Rapid Propagation And Octaploid Breeding Of Celosia Cristata L.

Celosia cristata L.is an annual herb,which belongs to the Celosia of Amaranthaceae.The Inflorescence of Celosia cristata L.is acrogenous,and its colour is bright.It is used as a pot culture or a open culture.In addition,it can be made into cut flower or dry flower materials,Meanwhile,it has extremely high ornamental,medicinal and edible value.In the study the seeds of Celosia cristata L.were used as explants in tissue culture for rapid propagation.and then based on tissue culture and used chromosome engineering,the methods of inducing Celosia cristata L.octaploid were tested by colchicines.In order to obtain the valuable germplasm which can be used in the polyploidy breeding for future.The main results are the following:The result showed:The seeds were dipped in the scour 10 minutes and washen 30min by tap water,then sterilized 30 seconds by 75%alcohol and 10min by 0.1%HgCl₂,rinsed 4～6 times by sterilized water,the appropriate medium for inducing the differentiation on bud of the first culture about Celosia cristata L.was MS+1.0mg/L6-BA+0.2mg/LNAA,Coefficient of multiplication was 2.17;MS+6-BA 1.0 mg/L +NAA 0.1 mg/L and MS+6-BA 1.0 mg/L +NAA 0.02 mg/L were the favorable proliferate medium for adventitious buds obtained from budsand stems,2.43 and 4.67 were their coefficient of multiplication;the best rooting medium was 1/2 MS+IBA 0.4 mg/L,the induction rate was 95%,The surviving rate of plantlets was above 90%after transplanted to the ground.,hormones have effect on the flowering in vitro of Celosia cristata L.,the best medium was MS+6-BA 1.0 mg/L +NAA 0.2 mg/L.On the base of Celosia cristata L.tissue culture,the inducing polyploidy of Celosia cristata L.was carried out by colchicines.Two methods were used.The tetraploid plantlets were obtained by immersing buds in various concentrations of colchicine solution,and inoculating buds in the mediums containing colchicine.The result indicated that the way of immersing buds on colchicine was better.It was the most effectively induced by immersing buds of Celosia cristata L.in 0.15% colchicine solution for 36h,which had the most tetraploid plantlets,inducing ratio was 23.3%.Buds of Celosia cristata L.were inoculated in the medium contained 0.1%colchicine for 15 days,had the most tetraploid plantlets,inducing ratio was 16.7%. The leaf,stoma,guard cell and chloroplast characteristics of octaploids(2n=8x=72)and tetraploids(2n=4x=36)Celosia cristata L.were compared.The result indicated that octaploid leaves were thicker and lengther,leaf index was bigger.The thickness leaves,length,leaf index of octaploid were 205%,144%and116%of those of the tetraploid respectively.The octaploid of Celosia cristata L.with fewer stoma densitie which was 49%of that of the tetraploid.The guard cell of the octaploid was evidently bigger,The guard cells' length of octaploid was 170%of that of the tetraploid and the width was 164%.The numbers of chloroplast in the guard cells increased evidently and there was 178%of that of the tetraploid.Content of chlorophyl of the octaploid was 145%of that the tetraploid.By the analysis,between octaploid and tetraploid,leaf thickness,leaf length,stoma density, guard cell size,chloroplast number were mighty significantly different.So,leaf thickness,leaf length, stoma density,guard cell size and chloroplast number can be used to identify tetraploid and octaploid of Celosia cristata L..The resistance was measure and compared between the octaploid and tetraploid.the result of cold resistance that to treated 24h under the 5℃,the MDA content of tetraploid was 208%that of octaploid,compared with control variance analysis,their variance were extreme level of significance,then It shows that the octaploid cold resistance of Celosia cristata L.are stronger than the tetraploid.Research of the drought resistance indicated that behind the treatment of 20%PEG,the exosmosis rate of electrolyte of treated plants of tetraploid and its check plants were 182%,203% those of octaploid respectively,MDA content of the tetraploid's treated plants was 226%that of octaploid,all were extreme level of significance.Accordingly,the determination result of two physiological index indcated that the octaploid drought resistance of Celosia cristata L.are stronger than the tetraploid.