Abstract: Leaf functional trait reflects resource capture ability and use efficiency of plants. To determine leaf functional traits of common plant species from the eastern Guangdong, and whether variation in leaf traits among species is related to phylogeny, life history attributes, and/or other environmental factors, we surveyed leaf traits of 89 species including leaf area (LA), specific leaf area (SLA), leaf dry matter content (LDMC), and leaf N content (LNC). The effects of family grouping, life form, plant height, distribution, origin and habitats on leaf traits of 89 plant species were determined using oneway ANOVAs and the least significant difference test (LSD). The effects of single variables and interaction of multiple factors on variance in leaf traits among 89 species were analyzed using general linear model (GLM). The result showed that the average values of LA, SLA, LDMC and LNC of 89 species were 20.59 cm², 300.149 cm²·g^-1, 0.2213 g·g^-1 and 2.55%, and coefficients of variation were 145.06%, 97.21%, 36.40% and 27%, respectively. There was a significant negative correlation between LDMC and SLA among the 89 plant species (P<0.001). There was a significant difference in SLA and LDMC between those species from different family groupings. Gramineae species had the maximum value of LDMC (0.359 g·g^-1) and minimum value of SLA (163.749 cm²·g^-1), and Umbelliferae species had the minimum value of LDMC (0.136 g·g^-1) and the maximum value of SLA (1091.42 cm²·g^-1). The LA of shrubs and liana species was significantly greater than that of herbs (P<0.01), and LA of high plants was greater than that of short species (P<0.05). Family groupings of species had an important impact on variation of leaf traits, explaining 26.3%, 30.2%, 40.9%, and 13.8% of variation in LA, SLA, LDMC, and LNC, respectively. The interactions between family groupings, plant height, and life form explained 82.5%, 80.9%, 79.4%, and 56.7% of variation in LA, SLA, LDMC, and LNC, respectively. The distribution area, origins, and habitats of species had no or less influence on leaf traits (P>0.05). Overall, the variation of leaf traits among species may be mainly influenced by phylogeny and life history traits.

Key words: ecological quality index, Beijing-Tianjin-Hebei (BTH) urban megaregion, ecological quality assessment, remote sensing.