Abstract: The effects of light condition (12 h photoperiod and 24 h dark) on the seed germination of differentaltitude Spiraea rosthornii (2500, 2700, 3020, and 3300 m) and Berberis aggregata (2160, 2760, 3000, and 3250 m) from the eastern QinghaiTibet plateau were studied. The results are as follows: (1) The seed size of S. rosthornii was significantly negatively correlated with altitude, and the seed size of B. aggregata had no significant correlation with altitude. (2) The germination rates of S. rosthornii seeds under light or dark and germination percentage under dark hada significant positive correlation with altitude, but a weak positive correlation was found for germination percentage under light. The germination rate and germination percentage of B. aggregata seeds under light or dark condition had no correlation with altitude, but the germination rate or germination percentage had significant difference among the seeds from different altitudes. The B. aggregata seeds from 2760 m altitude had the highest germination ability, the higher or lower altitudes both led to lower germination. (3) The seeds of S. rosthornii from different altitudes had significantly higher germination rates and germination percentages under light than under dark, but the difference was not significant when the seeds were from 3250 m altitude. The light condition had no effects on seed germination rate and germination percentage of B. aggregata from different altitudes. These results indicated that the altitude and light condition were the main reasons that led to lower germination ability of S. rosthornii seeds. For B. aggregata, the seeds from different altitudes had different germination abilities, but light condition had no effects on the germination.

Key words: vegetation restoration, root, soil, plant aboveground part, litter