关键词: 生态过程, 空间布局, 营养级联效应, 空间连通性, 空间形状, 空间方向, 空间大小

Abstract: The trade-off relationship among plant leaf traits reflects the high adaptability of plants and their self-regulation ability in complex habitats. Understanding the trade-offs among leaf traits of urban greening tree species in sem-arid regions, and comparing the allometric growth of tree species with different growthforms (coniferous and broadleaved) would help to further understand the evolutionary of plants. Here, we measured leaf traits of 13 coniferous tree species and 47 broadleaved tree species, which are typical greening tree species in Lanzhou. We compared the trade-off relationships among leaf traits by the standardized major axis estimation (SMA) and phylogenetically independent contrast analysis (PIC). The results showed that the relationship between leaf area, leaf volume and leaf dry weight of different life-form tree species was isometric, with no significant difference between coniferous and broad-leaved tree species. A weak trade-off relationship was found between leaf thickness and leaf area. The allometric coefficient between leaf length and leaf width of broad-leaved species was 0.764. The trade-off among leaf traits of typical greening tree species in Lanzhou suggested long-term adaptation of those species to the habitat of Loess Plateau and a covariant relationship among some traits. The trade-offs in broad-leaved tree species indicated that those species showed the characteristics of rapid investment-return.

Key words: spatial connectivity, spatial distribution, ecological process., spatial size, trophic interaction, spatial orientation, spatial shape