中文摘要：

[目的]通过不同群落毛红椿天然林林地土壤及其真菌对种子萌发和幼苗存活影响的研究，探讨影响毛红椿天然更新的障碍因素。[方法]在江西九连山国家级自然保护区内的3个毛红椿天然优势群落中，分别取距离毛红椿母树3个不同距离（2．5、5．0、7．5m）处的根区土壤和远离毛红椿母树（25m以外）的非根区土壤，以非林地土为对照开展室内模拟播种和以根区土壤真菌的水或根系分泌物悬液对毛红椿幼苗进行灌根接种，观察种子萌发、幼苗存活和幼苗感病情况。[结果]各群落土壤中种子发芽均呈先上升后下降规律，且基本在第8～10天达到高峰；林地土与非林地土种子发芽率差异不显著，但林地根区土幼苗的存活率极显著低于非林地土和林地非根区土；距母树3个不同距离根区土的幼苗存活率差异不显著。灌根接种不同处理间幼苗存活率差异极显著，具体表现为接种RS2，RS5根区真菌的幼苗感病率显著高于根系分泌物及无菌水空白对照，且RS2真菌的根系分泌物悬浮液幼苗感病率显著高于其无菌水悬浮液。[结论]毛红椿种子萌发不受土壤环境的影响，但幼苗建成受根区范围内土壤的影响，根系分泌物和致病菌的互作显著降低幼苗保存率。由此推断，毛红椿根区土壤内存在幼苗的潜在致病菌及根系分泌物可增强其致病性。

英文摘要：

[ Objective ] The barrier factors influencing the natural regeneration of Toona ciliata var. pubescens were explored through investigating the effects of forest soil and fungi in different natural communities on seed germination and seedling survival. [ Method] Soil samples were collected from the root zone at three distances （2.5, 5.0, and 7.5 m） from the mother trees as well as the natural forest stands 25 m away from the mother trees in Jiulianshan Na- tional Nature Reserve. The seed germination trial on soils was carried out in the laboratory with non-forest soil as the control. In addition, the seedling infection trial in soil was also performed in the laboratory with root irrigation by fungi isolated from root zone soil and suspended with water or root exudates. The seed germination, seedling survival and seedling susceptibility were observed. [ Result] The germination of seed in all kinds of soil revealed the tenden- cy of increasing at initial and then decreasing, and reached the peak during the eighth to tenth day after sowing.There were no significant differences between forest soil and non-forest soil in germination rate, while the seedling survival rate of forest soil was significantly lower than that of non-forest soil. There were significant differences be- tween root zone soil and non-root zone soil in seedling survival rate, and the seedling mortality of root zone soil was higher. It was also found that there were no significant differences in seedlings survival rate of root zone soil among different distances from the mother trees. It addition, there were extremely significant differences in seedling infec- tion treatments, and the seedling disease incidence rates of RS2, RSssoil-borne fungi were significantly higher than those of the two blank controls, water （W） and root exudates （R）. Moreover, the disease infection rate of RS2 root exudates suspension was significantly higher than that of RS2water suspension. [ Conclusion]Forest soil of different natural communities has no effect o