ABSTRACT
Salinity tolerance is rare among Angiosperms and seems to rely on different mechanisms in different lineages. Here we present the outcome of a detailed evolutionary correlative statistical analysis of where salt tolerance is most common across Angiosperms. Using a plant trait database supplemented with two KeW databases, we show that strong correlations exist between salinity tolerance and genome size across all Angiosperms. In Eudicotyledonous species, salinity tolerance also strongly correlates with specific leaf area and leaf nitrogen. Moreover, seed mass is generally low in salt-tolerant species, except for a limited number of heavy seeded water dispersed species. Photosynthetic metabolic pathway is skewed towards C4 photosynthesis in salt-tolerant species. All the patterns we identified can be explained as plant characteristics that provide these species with a tight control over water loss. Alternatively, the correlation between salt tolerance and genome sizes may reflect recent speciation events of small-genome salt-tolerant species.
