| Fraxinus bungeana is a deciduous tree which belongs to the genus Fraxinus of Oleaceae.It is tall,beautiful and has strong stress resistance.It is an excellent tree species for building timber forest and farmland protection forest.With the aggravation of greening task,the demand for Fraxinus bungeana seedlings is increasing year by year.However,the traditional seedling raising method has a long cultivation cycle and slow growth,which makes its natural regeneration face severe challenges and become an endangered tree species.Therefore,the purpose of this study is to explore the biological characteristics of Fraxinus bungeana seeds,and to provide scientific basis for solving the problem of low seed emergence rate;The seeds of Fraxinus bungeana were used as experimental materials,the optimal disinfection time was determined by different disinfection treatments,the transplanting seedlings were successfully obtained by studying the ratio of medium and hormone in primary generation,subculture and rooting stages,the rapid propagation system with tissue culture as the breeding mode was established,which could be expanded without seasonal restriction,and thus the germplasm resources of Fraxinus bungeana could be preserved,saving endangered tree species,it is of great significance to the development and utilization of landscape trees in China.(1)Through the study on the biological characteristics of Fraxinus bungeana seeds,it is concluded that the average 1000 seed weight of Fraxinus bungeana can reach 15.32 g,which is a large seed;the results showed that the length of the wings ranged from 16.62 mm to 23.83 mm,and the width ranged from 3.00 mm to 4.55 mm,the longitudinal axis diameter of the inner species ranged from 5.77 mm to 9.72 mm,and the transverse axis diameter from 1.39 mm to 2.60 mm;the seed viability of Fraxinus bungeana was 82%,and the seed viability was higher,it was a healthy and vigorous seed,and germination was easier;the average moisture content of seeds was 8.78%,and the seeds could be dried to constant weight after 10 hours drying;the water absorption rate was 58.39%,and reached saturation after 16 hours of water absorption,indicating that Fraxinus bungeana seed coat has certain water permeability;the best soaking time was 6 hours,there was no significant correlation between electrical conductivity and germination rate under different soaking temperature;the germination rate and germination potential in the culture dish were significantly higher than those in the tray,and the seeds in the petri dish began to germinate only on the fourth day,therefore,the fastest way to promote germination is to pad the petri dish with gauze;the optimum temperature of soaking seeds before sowing was 25 ?.(2)Through in vitro culture of Fraxinus bungeana seeds,different gradient of mercuric chloride disinfection time set,the results showed that the best sterilization method was as follows:70% alcohol disinfection for 30 seconds + 0.1% mercuric chloride immersion for 10 minutes,a large number of sterile seedlings of Fraxinus bungeana have been obtained successfully,the germination rate of the seeds inoculated in WPM medium was the highest,and the germination rate was 91%;aseptic seedlings with good growth were selected for proliferation culture,when the aseptic seedlings were inoculated on WPM + 0.5 mg / L 6-BA + 0.05 mg / L NAA + 20 g / L sucrose + 6 g / L agar,the growth of tissue culture seedlings was the best;the best medium for rooting was WPM + 0.5 mg / 6-BA + 0.05 mg / NAA + 20 g / L sucrose + 6 g / L agar,taproot robust,more fibrous roots;before transplanting,the best time for rooting seedlings is 3 days,the best transplanting medium was peat soil: vermiculite = 1:1,after transplanting,the survival rate of plantlets was 87.3%,the plantlets were transplanted successfully. |
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