Host growth responses to sympatric and allopatric rhizobial strains.

<p>(a) The symbiotic response of six host plants to rhizobial strains originally collected from a given host species and tested with all hosts. The three strains collected from the same host are depicted with the same colour and the colours correspond to those in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023545#pone-0023545-g004" target="_blank">Fig. 4b</a>. (b) The symbiotic response of hosts to the same rhizobial strains grouped as sympatric (originally collected from the same host species), and allopatric (strains originally collected from other hosts species). Error bars are based on standard errors of means. In both (a) and (b) the solid line at 1 on the y-axis indicates the level where the host did not gain or lose anything from the rhizobial interaction relative to the N⁻ control treatment. Host species abbreviations are as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023545#pone-0023545-g001" target="_blank">Fig. 1</a>.