Multivariate Perspectives on the Ecology of Plant Mineral Element Composition

Abstract

The mineral element composition of plants, being a multivariate phenotypic trait, reflects the genotypic and environmental interactions influencing chemical content, including those related to ecological niche. Multivariate discriminant analysis was used to describe the position and area of nine different plant species in an "elemental hyperspace" based on the mineral element composition of leaves. With the exception of woody species, there was considerable interspecific variation in elemental concentrations and distinct separation among species in the element space. Semiaquatic macrophytes were quite distinct in their mineral element composition. The region each species occupies in the element space presumably corresponds to an adaptive zone of mineral element concentrations that enable each species to survive in the environment. Some evidence presented indicates that phenotypic variation in mineral element composition in a species reflects niche size in the nutrient environment. Interelement correlations in concentrations across 110 plants species were explored using principal components analysis. Four principal components were extracted from a correlation matrix. The component structure was interpreted on the basis of biochemical functions of elements in cells. Principal component 1 was a nucleic acid-protein set correlated with concentrations of P, N, Cu, S, and Fe. Component 2 was a structural and photosynthetic set correlated with concentrations of Mg, Ca, and Mn. Component 3 was an enzymatic set correlated with concentrations of Mn, K, and Mg. Future research on the mineral element composition of different plant species might begin by considering these three hypothetical element sets.