中文摘要：

植物种子质量（大小）是植物的关键生态功能性状,种子质量的海拔格局研究有助于理解物种分布的环境约束以及植物功能性状之间的相互联系。该研究通过野外收集长江三峡大老岭国家自然保护区内主要木本植物59科87属201种的成熟种子,并测量其种子质量和长度、厚度值,分析该地区木本植物种子大小的海拔格局及植物生长型之间的差别。结果表明：1）大老岭地区常见木本植物种子质量、长度和厚度值均服从对数正态分布,质量值变异性最大（跨5个数量级）。种子质量、长度和厚度值之间均显著正相关。2）乔木和小乔木的种子质量显著大于灌木和木质藤本的种子质量;常绿阔叶种的种子质量显著大于落叶阔叶和针叶种。全部物种的种子质量随海拔上升而有较小但统计显著的减小趋势。3）不同生长型和叶性状的木本植物种子质量的海拔格局不一致。群落不同结构组分（按生长型和叶性状分）的木本植物种子质量（大小）海拔梯度格局差异意味着局域群落结构是理解宏观生态格局变异的一个重要方面。

英文摘要：

Aims Seed size is one of the most important characteristics of plant seeds, and has significant implications in plant ecological functions. Exploring the altitudinal pattern of seed size would help to detect environmental con- straints on species distribution and understand the linkage between plant ecological function traits. Methods The present study measured the quantitative features of seed size, including weight of I 000 grain seeds, lengths of longer and shorter axes, and analyzed the relationships between seed size and altitude, as well as the influence of growth form. Seed samples were all collected from 201 locally common woody plants （belonging to 59 families and 87 genera） in the Dalaoling Natural Reserve in Yichang City, Hubei Province. Importantfindlngs Measured values of the seed mass, the longer axis, and the shorter axis of the 201 woody plant species all follow the lognormal distribution. Measurements of seed mass vary across five orders of magni- tude. Significant correlation was found between seed mass, seed length of the longer and shorter axes （R2 = 0.755; 0.819; 0.630, p 〈 0.01）. Moreover, seed mass of trees and small trees are significantly heavier than those of shrubs and woody vines. Seed mass values of evergreen broad leaved species are significantly heavier than those of de- ciduous broad leaved species and needle leaved species. Seed mass of all 201 species shows a slightly but statisti- cally significant decreasing trend with the increase of altitude. In addition, altitudinal patterns of seed mass varied between species with different growth form. Our results indicated the variation of altitudinal trends of seed mass for different structural components of plant communities, implying the local community structure as a critical as- pect of variation in macro-ecological patterns.