East China Coastal Forest Ecosystem Long-term Research Station, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, Zhejiang 311400, PR China.
Department of Forestry and Environmental Conservation, Clemson University, Clemson, SC 29634-0317, USA.
Sci Total Environ. 2018 Mar 15;618:1-6. doi: 10.1016/j.scitotenv.2017.11.030. Epub 2017 Nov 7.
Latitudinal patterns of leaf stoichiometry and nutrient resorption were not consistent among published studies, likely due to confounding effects from taxonomy (e.g., plant distribution and community composition), and environment, which is also influenced by altitude and longitude. Thus, the latitudinal patterns and environmental mechanism could be best revealed by testing a given species along a latitude gradient with similar altitude and longitude. We determined nitrogen (N) and phosphorus (P) concentrations of green (leaf) and senesced leaves (litter) from eight Metasequoia glyptostroboides forests along the eastern coastline of China, with similar altitude and longitude. Leaf N, P concentrations increased along latitude, mainly driven by mean annual temperature (MAT), mean annual precipitation (MAP), annual evaporation (AE), aridity index (AI), and annual total solar radiation (ATSR); While leaf N:P ratio was stable with no latitudinal pattern. Nitrogen resorption efficiency (NRE) increased along latitude, and was also mainly influenced by MAT, MAP, AE, and AI. Phosphorus resorption efficiency (PRE) first increased and then decreased with latitude, which was impacted by soil available P. These results indicated that only climate (such as heat, water, and light) controlled the shift in leaf stoichiometry and NRE, while soil nutrient was likely responsible for the shift in PRE along eastern China. Our findings also suggested that leaf N, P stoichiometry and NRE displayed similar latitudinal patterns at regional scale when studied for a given species (this study) or multi-species (previous studies).
叶片化学计量特征和养分再吸收在已发表的研究中没有一致的纬度模式，这可能是由于分类学（例如，植物分布和群落组成）和环境的混杂效应造成的，而环境也受到海拔和经度的影响。因此，通过在具有相似海拔和经度的纬度梯度上测试给定物种，可以最好地揭示纬度模式和环境机制。我们测定了中国东部沿海地区 8 个水杉林中绿色（叶片）和衰老叶片（凋落物）的氮（N）和磷（P）浓度。叶片 N、P 浓度随纬度增加而增加，主要受年均温（MAT）、年均降水量（MAP）、年蒸发量（AE）、干燥度指数（AI）和年总太阳辐射（ATSR）驱动；而叶片 N：P 比则没有纬度模式，保持稳定。氮再吸收效率（NRE）随纬度增加而增加，主要受 MAT、MAP、AE 和 AI 影响。磷再吸收效率（PRE）随纬度先增加后减少，受土壤有效磷的影响。这些结果表明，只有气候（如热量、水分和光照）控制着叶片化学计量特征和 NRE 的变化，而土壤养分可能是造成中国东部 PRE 变化的原因。我们的研究结果还表明，当研究特定物种（本研究）或多物种（先前的研究）时，叶片 N、P 化学计量特征和 NRE 在区域尺度上表现出相似的纬度模式。
