中文摘要：

采用土芯法获取福建省三明市米槠人工林、米槠人促更新林和米槠天然更新林的细根（直径〈2 mm），研究树种多样性对细根生物量、垂直分布及形态特征的影响.结果表明： 米槠人工林、米槠人促更新林和米槠天然更新林0～80 cm土层的细根生物量分别为（182.46±10.81）、（242.73±17.85）和（353.11±16.46） g·m-2，细根生物量随树种多样性的增加呈增加趋势.3种米槠林分0～10 cm土层细根生物量占细根总生物量的35%以上，各林分细根生物量均随土层变化显著.林分类型和土层深度对细根分布没有显著的交互作用，表明树种多样性的增加没有引起米槠林细根空间上的生态位分化.3种米槠林细根的根表面积密度和根长密度均以米槠天然更新林最高，米槠人工林最低.比根长的大小顺序为米槠人促更新林＞米槠人工林＞米槠天然更新林，比表面积的大小顺序为米槠天然更新林＞米槠人工林＞米槠人促更新林，林分类型和土层的交互作用对二者均无显著影响，表明林分水平的细根形态可塑性对树种多样性响应不显著.

英文摘要：

Fine roots in the Castanopsis carlesii plantation forest （MZ）, the secondary forest of C. carlesii through natural regeneration with anthropogenic promotion （AR）, and the secondary forest of C. carlesii through natural regeneration （NR） in Sanming City, Fujian Province, were estimated by soil core method to determine the influence of tree species diversity on biomass, vertical distribution and morphological characteristics of fine roots. The results showed that fine root biomass for the 0-80 cm soil layer in the MZ, AR and NR were （182.46±10.81）, （242.73±17.85） and （353.11±16.46） g·m-2, respectively, showing an increased tendency with increasing tree species diversity. In the three forests, fine root biomass was significantly influenced by soil depth, and fine roots at the 0-10 cm soil layer accounted for more than 35% of the total fine root biomass. However, the interaction of stand type and soil depth on fineroot distribution was not significant, indicating no influence of tree species diversity on spatial niche segregation in fine roots. Root surface area density and root length density were the highest in NR and lowest in the MZ. Specific root length was in the order of AR〉MZ〉NR, while specific root surface area was in the order of NR〉MZ〉AR. There was no significant interaction of stand type and soil depth on specific root length and specific root surface area. Fine root morphological plasticity at the stand level had no significant response to tree species diversity.