Contrasting global patterns and trait controls of major mineral elements in leaf

Aim

Multiple mineral elements in leaf are the foundation of plant life and regulate many ecosystem functions. However, whether a common mechanism governs the variations of all leaf mineral elements is still unknown.

Location

Global.

Time period

1970–2020. 10.

Major taxa studied: Plants.

Methods

Here, we demonstrate the global-scale biogeographic patterns of 12 major mineral elements (nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, aluminium, iron, manganese, sodium, zinc and copper) by compiling a global data set including 2710 records of leaf mineral elements for 1073 species and of associated climate and soil indices.

Results

In general, like nitrogen and phosphorus, elements including potassium, calcium, magnesium, sodium and copper in leaf declined towards the equator, which supported both plant physiological hypothesis and soil substrate age hypotheses developed on the basis of nitrogen and phosphorus. By contrast, other elements responded to latitude in a contrary manner as nitrogen and phosphorus, in line with a competing mechanism, temperature–biogeochemistry hypothesis. Besides, plant functional types intrinsically differed in mineral concentrations, and to a certain extent, shifts of their composition in turn exacerbated the latitudinal patterns of respective elements as predicted by the species composition hypothesis.

Main conclusions

The fundamentally different dynamics and control mechanisms of patterns of some elements compared with those of nitrogen and phosphorus challenge the idea that common hypotheses can predict biogeographic patterns across all mineral elements; thus, current paradigms of element biogeochemical models and ecological plant nutrition require revision.