Variation In Quercus Variabilis Leaf Traits In Relation To Environmental Factors

Leaf traits (morphological traits, nutrients resorption and stoichiometry) are sensitive to environmental changes in the process of evolution and may vary with changes in environment. Therefore, the study to investigate the pattern of variation in plant leaf traits and relation of it to environmental factors at regional scale in the context of global change has important theoretical significance. Quercus variabilis (Oriental oak) is one of the most widely distributed trees in Asia, stretching from temperate to subtropical zone, which provides ideal condition for understanding the correlation between plant leaf traits and environmental factors across climatic zones.In our study, we collected leaf specimens and composite soil samples from 25 populations between 24.43°and 40.25°N, 102.44 and 122.96°E in east-central China with compilation of climatic datas to test the characteristics of variation in important leaf traits (for example, leaf width, leaf area, specific leaf area, nutrients resorption efficiency and stoichiometry and its relation to environmental factors. Main results are listed as follow:1) The leaf morphology and nutrients concentration of Q.variabilis vary significantly within and among the populations respectively. For example, the coefficient of variation of leaf width, leaf length and leaf area among populations are 8.94%, 5.65% and 11.60%, respectively, the CV of the nitrogen (N) concentration and phosphorus (P) resorption efficiency are 20.5%,12.7%, respectively.2) Leaf width is significantly negative with mean annual temperature (MAT), leaf width and leaf both are significantly positive with latitude, which shows the index of leaf width and leaf area in comparison with the rest of leaf morphological traits are more sensitive to changes in climatic factors.3) The average resorption efficiency of P, is 68.2% (36.32 - 78.66%), is higher than average resorption efficiency of N which is 57.2%(37.6 - 76.28%). The resorption efficiency of N and P both are related with N and P concentration of litter leaf respectively (P < 0.001), but is not with green leaf (P > 0.05).4) The mean value of N:P ratio of green is 19.8 (13.29 - 29.07), that of litter is 31.2 (6.54 - 71.04) and that of soil is 4.7 (1.07 - 8.64). The N:P ratio of leaf is significantly correlated with that of litter (P < 0.001), and the N:P ratios of leaf and of litter both are significantly correlated with N:P ratio of soil, respectively (P < 0. 001).The main feature of this study is to study the leaf traits and relation of it to environmental factors for a single species at large regional scale across climatic zones. Few such studies have been done and herein the results from our study necessarily explored the characteristic variance in pattern of leaf traits and its response to climate change and contribute to understanding of correlation between general leaf traits and environmental factors to some extent.