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Linear relationships between shoot magnesium and calcium concentrations among angiosperm species are associated with cell wall chemistry

White, Philip J, Broadley, Martin R, El-Serehy, Hamed A, George, Timothy S, Neugebauer, Konrad
Annals of botany 2018 v.122 no.2 pp. 221-226
Caryophyllales, Liliopsida, calcium, cation exchange capacity, cell walls, magnesium, vacuoles
Linear relationships are commonly observed between shoot magnesium ([Mg]ₛₕₒₒₜ) and shoot calcium ([Ca]ₛₕₒₒₜ) concentrations among angiosperm species growing in the same environment. This article argues that, in plants that do not exhibit ‘luxury’ accumulation of Mg or Ca, (1) distinct stoichiometric relationships between [Mg]ₛₕₒₒₜ and [Ca]ₛₕₒₒₜ are exhibited by at least three groups of angiosperm species, namely commelinid monocots, eudicots excluding Caryophyllales, and Caryophyllales species; (2) these relationships are determined by cell wall chemistry and the Mg/Ca mass quotients in their cell walls; (3) differences between species in [Mg]ₛₕₒₒₜ and [Ca]ₛₕₒₒₜ within each group are associated with differences in the cation exchange capacity (CEC) of the cell walls of different species; and (4) Caryophyllales constitutively accumulate more Mg in their vacuoles than other angiosperm species when grown without a supra-sufficient Mg supply.