中国不同草本功能群叶片钾含量的空间格局及控制因素

Spatial patterns and impacting factors of leaf potassium content among different functional groups of herbaceous plants across China

【目的】钾是维持植物生长和水分高效利用的重要生命元素,特别在当前干旱化趋势增强的背景下尤为重要。但是,前人关于植物钾元素的研究主要集中在局部尺度上,仍然不清楚大尺度上不同草本功能群叶片钾含量的空间格局及控制因素有何差异。【方法】本研究基于中国164个地点739种草本植物,旨在揭示不同功能群叶片钾含量的空间格局及其与气候、土壤养分之间的定量关系。【结果】(1)中国草本叶片钾含量随纬度线性增加,但随经度线性降低。并且不同草本功能群叶片钾含量的空间格局存在差异。(2)总体上来说,中国草本叶片钾含量主要受湿润指数和土壤全氮的共同影响。(3)不同功能群叶片钾含量的影响因素存在差异。如一年生草本叶片钾含量主要受湿润指数和土壤全氮的共同作用,而多年生草本只受土壤全氮的影响。低钾利用效率草本的叶片钾含量主要受湿润指数和土壤全氮的影响,而高钾利用效率草本则受土壤全氮和全磷的作用。菊科和莎草科植物叶片钾含量的主控因素为土壤全氮,而禾本科植物为湿润指数。【结论】本研究首次系统比较和揭示中国不同草本功能群叶片钾含量的空间格局及影响因素的异同,对理解全球干旱化趋势日趋严峻背景下植物功能群的适应策略以及植物群落组成动态变化具有重要的参考价值。

[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.