Objective Potassium (K) is a vital element to sustain plant growth and high water-use efficiency, especially in the current context of increasing aridification. However, previous studies on plant K have mostly been conducted at local scale, and it is still unclear that what difference exists in the spatial patterns and controlling factors of leaf K content among different herb functional groups across large scale.
Method Based on an analysis of 685 herbaceous plants across 158 sampling sites in China, this study aims to reveal the spatial patterns of leaf K content among different herb functional groups, and further quantify the relationship of leaf K with climate or soil nutrients.
Result Our results showed that: (1) herb leaf K content across China increased linearly with latitude, but decreased with longitude. Its spatial patterns were different among varied functional groups. (2) These patterns of leaf K were mainly driven by humid index and soil total nitrogen. (3) The impacting factors of the spatial patterns were different among varied functional groups. Leaf K in annual herb was significantly affected by both humid index and soil total nitrogen, while it was only influenced by soil total nitrogen for perennial herb. Leaf K in herbs with low K use efficiency was mainly affected by humid index and soil total nitrogen, but it was impacted by soil total nitrogen and total phosphorus for herbs with high K use efficiency. The main impacting factor of leaf K in Asteraceae and Cyperaceae herbs was soil total nitrogen, but humid index for Poaceae herbs.
Conclusion This study is the first to systematically compare and reveal the difference in the spatial patterns and key controlling factors of leaf K among different herb functional groups across China. These results have important implications for understanding the adaptive mechanisms of plant functional groups and the dynamics of plant community composition with increasing global aridification.
DownLoad: