Fig. 2.

Soil salinity levels determine the proportion of nifH at 16S rDNA copy numbers in stems and roots of S. europaea. (a) The gene copy number of nifH and 16S rDNA (per µg of DNA) in different plant organs of S. europaea (stems and roots) growing at two saline test sites (S1 and S2) was analyzed using quantitative real-time PCR (qPCR), and (b) the data used to calculate the proportion of potential diazotrophic bacteria (nifH gene copy number) at total bacterial counts (16S rDNA copy number). Bars indicate standard error at P ≤ 0.05.