Studies On Rapid Propagation And Polyploid Breeding Of Kalanchoe Blossfeldiana T.

Kalanchoe blossfeldiana T.is also called Christmas laciniate kalanchoe herb,red kalanchoe, and is a multi-plasm plant.The initial species from Madagascan.Because of Kalanchoe blossfeldiana have long anthesis,can hearing drought,easily cultivation,have good ornamental effect,and all plant of it can as drug and have effect of relieve fever,dissipate blood stasis,attenuating, anthemorrhagicing.The development outlook is very good.The common propagation method of Kalanchoe blossfeldiana is cutting with stem and leaf,but the propagation speed was slow and have great influence with the change of season.At present,there were some report about single explant such as leaf or shoot tip culture and rapid propagation,the research about several explants were seldom,therefore it lacked system research.But the correlated report was seldom in breeding in China.In the study,fine Kalanchoe blossfeldiana variety Petero was as thetrial material.The rapid micropropagation system in vitro of Kalanchoe blossfeldiana was studied for finding the best explant and culture condition.Additionally,the methods of inducing Kalanchoe blossfeldiana polyploid were tested by colchicine for obtaining tetraploid germplasm. Then the characteristics of tetraploid and diploid Kalanchoe blossfeldiana were compared.The research established the base for polyploid breeding of Kalanchoe blossfeldiana,having a great value in Kalanchoe blossfeldiana breeding.The result shows that the best sterile method is that 30min overwashing by tap water,sterilizing 60seconds by alcohol and 5min by 0.1%Hgcl₂,rinsed3～5 times by sterilized water,the bud survival rate reached 70%.In this experiment,the leafstalk,leaf blade and no axillary bud as explants in primary culture,the best explant is leaf blade,the appropriate medium for inducing the differentiation on bud of the first culture about Kalanchoe blossfeldiana is MS+6-BA 2.5mg/L+IBA 1.0mg/L.The appropriate medium on step-generation and propagation of bud is MS+6-BA 2.0mg/L +IBA 0.1mg/L.It is easy to root for Kalanchoe blossfeldiana,the appropriate medium is 1/2MS+ IBA 0.1mg/L,the rate of rooting is 95%.The ploidy of plantlets in vitro were identified and the numbers of chromosome were 34(2n=2x=34).Under the condition of tissue culture,the inducing polyploid of Kalanchoe blossfeldiana was carried out by colchicine.Two methods were used and compared.The tetraploids plantlets were obtained by immersing stem-tip in various concentrations of colchicine solution,and inoculating buds in the mediums containing colchicine.The result indicated that the way of immersing buds was better.It was the most effectively induced by immersing buds in 0.3% colchicine solution for 24h,the highest inducing rate is 20%.Some of homozygosis tetraploids or some of 2x and 4x chimera in regenerated plantlet.By separated we can obtaining homozygosis tetraploids.The leaf,stoma,guard cell and chloroplast characteristics of tetraploids and diploids Kalanchoe blossfeldiana were compared.The result indicated that:in the same environmental condition and growth stage,tetraploid plants have many characteristic.The leaves were thicker and greener,the leaf index was shrinker,flower stems were thickeningand the number of flower were increasing.The length,width,thickness and the leaf indx of leaves of tetraploids were 157.1%,227.3%,166.7%,68.4%of those of the diploids respectively;On the comparison of stomatal characteristics,the guard cells' diameter of tetraploids were 150.6%and 154.2%of those of the diploids respectively. The numbers of their chloroplast in the guard cells increased evidently and there were 140.7%of those of the diploids,but the stomtal density of the tetraploids was decreased,approximately for 60% of the diploids.The electrical conductivity was measured and compared between the tetraploids and diploids.The electrical conductivity of tetradiploids was 35.6μS·cm^-1when stressed with 40℃while that of diploids was 58.5μS·cm^-1.The electrical conductivity of tetraploids were significantly lower than that of diploids,whose differences were very significant,when treated with 40℃,the exosmosis rates of diploid were obviously exceed tetradiploids,is 3.27 than that of tetradiploids.the variance between tetraploids and diploids were very significance level,indicating the antireversion force of tetraploids increase than that of diploids.The comparison of tetraploids and diploids have some difference after blooming.The flower stem thickness,length of Kalanchoe blossfeldiana of tetraploids were 2 times and 1.39 times of those of the diploids respectively,the number of flower is more 57.6than the diploids,the size is for 1.16 times of the diploids,the efflorescence was delay 13 days but viewing flower date extend 12 days. All these shows that gagantic of nutritive organ,and the stem become sturdily,the number of flower increased and the ornamentals enhanced.In this study,not only the rapid propagation system have been established but also breeded new germplasm.