Establishment of an In Vitro Regeneration System for Stem Segments of Cultivated Dioscorea polystachya
To establish a tissue culture regeneration system for cultivated Chinese yam(Dioscorea polystachya),the effects of different concentrations of plant growth regulators,and stem segments on axillary bud induction and plant re-generation were investigated with different concentrations of plant growth regulators,media types,and shoot tips and stem segments at four different positions under the shoot tip as explants.The results revealed that MS+1.0 mg·L-16-BA+0.5 mg·L-1 KT hormone ratio and 12-20 cm stem segment under the stem tip were the best formulas for the induc-tion of adventitious buds in D.polystachya,and the induction rate reached 90.0%.In the subculture,the optimal concen-tration was MS+0.5 mg·L-1 6-BA+0.05 mg·L-1 NAA+0.1 mg·L-1 KT,and the proliferation coefficient increased with in-creasing of 6-BA within a certain range when the low concentration of NAA was constant.With the same concentration of exogenous hormones,DKW medium was significantly better than the conventional 1/2MS medium,and the rooting rate is significantly improved,reaching 92.86%.Adding 1 mg PVP(polyvinylpyrrolidone)and increasing the number of transfers can significantly reduce browning.This study effectively solved the problem of optimizing the explant position for the sta-ble of in vitro propagation of cultivated yam germplasm resources,laying a good foundation for the large-scale production of their high-quality virus-free seedlings.
Dioscorea polystachyastem segmentstissue culturein vivo regeneration