Control of explant browing during the tissue culture of Smilax riparia A.DC

The present experiment was conducted to study the effects of different explants,sterilization time,antioxidant and anti-browning agents and culture media combinations on browning control of Smilax riparia A.DC explants.The young leaf,apical bud and stem of Smilax riparia A.DC were used as explants.The results showed that the browning rate of young leaf,apical bud and stem increased with the elongation of sterilization time in 0.1% mercury bichloride solution,while the induction and contamination rate were decreased.The best explant was found to be the apical bud,which showed 70.0% induction rate when sterilized for 10 min.All the three antioxidative agents were found to inhibit the browning of apical buds,when pretreated for 20 min,of which the effects of polyvinyl pyrrolidone(PVP) was the best,followed by vitamine C(Vc)and Na2S2O3,the Vc solution was also found to promote the germination and growth of axillary buds.Three anti-browning agents showed varied effects on controlling the browning of stem,and the effects of 0.3% activated charcoal(AC) were found to be the best due to complete control of browning and well growth of axillary buds.An early browning was observed with increasing the concentrations of 6-BA and NAA in the media.However,the induction rate of explants was found the highest(63.4%) in MS medium supplemented with 6-BA(2.0 mg/L) and NAA(0.2 mg/L).Compared with the basic and 1/2MS medium,the browning of explants in low salt woody plant medium(WPM) was lesser and found to be delayed.The present studies revealed that suitable explants,proper sterilization time,use of antioxidant and anti-browning agents,and proper hormone combinations in basic medium could effectively control the browning of Smilax riparia A.DC explants and increase the induction rate.