华南人工林乔木树种叶片氮、磷、硫生态化学计量特征

为研究南亚热带人工林植物叶片氮（N）、磷（P）、硫（S）生态化学计量特征在近源类群、不同生长阶段间的差异，在佛山市云勇林场人工改造恢复形成的3~11 a生的针阔混交林和桉树林中，选择21个优势造林树种，测量了叶片N、P、S含量并计算了N:P，分析了这些指标之间的相关性以及不同生长阶段共有种生态化学计量特征的差异。结果显示：21个树种叶片平均N、P、S含量分别为16.71±0.79,1.07±0.05,1.56±0.09 mg/g，N:P为16.51±0.76，生态化学计量特征在不同树种间存在显著差异。叶片N、P、S含量相互之间显著正相关。近源类群（木兰科、樟科）植物对氮的吸收有较大差异，对磷和硫的吸收差异不大。不同生长阶段的6个共有树种的N、P、S生态化学计量特征随生长的变化因物种而异，整体上N:P随生长无明显变化趋势。本研究说明南亚热带人工林的施肥抚育管理要考虑养分利用的种间差异特性。

Ecological Stoichiometry Characteristics of Leaf Nitrogen, Phosphorous and Sulfur of Tree Species of Plantation in South China

The objective of this study was to explore the ecological stoichiometry of nitrogen, phosphorous and sulfur of plantation at different ages in south subtropics. We collected the leaves of 21 afforestation tree species in needle-broadleaf mixed plantations and Eucalyptus plantations in Yunyong Forest Farm in Foshan, Guangdong. The N, P and S concentrations were determined to analyze the correlations between these elements and ecological stoichiometry differences at different ages. The results were as following: the average concentrations of N, P and S in leaves were 16.71±0.79,1.07±0.05 and 1.56±0.09 mg/g, respectively. There were significant differences of ecological stoichiometry characteristics among species. N, P and S concentrations were positively related with each other. Closely related species were significantly different at absorbing N, but similar at P and S. For the 6 common species at different age, changing trends of N, P and S ecological stoichiometry characteristics with growth were different among species. There was no apparent change trend of N:P with age for 32 samples. This study indicate that species specificity should be paid more attention in plantation fertilization management in south subtropics.