Improvement of seed dehiscence and germination in ginseng by stratification, gibberellin, and/or kinetin treatments

Korean ginseng (Panax ginseng C.A. Meyer) is a largely sought after resource due to its substantial health benefits. However, large-scale culture of ginseng seeds is limited because of its long maturation time and triple-dormancy. To develop new strategies to improve the dehiscence, germination, and breaking dormancy, we investigated the effects of stratification, gibberellin (GA3), and/or kinetin treatments on the dehiscence, development and germination of P. ginseng. Indehiscent seeds for the dehiscence test and dehiscent seeds for the germination test were immersed in a solution containing 288.7 μM GA3 and/or 232.3 μM kinetin for 24 h, respectively, at 25 °C. After dehiscence, a cold stratification experiment was conducted at 2 °C for 15, 30, 45, 60, and 90 days in the dark. Exogenous GA3 and kinetin treatments significantly improved the dehiscence rate. In addition, both plant growth regulators (PGRs) appeared to enhance the zygotic embryo development of ginseng seeds. GA3 on its own had a slight effect on breaking dormancy and germination, but the effect was not sufficient to serve as a complete substitute for the cold stratification requirement due to the deep physiological dormancy characteristic of P. ginseng. Kinetin treatment had a significant effect on germination and breaking dormancy, although a short period of cold stratification was also required. The combination of GA3 and kinetin treatments was more effective at enhancing both seed dehiscence and germination than either PGR treatment alone.