[Relationships between leaf functional traits of Machilus pauhoi understory seedlings from different provenances and geographical environmental factors.]

To understand the adaptation mechanism of Machilus pauhoi seedlings to environmental changes, leaf functional traits of M. pauhoi seedlings from nine provenances, as well as relationships between leaf traits and environmental factors were analyzed. The results showed that leaf functional traits of M. pauhoi seedlings from different provenances showed significant intraspecific variations, with the coefficient of variation ranging from 8.8% to 28.2%. Specific leaf area, leaf relative water content, leaf tissue density and leaf thickness differed significantly among seedlings from different provenances, implying high leaf morphological plasticity. Moreover, leaf tissue density was positively correlated to leaf dry matter content and leaf relative water content, but negatively correlated to specific leaf area and leaf thickness. Specific leaf area showed significantly negative correlations with leaf dry matter content and leaf area. The covariation among those traits examined here indicated that M. pauhoi seedlings could adjust and balance the combination of leaf traits in response to environmental changes. Longitude, latitude, >10 ℃ annual accumulated temperature and mean annual temperature contributed largely to the variation of leaf functional traits of M. pauhoi seedlings. Leaf thickness decreased with the increase of longitude, while leaf dry matter content and leaf relative water content increased with the increase of longitude. Leaf tissue density was positively correlated with longitude and mean annual temperature, suggesting that longitude rather than mean annual temperature had greater effects on it. Leaf area was positively correlated with >10 ℃ annual accumulated temperature and longitude, indicating that annual accumulated temperature rather than longitude had greater effects on the variation of leaf area.