Study On Mutagenic Effects Of Two Mutagens On Buddleja Lindleyana

Buddleja lindleyana Fortune is an excellent flowering shrub in the garden,which belongs to the Buddleja of Scrophulariaceae.It is a common excellent flowering shrub,an important metal indicator plant and medicinal plant.It is a dominant tree species in the garden with with great development potential,but the plant shape is scattered and the growth posture is poor.Pruning is often required in garden applications,and the flower buds are often destroyed after pruning,which greatly reduces its ornamental effect.In order to enrich the germplasm resources of B.lindleyana and its garden application forms,and enhance the ornamental value,this paper used two chemical mutagens,EMS and colchicine,to induce the mutagenicity of B.lindleyana seeds.Related researches were carried out from four aspects:the germination of seedlings,the growth of seedlings after transplanting seedlings,the selection of morphologically variant plants and the identification of variant plants.The research results were as follows:1.EMS and colchicine mutagen had effects on the germination of B.lindleyana seed,and the inhibitory effects of different concentrations and treatment time were different.The effect of high concentration and prolonged soaking treatment on seed germination was more significant.EMS and colchicine had toxic effects on B.lindleyana seeds.Based on the semi-lethal amount of seeds combined with the results of morphological mutagenesis,it was found that the treatment with 3.0 % for 48 h was the best combination for EMS mutagenic B.lindleyana.In the colchicine treatment group,3 tetraploid plants were successfully doubled after being treated at 3.0 %concentration for 48 h,and the mutagenic effect was better,which could provide a reference for the technology of polyploidy of B.lindleyana.2.EMS and colchicine had inhibitory effects on the growth of B.lindleyana seedlings.Through the measurement of different growth indicators,it was found that the treatment of seeds by the two mutagens had significant effects on the growth parameters of B.lindleyana seedlings,and with the increase of the concentration of the modifier,the growth indicators of the seedlings as a whole showed a downward trend.3.After treatment with EMS and colchicine,B.lindleyana mainly had three types of variation: leaf shape,leaf color,and plant shape variation,among which leaf shape variation was the most common,and multiple variation characters may appear on the same mutant plant.During the continuous selection process of morphological mutants for 60-90 days,some of the mutants died normally.In the EMS mutagenesis population,47 morphological mutants were screened out,of which 45 were leaf-shaped mutants,1 leaf-colored mutant,and 1 shape-variant strain;30 strains with morphological variation were selected from the colchicine mutagenic population,all of which were leaf-shaped mutants.4.The analysis of ISSR-PCR test results found that:(1)The morphological mutations induced by EMS and colchicine were rich in genetic variation,and all had high polymorphism.The average polymorphism percentages accounted for 95.06%and 91.18%,respectively.(2)Both types of mutagen showed no significant relationship between the type of mutation and the magnitude of the mutation,and the mutation was highly random.Different concentrations and time treatments did not show obvious regular changes in the degree of mutation.5.Treatment of B.lindleyana seed with colchicine finally get 3 tetraploid and 5chimeric.Tetraploids had significantly different stomata and guard cell structures compared to Primary diploids(CK),while chimeras had no significant differences.In terms of morphological characteristics,the leaves of tetraploid plants were wider than the diploids,and the leaf shape index was smaller,and the chimeras mostly showed irregular leaf changes.6.There were two ways of colchicine treatment for B.lindleyana seed variation:genetic mutation and chromosome doubling.Clustering analysis shows that the genetic distance results of the same ploidy plants are different.Chromosome doubling and gene mutation may occur in the same plant at the same time.