments were carried out on plus tree cuttings using hormone types,concentration and treatment time.The results showed that the optimum combination of cutting rooting test for Pteroceltis tatarinowii No.1,5 and 20 were A1B1C1,i.e.1000 mg/L IBA for 20 seconds.The rooting rate of cuttings was 58.89%,60.00%,63.33%,the average root length was 4.33 cm,4.10 cm,4.77 cm,the average number of roots was 3.90,4.57,4.13,and the root effect index was 0.56,0.63,0.66,respectively. |
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