Breaking dormancy by successive low and high temperature on the seed germination of Glehnia littoralis

Glehnia littoralis Fr. Schmidt ex Miquel (Apiaceae, syn., Umbelliferae) is one of the typical seaside plants and is endemic to Japan, Korea, and China. The tap root has been used as a Kampo medicine and as a vegetable for the Japanese traditional dishes. In recent years, the extinction of Glehnia littoralis is worried about because of illegal harvesting from its natural habitats. For vegetation recovery, it is necessary to do seed propagation from seeds gathered in the same indigenous place to avoid disturbance of each ecosystem. Therefore we tried to clarify the effect of low temperature and successive low and high temperature treatments to seeds before sowing on the germination rate. Low temperature treatment promoted germination. However, germination rate of each fruit cluster was obviously different. The successive low (L), high (H) and low (L) temperature treatment remarkably accelerated seed germination compared with H and L treatments. Especially the L4H4L4 treatment caused the highest rate (58%) through these all experiments.