Study On High Frequency Regeneration System And Polyploid Induction Of Callistephus Chinensis (L.)Nees

Aster is annual or biennial herbaceous plant,which belongs to the Compositae genus aster.The experiments were carried out on the regeneration system of Aster cultivar "library Lei Na"showed:The best disnfection methods suitable for aster seed;the best callus induction and redifferentiation medium in use of the petiole,stem segments as explants;rooting culture medium. Study of colchicines induced polyploidy showed:The best way to induce aster polyploidy;the best system on aster root-tip chromosome preparation,and physiological characteristics of Aster tetraploid.The regeneration system of China aster:Seeds are first taken to disinfect for 75% alcohol 10s+2% NaclO 25 to 28 min,and then are inoculated into 1/2MS medium,pollution rate is almost 0. The establishment of regeneration system of aseptic seedlings as materials, study shows:the stems of seedlings were used as explantsto obtain a higher regeneration frequency of 82.2%.callus induction medium was MS+2.0mg/L6-BA+0.2mg/L NAAcallus induced medium for adventitious buds differentiation was the best MS+1.0mg/L6-BA+0.1mg/LNAA,the best of adventitious buds the rooting medium was 1/2MS.The best callus induced medium for petile is MS+4.0mg/L6-BA+0.2mg/LNAA callus induced medium for adventitious buds differentiation was the best MS+1.0mg/L6-BA+0.1mg/LNAA,the best of adventitious buds the rooting medium was 1/2MS.The best callus induced medium for petile is MS+4.0mg/L6-BA+0.2mg/LNAA,but the induced callus differentiation medium can only differentiate into adventitious roots,that 6-BA,NAAconcentrations which are in the range of 0.5～2mg/L,0.05～0.2mg/L is not suitable for petiole callus differentiation of adventitious buds.Different organs of Aster differ greatly in the selection medium for induction of callus andadventitious buds differentiation.Method for inducing polyploidy aster with colchicines has soked seeds soaking method,cluster buds and shoot tip of dropping liquid method.The best one is soaking cluster buds,among the colchicines concentration is 0.05%,the processing time for 24h,mutation rate as high as 47.3%. But this method with a high death rate for 45.5%. Seed soaking method,the concentration of 0.05% colchicines treated seed about 18h,with the highest induction rate,up to 10%.shoot tip of dropping liquid method:Combination of colchicines concentration and treatment time is 0.1%/2d,the highest induction rate was 13.3%.The number of tetraploid chromosome after chimerism separation is 2n=4x=36, Tetraploid plantlets were in the MS+2.0mg/L6-BA+0.1mg/LNAA medium added training,and take root in the 1/2MS medium, having good growth status,and transplanted to a matrix (earthworm soil:Perlie=1:1),the survival rate reached 55%.The external morphology and stomatal characteristics of tetrapliod and diploid aster were compared and analyzed,the results showed that:in the same environment conditions and the same growth stage,the tetraploid plant grows slowly,having deep green leaves,and stem segment thickening.Tetraploid leaf thickness,leaf width were higher than diploid,respectively 168.4%,133.8% diploid,fully demonstrated.the great of tetraploid;Tetraploid leaf length,leaf index were less than the diploid,respectively 77.3%,57.7% diploid,there was significant difference.Tetraploid leaf stomata length,width and length og guard cell and width was significantly increased,respectively were 138.5%,123.2%,138.9%,129.7% of diploid leaf stomatal,porosity increases:stomatal density of leaves were lower than diploid tetraploid,as 49.7%of diploid;guard cell chloroplast number was greatly increased,as 184.2% of diploid,significant difference.Therefore,leaf shape,leaf thickness,stoma density,guard cell size and guard size chloroplast number can be used as an important index in differential tetraploid and diploid Callistephus chinensis.Using the same diploid and tetraploid plantlet leaves,we respectively extracts in leaves of MDA,SOD,proline and detection.The results showed that the content of tetraploid MDA was less than the diploid aster,and SOD activity was higher than that of diploid,tetraploid aster,and SOD activity was higher than that of diploid,tetraploid aster proline content in before and after hig temperature treatment were higher than diploid.The tetraploid aster resistance was stronger the diploid.