Evolutionary origins of abnormally large shoot sodium accumulation in nonsaline environments within the Caryophyllalesdoi: 10.1111/nph.14370
Wright1, Philip J. White1,2, Helen C. Bowen3, Martin R. Broadley4, Hamed A. El-Serehy5, Konrad Neugebauer1,4, Anna Taylor1, Jacqueline A. Thompson1 and Gladys . 2017
The prevalence of sodium (Na)-‘hyperaccumulator’ species, which exhibit abnormally large
shoot sodium concentrations ([Na]shoot) when grown in nonsaline environments, was investigated
among angiosperms in general and within the Caryophyllales order in particular.
Shoot Na concentrations were determined in 334 angiosperm species, representing 35
orders, grown hydroponically in a nonsaline solution.
Many Caryophyllales species exhibited abnormally large [Na]shoot when grown hydroponically
in a nonsaline solution. The bimodal distribution of the log-normal [Na]shoot of species within the
Caryophyllales suggested at least two distinct [Na]shoot phenotypes within this order. Mapping
the trait of Na-hyperaccumulation onto the phylogenetic relationships between Caryophyllales
families, and between subfamilies within the Amaranthaceae, suggested that the trait evolved
several times within this order: in an ancestor of the Aizoaceae, but not the Phytolaccaceae or
Nyctaginaceae, in ancestors of several lineages formerly classified as Chenopodiaceae, but not in
the Amaranthaceae sensu stricto, and in ancestors of species within the Cactaceae, Portulacaceae,
Plumbaginaceae, Tamaricaceae and Polygonaceae.
In conclusion, a disproportionate number of Caryophyllales species behave as
Na-hyperaccumulators, and multiple evolutionary origins of this trait can be identified within
this order.
