Somatic Embryogenesis And Construction Of Stem Regeneration System Of Chionanthus Retusus

Chionanthus retusus is a kind of Chionanthus in Oleaceae family.It is a national second-class rare plant,deciduous shrub or tree.It has a combination of edible,medicinal,ornamental and economic values.It is resistant to salt,drought and cold,and has strong adaptability to the complex climate of North and South China.At present,the traditional propagation mode of Chionanthus retusus is mainly sowing propagation,with long production cycle and low germination rate.In order to promote the rapid development of Chionanthus retusus,the following research is carried out.In this experiment,the young embryo of Chionanthus retusus was used as the explant,and the suitable medium and culture conditions were selected through the research of the somatic embryogenesis of Chionanthus retusus,and the regenerated plant of somatic embryo of Chionanthus retusus was cultured.Secondly,the main physiological and biochemical indexes of different development stages of somatic embryo of Chionanthus retusus were measured to further reveal its physiological mechanism.Finally,the stem segment was used as the explant Medium and different hormone ratio of stem rapid propagation technology.The results are as follows:1.Somatic embryogenesis of Chionanthus retusus（1）The most suitable medium for induction of somatic embryogenesis was WPM+1.0 mg/L 6-BA+2.0mg/L 2,4-D.the rate of somatic embryogenesis was 12.36%.（2）The most suitable medium for inducing and guiding the germination of somatic embryos was MS+1.0mg/L 6-BA+1.0 mg/L GA3,the germination rate was 41.3%,and the seedling rate was 29.82%.（3）The results showed that the best condition was complete dark culture.After 90 days of culture,the induction rate of somatic embryos was 11.18%.（4）By comparing the effects of young cotyledons,young leaves,mature hypocotyls and mature cotyledons on the induction of somatic embryos,it was found that young cotyledons were the most suitable explants for the induction of somatic embryos in Chionanthus retusus,and the induction rate of somatic embryos could reach 11.20%.（5）In the whole process of somatic embryogenesis of Chionanthus retusus,the content of soluble sugar increased,the content of soluble protein and the activity of pod enzyme increased,the activity of SOD enzyme increased.2.Germination and seedling formation of mature embryo of Chionanthus retusus（1）The best way to disinfect explants is 75%alcohol for 30 seconds,sterile water for 3-4 times,then 0.1%HgCl2 solution for 5 minutes,sterile water for 4-5 times（2）The best medium for germination of mature embryo was WPM+1.0 mg/l 6-BA+0.5 mg/l TDZ,the germination rate was 91.02%,and the seedling rate was 86.5%.（3）By comparing the germinating rate and seedling rate of mature seed embryo at 0 d,90 d,100 d,110dand 120 d in sand storage treatment,when the seed embryo at 110 d in sand storage treatmen grows for 4d,the embryo reaches 1.1 cm,and the growth height can reach 4.95 cm after 28 d,so the mature seed embryo at 110 d in sand storage treatmen is the most favorable for germination and seedling.3.Regeneration system of the stem of Chionanthus retusus（1）When WPM+0.5 mg/L KT+1.5 mg/L 6-BA was used,the height of stem segment could reach 2.89cm,the number of newly developed leaves was 5.67,and the propagation coefficient was 3.13;2)With the increase of GA₃ Concentration,the elongation height of stem increased first and then decreased.When GA₃ concentration was 2.0 mg/L,the length of stem segment was 3.01 cm and the height of growth was 5.01 cm.（3）The best rooting medium for stem segment was WPM+1.0 mg/L IBA+0.5 mg/L NAA.The rooting rate was 62.15%...