[Germination and seedling growth of Artemisia halodendron under different incubation environments]

Artemisia halodendron is a dominant species in mobile and semi-mobile dunes of Horqin Sand Land. To investigate the germination character and seedling growth under different temperature and light conditions, the germination rate, germination index and growth of radicle and plumule were measured after treatments in laboratory and heating cabinet incubations. In the laboratory the light and temperature were near to nature condition, while in the heating cabinet it was kept at 25 degrees C with varying durations of light supply, including 24-, 12- and 0-hour light per day. Germination rate (66.6%) and germination index (19.1%) under laboratory condition were both significantly lower than in the heating cabinet (P < 0.05). In the heating cabinet, the germination rate under 0-hour light was 70.2%, which was insignificantly lower (P > 0.05) than under 12- and 24-hour light conditions (both 73.4%), and the germination index under 24-hour light was 28.2%, which was significantly (P < 0.05) lower than under 0- and 12-hour light conditions (31.3% and 30.8%, respectively). Radicle and plumule growth responded to light more readily than the seed germination rate and germination index during the process of germination, and the radicle growth was inhibited by darkness while promoted by light, and the plumule lengths under 0- and 12-hour light conditions were 2.81 cm and 1.51 cm, respectively, significantly higher than under 24-hour light (1.21 cm) and natural condition (1.27 cm). It was concluded that temperature was a main factor in seed germination, and seedling growth was mainly influenced by light regime.