Studies On In Vitro Culture And Rapid Propagation Of Cymbidium Hybridium

Tissue culture is an important way to increase the productivity of Cymbidium hybridium ’Fuku No Kami’ and bring great economic interests.In this study,the shoot tips,pseudobulbs,young pedicels of C.hybridium were used as explants and its induction,proliferation,germination,rooting and browning control methods were studied. A highly efficient,fast and economic reproductive system was established,which might provide some useful points for industrial production.（1） Different concentration and ratio of inorganic salt,sugar and hormones were used to study the effects on induction,multiplication,buds germination and rooting of PLB The results are shown below:①The optimal medium for PLB induction was MS medium supplemented with 0.2 mg L^-1 NAA and 1.0mg L^-1 6-BA.②The optimal medium for PLB multiplicaiton was 2MS medium,20g L^-1 sucrose and 0.2 mg L^-1 NAA and 0.5 mg^L-1 6-BA were the best.Liquid suspension cultivation results in a higher PLB multiplication rate.③The optimal medium for buds germination was 1/2MS medium,10g L^-1 sucrose and 0.4 mg L^-1 NAA and 0.5 mg L^-1 6-BA were the best.Solid medium yields highest buds germination rate.④The optimal medium for rooting was 1/4MS medium,40g L^-1 sucrose and 0.2 mg L^-1 NAA were the best.Solid medium yields highest rooting rate.（2）The browning control methods of C.hybridium in vitro propagation was studied, the results are shown below:①Among different explants,pseudobulb and pedicel segments would lead to severe browning,whereas shoot tips yield a better effect.②Among the three kinds of medium,i.e.,MS,improved MS and 1/2 MS,1/2 MS medium with low concentrations of inorganic salt is best in inhibiting browning. Meanwhile,liquid cultivation is more efficient in inhibiting browning than solid cultivation.Differentiation rate wasn’t different significantly,and the differentiation rate by solid medium was slightly higher than that by liquid medium. ③Browning could be reduced by the medium with polyvinylpyrrolidone（PVP）, sodium thiosulfate,activated carbon and vitamin C,and the medium with 500mg L^-1PVP give the best effect.④The pretreatment was necessary for browned explants.In this study,20 mins pretreatment using PVP(2g L^-1) and sodium thiosulfate(2g L^-1) brought better effect in inhibiting browning.