光照对青藏高原东缘伞形科常见物种幼苗建植的影响.docVIP

  光照对青藏高原东缘伞形科常见物种幼苗 建植的影响# 王 君，张春辉，杜国祯** 5 10 15 20 25 30 35 40 （兰州大学干旱与草地生态实验室，兰州 730000） 摘要：本文以青藏高原东缘伞形科（Umbelliferae）常见的 18 个物种为研究对象，以幼苗出 土率、存活率和建植率为指标，研究了野外条件下不同光照强度（透光率分别为 4%、35%、 67%、100%）对这些物种幼苗建植过程的影响。研究发现这些物种在低光强（4%）和高光 强（100%）条件下均有着较小的幼苗出土率和建植率，说明其幼苗建植需要适度的遮阴 （35%、67%），低光照（4%）还会显著降低其幼苗存活率，由此表明研究物种不是其所在 地区群落演替的先锋种，且耐阴性也不强。联系种子大小分析其对幼苗建植的影响，发现在 高光强（100%、67%）条件下小种子物种相比大种子物种有着较高的幼苗出土率和建植率， 而在低光强（35%、4%）条件下这一趋势不显著。在所有光照条件下，种子大小对幼苗存 活率均没有显著的影响。 关键词：光照；种子大小；幼苗建植；伞形科；青藏高原 中图分类号：Q14 Effects of light on seedling establishment of Umbelliferae common species from the eastern Qinghai-Tibetan Plateau WANG Jun, ZHANG Chunhui, DU Guozhen (Ministry of Education Key Labratory of Arid and Grassland Ecology, Lanzhou University, Lanzhou 730000) Abstract: 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. Key words: light; seed size; seedling establishment; Umbe