Objective The seed germination of Nicandra physaloides was seriously affected by external colloid. The study was conducted in order to explore the effects of different hormone treatments on germination of N. physaloides seeds and increase the seed germination rate.

Method The seeds of N. physaloides were used as test materials, and the random block method was used to set 4 ℃ low temperature treatment with seeds put on gauze and MS medium treatments of gibberellin (GA₃), 6-benzylaminopurine (6-BA) and naphthylacetic acid (NAA), and the results of the four treatments were regularly observed and recorded.

Result Compared with the normal temperature control, low temperature treatment at 4 ℃ on gauze significantly promoted the germination of N. physaloides seeds, and the highest germination rate was 25% after 48 h of treatment. The germination rate and germination index of N. physaloides seeds treated with 10 mg/L GA₃ were 92.00% and 9.58, which were 4.27% and 1.33 higher than those of CK, respectively. The germination rate of the seeds treated with 1 mg/L 6-BA was the highest as 96.63%, and the germination potential of the seeds treated with 2 mg/L 6-BA was the highest as 73.33%, which were 8.9% and 10.07% higher than those of CK, respectively. The germination rate of the seeds treated with 1 and 2 mg/L NAA was 88.86%, but both the germination potential and germination index were lower than CK. Compared with CK, 10 and 50 mg/L GA₃ treatment significantly increased hypocotyl length, while 6-BA and NAA treatments significantly decreased hypocotyl length.

Conclusion Low temperature treatment can significantly promote the germination of N. physaloides seeds, and low concentration hormone treatment on MS medium can improve the germination rate of N. physaloides seeds. Through comprehensive comparison of germination rate, germination potential, germination index and hypocotyl length, the best hormone treatment for N. physaloides seeds is MS + 10 mg/L GA₃.