Factors affecting explant browning in tissue culture of Hippophae rhamnoides L.

To control the browning and dying of the Hippophae rhamnoides L.tissue cultures,the analysis of seven factors which influence the rate of browning of explants,such as the concentration of inorganic salt,temperature and light,the different concentration of 6-BA,the length of cycle,the hardness of medium and AC.The results indicate that the rate of browning was significantly different when we choose dormancy buds,which have been cultured in water for two weeks,and annual or biennial as explant respectively.The medium 1/4MS+6-BA 0.5 mg/L+NAA 0.2 mg/L reduces the rate of browning and promotes growth.Five days dark processing after inoculation delayed the time of browning,and the rate of browning reduced by 30% or so.After putting 6～7 g/L agar in medium,the rate of browning reduced to 12.67%.Before browning occurs at the beginning,inoculation was performed first,then every fourteen days,when the rate of browning reduced by 30%,and it reduced by 50% while innoculation was done every twenty-five days.The adding of 1～2 g/L AC shortened the diameter of browning substance and delayed the exudation time of browning,so it decreased the rate of browning.