关键词: 叶片, 吸收根, 功能性状, 经济谱, 丛枝菌根, 外生菌根

Abstract: Leaves and absorptive roots (i.e., first-order roots) are resource acquisition organs of above and belowground for plants. Understanding the relationship between functional traits of leaves and absorptive roots and their influencing factors would be helpful to further understand the utilization and allocation of resources during plant growth. In this study, we measured morphological traits (leaf thickness, specific leaf area, leaf tissue density, root diameter, specific root length, root tissue density) and chemical traits (leaf and root carbon concentration, nitrogen concentration, and carbon to nitrogen ratio) of leaves and absorptive roots for 10 arbuscular mycorrhizal (AM) and 8 ectomycorrhizal (EM) tree species in the Jiulianshan National Nature Reserve in Jiangxi Province. We analyzed the variation and correlation among these functional traits between AM and EM tree species. The results showed that EM tree species had thicker leaves, smaller specific leaf area, finer root diameter, lower root tissue density, lower root carbon concentration and carbon to nitrogen ratio than AM tree species. There was no correlation in morphological traits of leaves and absorptive roots for both AM and EM tree species. There was a positive correlation between leaves and roots in the chemical traits (nitrogen concentration and carbon to nitrogen ratio) for AM tree species, but not for EM tree species. The results of principal component analysis showed specific leaf area and specific root length was orthogonal, regardless of AM or EM tree species, suggesting that leaves and absorptive roots were independent in acquiring resources. In addition, root diameter was positively correlated with root nitrogen concentration among all tree species and among AM tree species, but exhibited a marginally negative correlation among EM tree species. Root diameter was always positively correlated with specific root length among different tree species, regardless of mycorrhizal type. In summary, this study emphasized the importance of mycorrhizal type in shaping the relationship between functional traits of leaves and absorptive roots. Mycorrhizal type should be considered when evaluating multidimensional variation of root traits and different functional trait relationships of leaves and roots for woody plants.

Key words: leaf, absorptive root, functional trait, economic spectrum, arbuscular mycorrhiza, ectomycorrhiza.