State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Haidian District, Beijing, China.
College of Resources Science & Technology, Beijing Normal University, Haidian District, Beijing, China.
PLoS One. 2018 Aug 2;13(8):e0201350. doi: 10.1371/journal.pone.0201350. eCollection 2018.
Phosphorus (P) is arguably more limiting than nitrogen for forest ecosystems being free of disturbances for lengthy time periods. The elucidation of multivariate relationships between foliar P and its primary drivers for dominant species is an urgent issue and formidable challenge for ecologists. Our goal was to evaluate the effects of primary drivers on foliar P of Quercus wutaishanica, the dominant species in broadleaved deciduous forest at the Loess Plateau, China. We sampled the leaves of 90 Q. wutaishanica individuals across broad climate and soil nutrient gradients at the Loess Plateau, China, and employed structural equation models (SEM) to evaluate multiple causal pathways and the relative importance of the drivers for foliar P per unit mass (Pmass) and per unit area (Parea). Our SEMs explained 73% and 81% of the variations in Pmass and Parea, respectively. Pmass was negatively correlated to leaf mass per area, positively correlated to leaf area, and increased with mean annual precipitation and total soil potassium. Parea was positively correlated to leaf mass per area, leaf dry weight, and increased significantly with total soil potassium. Our results demonstrated that leaf P content of Q. wutaishanica increased with total soil potassium in the Loess Plateau accordingly.
磷（P）对于长时间不受干扰的森林生态系统来说，可能比氮更具限制性。阐明主要驱动因素与叶片 P 之间的多元关系是生态学家面临的紧迫问题和巨大挑战。我们的目标是评估主要驱动因素对中国黄土高原落叶阔叶林优势种——辽东栎叶片 P 的影响。我们在中国黄土高原跨越广泛的气候和土壤养分梯度，对 90 株辽东栎个体的叶片进行了采样，并利用结构方程模型（SEM）评估了多种因果途径以及驱动因素对单位质量叶片 P（Pmass）和单位面积叶片 P（Parea）的相对重要性。我们的 SEM 分别解释了 Pmass 和 Parea 变化的 73%和 81%。Pmass 与叶面积比呈负相关，与叶面积呈正相关，与年平均降水量和土壤全钾呈正相关。Parea 与叶面积比、叶干重呈正相关，与土壤全钾呈显著正相关。我们的结果表明，黄土高原辽东栎叶片 P 含量随土壤全钾的增加而增加。
