光照对青藏高原东缘伞形科常见物种幼苗建植的影响

In this study, we used 18 Umbelliferae common species from the eastern Qinghai-Tibetan Plateau to study the effects of different light (light transmission rates were 4%, 35%, 67%, 100%) on the process of seedling establishment under field conditions, using seedling emergence rate, survival rate and establishment rate as index. The study show that these species all have a low emergence rate and establishment rate in low light (4%) and high light (100%) condition, suggests that seedling establishment of these species need to be shaded moderately (35%, 67%), low light (4%) condition also reduced seedling survival rate significantly, these results demonstrate that the studied species are not the pioneer species of community succession in their area and their shade tolerance is not strong. Analysed the impact of seed size on seedling establishment, we found that in high light (100%, 67%) condition species having small seeds have a higher seedling emergence rate and establishment rate than species having large seeds, but in low light (35%, 4%) condition, this trend is not significant. In all light conditions, seed size do not affect seedling survival rate significantly.