Study Of Somatic Embryogenesis And Induction Of Adventitious Buds In Larch

In this study,somatic embryogenesis were induced from immature zygote of hybrid larch and organogenesis were induced from mature zygote of Korean larch.The influence factors of somatic embryogenesis in larch hybrid and organogenesis in Korean larch have been studied systematically.Plant regeneration protocols through somatic embryogenesis of larch hybrid and organogenesis of Korean larch have been established.The main results were as follows:Embryogenic callus were initiated in Larix leptolepis×L.olgensi and L.leptolepis×L. gmelinii family have the ability of Plant regeneration.The optimal time of collecting zygotic embryo is from 27th,June to 4th,July in a year for somatic embryogenesis of larch hybrid.The suitable conditions for induction of embryogenic callus are MS,S Mediums with 0.5,1.0mg/L 2,4-D,0.05mg/L BA,0.05mg/L KT.The mother tree of explants has significant influence on somatic embryogenesis.Zygotic embryo produced from Larix leptolepis 5×L.olgensi 77-3 family can induced embryogenic callus at four stages and inclined to induce embryogenic callus.2,4-D with different concentrations have significant influence on the proliferation of embryogenic callus.The proliferation rate declines with the increasing of 2,4-D concentration. BA with different concentrations has not significant influence on the proliferation of embryogenic callus.When 0.1 mg/L 2,4-D+0.1 mg/L BA+0.05 mg/L KT are added, proliferation of embryogenic callus could increase most rapidly,the proliferation rate is 4.1 times.Media with different combinations of plant growth regulators have remarkable effect on the proliferation and maintenance of embryogenic callus.The best solution for proliferation and maintenance of embryogenesis is to add 0.5mg/L NAA+0.05mg/L BA+0.05mg/L KT and 0.1mg/L 2,4-D+0.05mg/L BA+0.05mg/L KTDifferent pro-treat has significant influence on the amount of somatic embryo.The embryogenic callus developed the most amount of somatic embryo when transfered to mature medium from subculture medium directly.Different concentrations of ABA have remarkable effect on the maturity of somatic embryo.The number of somatic embryo increasing with the concentration of ABA,the number of somatic embryo can develop the most on the mature medium with 45mg/L ABA.1g embryogenic callus produced 340.2 somatic embryos on average.On the medium with 0.2mg/L IBA+15mg/L ABA,163.8 somatic embryos can be developed per gram embryogenic callus on average.The somatic embryos have increased by 5.4 times comparing to solely using 15mg/L ABA.The optimal concentration of inositol,casein hydrolysate and glutamine in somatic mature medium are 250mg/L,250mg/L and 750mg/L respectively.Agar is more suitable for maturing of somatic embryo than gelrite.When the concentration of agar was 9g/L,both the number of somatic embryo and plant regeneration rate reached the highest.There were 411.4 somatic embryos in each 1mg embryogenic callus and the plant regeneration rate was 42.1%.1/2MS,1/2GD,1/2BM medium were tested.1/2MS is suitable for germination of somatic embryo and plant regeneration.On this medium,sturdy somatic embryo with black-green color and fast-growing extension of apical buds and root.Added 200mg/L actived carbon enhanced germination of somatic embryo.The times of germination of somatic embryo on this medium is shorter than without actived carbon and the plantlets are vigorous.Prolonged the mature period can improve germination rate of somatic embryo and plant regeneration rate. When cultured 12 weeks on mature medium,both the germination rate and plant regeneration rate are highest(97.6%,70.5%).In darkness,the callus induced from Korean larch mature zygote was suitable for induction of adventitious buds.More adventitious buds were differentiated by solely added 1.0 mg/L BA than combined with NAA.The best induction effection was on BM medium supply with 1.0 mg/L BA only under the light condition.Callus growth faster,adventitious bud differentiation frequency were 73.8%.10mg/L actived carbon added to BM medium can enhance adventitious bud elongation.In this research,the root was induced on 1/2B2和B1 medium,induction rate is 13.3%and 10%respectively.The adventitious bud can not form root on 1/2MS.This study is the basis for preparation of superior clone reproduction,germ plasm conservation,genetic improvement,and artificial seed and other aspects.