Abstract:
Cupressus chengiana is a rare and endangered species in China, a national class II key protected wild plant and endemic to Sichuan and Gansu Province. The ancient
C. chengiana trees contain a variety of genes and are valuable genetic germplasm materials. The seeds of 4 ancient
C. chengiana trees (350-1200 years) in Lixian County, Aba Prefecture were used as test materials, and the seeds of
C. chengiana (20 years old) in Jinchuan County was used as control. Based on the study of the seed morphological characteristics and germination characteristics of ancient
C. chengiana, the germination characteristics of their seeds were revealed. The results showed that the average seed length, width and of thickness of ancient
C. chengiana trees was 3.83mm, 3.20mm and 1.29mm, and the average number of seeds in a single cone was 42.42. Compared with the control, the 100-seed weight, viability and germination rate of seeds decreased significantly, which were only 0.25g, 28.27%, 14.59%. The initial germination time and the germination period (13.75 days and 35 days) increased significantly, showing obvious physiological function decline. The initial germination time of 1200-year-old ancient trees was significantly lower than that of other ancient trees, and there was no significant difference in germination rate, germination potential and germination index among different ancient trees. The suitable germination temperature of ancient tree seeds was 20 ℃, the germination rate, germination potential and germination index were 14.58%, 5.42% and 0.29 respectively, and the average initial germination time was 13.46 days.