Latitudinal Variation of Leaf Phosphorus Fractions Provides Physiological Insights Into Plant Phosphorus‐Use Strategy at Large Scales
Qingquan Meng, Zhengbing Yan, Zhijuan Shi, Tingting Dong, Jia Wang, Hans Lambers, Wenxuan Han
Abstract
Three major hypotheses aim to explain latitudinal trends of leaf phosphorus (P) concentration: the Temperature-Plant Physiological Hypothesis (TPH), Soil-Nutrient Hypothesis (SNH) and Evergreen-Deciduous Hypothesis (EDH). However, these hypotheses only address leaf total P, preventing a deeper insight into the underlying physiological mechanisms. We extended these hypotheses to include variations in leaf P fractions with different physiological functions (extended TPH, SNH and EDH, respectively). We analysed latitudinal variation in leaf P fractions and their correlations with mean annual temperature (MAT), soil total P concentration (soil TP), and leaf habit. Leaf total P and P-fraction concentrations increased with increasing latitude in the Northern Hemisphere, with metabolic P increasing most. The concentrations of all leaf P fractions, higher in deciduous than in evergreen plants, increased with decreasing MAT and increasing soil TP. The proportion of metabolic P was higher at low MAT and in deciduous plants, while that of residual P increased with increasing soil TP. MAT had a much stronger influence than other factors on leaf P fractions, especially for their allocation proportions. Our results predominantly supported the extended TPH, but also generally supported the other two hypotheses, highlighting eco-physiological mechanisms underpinning the macroecology of plant P-use strategy.