中国东部南北样带654种植物叶片氮和磷的化学计量学特征研究

Leaf Nitrogen and Phosphorus Stoichiometry Across 654 Terrestrial Plant Species in NSTEC

大尺度的叶片的氮（N）和磷（P）的化学计量学特征是植物对环境条件的长期适应的结果，并能为大尺度模型的发展提供数据基础．通过对文献数据的搜集整理，对中国东部南北样带168个采样点的654种植物的N和P的化学计量学特征、空间格局及其与气候因子（年均温度）的关系进行了研究．结果表明，中国东部南北样带654种植物叶片的N和P的化学计量学特征存在很大的变异性．叶片N的变化范围为2．17～52．61mg·g^-1，几何平均数为17．55mg·g^-1，叶片P的变化范围为0．10～10．27mg·g^-1，几何平均数为1．28mg·g^-1，叶片N／P的变化范围为1．7～74．6，几何平均数为13．5．中国东部南北样带乃至中国区域叶片P的含量显著低于全球尺度的其它研究结果，这说明与全球尺度相比，中国区域植被生长更易受到P的限制．在所研究的不同功能群间，以叶片N含量的差异最大，P次之，N／P的差异最小，这与在多数的功能群内，其叶片N和P含量间存在显著相关性有关．另外在系统发育上亲缘越远的功能群N和P含量差异越大（蕨类植物与种子植物），亲缘越近的差异越小（双子叶植物与单子叶植物）．叶片的N和P含量与纬度和年均温度间存在极显著的相关关系，随着纬度升高和年均温度的降低，叶片N和P含量极显著地增加（P〈0．001）．可是N／P与纬度和年均温度的相关性较弱（P=0．386和P=0．342），这可能是由于N和P含量随纬度和年均温度的变化趋势相同且变异性较大，并且相对于全球尺度而言本研究的区域范围相对较小等多种因素共同导致的．

Stoichiometry of leaf N and P is a characteristic of plant to adapt to environment, and can provide data for process-based modeling at large scale. Leaf nitrogen and phosphorus stoichiometry of NSTEC terrestrial plants were studied based on a NSTEC data set including leaf nitrogen and phosphorus observations for 654 plant species at 168 sites. The results showed that leaf nitrogen and phosphorus stoichiometry in NSTEC exhibited large variations, primarily ranging 2.17 - 52.61 mg·g^-1 for N, 0.10 - 10.27 mg·g^-1 for P, 1.7 - 74.6 for N/P ratio. Geometric means for all plant species were 17.55 mg· g^-1 , 1.28 mg·g^-1 and 13.5, respectively. Leaf P of NSTEC （ever across China） was lower than global level, therefore plant growth was more limited by P in China region comparing to global environment. For all functional groups, the difference of leaf N was largest, but that of N/P ratio was smallest, since leaf N and P closely related in most of functioning groups; for leaf N and P of the different phylogenic functional groups, the difference was largest for farthest relative （seed vs fern）, least for closest relative （monocotyledon vs dicotyledon）. There were obvious correlation between leaf N （or P） and latitude （or mean annual temperature, MAT）. Leaf N and P significantly increased with latitude increasing （or MAT decreasing）, but the relationship between N/P ratio and latitude （or MAT） wasn＇t significant （p = 0.386 and p = 0.342）, and the reason maybe include, leaf N and P had the same tendencies and large variations, and region in this research was smaller than global research.